Anatomy & Physiology 34A Lecture
Chapter 10: The Muscular System
I. Overview
A. Introduction to the Muscular System
B. Structure of Skeletal Muscles
C. Naming Skeletal Muscles
D. Muscles of the Axial Skeleton
E. Muscles of the Appendicular Skeleton
II. Introduction to the Muscular System
A. ______________ is the study of muscles.
There are more than _____ skeletal muscles in
the body; together they comprise about ____% of our total body weight
B. Five functions of muscles are
1. _____________ – work with bones as levers to move the body
2. ___________ – maintain posture and hold some joints in place
3. __________________ – via facial expressions, writing, speech
4. ______________ of body openings – muscle sphincters open and close body
openings (e.g., in anus, urethra, etc.)
5. ________ production – a by-product of cellular respiration, helps to maintain body
temperature
C. The three types of muscle tissue in the body include:
1. ________ muscle - ____________, spindle-shaped, uninucleate, _____________
contractile tissue found primarily in the walls of hollow organs (e.g.: GI tract,
respiratory tract)
2. ___________ muscle - __________, uninucleate, involuntary contractile tissue with
__________ _______ that separate cells; found mainly in the myocardium (_______
muscle)
3. ___________ muscle - ______ multinucleate cells (myofibers), ____________
contractile tissue found attached to the skeleton. The muscular system refers to
skeletal muscle.
D. Lever Systems: Bone-Muscle Relationships
1. A ________ is any rigid structure that turns about a _________ when force is applied.
The 4 elements in the functions of a lever are:
a. the rigid _______
b. a pivot or _________
c. an object of ___________ to be moved
d. a _________ applied to the rigid structure
2. In the body, _________ joints serve as the fulcra (F), ________ provide the force
(effort=E), and the ________ act as levers that move the resisting (R) object. There
are 3 kinds of levers:
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a.
First-class lever (____) - fulcrum is positioned between the effort and the
resistance, like _________ (e.g.: atlantoccipital joint)
b. Second-class lever (____) - resistance is positioned between the fulcrum and the
effort, like a ______________ (e.g.: contraction of the calf to elevate the body on
the toes)
c. Third-class lever (____) - the effort lies between the fulcrum and the resistance,
like a ________ grasping something; most skeletal muscles are this type of lever
(e.g.: elbow flexion)
E. All muscle tissue has four major properties, which are all involved in movement:
1. ______________ (irritability) – receives and responds to stimuli from nerve impulses
2. ________________ - responds to nerve stimuli by contracting lengthwise, or
shortening
3. _______________ - once a stimulus has subsided and muscle fibers relax, they may
be stretched beyond their resting length by a contraction of an opposing muscle
4. ______________ - after being stretched, muscle fibers tend to recoil to their original
resting length
III. Structure of Skeletal Muscles
A. Muscle Attachments
1. _________, composed of dense regular fibrous CT, attach most muscles to bones (a
few muscles attach by direct attachments)
2. _________ – is the less movable point of a muscle’s attachment
3. _______________ – is the more movable point of a muscle’s attachment
4. In muscles of girdles and appendages, the insertion is the ____________ attachment
and the origin is the _______________ attachment
5. Muscle contraction ________ the muscle, causing movement of associated bones at
their synovial joint (insertion toward _____)
6. The fleshy, thick part of a muscle is called its _______ (gaster).
7. ________________ are flattened, sheetlike tendons (e.g.: illeotibial tract on the
lateral thigh)
8. Certain muscles (in wrist & ankle) are enclosed by tendon _________, which in turn
are covered by a thin, strong band of CT called a _______________
B. Connective Tissues of a Muscle
1. Muscle tissue is surrounded by CT that protects, ________, and binds muscle fibers
into bundles and binds the bundles together
2. Three types of muscle associated ____ are:
a. ____________ CT surrounds individual muscle fibers (cells), binds the fibers
together, and supports capillaries and nerve endings
b. _____________ CT binds muscle fibers together into bundles called
___________ and supports the blood vessels and nerve fibers serving the fascicles
c. _____________ CT covers the entire muscle, all three layers are continuous with
the associated _________
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3.
_________ is fibrous CT that covers muscle and attaches to the skin
a. __________ (subcutaneous) fascia secures skin to underlying structures and is
usually laced with __________ tissue
b. _______ fascia - inward extension of the superficial facia, lacks adipose tissue
and blends with the ____________
C. Arrangement of ____________ in Muscles
1. ______________ - muscle is relatively long and straplike (e.g.: sternocledomastoid,
sartorius, rectus abdominis)
2. ______________ muscle has an expanded central belly (e.g.: biceps brachii,
gastrocnemius)
3. _____________ - muscle is fan-shaped, with a broad origin and narrow insertion
(e.g.: pectoralis major)
4. Circular (__________) - fibers circularly arranged around a body opening
(________); closes the orifice when contracted (e.g.: obicularis oris, obicularis oculi)
5. ____________ - short fascicles & long tendon running most of the muscle length;
fascicles run obliquely into the tendon like the plumes of a __________; strong
muscles; three types are:
a. ____pennate - has all fascicles on ____ side of tendon (e.g.: semimembranosus)
b. ____pennate - has fascicles on ___ sides of the tendon (e.g.: rectus femoris)
c. _____ pennate - has ______ tendons (e.g.: deltoid)
D. Skeletal Muscle Interactions
1. ________ mover (agonist) - muscle primarily responsible for producing a movement
(e.g.: biceps brachii _______ forearm)
2. _____________ muscles contract __________ to accomplish a movement (e.g.:
biceps brachii and brachialis contract together to _______ the elbow joint)
3. ____________ - muscles that perform ___________ functions, and are usually
located on the __________ sides of a joint (e.g.: the triceps brachii is antagonistic to
the _______ brachii; triceps contraction __________ the elbow)
4. ____________ are ____________ muscles that hold a bone in place to stabilize it for
the prime mover (e.g.: rotator cuff muscles that fix the scapula when the arm moves)
IV. Naming Skeletal Muscles - muscles are named on the basis of their shape, location,
attachment, fiber orientation, relative position, or function
A. _____________ of Muscle - some named for area of body or associated bone (e.g.:
intercostal = bet. ribs, brachii = _____)
B. _________ of Muscle - deltoid = triangle; trapezius = trapezoid, rhomboideus =
rhomboid, teres = round)
C. Number of ________ of origin - biceps (_), triceps (_), quadriceps (_)
D. _________ of Muscle
1. Major – _________ (pectoralis major)
2. Minor – _________ (pectoralis minor)
3. Maximus – ___________ in a muscle group (gluteus maximus)
4. Minimus - ___________ in a muscle group (gluteus minimus)
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5.
6.
Longus - _______ (peroneus longus)
Brevis - ________ (peroneus brevis)
E. _______________ of fascicles & muscle fibers
1. ______________ - fibers run parallel to a midline (rectus abdominis)
2. _______________ - fibers run perpendicular to midline (transversus abdominis)
3. _______________ - fibers run diagonally to midline (ext. and int. obliques)
F. ____________ of Attachments - some named according to origin & ______________
(sternocleidomastoid)
G. __________ of Muscle - adductor, __________, flexor, _________, pronator,
___________, and levator, _________
V. Muscles of the Axial Skeleton
A. Muscles of the anterior Neck & Throat - allow _____________
1. _________hyoid (above hyoid) Muscles - control hyoid bone movement; all insert on
__________ bone
a. ____________ - two bellied muscle; O = mandible & mastoid process; A = opens
mouth
b. ________hyoid - O = temporal styloid process; A = elevates and retracts tongue
c. ________hyoid - O = mandible; A = elevates hyoid and floor of mouth
d. _________hyoid - O = inner mandibular symphysis; A = pulls hyoid superiorly &
anteriorly
2. __________hyoid (below hyoid) Muscles - most insert on _________
a. _________hyoid - O - manubrium & clavicle; A=depresses hyoid
b. Sterno_________ - O = manubrium; I = thyroid cartilage; A = depresses thyroid
cartilage
c. _______hyoid - O = superior scapula; A = depresses hyoid
d. _________hyoid - O = thyroid cartilage; A = elevates thyroid
B. Posterior & lateral ________ muscles that move the head
1. ________cleido________ – strap-like neck muscle; O = manubrium & clavicle; I =
temporal mastoid process; A = turns head to side & flexes neck
2. _____________ capitis - broad muscle deep to trapezius; extends and hyperextends
the head & neck
3. ________________ capitis - paired deep neck muscles that extend the head
C. Muscles of Respiration
1. During _____________ (inhalation), the contracting muscles are the
a. _____________ - separates thoracic and abdominal cavities; O = xiphoid process,
ribs 7-12, lumbar vertebrae; I = central tendon; A = contracts for inspiration
(_________ mover)
b. ____________ intercostals – outer rib muscles; O = inferior border of upper rib,
I = superior border of lower rib; A = __________ ribs
c. _________ – O = cervical transverse processes; I = ribs 1-2;
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2.
3.
A = __________ ribs 1-2
The above muscles _____________ during expiration (exhalation)
Muscles that contract during forced __________________ include:
a. _____________ intercostals – inner rib muscles; O = superior border of lower
rib; I = inferior border of upper rib; A =___________ ribs
b. _______________ muscles (described below)
D. Muscles that move the _________- 4 pr. of flat, sheet-like muscles
1. ______ abdominal _________ - most superficial of the 3 lateral abdominal muscle
layers; fibers form a “__”; O = ribs 5-12, I = pubic & iliac crest, and linea alba; A =
___________ abdomen
2. ____ abdominal ________ - deep to ext. abdom. oblique; fibers form an inverted
“___” O = iliac crest, lumbar fascia, inguinal ligament; I = linea alba & ribs 9-12; A =
___________ abdomen
3. ___________ abdominis - deepest layer; O = iliac crest, lumbar fascia, inguinal
ligament, ribs 7-12; I = linea alba, pubis; A = ___________ abdomen
4. ____________ abdominis - long, anterior, medial straplike muscle enclosed in a
fibrous sheath from the aponeuroses of the other 3 muscles; O = pubic crest &
symphysis, I = xiphoid process & ribs 5-7; A = __________ abdomen, _____
abdomen
E. Muscles that move the Vertebral Column
1. _________ abdominis – antagonistic to posterior trunk muscles; A = flexes trunk
2. __________________ - posterior, superficial muscle group that extends from the
sacrum (O) to the skull (I); A = all ________ the trunk (prime mover of back
extension); 3 muscle groups:
a. _______________ - lateral muscles
b. _______________ - intermediate muscles
c. _____________ - medial muscles
VII. Muscles of the Appendicular Skeleton - pectoral girdle, arm, forearm, wrist, hand, and
fingers; pelvic girdle, thigh, leg, ankle, foot, and toes
A. Muscles that move the shoulder (__________)
1. Anterior trunk
a. ___________ anterior – fan-shaped “________” muscle; O = ribs 1-8, I =
superior scapula; A = ________ & _________ scapula (“boxer’s muscle” - prime
mover in punching, throwing, pushing)
b. __________________ - deep to pec. major; O = ribs 3-5, I = scapula corocoid
process; A = _________ to serratus anterior
2. Posterior trunk
a. ___________ - triangular upper back muscle; O = occipital bone, ligamentum
nuchae, spines of C7 & all thoracic vertebrae; I = scapula spine, acromion, &
clavicle; A = elevates, __________, & __________ scapula, also extends head
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b.
c.
__________ scapulae - O = C1-C4 transverse processes; I = medial scapula
border; A = __________ scapula
Major & minor _______________ - O = lower ligamentum nuchae, C7, T1-T5
spines; I = medial scapula; A = ________ & ____________ scapula (paddling
muscles)
B. Muscles That Move the ____________
1. Trunk muscles - 2 that do ____ originate on the scapula
a. _____________ - O = clavicle, sternum, cartilage of ribs 1-6; I = humerus greater
2.
tubercle; A = ________, _________, _________ humerus medially
b. _________________ – inferior to trapezius; O = T7-L5 spines, iliac crest, ribs 812, inferior scapula; I = humerus intertubercular groove; A = _________,
_________, _______ humerus medially (“__________” muscle)
Scapular muscles - 7 that originate on the __________
a. ___________ - O = scapular spine, acromion and clavicle; I = humerus deltoid
tuberosity; A = abducts, extends, flexes, and rotates humerus (prime mover of arm
____________)
b. _______spinatus - a rotator cuff muscle; O = supraspinous fossa; I = humerus
greater tubercle; A = _______ & laterally rotates humerus
c. _______spinatus - a rotator cuff muscle; O = infraspinous fossa; I = greater
tubercle; A = ________ humerus laterally
d. ______________ - a rotator cuff muscle; O = subscapular fossa; I = lesser
tubercle; A = ________ humerus medially
e. Teres ____________ - a rotator cuff muscle; O = lateral scapula; I = greater
tubercle; A = _________ humerus laterally
f. Teres ___________ - O = scapula inferior angle; I = lesser tubercle; extends; A =
_________, & _______ humerus medially
g. _________brachialis - O = scapula corocoid process; I = medial humerus shaft;
A = _______ & flexes humerus
C. Muscles of the Arm that Move the __________ at the Elbow Joint
1. _________ brachii - O = scapular coracoid process & upper glenoid cavity; I = radial
2.
3.
4.
tuberosity; A = ________ & supinates forearm (prime mover of forearm flexion)
_____________ - deep to biceps brachii on distal humerus; O = anterior humerus; I =
ulnar coronoid process; A = ______ elbow
______________ - muscle of lateral forearm; O = distal, lateral humerus; I = near
radial styloid process; A = ________ elbow
__________ brachii - on posterior arm; O = inferior glenoid cavity & post. humerus,
; I = ulnar ___________ process; A = _______ forearm (prime mover)
D. Muscles of the Forearm that move the ________, hand, & fingers
1. Anterior, Superficial ________ of the Hand– all originate on humerus ___________
epicondyle (medial to lateral):
a. Flexor carpi ______ - I = carpals & metacarpals; A = _____ & __________ hand
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b.
c.
2.
_________ longus - I = palmar aponeurosis; A = weak _____
Flexor carpi ___________ - I = base 2nd & 3rd metacarpals; A = ________ &
__________ hand
d. ___________ teres - O = med. epicondyle, ulnar coronoid process; I = lateral
radius; A = _________ forearm & hand
e. ____________________ (described previously)
(Ugly Ladies Ride The Bus)
Posterior ______________ of the Hand – most originate on humerus _________
epicondyle (medial to lateral)
a. Extensor carpi _______ - I = 5th metacarpal; A = _______ & __________ hand
b. Extensor digiti ________ (lateralis in cat) - I = 5th phalange; A = extends 5th digit
& hand
c. Extensor _________ (communis in cat) - I = phalanges 2-5; A = extends hand &
phalanges
d. Extensor carpi ___________ (longus & brevis) - O = lateral epicondyle &
supracondylar ridge; I = 2nd & 3rd metacarpal; A = _________ and _________
wrist
(Ugly Men Drive Ramblers)
E. Muscles That Move the _________ at the Hip Joint
1. Anterior Hip = thigh ____________
a. _____________ - iliacus + psoas major; O = ilium & lumbar vertebrae; I = femur
lesser trochanter; A = prime mover of thigh flexion, also flexes trunk
b. _______________ - O = ant. sup. iliac spine; I = proximal medial tibia; A = _____
& ________ hip, ________ thigh laterally (“tailors” muscle, allows crossed legs)
2. Lateral Hip & Buttocks = mostly thigh ___________ and ______________
a. Gluteus __________ - O = dorsal ilium, sacrum, coccyx; I = femur gluteal
tuberosity & iliotibial tract; A = ________, abducts, & __________ thigh laterally
(stair-stepper muscle)
b. Gluteus ________ & minimus - O = lateral ilium; I = femur greater trochanter;
A = _________ & rotate thigh ____________
c. ___________ fasciae _________ - O = ant. iliac crest & ant. sup. spine; I =
iliotibial tract; A = ____________ & rotate thigh medially
3. Lateral Thigh _____________ surround the hip joint; most rotate the thigh laterally;
include the _____________, obturators, gemelli, and quadratus femoris.
4. Medial = thigh _______________ (“thigh master” muscles)
a. ____________ - O = lower pubis; I = proximal medial tibia; A = _________ thigh
b. ______________ - O = pubis; I = post. proximal femur; A = __________, flexes,
& medially ___________ thigh
c. Adductor _________ & _______ - O = near pubic symphysis; I = femur linea
aspera; A = __________ & medially _________ thigh
d. Adductor __________ (cats=femoris) - O = inf. ishium & pubis; I = linea aspera;
A = _________, flexes, & medially ____________ thigh
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F. Muscles of the _________ that Move the lower leg at the __________ joint
1. Anterior = mostly leg ___________
a. _______________ femoris - 4 muscle group that all _________ via quadriceps
tendon on the patella & tibial ______________ via patellar ligament; A = all
____________ the knee
1) Rectus femoris - O = ant. inf. iliac spine & acetabulum; A = extends leg and
flexes thigh
2) Vastus lateralis, medialis, intermedius - O = proximal femur (intermedius is
deep to rectus femoris)
2. Posterior =leg flexors = __________________ - A = all _______ the thigh and
______ the lower leg (at knee)
a. _________ femoris - 2-Os = ishial tuberosity & linea aspera; 2-Is = fibula head &
tibia lateral condyle; A = ________ knee & laterally _________ thigh
b. Semi_____________ - O = ishial tuberosity; I = proximal medial tibia; A =_____
knee & medially ____________ thigh
c. Semi_______________ - O = ishial tuberosity; I = tibia medial condyle; A =
same as above.
3. Medial = leg flexor = ______________ – O = inf. pubis & ishium; I = proxial, medial
tibia; A = ________ & medially ____________ leg
G. Muscles of the ________ that move the ______ at the knee
1. ________________ (post. to knee) – O = femur lat. condyle; I = proximal tibia; A =
unlocks knee to allow __________
H. Muscles of the Leg that Move the Joints of the Ankle, Foot, & Toes (_________ muscles
= shank or lower leg)
1. Anterior Crural Muscles that _______flex the foot
a. _____________ anterior - O = proximal lateral tibia; I = 1st metatarsal & 1st
cuneiform; A = prime mover of foot ______flexion, also _________ foot
b. ___________ ______________ longus – O = tibia lateral condyle & fibula; I =
phalanges II-V; A = _______flexes & _________ foot, extends digits II-V
2. Lateral Crural Muscles that ___________ flex the foot
a. ___________ (peroneus) _______ - O = head & proximal fibula; I = 1st cuneiform
& metatarsal; A = _________ flexes and _________ foot
b. Fibularis (peroneus) ________ – O =distal fibula; I = 5th metatarsal; A = same as
peroneus longus
3. Posterior Sural Muscles that __________ flex the foot
a. _________________ - O = 2 heads on lateral & medial femur condyles; I = post.
calcaneous via _________________ (achilles) tendon; A = prime mover of foot
________ flexion, weak knee flexor
b. ____________ - deep to gastroc.; O = head of tibia & fibula; I = same as gastroc.;
A = ___________ flexes foot (gastrocnemius and soleus are called the triceps
surae)
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c.
d.
_________ ____________ longus – O = posterior tibia; I = phalanges II-V; A =
_______ flexes & _________ foot, flexes distal phalanges
_________ __________ – O = proximal tibia & fibula; I = navicular, cuneiforms,
metatarsals II-IV; A = _________ flexes & _________ foot and supports arches
VIII. Muscles of the face and eye
A. Muscles of ________ Expression - All originate on ______ bones or facia and insert
into the _____. Most are enervated by Cranial Nerve ____, the facial nerve
1. ____________ (occipitofrontalis) two scalp muscles connected by the galea
aponeurotica; consists of:
a. ___________ - forehead muscle; raises eyebrows.
b. _________ - muscle at base of skull; draws scalp posteriorly.
2. Orbicularis _______ - circular muscle around eye; closes eye.
3. ____________ supercilii - deep to obicularis oculi in superior
orbital ridge (below eyebrow); draws eyebrow inferiorly (______).
4. ____________ - oblique cheek muscle, insertion deep beneath masseter; causes cheek
to cave inward (___________).
5. ___________ - V-shaped rectus at chin; elevates and protrudes lower lip
(_________).
6. Orbicularis ________ - circular muscle around mouth; shapes lips during speech (&
_________).
7. _______________ - major and minor, oblique direction, O = zygomatic; I=obicularis
oris; A=draws mouth upward (______).
8. _________ labii superioris - oblique between obicularis oris & inferior eye margin;
elevates upper lip.
9. ___________ labii inferioris - rectus orientation, deep beneath platysma, on each
side of mentalis; depresses lower lip (_____).
10. Depressor __________ oris - small muscle lateral to depressor labii inferioris;
draws corners of mouth downward.
11. __________ - longitudinal, superior to platysma; O = fascia by ears; I=skin at mouth
angle; A=draws mouth laterally (______).
12. __________ - superficial, over neck and on chin up to Risorius; draws lower lip
back & down, tenses skin of neck.
B. Muscles of Mastication (O = origin, I = insertion, A = action)
1. __________________ - fan-shaped muscle; O = temporal, frontal, parietal bones; I =
2.
3.
coronoid process of mandible; A = elevates and retracts mandible.
_______________ - over ramus on mandible; O = zygomatic arch; I = lateral & angle
of mandible; A = closes mouth.
________________ - keeps food between grinding teeth surfaces
C. Ocular (______) Muscles - move the eyeball and are controlled by 6 extrinsic muscles
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Muscle
Superior rectus
Inferior rectus
Lateral rectus
Location
on ______________ eye surface
on ______________ eye surface
on ______________ eye surface
Action
1
looking up
2
looking down
3
lateral eye
movement
4 Medial rectus
on ____________ surface of eye crossing eyes
5 Inferior oblique
circles _____________ of eye
looking up &
laterally
6 Superior oblique
attaches via ____________ bet.
looking down &
super. & inf. lateral rectus
laterally
The rectus muscles all originate on the annular _________, posterior to eye orbit, and insert on
the anterior eyeball.