Practice Practical Oral Question 2008-Answer Key
1. Describe the muscles, attachments, innervation and action of muscles comprising the
rotator cuff.
SupraspinatusNerve supply: suprascapular nerve from fifth and sixth cervical
Origin: medial two-thirds of the supraspinatus fossa of the scapula
Insertion: superior facet of the greater tubercle of the humerous
Action: initiates abduction of upper extremity to 15° at glenohumeral
joint
InfraspinatusNerve supply: suprascapular n. from fifth to sixth cervical spinal nerves
Origin: medial two-thirds of the infraspinatus fossa of the scapula
Insertion: middle facet of the greater tubercle of the humerous
Action: lateral rotation and extension of the arm at the glenohumeral
joint.
Teres minorNerve supply: axillary n. from fifth and sixth cervical spinal nerves
Origin: upper two-thirds of the lateral border of the scapula
Insertion: inferior facet of the greater tubercle of the humerous
Action: adduction & lateral rotation of the arm at the glenohumerol
joint.
SubscapularisNerve supply: superior and inferior subscapular nerves from the
posterior cord of the brachial plexus (fifth and sixth
cervical spinal nerves)
Origin: medial two-thirds of the subscapular fossa.
Insertion: lesser tubercle of the humerous.
Action: medial rotation of the arm at the glenohumeral joint.
2. Describe the components, attachments, innervation and function of the erector spinae.
Erector spinaeNerve supply: dorsal primary rami of spinal nerves
Origin: from sacrum, ilium, and spines of lumbar vertebrae; it divides
into three columns, iliocostalis musculus, longissimus musculus,
and spinalis
musculus
Insertion(s): ribs and vertebrae with additional muscle slips joining the
columns at successively higher levels
Action: extends and laterally flexes the vertebral column
IliocostalisNerve supply: dorsal primary rami of spinal nerves
CervicalOrigin: angles of upper six ribs
Insertion: transverse processes of middle cervical
vertebrae
Action: extends, abducts, and rotates cervical vertebrae
ThoracisOrigin: medial side of angles of lower six ribs
Insertion: angles of upper six ribs & transverse process of
C7
Action: extends, abducts, and rotates thoracic vertebrae
LumborumOrigin: posterior aspect of sacrum and thoracolumbar
fascia
Insertion: angles of lower six ribs
Action: extends, abducts and rotates lumbar vertebrae
LongissimusNerve supply: dorsal primary rami of spinal nerves
CapitisOrigin: transverse processes of upper (4 or 5) thoracic and
transvers & artiluar process of lower and middle
(3 or 4) cervical vertebrae
Insertion: posterior margin of the mastoid process
Action: keeps head erect and draws it backward or to one
side
CervicisOrigin: transverse processes of upper thoracic vertebrae
Insertion: transverse process of middle and upper cervical
vertebrae (C2-6)
Action: extends cervical vertebrae
ThoracisOrigin: with iliocostalis and from transverse process of
lower thoracic vertebrae
Insertion: by lateral slips into most or all of the ribs
between angles and tubercles and into tips of
transverse process of upper lumbar and
transverse process of thoracic vertebrae
Action: extends vertebral column
SpinalisNerve supply: dorsal primary rami of spinal nerves
CapitisAn inconstant extension of spinalis cervicis to the occipital
bone, sometimes fusing with semispinalis capitis.
CervicisOrigin: lower part of Ligamentum nuchae and spinous
process of sixth and seventh cervical vertebrae
Insertion: spinous processes of axis and third cervical
vertebra
Action: extends cervical spine
ThoracisOrigin: spinous process of T10-L2
Insertion: spinous processes of T1-T8
Action: supports and extends vertebral column
3. Describe the muscles, actions and innervation of the muscles that move the scapula?
Levator scapulaeNerve supply: dorsal scapular n.
Origin: posterior tubercles of transverse processes of C1-4
Insertion: superior angle of scapula
Action:elevates the scapula.
TrapeziusNerve supply: spinal accessory n. (C11)
Origin: medial third of superior nuchal line, external occipital
protuberance, ligamentum nuchae, spinous processes of
seventh
cervical and the thoracic vertebrae (C7-T12) and
corresponding
supraspinous ligaments
Insertion: lateral third of posterior surface of clavicle, anterior side of
acromion, and upper and medial border of the spine of the
scapula
Action: when scapulae are fixed, portions of muscle can act
independently:
-cervical portion elevates scapula, thoracic portion
contributes to depression of scapula; upper and
lowermost portions act simultaneously to rotate glenoid
fossa superiorly
-when the entire muscle and especially middle part
contracts, the scapulae retract; draws head to one side or
backward
Rhomboid majorNerve supply: dorsal scapular n.
Origin: spinous processes and corresponding supraspinous ligaments
of
first four/five thoracic vertebrae
Insertion: medial border of scapula below spine of scapula
Action: draws scapula toward vertebral column (adducts & elevates)
Rhomboid minorNerve supply: dorsal scapular n.
Origin: spinous processes of sixth and seventh cervical vertebrae & T1
Insertion: medial margin of scapula above spine of scapula
Action: draws scapula toward vertebral column and slightly upward
4. Name 2 muscles that move the thumb? Include action and innervations.
Palmer interosseiNerve supply: deep ulnar
Action: adduction of thumb
Adductor pollicisNerve supply: deep ulnar
Action: adduction of thumb
Abductor pollicis brevisNerve supply: recurrent median
Action: abducts thumb at metacarpalphalangeal joint
Abductor pollicis longusNerve supply: ulnar-posterior interosseous (radial)
Action: abducts carpolmetacarpal joint of thumb; accessory extensor
Opponens pollicisNerve supply: recurrent median
Action: medially rotates thumb (acts at carpometacarpal joint to “cup”
palm, enabling one to oppose thumb to other fingers)
Flexor pollicis brevisNerve supply:recurrent median (median (superficial head) and deep
branch of ulnar (deep head))
Action: flexes proximal phalanx of thumb
Flexor pollicis longusNerve supply: median (anterior interosseous)
Action: flexes thumb at interphalangeal joint
Extensor pollicis brevisNerve supply: ulnar-posterior interosseous
Action: extends and abducts the thumb at metacarpophalangeal joint
Extensor pollicis longusNerve supply: ulnar-posterior interosseous
Action: extends distal phalanx of thumb
5. Demonstrate how you would test the dermatomes of the upper extremity.
6. Compare a median nerve injury at the elbow versus carpal tunnel syndrome.
Median nerve at elbow would cause loss of function in Palmaris longus, flexor carpi radialis,
pronator teres, flexor digitorum superficialis, flexor pollicis longus, and prontor quadrates
resulting in weakened flexion of the wrist and loss of pronation ability. Additionally, loss of
function to lateral two lumbricals, opponens pollicis, abductor pollicis brevis, and flexor pollicis
brevis resulting in primary loss of thumb movement.
Carpal tunnel syndrome is the most common nerve entrapment syndrome, characterized by
nocturnal hand paresthesia and pain, and sometimes sensory loss and wasting in the median
hand distribution (thenar muscles & lateral two lumbricals); affects women more than men and
is often bilateral; caused by chronic entrapment of the median nerve at the wrist, within the
carpal tunnel.