Muscular Skeletal Quiz Answers
1.
The __________ muscle participates in downward rotation of the scapula.
A) levator scapulae
B) lower (inferior) fibers of serratus anterior
C) teres minor
D) lower (inferior ) fibers of trapezius
Feedback: A. The levator scapulae elevates the scapula and tilts the glenoid cavity inferiorly by rotating
the scapula (downward rotation). B. The lower fibers of the serratus anterior elevate the glenoid cavity
(upward rotation). C. The teres minor laterally rotates the arm, which does not cause rotation of the
scapula. D. The lower fibers of the trapezius rotate the glenoid cavity superiorly (upward rotation).
Correct Answer(s):
A
2.
Weeks after a nasty fall forward onto both hands, a patient arrives in the doctor’s office complaining of
clumsiness with the right thumb. The patient has no problem holding paper between any two fingers
and has no difficulty in flexing the metacarpophalangeal (MP) joints and extending the interphalangeal
(IP) joints of the fingers. Flexion and abduction of the thumb are weak and the thenar eminence is flat.
However, sensation is normal over the thenar eminence, and extension and adduction of the thumb are
normal. The nerve most likely affected is the
A) recurrent branch of the median nerve.
B) palmar cutaneous branch of the median nerve.
C) median nerve in the cubital fossa.
D) deep ulnar nerve.
E) deep radial (posterior interosseous) nerve.
Feedback: A. The recurrent branch of the median nerve serves the thenar muscles: Abductor pollicis
brevis abducts thumb (and helps oppose it), flexor pollicis brevis flexes thumb, opponens pollicis flexes
and medially rotates the 1st metacarpal during opposition. Damage to this nerve therefore
compromises abduction, flexion and opposition of the thumb. The thenar muscles form the thenar
eminence on the lateral surface of the palm. If these muscles are not used they will undergo atrophy
and the thenar eminence will be flatter than normal. B. The palmar cutaneous branch of the median
nerve supplies the skin of the thenar eminence. Since sensation is normal over the thenar eminence it
cannot be affected. C. If the median nerve in the cubital fossa were affected the patient would not be
able to flex the MP joints and extend the IP joints of the 2nd and 3rd digits because the median nerve
supplies the lateral two lumbricals. D. If the deep ulnar nerve were affected patient would not be able to
flex the MP joints and extend the IP joints due to paralysis of the palmar and dorsal interossei muscles
and the medial two lumbricals. Paralysis of these same muscles would affect abduction and adduction of
the digits and the patient would not be able to hold the paper between their fingers. E. Injury of the
deep radial nerve would result in difficulty extending the thumb (extensor pollicis brevis and longus). It
would also compromise abduction of the thumb (abductor pollicis longus) that this patient exhibits, but
both extension and abduction of the thumb would have to be compromised for the deep radial nerve to
be involved.
Correct Answer(s):
A
3.
The __________ muscles cross the metacarpophalangeal (MP) joint of the thumb.
A) abductor pollicis longus and oponens pollicis
B) oponens pollicis and flexor pollicis brevis
C) flexor pollicis brevis and extensor pollicis brevis
D) extensor pollicis brevis and abductor pollicis longus
Feedback: The flexor pollicis brevis and the extensor pollicis brevis cross the MP joint of the thumb, as
their distal attachment is on the base of the proximal phalanx of the thumb. The abductor pollicis longus
and opponens pollicis do not cross the MP joint, as they attach to the first metacarpal.
Correct Answer(s):
C
4.
Two muscles that medially (internally) rotate the glenohumeral joint are the
A) infraspinatus and subscapularis.
B) subscapularis and pectoralis major.
C) latissimus dorsi and infraspinatus.
D) teres minor and teres major.
Feedback: The pectoralis major, subscapularis, latissimus dorsi and teres major medially (internally)
rotate at the glenohumeral joint. The infraspinatus and teres minor laterally (externally) rotate at the
glenohumeral joint.
Correct Answer(s):
B
5.
Examination of a patient’s injured upper limb reveals normal extension at the elbow, but sensory
deficits on the thumb, marked weakness in supination and an inability to extend at the wrist (wrist drop)
or the metacarpophalangeal (MP) joints. These findings would suggest that the __________ has been
severed.
A) posterior cord
B) radial nerve at its origin
C) radial nerve just distal to the spiral (radial) groove
D) deep radial (posterior interosseous) nerve at its origin
E) superficial radial nerve at its origin
Feedback: A. Severing the posterior cord would result in paralysis of the triceps as well as the other
symptoms exhibited by this patient. All of these deficits would have to be present if the posterior cord
were severed. B. Severing the radial nerve at its origin would result in paralysis of the triceps as well as
the other symptoms exhibited by this patient. C. The radial nerve gives branches to the triceps within or
proximal to the spiral (radial) groove. Severing the nerve distal to the groove will not affect triceps,
therefore extension at the elbow will be normal. All the other deficits exhibited by the patient are
explained by injury at this point since both the deep and superficial radial nerves will be affected. D.
Damage to the deep radial nerve affects the posterior compartment of the forearm and results in an
inability to extend the wrist or MP joints. It innervates the supinator, thus damage will weaken
supination (but not eliminate, as the biceps brachii also supinates). The deep radial nerve does not have
any cutaneous distribution, so damage could not account for the sensory deficits on the thumb. E. The
superficial radial nerve is entirely cutaneous in distribution, supplying parts of the thumb (and also parts
of the dorsal hand and digits). Damage to this nerve could not account for any muscular weakness.
Points Earned: 0.0/1.0
Correct Answer(s):
C
6.
Fractures of the olecranon are usually transverse. The proximal fragment is pulled superiorly by the
_____________ muscle and the ___________ nerve may be damaged.
A) biceps brachii --- median
B) triceps brachii --- ulnar
C) supinator --- deep radial (posterior interosseous)
D) extensor carpi ulnaris --- deep radial (posterior interosseous)
Feedback: A. The distal attachment of biceps brachii is not on the olecranon (it’s on the radial tuberosity
and bicipital aponeurosis). The median nerve is too anterior to the olecranon to be affected (it’s on the
medial side of the cubital fossa). B. A distal attachment of triceps is the proximal end of the olecranon.
The ulnar nerve lies in the groove for the ulnar nerve on the posterior aspect of the medial epicondyle of
the humerus. This is just lateral to the olecranon fossa. C. The supinator has no attachments to the
olecranon (all posterior attachments are inferior to olecranon). The deep radial nerve is too anterior to
the olecranon to be affected. D. The extensor carpi ulnaris has no attachments to the olecranon (it’s
proximal attachment is the lateral epicondyle of humerus and posterior border of ulna). The deep radial
nerve is too anterior to the olecranon to be affected.
Correct Answer(s):
B
7.
The __________ muscle is probably torn when a gymnast experiences sudden lumbar pain and muscle
spasm while doing pulls-ups (chin-ups) on a high bar (extension against resistance).
A) erector spinae
B) deltoid
C) latissimus dorsi
D) trapezius
E) serratus anterior
Feedback: The erector spinae, deltoid, trapezius and serratus anterior do not cause extension at the
shoulder joint. The latissimus dorsi is the important climbing muscle, as it raises the trunk to the arm
(extension at the shoulder joint).
Correct Answer(s):
C
8.
The tapering inferior part of the spinal cord is called the
A) conus medullaris (medullary cone).
B) lumbosacral enlargement.
C) filum terminale.
D) cauda equina.
E) denticulate ligament.
Feedback: A. The tapering inferior part of the spinal cord is called the conus medullaris. B. The
lumbosacral enlargement is superior to the conus medullaris. It extends from the T11 to L1 segments of
spinal cord. C. The filum terminale starts at the inferior end of the conus medullaris, descends with the
spinal nerve roots in the cauda equina and attaches to the coccyx. D. The cauda equina is a bundle of
spinal nerve ventral and dorsal roots caudal to the end of the spinal cord. E. Denticulate ligaments are
lateral extensions of the pia mater that hold the spinal cord in position within the subarachnoid space.
Correct Answer(s):
A
9.
The ligamenta flava are elastic ________ joints that stretch during _______ of the vertebral column.
A) synarthrodial --- flexion
B) synarthrodial --- extension
C) diarthrodial (synovial) --- flexion
D) diarthrodial (synovial) --- extension
Feedback: Ligamenta flava are elastic fibrous tissue that connects the laminae of adjacent vertebrae.
The space between laminae is increased when the vertebral column is flexed, thereby stretching the
ligamenta flava. Joints with a solid (i.e. fibrous or cartilaginous) connection between bones are
considered synarthrodial.
Correct Answer(s):
A
10.
A patient's subclavian artery is ligated just lateral to the anterior scalene muscle between the
suprascapular artery and the thyrocervical trunk. In this patient, the dorsal scapular and transverse
cervical arteries are branches of the thyrocervical trunk. The suprascapular artery is a direct branch of
the subclavian. To fill the distal subclavian & the axillary arteries, the flow of blood reverses direction in
both the ________ and _________ arteries.
A) transverse cervical --- posterior intercostal
B) dorsal scapular --- circumflex scapular
C) suprascapular --- dorsal scapular
D) circumflex scapular --- suprascapular
E) dorsal scapular --- transverse cervical
F) posterior intercostal --- circumflex scapular
Feedback: Blood flow will reverse in arteries distal to the ligation, including the circumflex scapular and
suprascapular arteries. Blood flow in arteries proximal to the ligation will not reverse direction (i.e.
thyrocervical trunk, dorsal scapular, transverse cervical, posterior intercostals).
Correct Answer(s):
D
11.
The radial nerve lies on the posterior surface of the humerus between the humeral attachments of the
__________ heads of the triceps and is accompanied by the ________.
A) long & lateral --- deep artery of the arm (profunda brachii)
B) long & lateral --- brachial artery
C) long & medial --- deep artery of the arm (profunda brachii)
D) long & medial --- brachial artery
E) lateral & medial --- deep artery of the arm (profunda brachii)
F) lateral & medial --- brachial artery
Feedback: Only the lateral and medial heads of the triceps have proximal attachments to the humerus.
The radial groove lies in between these attachments. The proximal attachment of the long head is to the
infraglenoid tubercle of the scapula. The deep artery of the arm accompanies the radial nerve through
the radial groove in the humerus. The brachial artery lies medial and/or anterior to the humerus.
Correct Answer(s):
E
12.
Release of acetylcholine results in contraction of the
A) arrector pili muscles in the skin.
B) walls of blood vessels in the body wall (vasoconstriction).
C) biceps muscle.
Feedback: Acetylcholine is released by motoneurons at the neuromuscular junction and results in
contraction of skeletal muscles (i.e. biceps). Postsynaptic sympathetic axons that innervate arrector pili
and the walls of blood vessels in the body wall release norepinephrine.
Correct Answer(s):
C
13.
Glial cells called __________ surround all axons in the peripheral nervous system. A connective tissue
layer called the __________ surrounds each myelinated axon.
A) oligodendrocytes --- epineurium
B) oligodendrocytes --- perineurium
C) oligodendrocytes --- endoneurium
D) Schwann cells --- epineurium
E) Schwann cells --- perineurium
F) Schwann cells --- endoneurium
Feedback: Glia that surround axons in the peripheral nervous system are called Schwann cells. In the
central nervous system, they are called oligodendrocytes. The endoneurium surrounds each myelinated
axon. The perineurium encloses a bundle (fascicle) of nerve fibers. The epineurium is a loose connective
tissue that surrounds the perineurium wrapped nerve bundles.
Correct Answer(s):
14.
F
Dendrites are characterized by the _________ of Nissl substance and a _________ thickness from their
proximal to distal ends.
A) absence --- constant
B) absence --- decreasing
C) presence --- constant
D) presence --- decreasing
Feedback: Dendrites and the neuronal cell bodies have Nissl substance. Axons and axon hillocks do no
have Nissl. Nissl represents the presence of ribosomes. Dendrites have a tapering diameter from
proximal to distal ends. Axons retain their diameter.
Correct Answer(s):
D
15.
Imagine a radiograph of a normal elbow in the AP projection. The __________ will have their shadows at
least partially superimposed on this image.
A) olecranon and trochlea
B) head of the radius and the medial epicondyle of the humerus
C) coronoid process of the ulna and capitulum
D) lateral epicondyle of the humerus and the shaft of the radius
Feedback: A. The olecranon (on the posterior ulna) lies posterior to the trochlea (on the anterior
humerus). Their region over overlap can best be appreciated by the presence of the trochlear notch on
the anterior surface of the olecranon. B. The medial epicondyle of the humerus is supero-medial to the
head of the radius. C. The coronoid process of the ulna is infero-medial to the capitulum of the humerus.
D. The lateral epicondyle of the humerus is superior to the shaft of the radius.
Correct Answer(s):
A
16.
An untreated pin prick in the index finger (1st finger, 2nd digit) may result in an infection which leads to
pain, tenderness and inflammation in the ________________. If the synovial membrane of this structure
were to rupture, the infection and accompanying symptoms would most likely spread to the
_____________ space.
A) radial bursa --- midpalmar
B) radial bursa --- thenar
C) digital synovial sheath of index finger --- midpalmar
D) digital synovial sheath of index finger --- thenar
Feedback: The digital synovial sheath surrounding the flexor digitorum superficialis and profundus in the
index finger can be punctured by a deep pin prick. The radial bursa is the synovial sheath that encloses
the tendon of flexor pollicis longus and goes to the thumb. There are two fascial spaces deep to the
palmar aponeurosis. The thenar space is the lateral space that contains flexor pollicis longus tendon and
the other flexor tendons of the index finger. The midpalmar space is the medial space that contains the
flexor tendons of the medial three digits.
Correct Answer(s):
D
17.
The presence of an anomalous, unilateral accessory rib articulating with vertebra C7 and attaching on rib
1 causes increasing pain, tingling and/or numbness along the medial side of the arm, forearm and hand
of an elderly patient. There are no other cutaneous sensory deficits. Furthermore, examination revealed
weakness in initiating pronation against resistance and weakness in flexion of the proximal (PIP) and
distal (DIP) interphalangeal joints of the fingers and the interphalangeal joints of the thumb. There is no
muscle weakness when extending the neck and upper part of the vertebral column. These neurological
signs indicate that the rib may be stretching and exerting pressure on some axons of the __________.
(All symptoms are from one injury site only)
A) dorsal root of spinal nerve C7
B) dorsal ramus of spinal nerve C7
C) medial cord of the brachial plexus
D) middle trunk of the brachial plexus
E) dorsal root of spinal nerve C8
F) dorsal ramus of spinal nerve C8
Feedback: The skin on the medial side of the arm, forearm and hand is supplied by C8 (5th digit, medial
side of hand, and forearm) and T1 (middle of forearm to axilla). This is where there is tingling. The
pronator quadratus initiates pronation and is assisted by the pronator teres. The pronator quadratus is
innervated by the anterior interosseous nerve (C8, T1 - a branch of the median nerve). Initiation of
pronation is compromised. The flexor digitorum superficialis flexes the medial 4 digits at the PIP. It is
innervated by the median nerve (C7, C8, and T1). Flexor digitorum profundus flexes the medial 4 digits
at the DIP. It is innervated by the medial part of ulnar nerve (C8, T1) and the lateral part of median nerve
(C8, T1). The flexor pollicis longus flexes the phalanges of the thumb. It is innervated by the anterior
interosseous nerve (C8, T1 - a branch of the median nerve). These movements are compromised.
Extension of the neck and upper vertebral column is done by the intrinsic back muscles. These muscles
are innervated by the dorsal rami of spinal nerves. This function is normal. Therefore B and F are wrong.
Since there is muscular weakness, damage to a dorsal root (all GA axons) would not account for the
deficits seen in this patient. Therefore A and E are wrong. The deficits can be explained by damage to
the ventral rami of C8 and T1. Damage to the medial cord would affect both (answer C). The middle
trunk is entirely C7 (answer D).
Correct Answer(s):
C
18.
All or part of the ______________ lies directly posterior to the anterior scalene muscle.
A) phrenic nerve
B) subclavian artery
C) subclavian vein
D) subclavius muscle
E) suprascapular nerve
Feedback: A. The phrenic nerves are located anterior to the anterior scalene muscles. B. Each subclavian
artery arches superiorly, posteriorly, and laterally. As the arteries ascend and reach their apex, they pass
posterior to the anterior scalene muscles. C. The subclavian vein, the continuation of the axillary vein,
passes over the 1st rib parallel to the subclavian artery, but it is separated from it by the anterior
scalene muscle. Thus, subclavian vein passes anterior to the anterior scalene. D. The proximal
attachment of subclavius is the junction of the 1st rib and the costal cartilage. It lies almost horizontally
in anatomical position, attaching to the inferior surface of middle third of clavicle. The anterior scalene
also attaches to the 1st rib, but more posteriorly and laterally. Thus, subclavius lies anterior to anterior
scalene (and also lies anterior to subclavian vein). E. The suprascapular nerve arises from the superior
trunk of the brachial plexus, and runs laterally across the posterior triangle. It is the roots of the brachial
plexus that emerge posterior to anterior scalene.
Points Earned: 0.0/1.0
Correct Answer(s):
B
19.
The upper and lower subscapular nerves both arise from the ______________ cord of the brachial
plexus. They can be differentially identified based on the innervation of the ________________ muscle.
A) lateral --- subscapularis
B) lateral --- teres major
C) posterior --- subscapularis
D) posterior --- teres major
E) medial --- subscapularis
F) medial --- teres major
Feedback: The upper subscapular and lower subscapular nerves both arise from the posterior cord. The
upper subscapular nerve only innervates the subscapularis while lower subscapular nerve innervates the
subscapularis and teres major.
Correct Answer(s):
D
20.
The ventral roots of thoracic spinal nerves contain
A) presynaptic (preganglionic) sympathetic axons.
B) presynaptic (preganglionic) parasympathetic axons.
C) postsynaptic (postganglionic) sympathetic axons.
D) postsynaptic (postganglionic) parasympathetic axons.
Feedback: Presynaptic sympathetic neuronal cell bodies are located in the spinal cord from T1 through
L2, therefore the ventral roots of thoracic spinal nerves will contain presynaptic sympathetic axons.
Postsynaptic sympathetic axons would be found in the ventral and dorsal rami of all spinal nerves.
Presynaptic parasympathetic axons would be found in the ventral roots of S2 to S4. Postsynaptic
parasympathetic axons never distribute with spinal nerves.
Correct Answer(s):
A
21.
The intervertebral foramen between vertebrae L3 and L4 contains spinal nerve _____. The segment of
spinal cord giving rise to this nerve is __________ to this intervertebral foramen.
A) L3 --- superior
B) L3 --- adjacent
C) L3 --- inferior
D) L4 --- superior
E) L4 --- adjacent
F) L4 --- inferior
Feedback: Lumbar spinal nerves emerge inferior to the vertebra with the same number. Therefore the
spinal nerve between vertebrae L3 and L4 will be spinal nerve L3. Due to differential growth, the lumbar
spinal cord segments are superior to the lumbar vertebrae.
Correct Answer(s):
A
22.
The axon hillock is located within the __________. It __________ contain Nissl bodies.
A) cell body --- does
B) cell body --- does not
C) axon terminal --- does
D) axon terminal --- does not
Feedback: The axon hillock is located at the proximal end of the axon, within the cell body. The axon
terminal is the distal end of the axon. Axons and axon hillocks do no have Nissl bodies. Nissl bodies
represent the presence of ribosomes. Dendrites and the neuronal cell bodies have Nissl bodies.
Correct Answer(s):
B
23.
A surgeon (not from Downstate) excises a tumor from the apex of the left lung and accidentally cuts the
anterior division of the superior trunk of the brachial plexus. As a result, there is Wallerian degeneration
in the
A) superior trunk.
B) axillary nerve.
C) lateral cord.
D) median nerve.
E) superior trunk and axillary nerve.
F) lateral cord and median nerve.
G) superior trunk, axillary nerve, lateral cord and median nerve.
Feedback: Wallerian degeneration occurs in a nerve distal to a cut. The lateral cord, median nerve, and
musculocutaneous nerve are all distal to the anterior division of the superior trunk. The superior trunk is
proximal to the cut, thus is incorrect. The axillary nerve is distal to the posterior division of the superior
trunk, thus will be intact.
Correct Answer(s):
F
24.
The nerve that innervates all or most of the clavicular head of the pectoralis major is a branch of the
________ cord of the brachial plexus. It ________ have cutaneous branches that innervate the skin over
the clavicle.
A) lateral --- does
B) lateral --- does not
C) medial --- does
D) medial --- does not
Feedback: The lateral pectoral nerve, a branch of the lateral cord, innervates the clavicular head of the
pectoralis major while the medial pectoral nerve, a branch of the medial cord, innervates the
sternocostal head of the pectoralis major. Neither the lateral nor medial pectoral nerves have a
cutaneous component. The supraclavicular nerves innervate the skin over the clavicle.
Correct Answer(s):
B
25.
____________ a prominent characteristic of all cervical vertebrae.
A) Costal facets are
B) A large, massive vertebral body is
C) Transverse foramina (foramina transversaria) are
D) A long spinous process is
Feedback: A. Costal facets are characteristic features of thoracic vertebrae. This is where the ribs
articulate. B. Large massive vertebral bodies are characteristic of the lower half of the vertebral column
(i.e. lower thoracic and lumbar vertebrae). C. The transverse foramina are a characteristic feature of all
cervical vertebrae. D. A long spinous process is characteristic of vertebra C7.
Correct Answer(s):
C
26.
The acromioclavicular joint is small and the acromioclavicular ligament is weak. Another ligament
responsible for maintaining the integrity of this joint is the __________ ligament.
A) coracoacromial
B) coracoclavicular
C) suprascapular
D) coracohumeral
Feedback: A. The coracoacromial ligament extends from the coracoid process to the acromion and is a
ligament of the glenohumeral joint, not the acromioclavicular joint. B. The coracoclavicular ligament,
which consists of the conoid and trapezoid ligaments, reinforces the acromioclavicular joint. C. The
suprascapular (superior transverse scapular) ligament converts the suprascapular notch into a foramen.
It does not maintain the acromioclavicular joint. D. The coracohumeral ligament extends from the
coracoid process to the greater tubercle of the humerus and is a ligament of the glenohumeral joint, not
the acromioclavicular joint.
Correct Answer(s):
B
27.
A patient arrives at the emergency room bleeding profusely and screaming that he has been stabbed in
the shoulder. Pressure is applied to the wound and the bleeding is brought under control. You suspect
that the knife cut may have resulted in nerve damage. Flexion, extension, abduction and adduction at
the glenohumeral joint are normal. Extension at the elbow joint and pronation are also normal,
however, flexion at the elbow joint is greatly weakened while supination is somewhat weakened. You
continue your exam by determining whether there are any other motor deficits and find that
movements at the wrist joints are normal, as are movements of the fingers. Using an open safety pin,
you also determine that there is a loss of sensation on the lateral surface of the forearm. All other
cutaneous innervation of the upper limb is normal. From the diagram below, choose the most likely
position for the nerve lesion.
A) A
B) B
C) C
D) D
E) E
Feedback: Loss of sensation over the lateral surface of forearm indicates damage to the lateral
antebrachial cutaneous nerve, the terminal part of musculocutaneous nerve. Thus only A
(musculocutaneous) or B (lateral cord) can be correct.If B was cut, the median nerve would also be
affected and the patient would exhibit weakened pronation (pronator teres, pronator quadratus),
opposition of thumb (opponens pollicis via recurrent branch of median n.) and movement of the fingers
at the interphalangeal joints. These movements are all normal.Flexion at the elbow joint is greatly
weakened. The brachialis, biceps brachii, brachioradialis, and pronator teres are all flexors of the
forearm. The musculocutaneous nerve innervates both the brachialis and biceps brachii, so damage at A
would cause greatly weakened flexion at the elbow.Supination is somewhat weakened. The supinator is
unaffected since it is innervated by the deep radial nerve (not shown on this diagram). However, the
biceps also helps with supination so damage to the musculocutaneous would compromise
supination.Injury at the medial cord (D) or ulnar nerve (E) would compromise movements of the fingers,
and also result in a loss of sensation on the medial surface of the hand.
Correct Answer(s):
28.
A
The student in the picture is hitchhiking back to Downstate (not a good idea!). His thumb is fully
__________. This movement occurs in the __________ plane.
A) abducted --- coronal
B) abducted --- sagittal
C) extended --- coronal
D) extended --- sagittal
Feedback: Flexion and extension of the thumb occurs in the coronal plane, while abduction and
adduction occur in the sagittal plane. In the picture the thumb is fully extended.Remember to always
refer to anatomical position, not the way it looks in the picture.
Correct Answer(s):
C
29.
A patient arrives in the emergency room after a car accident in which they severely damaged their
elbow joint. You notice that at rest the patient holds their wrist slightly flexed and adducted. When you
ask the patient to actively adduct OR flex at the wrist they always perform the two movements together
and cannot separate them. When you ask the patient to extend at the wrist, they are unable to do so.
This combination of deficits causes you to suspect that this person has sustained injury to the
A) ulnar nerve alone.
B) radial nerve alone.
C) median nerve alone.
D) both ulnar and median nerves.
E) both radial and median nerves.
Feedback: In order to flex at the wrist without adducting or abducting, both the flexor carpi radialis
(innervation = median n.) and flexor carpi ulnaris (innervation = ulnar n.) must be functioning. In order
to adduct without flexing at the wrist, both the flexor carpi ulnaris (innervation = ulnar n.) and extensor
carpi ulnaris (innervation = posterior interosseous/deep radial) must be functioning. Since this patient
cannot separate flexion and adduction of the wrist, and is unable to extend at the wrist (innervation =
posterior interosseous/deep radial n.), the ulnar nerve must be intact and the radial and median nerves
must be injured.
Correct Answer(s):
E
30.
Fractures of the scaphoid bone, usually from a fall on the outstretched hand, produce tenderness and
swelling over the
A) hypothenar eminence.
B) dorsal (extensor) expansion of the index finger (2nd digit, 1st finger).
C) common flexor sheath (ulnar bursa).
D) anatomical "snuff box."
Feedback: A. The hypothenar eminence is on the medial side of the palm, while the scaphoid bone is on
the lateral side. B. The extensor expansion of the 2nd digit is an aponeurosis that runs from the proximal
phalanx of the 2nd digit to the dorsal “hood” of the distal phalanx. This is too distal to be affected by the
scaphoid fracture. C. The common flexor sheath contains the tendons of the flexor digitorum
superficialis and profundus. It is too medial to be affected by the scaphoid fracture. D. The scaphoid and
trapezium lie in the floor of the anatomical snuff box. Injury to these bones results in localized
tenderness in the anatomical snuff box.
Correct Answer(s):
D
31.
Edema (swelling) in the carpal tunnel exerts pressure on the ___________ nerve and the ____________,
resulting in severe pain and disability in the wrist and hand.
A) posterior interosseous --- extensor digitorum tendons
B) median --- palmaris longus tendon
C) superficial radial --- extensor digitorum tendons
D) ulnar --- ulnar artery
E) median --- flexor digitorum profundus tendons
Feedback: The carpal tunnel is formed anteriorly by the flexor retinaculum and posteriorly by the carpal
bones. It transmits the median nerve and the tendons of flexor pollicis longus, flexor digitorum
profundus, and flexor digitorum superficialis muscles. A. The posterior interosseous nerve is the
terminal branch of the deep branch of the radial nerve. It passes deep to extensor pollicis longus and
ends on the interosseous membrane, which is proximal to the carpal tunnel. Extensor digitorum tendons
lie posterior to the carpal bones, thus are not in the carpal tunnel. B. The median nerve is in the carpal
tunnel. However, the palmaris longus tendon lies anterior to the flexor retinaculum, thus it is not in the
carpal tunnel. C. The superficial branch of the radial nerve passes posterior to the extensor retinaculum
to reach the dorsum of the hand. Thus, it is too posterior to be in the carpal tunnel. The extensor
digitorum tendons lie posterior to the carpal bones, thus are not in the carpal tunnel. D. The ulnar nerve
and artery lie anterior to the flexor retinaculum, thus are not in the carpal tunnel. E. The carpal tunnel
contains the median nerve and the tendons of the flexor digitorum profundus.
Correct Answer(s):
E
32.
The bleeding was probably due to damage to both the __________ vein and branches of the
__________ artery.
A) basilic --- lateral thoracic
B) basilic --- thoracoacromial
C) cephalic --- lateral thoracic
D) cephalic --- thoracoacromial
Feedback: The cephalic vein is located in the deltopectoral triangle, where it pierces the clavipectoral
fascia and joins the axillary vein. The basilic vein penetrates the deep fascia on the medial side of the
middle part of the arm and then joins with the brachial veins to form the axillary vein. The basilic vein
does not pass through the deltpectoral triangle. Both the deltoid and acromial branches of the
thoracoacromial artery are found in the deltopectoral triangle. The lateral thoracic artery descends
along the axillary border of the pectoralis minor and follows it onto the thoracic wall. It is too inferior to
be in the deltopectoral triangle.
Correct Answer(s):
D
33.
The tissue normally supplied by the damaged artery does not become necrotic (death resulting from
local deprivation of blood supply), because there are sufficient direct anastomoses between it and other
arteries such as the __________ artery.
A) superior (supreme) thoracic
B) dorsal scapular
C) thoracodorsal
D) scapular circumflex
Feedback: In order for an artery to anastomose, it must supply an adjacent area (in this case, adjacent to
the deltopectoral region). A. The superior thoracic artery runs anteromedially along the superior border
of pectoralis minor and then passes between it and pectoralis major to the thoracic wall. It is supplying
an area adjacent to that supplied by the pectoral branches of the thoracoacromial artery. B. The dorsal
scapular artery runs deep to levator scapulae to reach the scapula and supply the rhomboids. It supplies
the dorsal aspect of the scapula while the deltopectoral triangle is anterior. C. The thoracodorsal artery
supplies the latissimus dorsi muscle and the lateral thoracic wall. It is inferior to the deltopectoral
triangle and does not have any direct anastomoses. D. The circumflex scapular artery curves around the
axillary border of scapula to enter the infraspinous fossa. It anastomoses with arteries on the dorsal
aspect of the scapula.
Correct Answer(s):
34.
A
You also suspect that the knife cut may have resulted in nerve damage. Flexion at the glenohumeral
joint appears somewhat compromised, while abduction, adduction and extension are normal. To further
test flexion, you ask the patient to abduct his left arm to 90° and ask him to move the arm forward while
you try to prevent him from doing so (i.e., he’s then flexing against resistance). With your other hand,
you palpate immediately inferior to the clavicle and feel no contraction of muscle. You continue your
exam by determining whether there are any other motor deficits and find that movements at the elbow
and wrist joints are normal, as are movements of the fingers. Using an open safety pin, you also
determine that cutaneous innervation of the upper limb is normal. From the diagram below, choose the
most likely position for the nerve lesion.
A) A
B) B
C) C
D) D
E) E
F) F
Feedback: Your examination reveals that the clavicular head of the pectoralis major is paralyzed. This
indicates that the knife wound injured the lateral pectoral nerve, a branch of the lateral cord
(remember, the medial pectoral nerve innervates the sternocostal head of the pectoralis major).
Severing at site B (the lateral cord) or site C (the lateral pectoral nerve) could account for this loss of
function. If the lateral cord were severed, the patient would have many additional muscular and
cutaneous deficits (i.e. difficulty flexing at the elbow and wrist, numbness over the lateral arm and
forearm). Since none of these deficits are present the knife must have severed at site C (the lateral
pectoral nerve).
Correct Answer(s):
35.
C
In view of the nerve damage, you know that neuronal cell bodies in the __________ of the spinal cord
will be undergoing chromatolysis, and that degenerating axons __________ found in one of the trunks
of the brachial plexus.
A) dorsal horn --- would be
B) dorsal horn --- would not be
C) ventral horn --- would be
D) ventral horn --- would not be
Feedback: Chromatolysis occurs in the neuronal cell bodies of axons that have been cut. The lateral
pectoral nerve contains GSE, GVE and GA axons whose cell bodies are respectively located in the ventral
horn of the spinal cord, intermediolateral horn of the spinal cord and dorsal root ganglia. All of these
sites would exhibit neuronal cell bodies with chromatolysis if the lateral pectoral nerve were cut. The
dorsal horn of the spinal cord contains the terminals of the central axons of GA neurons. Wallerian
degeneration occurs in nerves distal to the site of a cut. In this case, all branches of the lateral pectoral
nerve would exhibit degenerating axons. The axons in the superior trunk of the brachial plexus, some of
which are also in the lateral pectoral nerve, are proximal to the site of the damage; therefore they
would not undergo degeneration.
Correct Answer(s):
D
36.
In this radiograph, region "A" is more __________ than region "B", because it is __________ than region
"B."
A) radiolucent --- thicker
B) radiolucent --- denser
C) radiopaque --- thicker
D) radiopaque --- denser
Feedback: A tissue that absorbs a relatively large fraction of the x-ray beam passing through it is
described as radiopaque (looks whiter/lighter in an x-ray), while a tissue that absorbs a relatively small
fraction of the x-ray beam passing through it is described as radiolucent (looks blacker/darker in an xray). Absorption of x-rays by tissue is proportional to tissue density and thickness: the denser or thicker
the tissue, the more x-rays it will absorb. However, the areas shown in A and B in this image are of
similar thickness, therefore they differ in density. Bone is denser than soft tissue (i.e. muscle, blood).
Correct Answer(s):
D
37.
This is an image from an MRI exam of a normal wrist in the coronal plane. The first metacarpal is marked
with an asterisk. The black dot is placed over the
A) lunate.
B) trapezoid.
C) trapezium.
D) capitate.
Feedback: The carpal bone that articulates with the first metacarpal is the trapezium. The trapezoid and
capitate articulate with the second and third metacarpals, respectively. The lunate is in the proximal row
of carpal bones and does not articulate with a metacarpal.
Correct Answer(s):
C
38.
This is a/an horizontal/axial MR image of a normal shoulder. The arrow points to the
A) greater tuberosity (tubercle) of the humerus.
B) lesser tuberosity (tubercle) of the humerus.
C) intertubercular sulcus.
D) glenoid fossa (cavity).
E) coracoid process.
Feedback: A. The greater tuberosity is lateral to the arrow.B. The arrow points to the lesser tuberosity.C.
The intertubercular sulcus is the groove between the greater and lesser tuberosities. You can see the
biceps tendon in this sulcus.D. The glenoid fossa (or cavity) is the depression on the scapula at the site of
the glenohumeral joint. This is medial and posterior to the arrow.E. The coracoid process of the scapula
is not seen in this image.
Correct Answer(s):
B
39.
_________ plane divides the body into equal left and right sections.
A) The median sagittal (midsagittal)
B) A coronal (frontal)
C) A horizontal (transverse)
Feedback: A. The median sagittal plane is a vertical plane passing longitudinally through the body,
dividing it into right and left halves. B. Coronal planes are vertical planes passing through the body at
right angles to the median plane, dividing it into anterior and posterior parts. C. Horizontal planes pass
through the body at right angles to the median and coronal planes, dividing the body into superior and
inferior parts.
Correct Answer(s):
A
40.
Flexion and extension of the thumb occur within _________ plane.
A) the median sagittal (midsagittal)
B) a coronal (frontal)
C) a horizontal (transverse)
Feedback: Flexion and extension of the thumb occurs in the coronal plane (abduction and adduction
occur in the sagittal plane). Remember that this is different from the fingers. Flexion and extension of
the fingers occurs in the sagittal plane (abduction and adduction occur in the coronal plane).
Correct Answer(s):
B
41.
There are cell bodies of sensory general afferent (GA) neurons in
A) paravertebral (sympathetic chain) ganglia.
B) dorsal root (spinal) ganglia.
C) the ventral horn of the spinal cord.
D) the intermediolateral nucleus (horn) of the spinal cord.
Feedback: A. Paravertebral ganglia contain the cell bodies of postsynaptic sympathetic general visceral
efferent (GVE) neurons. B. Dorsal root ganglia contain the cell bodies of sensory general afferent (GA)
neurons. C. The ventral horn of the spinal cord contains the cell bodies of general somatic efferent (GSE)
neurons. D. The intermediolateral nucleus of the spinal cord contains cell bodies of presynaptic
sympathetic general visceral efferent (GVE) neurons.
Correct Answer(s):
B
42.
The intervertebral foramen between the tenth and eleventh thoracic vertebrae contains spinal nerve
__________ and __________ its dorsal root (spinal) ganglion.
A) T10 --- also
B) T10 --- not
C) T11 --- also
D) T11 --- not
Feedback: Thoracic spinal nerves emerge inferior to the vertebra with the same number. Therefore the
spinal nerve between vertebrae T10 and T11 will be spinal nerve T10. Dorsal root ganglia at all levels are
located in the intervertebral foramina.
Correct Answer(s):
A
43.
Transection of the middle trunk of the brachial plexus results in Wallerian degeneration of axons in the
A) ventral root of spinal nerve C7 and the axillary nerve.
B) axillary and radial nerves.
C) radial and median nerves.
D) median nerve and the ventral root of spinal nerve C7.
Feedback: Wallerian degeneration occurs in nerves distal to the site of a cut. Transecting the middle
trunk would result in Wallerian degeneration in divisions, cords or terminal branches of the brachial
plexus that contain C7 axons. The ventral root of spinal nerve T7 is proximal to the middle trunk of the
brachial plexus, thus would not undergo Wallerian degeneration. The axillary nerve contains axons of
C5, 6, therefore it will not be affected. The radial nerve contains axons of C5, 6, 7, 8 and T1; therefore
some of the axons in the radial nerve would undergo Wallerian degeneration. The median nerve
contains axons of C(5), 6, 7, 8 and T1; therefore some of the axons in the median nerve would undergo
Wallerian degeneration.
Correct Answer(s):
44.
C
Postganglionic (postsynaptic) parasympathetic neurons are __________ and therefore exhibit
__________ vesicles at synaptic terminals.
A) adrenergic --- clear
B) adrenergic --- electron-dense core
C) cholinergic --- clear
D) cholinergic --- electron-dense core
Feedback: Presynaptic and postsynaptic parasympathetic neurons are cholinergic (release the
neurotransmitter acetylcholine at their axon terminals). Cholinergic terminals contain clear vesicles.
Presynaptic sympathetic neurons are also cholinergic. Postsynaptic sympathetic neurons are adrenergic
(release norepinephrine), except for the neurons innervating the eccrine sweat glands (these are
cholinergic). Adrenergic terminals contain electron-dense cored vesicles.
Correct Answer(s):
C
45.
You are examining appropriately stained sections of the cat cervical spinal cord with a light microscope.
You would expect to be able to see ________ in both the gray matter and white matter.
A) myelinated axons
B) neuronal cell bodies
C) Schwann cells
D) Nissl bodies (substance)
E) dendrites
Feedback: A. Myelinated axons are found in both gray and white matter. B. Neuronal cell bodies are
found only in the gray matter. C. Schwann cells are the myelin-forming cells of the PNS. The spinal cord
is part of the CNS, so you would not see them. D. Nissl bodies are present in the neuronal cell body and
the dendrites, but not in the axon hillock or in the axon. You would only see Nissl in gray matter, not
white. E. Dendrites are found only in the gray matter.
Points Earned: 0.0/1.0
Correct Answer(s):
A
46.
Postsynaptic (postganglionic) sympathetic axons are located in the __________ of spinal nerve C5.
A) ventral and dorsal roots
B) dorsal root and ventral ramus
C) ventral and dorsal rami
D) dorsal ramus and ventral root
Feedback: Both the ventral and dorsal rami of spinal nerve C5 contain postsynaptic sympathetic axons.
Postsynaptic sympathetic axons are never found in the ventral or dorsal roots at any level of the spinal
cord.
Correct Answer(s):
C
47.
Contraction of __________ muscle in the walls of blood vessels in the skin is elicited by the firing of
action potentials of __________ neurons.
A) skeletal --- postsynaptic (postganglionic) sympathetic
B) skeletal --- postsynaptic (postganglionic) parasympathetic
C) skeletal --- general somatic efferent (GSE)
D) smooth --- postsynaptic (postganglionic) sympathetic
E) smooth --- postsynaptic (postganglionic) parasympathetic
F) smooth --- general somatic efferent (GSE)
Feedback: The walls of blood vessels contain smooth, not skeletal, muscle. In the skin, the smooth
muscle of blood vessels is innervated by postsynaptic sympathetic neurons.
Points Earned: 0.0/1.0
Correct Answer(s):
D
48.
The anterior boundary of the posterior triangle of the neck is formed by the
A) medial one-third of the clavicle.
B) anterior border of the trapezius muscle.
C) posterior border of the sternocleidomastoid muscle.
D) inferior belly of the omohyoid muscle.
Feedback: A. The middle third of the clavicle between the trapezius and the sternocleidomastoid is the
inferior boundary (base) of the posterior triangle. B. The anterior border of the trapezius is the posterior
boundary of the posterior triangle. C. The posterior border of the sternocleidomastoid is the anterior
boundary of the posterior triangle. D. The inferior belly of the omohyoid is contained within the
posterior triangle. It subdivides the posterior triangle into the occipital and omoclavicular (subclavian)
triangles.
Correct Answer(s):
C
49.
____________ occur at the joint that is just distal to the radioulnar articular disc.
A) Abduction (radial deviation) and flexion
B) Flexion and pronation
C) Pronation and supination
D) Supination and lateral rotation
Feedback: The joint just distal to the radioulnar articular disc is the radiocarpal (wrist) joint. The
following movements occur at this joint: adduction (ulnar deviation), abduction (radial deviation),
flexion and extension. Pronation and supination occur at the proximal and distal radioulnar joints.
Medial and lateral rotation occurs at the shoulder joint.
Correct Answer(s):
A
50.
The __________ lies directly anterior to the axillary artery.
A) anterior scalene
B) posterior cord of the brachial plexus
C) long thoracic nerve
D) pectoralis minor muscle
Feedback: A. The anterior scalene lies directly anterior to the subclavian artery. B. The posterior cord lies
posterior to the axillary artery. C. The long thoracic nerve bears no relationship to the axillary artery. It is
initially posterior to the subclavian artery in the posterior triangle of the neck and is then found on the
external surface of the serratus anterior. D. The pectoralis minor lies directly anterior to the axillary
artery.
Correct Answer(s):
D
51.
The lumbrical to the ring (3rd) finger is innervated by a branch of the ________ nerve that also
innervates the part of the flexor digitorum ________ that has its distal attachment on the same finger.
A) median --- superficialis
B) median --- profundus
C) ulnar --- superficialis
D) ulnar --- profundus
Feedback: The lumbrical to the 3rd (ring) finger is innervated by the deep branch of the ulnar nerve. The
ulnar nerve also innervates the part of the flexor digitorum profundus that has its distal attachment to
finger 3. The median nerve innervates all of the flexor digitorum superficialis.
Correct Answer(s):
D
52.
The lateral cord of the brachial plexus is located in the __________ and is formed by the union of the
__________ divisions of the upper and middle trunks.
A) axilla --- anterior
B) axilla --- posterior
C) posterior triangle of the neck --- anterior
D) posterior triangle of the neck --- posterior
Feedback: The cords of the brachial plexus are located in the axilla. The roots, trunks and divisions of the
brachial plexus are found in the posterior triangle. The union of the anterior divisions of the upper and
middle trunks forms the lateral cord. The posterior divisions of the upper and middle trunks contribute
to the posterior cord along with the posterior division of the lower trunk.
Correct Answer(s):
A
53.
An ulnar arterial pulse is taken just ______ to the pisiform bone. A radial arterial pulse is taken near the
wrist just ______ to the brachioradialis tendon.
A) lateral --- lateral
B) lateral --- medial
C) medial --- medial
D) medial --- lateral
Feedback: The ulnar artery passes just lateral to the pisiform bone. The radial artery is medial to the
brachioradialis tendon near the wrist.
Correct Answer(s):
B
54.
The spine of the __________ thoracic vertebra lies at the level of the inferior angle of the scapula.
A) third
B) fifth
C) seventh
D) ninth
Feedback: A. The medial end of the root of the scapular spine is at the level of the spine of vertebra T3.
B. No particular landmark of the scapula is at the level of the spine of vertebra T5. C. The inferior angle
of the scapula is at the level of the spine of vertebra T7. D. The spine of T9 is inferior to the scapula.
Correct Answer(s):
C
55.
The pectoralis minor is innervated by the ________ pectoral nerve and has an attachment to the
_______.
A) medial --- coracoid process
B) medial --- bicipital groove of the humerus
C) lateral --- coracoid process
D) lateral --- bicipital groove of the humerus
Feedback: The medial pectoral nerve innervates the pectoralis minor and the sternocostal head of the
pectoralis major. The lateral pectoral nerve innervates the clavicular head of pectoralis major. The
pectoralis minor has an attachment to the coracoid process of the scapula. The pectoralis major has an
attachment to the intertubercular (bicipital) groove of the humerus.
Correct Answer(s):
A
56.
The triangle of auscultation is an area used by physicians to listen for sounds of thoracic viscera. This
area overlies intercostal space _________ and is bounded by the latissimus dorsi, trapezius
and________________ muscles.
A) 6 --- rhomboid major
B) 6 --- serratus anterior
C) 9 --- rhomboid major
D) 9 --- serratus anterior
Feedback: The latissimus dorsi, trapezius and rhomboid major muscles bound the triangle of
auscultation. It is located medial to the scapula, just superior to the inferior angle of the scapula. The
serratus anterior is not in the triangle, since it is not located medial to the scapula. Intercostal space 6 is
located within this triangle. Intercostal space 9 is inferior to the scapula and is covered by the latissimus
dorsi.
Correct Answer(s):
A
57.
The levator scapulae has attachments to the __________ processes of cervical vertebrae and the
rhomboid major has attachments to the __________ processes of thoracic vertebrae.
A) spinous --- spinous
B) spinous --- transverse
C) transverse --- spinous
D) transverse --- transverse
Feedback: The levator scapulae has proximal attachments to the posterior tubercles of transverse
processes of vertebrae C1 through C4. The rhomboid major has proximal attachments to the spinous
processes of vertebrae T2 through T5.
Correct Answer(s):
C
58.
The most superior fibers of the trapezius muscle arise from the occipital bone and have a distal
attachment on the
A) vertebral border of the scapula.
B) spine and acromion of the scapula.
C) spines of the thoracic vertebrae.
D) lateral third of the clavicle.
Feedback: A. The trapezius does not attach to the vertebral border of the scapula. B. The middle and
inferior fibers of the trapezius have a distal attachment on the spine and the acromion of the scapula. C.
The spines of vertebrae C7 through T12 are the proximal attachments of the middle and inferior fibers
of the trapezius. D. The superior fibers of the trapezius have a distal attachment to the lateral third of
clavicle.
Correct Answer(s):
59.
D
Fibrocartilage is or can be present in
A) fibrous (syndesmosis) and primary cartilaginous (synchondrosis) joints.
B) primary cartilaginous (synchondrosis) and secondary cartilaginous (symphysis) joints.
C) secondary cartilaginous (symphysis) and synovial (diarthrosis) joints.
D) synovial (diarthrosis) and fibrous (syndesmosis) joints.
Feedback: Fibrous joints (syndesmoses) are a type of joint (synarthroses) where fibrous connective
tissue, not cartilage, connects the bones. Primary cartilaginous joints (synchondroses) and secondary
cartilaginous joints (symphysis) are types of joints (synarthroses) where cartilage connects the bones. In
primary cartilaginous joints hyaline cartilage connects the bones, while in secondary cartilaginous joints
fibrocartilage connects them. Synovial joints (diarthroses) can have a fibrocartilage disc (creating 2 joint
cavities).
Correct Answer(s):
C
60.
The internal and external vertebral plexuses form an elaborate system of valveless veins that connects
with veins in the neck, thorax, abdomen and pelvis. The internal vertebral plexus is located in the
_________________ space.
A) subarachnoid
B) subdural
C) epidural (extradural)
Feedback: A. The subarchnoid space is the space between the arachnoid layer and the pia mater. This
space is filled with cerebrospinal fluid (CSF). B. The subdural space is a potential space between the
arachnoid and dura. C. The epidural space lies between the walls of the vertebral canal and the dura
mater. It is external to the dura mater and contains the internal vertebral venous plexus and epidural
fat.
Correct Answer(s):
C
61.
The __________ nerves carry pain sensation from the glenohumeral joint.
A) axillary and median
B) median and ulnar
C) ulnar and suprascapular
D) suprascapular and axillary
Feedback: According to Hilton’s Law, joints are innervated by articular branches of the nerves supplying
the muscles that act on the joint. The axillary nerve innervates the teres minor and deltoid, both of
which act at the glenohumeral joint. The median nerve does not innervate any muscles that act at the
glenohumeral joint. The ulnar nerve does not innervate any muscles that act at the glenohumeral joint.
The suprascapular nerve innervates the supraspinatus and infraspinatus, both of which act at the
glenohumeral joint.
Correct Answer(s):
D
62.
The cauda equina ______________ bathed in cerebrospinal fluid (CSF) and contains the
______________ of spinal nerve S2.
A) is --- ventral ramus
B) is not --- ventral ramus
C) is --- dorsal root
D) is not --- dorsal root
Feedback: The cauda equina is composed of the dorsal and ventral roots of lumbar and sacral spinal
nerves. It is located caudal to the end of the spinal cord, within the subarachnoid space that contains
CSF. The spinal nerves are formed within the intervertebral foramina as a result of the union of dorsal
and ventral roots. Each spinal nerve divides almost immediately into ventral and dorsal primary rami
that supply the body wall.
Correct Answer(s):
C
63.
The suprascapular artery anastomoses directly with the ______ artery that passes through the ______
space to supply the ______ muscle.
A) circumflex scapular --- quadrangular --- teres minor
B) circumflex scapular --- quadrangular --- deltoid
C) circumflex scapular --- triangular --- teres minor
D) posterior humeral circumflex --- triangular --- deltoid
E) posterior humeral circumflex --- triangular --- teres minor
F) posterior humeral circumflex --- quadrangular --- deltoid
Feedback: The suprascapular artery anastomoses with a branch of the circumflex scapular artery on the
dorsal surface of the scapula. The posterior circumflex humeral artery is too far away to anastomose
with the suprascapular artery. The circumflex scapular artery passes through the triangular space, while
the posterior circumflex humeral artery passes through the quadrangular space. The circumflex scapular
artery will supply muscles on the dorsal surface of the scapula (for example, teres major and minor, and
infraspinatus). The posterior circumflex humeral artery will supply muscles in the arm (for example,
deltoid, triceps).
Correct Answer(s):
C
64.
In a CT image of the normal chest that includes both lungs and the heart, the image of the lungs will be
__________ the heart image because __________.
A) darker than --- air-filled lung is less dense than heart muscle and blood
B) darker than --- a voxel of lung tissue absorbs more x-rays than a voxel of heart muscle and/or blood
C) lighter than --- normal lung sends back a stronger radiowave signal than normal heart
D) lighter than -- there are more pixels in any given image of the lung than there are in the adjacent
heart image
E) the same shade as --- all the voxels in the slice of chest being studied are the same thickness
Feedback: Absorption of CT x-rays by tissue is proportional to tissue density: the denser the tissue the
more x-rays it will absorb and the lighter the film image. The normal lung has a large component of air
so it is much less dense than the heart that is entirely soft tissue density (muscle and blood). Therefore
the lungs appear blacker (radiolucent) on the CT image, while the heart appears lighter (a medium shade
of gray). A voxel of lung tissue absorbs less x-rays than a voxel of more dense heart muscle. An MR
image is based on the intensity of the returning radiowave. Tissue that has the least hydrogen atoms
(such as bones) turns out dark, while the tissue that has many hydrogen atoms (such as fatty tissue)
looks much brighter. Blood generally appears black because it moves out of the anatomic section being
imaged before it can emit a radio frequency signal. The number of pixels does not affect the darkness of
the image. A pixel is simply a 2-D representation of a 3-D voxel. Any given pixel can have a negative CT
number or positive CT number, producing a dark or light image, respectively. The normal lung,
composed almost entirely of air which is the least dense, appears black on the CT image. The heart
tissue is much denser than air so appears lighter. It is not tissue thickness that produces a black lung on
a CT image, but tissue density.
Correct Answer(s):
A
65.
A sudden occlusion of the deep brachial (profunda brachii) artery at its origin would initally result in
diminished blood flow
A) to the lateral head of the triceps.
B) to the short head of the biceps.
C) into the deep palmar arch.
D) into the common interosseous artery.
Feedback: The deep brachial (profunda brachii) artery branches off the brachial artery near its origin. It
accompanies the radial nerve through the radial groove in the humerus. A. The proximal attachment of
the lateral head of the triceps is just superior to the radial groove, thus the profunda brachii would
supply branches to this muscle. B. The deep brachial (profunda brachii) artery is not likely to supply the
short head of the biceps since the former is in the posterior (extensor) compartment of the arm, while
the short head of the biceps is in the anterior (flexor) compartment. C. The deep palmar arch is a direct
continuation of the radial artery. It would not be affected by occlusion of the deep brachial (profunda
brachii) artery. D. The common interosseous artery is a branch of the ulnar artery. It would not be
affected by occlusion of the deep brachial (profunda brachii) artery.
Correct Answer(s):
A
66.
The subacromial (subdeltoid) bursa lies immediately superior to the tendon of the __________ muscle.
This bursa __________ communicate with the cavity of the glenohumeral joint.
A) subscapularis --- does
B) subscapularis --- does not
C) supraspinatus --- does
D) supraspinatus --- does not
Feedback: The subacromial bursa is located between the acromion, coracoacromial ligament and deltoid
superiorly and the supraspinatus tendon and glenohumeral joint capsule inferiorly. The subscapular
bursa is located between the tendon of the subscapularis muscle and the neck of the scapula. The
subacromial bursa does not communicate with the glenohumeral joint. The subscapular bursa does
communicate with the glenohumeral joint.
Correct Answer(s):
D
67.
A patient has a fracture of the proximal end of the radius that completely severs the deep branch of the
radial nerve close to its origin. On the affected side this patient would
A) be completely unable to flex at the wrist joint.
B) be completely unable to extend at the elbow joint.
C) be unable to feel heat or cold on the dorsal surface of the forearm.
D) exhibit a weakness in supination.
Feedback: The radial nerve divides in the cubital fossa into the deep and superficial radial nerves. The
deep branch penetrates and supplies the supinator muscle to reach the posterior compartment of the
forearm to supply the muscles in that compartment. Damage to the deep radial nerve results in an
inability to extend at the wrist or the MP joints. A. Flexion at the wrist (anterior compartment of the
forearm) would be compromised by damage to the median and/or ulnar nerves. B. Extension at the
elbow joint (triceps) would be compromised by damage to the radial nerve near its origin. C. The ability
to feel heat or cold on the dorsal surface of the forearm would be compromised by damage to the
musculocutaneous and ulnar nerves. The deep radial nerve does not have a cutaneous distribution. D.
The deep radial nerve innervates the supinator, thus damage will compromise supination. This function
will not be eliminated since the biceps brachii will be unaffected.
Correct Answer(s):
D
68.
Destruction of the ventral ramus of spinal nerve C8 would result in
A) weakness of the deltoid muscle.
B) a decrease in the number of axons in the ulnar nerve.
C) a loss of cutaneous sensation in the lateral forearm.
D) weakness in flexion at the shoulder joint.
Feedback: A. The deltoid is innervated by the axillary nerve (C5, 6). There would be no weakness in the
deltoid as a result of cutting the ventral ramus of C8. B. The ulnar nerve is formed from the ventral rami
of C(7), C8 and T1. Cutting the ventral ramus of C8 would result in a decrease in the number of axons in
the ulnar nerve. C. The lateral forearm is innervated by the lateral cutaneous nerve of the forearm
(C5,6,[7]), which is the terminal part of musculocutaneous nerve. Cutaneous sensation in this area
would not be affected by cutting the ventral ramus of C8. D. The clavicular head of the pectoralis major
(innervation = lateral pectoral nerve C5, 6, 7), the deltoid (innervation = axillary nerve C5, 6), and the
coracobrachialis and biceps (innervation of both = musculocutaneous nerve C5, 6, [7]) are flexors at the
shoulder joint. Thus, cutting the ventral ramus of C8 would not affect flexion at the shoulder.
Correct Answer(s):
B
69.
Both the arachnoid mater and the ___________ are made up of ____________.
A) endoneurium --- simple squamous cells connected by tight junctions
B) endoneurium --- fibroblasts scattered among abundant collagen fibers
C) perineurium --- simple squamous cells connected by tight junctions
D) perineurium --- fibroblasts scattered among abundant collagen fibers
Feedback: The arachnoid mater is comparable to the perineurium, while the pia mater is comparable to
the endoneurium. The arachnoid and perineurium are made up of simple squamous cells connected by
tight junctions.
Correct Answer(s):
C
70.
A physician places a card between a patient's 1st (index) and 2nd (middle) fingers. The patient is asked
to hold the card tightly while the physician tries to pull the card away. To hold the card tightly, the
patient must contract the _________ interosseous muscle of the index finger and the _______
interosseous muscle of the middle finger.
A) dorsal --- dorsal
B) dorsal --- palmar
C) palmar --- palmar
D) palmar --- dorsal
Feedback: Abduction of the fingers involves moving away from the axial line that is through the 2nd
(middle) finger. Adduction involves movement of the fingers towards the axial line. The dorsal interossei
abduct and the palmar interossei adduct the fingers. Both interossei attached to the 2nd (middle) finger
are considered dorsal interossei, since in both cases the finger is moving away from the axial line. In
order to hold a card tightly between the 1st (index) and 2nd (middle) fingers, the index finger must
adduct (palmar interosseous) and the middle finger must abduct (dorsal interosseous).
Correct Answer(s):
D
71.
The physician has tested the integrity of the ______ nerve.
A) deep branch of the ulnar
B) superficial branch of the ulnar
C) median
D) deep branch of the radial
E) superficial branch of the radial
Feedback: A. The dorsal and palmar interossei are innervated by the deep branch of the ulnar nerve. B.
The superficial branch of the ulnar nerve supplies palmaris brevis and sensation to skin of the 4th (little)
and medial part of the 3rd (ring) finger. C. The median nerve supplies the thenar muscles (except
adductor pollicis and deep head of flexor pollicis brevis), the lumbricals of the 1st and 2nd fingers, and
provides sensation to skin of the lateral 3 and one-half digits. D. Damage to the deep radial nerve affects
the posterior compartment of the forearm and results in deficits such as an inability to extend the wrist
or MP joints. E. The superficial branch of the radial nerve has an entirely cutaneous distribution.
Correct Answer(s):
A
72.
The muscle labeled 3 is innervated by the __________ nerve.
A) long thoracic
B) lower subscapular
C) medial pectoral
D) lateral pectoral
Feedback: Muscle 3 is the serratus anterior. A. The serratus anterior is innervated by the long thoracic
nerve. B. The lower subscapular nerve innervates the subscapularis (muscle 4) and teres major (not
numbered). C. The medial pectoral nerve innervates the sternocostal head of the pectoralis major
(muscle 2) and the pectoralis minor (muscle 1). D. The lateral pectoral nerve innervates the clavicular
head of the pectoralis major (not visible in this plane of section).
Correct Answer(s):
A
73.
The muscle labeled _____ has an attachment to the lesser tuberosity of the humerus.
A) 1
B) 2
C) 3
D) 4
Feedback: A. Muscle 1 is the pectoralis minor. It does not attach to the humerus. B. Muscle 2 is the
pectoralis major that attaches to the intertubercular groove of the humerus. C. Muscle 3 is the serratus
anterior. It does not attach to the humerus. D. Muscle 4 is the subscapularis that attaches to the
subscapular fossa and the lesser tubercle of the humerus.
Correct Answer(s):
74.
D
When an infection in the thumb spreads, the ________ lymph trunk is most likely to become inflamed.
The ________ lymph nodes are usually the last to become involved before such an infection reaches the
circulating blood.
A) cephalic --- apical axillary
B) cephalic --- deltopectoral
C) basilic --- apical axillary
D) basilic --- deltopectoral
Correct Answer(s):
A
75.
A subject cuts his wrist and severs the tendon of the brachioradialis muscle along with a cutaneous
nerve that crosses the tendon. He has diminished sensation in an area that includes part of the thenar
eminence and the dorsal surface of the thumb. The insensitive area is a part of dermatome ____ that is
innervated by a branch of the ________ nerve.
A) C6 --- radial
B) C6 --- median
C) C7 --- radial
D) C7 --- median
Feedback: The C6 dermatome includes the thenal eminence and dorsal surface of the thumb. These
axons are carried in the superficial radial nerve. The C7 dermatome is the skin of the middle finger; the
axons are carried in the median nerve. Answer = A
Correct Answer(s):
A
76.
Action potentials in sensory (GA) axons that innervate the nail bed of the middle (2nd) finger pass
through both the ______ nerve and the ventral ramus of spinal nerve ______.
A) median --- C6
B) median --- C7
C) radial --- C6
D) radial --- C7
Feedback: The cutaneous innervation of the median nerve includes the nail bed of the middle finger.
The axons would be from C7 since this is the dermatome of the middle finger. Answer = B
Correct Answer(s):
B
77.
__________ are derived from the neural tube.
A) Alpha and gamma motoneurons
B) Dorsal root ganglion neurons
C) Postsynaptic (postganglionic) sympathetic neurons
D) Schwann cells
Correct Answer(s):
A
78.
Imagine that you are very tiny and scuba diving in the foregut at the end of the fourth week of
development. If you reach out and touch the wall, you will be touching __________. You would be able
to easily swim from the foregut into the __________ without crossing any membranes.
A) ectoderm --- allantois
B) ectoderm --- intraembryonic coelom
C) mesoderm --- allantois
D) mesoderm --- intraembryonic coelom
E) endoderm --- allantois
F) endoderm --- intraembryonic coelom
Correct Answer(s):
E
79.
__________ are both events that occur during the third week of development.
A) The initial appearance of the upper limb bud and the formation of the intraembryonic coelom
B) The formation of the intraembryonic coelom and the initial appearance of somites
C) The initial appearance of somites and implantation
D) Implantation and the initial appearance of the upper limb bud
Correct Answer(s):
B
80.
Fertilization can occur either in the
A) uterine tubes or the lumen of the uterus.
B) lumen of the uterus or the vagina.
C) vagina or the peritoneal cavity.
D) peritoneal cavity or the uterine tubes.
Correct Answer(s):
81.
D
A patient with _____________ probably developed hemivertebrae and skeletal deformities from an
embryonic failure of the sclerotome cells to migrate and surround the ____________ to form vertebral
bodies.
A) congenital scoliosis --- notochord
B) congenital scoliosis --- neural crest
C) spina bifida occulta --- notochord
D) spina bifida occulta --- neural crest
Correct Answer(s):
A
82.
*The little finger of the hand begins as cartilage in the upper limb bud derived from cells of the
____________ mesoderm and later ossifies through ___________ bone formation.
A) paraxial --- intramembraneous
B) paraxial --- endochondral
C) lateral plate --- intramembranous
D) lateral plate --- endochondral
Correct Answer(s):
D
83.
The ______________ are all derived from sclerotome cells of the somite. (Select the most complete
answer)
A) vertebrae
B) vertebrae and annulae fibrosus
C) vertebrae, annulae fibrosus and ulna
D) vertebrae, annulae fibrosus, ulna and supinator
Correct Answer(s):
B