Transcript Muscle Tissue Chapter 9

Muscle Tissue
Chapter 9
Functions of Muscle Tissue
Movement
 Maintenance of Posture
 Joint Stabilization
 Heat Generation
 Contractibility
 Excitability
 Extensibility
 Elasticity

3 Types of Muscle Tissue

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
Skeletal Muscle
- attach to and move the skeleton
- 40% of body weight
- voluntary
- striated
Cardiac Muscle
- only in the walls of the heart
- NOT voluntary but striated
Smooth Muscle
- walls of hollow internal organs
- involuntary
- no striations
Skeletal Muscle
1.skeletal (or voluntary/striated) muscle, the most
abundant tissue in the human body, producing
movement. Each skeletal-muscle fiber is roughly
cylindrical, contains many nuclei, and is crossed
by alternating light and dark bands called
striations. Fibers bind together, via connective
tissue, into bundles; and these bundles, in turn,
bind together to form muscles. Skeletal muscles
are controlled by the somatic nervous system
(SNS).
Skeletal muscle comprises approximately 40% of
the body weight and are voluntary structures.
Smooth Muscle
1. forming the muscle layers in the walls of the
digestive tract, bladder, various ducts, arteries and
veins, and other internal organs. Smooth- muscle
cells are elongated and thin, not striated, have
only one nucleus, and interlace to form sheets
rather than bundles of muscles. Smooth muscle is
controlled by the autonomic nervous system
(ANS).
These are non-voluntary structures.
Cardiac Muscle
1.a cross between the smooth and
striated muscles, comprising the heart
tissue. Like smooth muscle, it is
innervated by the autonomic nervous
system (ANS).
DEFINITIONS
The cells of SKELETAL and SMOOTH are called
FIBERS. They are very elongated.
 Within the cytoplasm of each fiber are
MYOFILAMENTS. The myofilaments are responsible
for contraction.
 There are two kinds of myofilaments. ACTIN and
MYOSIN.
 The plasma membrane of the fiber is called the
SARCOLEMMA. The cytoplasm is called the
SARCOPLASM.

CONNECTIVE TISSUE AND FASCICLES

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
Epimysium
- surrounds the entire MUSCLE.
- sometimes the epimysium blends with the deep connective
tissue fascia that is found between muscles.
Perimysium
- There are many fascicles that make up a muscle. Theses
fascicles consist of many cells (fibers) bound together by a
perimysium.
Endomysium
- Within the fascicle, there are many muscle fibers (cells). These
fibers have a thin sheath of connective tissue wrapping each
one. This covering is called the endomysium.
Neurovascularity
 Skeletal muscle is generally supplied by one
nerve, one artery, and one or more veins.
 These vessels enter the muscle near the middle
of its length.
 A nerve that will signal the muscle to contract will
join that muscle at the NEUROMUSCULAR
JUNCTION.
Muscle Attachments
Most skeletal muscles connect two bones and cross at
least one moveable joint.
 A muscle begins at a less moveable bone called the
ORIGIN. The origin is usually the more proximal bone.
The muscle travels to the moveable part called the
INSERTION. The insertion is usually the the more
distal bone.
 DIRECT attachments have the muscle abutting the
bone directly.
 INDIRECT attachments connect through a TENDON.

Arrangement of Muscle Fascicles




PARALLEL
- long axes run parallel to the long axis of the muscle itself.
CONVERGENT
- the origin of the muscle is broad and all the fibers attach at the insertion.
PENNATE
- fascicles are short and insert on a tendon that runs within the muscle belly.
- Unipennate –insert on only one side of the tendon.
- Bipennate – fascicles insert on both sides of the tendon.
- Multipennate – many shorter tendons attaching to a main tendon
CIRCULAR
- Fascicles form concentric rings with a central space.
Muscle Interactions
Skeletal muscles must work AGAINST each other.
 The muscle that has the responsibility for producing a
specific movement is known as the AGONIST.
 Muscles that help the agonist are known as
SYNERGISTS
 Muscles that oppose that movement are known as
ANTAGONISTS.

HOW ARE SKELETAL MUSCLES NAMED?
 Location
 Shape
 Size
 Direction of the fascicles
 Location of the attachments
 Number of origins
 Action
Muscles of the Upper Extremity
 HINT:
You need to know the origin, insertion,
action, and nerve supply.
 There are two anatomical compartments in the
arm.
 Superficial fascia, a dense connective tissue
physically separates the anterior and posterior
compartments.
The anterior compartment contains three flexors, the
posterior compartment contains the extensors.
 The anterior compartment is innervated by the
musculocutaneous nerve. They cause flexion of the
forearm (elbow).
 The flexor compartment (anterior) contains the BICEPS
BRACHII (medial), BRACHIALIS (lateral), and the
CORACOBRACHIALIS.
 The musculocutaneous nerve also innervates the skin.

 The posterior compartment (extensors) are
innervated by the radial nerve. The muscle is
the TRICEPS.
 The triceps has three heads: lateral, medial, and
long heads).
 There are two anatomical compartments of the
forearm.
 As in the upper arm, the anterior compartment
contains the flexors and the posterior
compartment contains the extensors.
 The posterior compartment muscles are ALL
innervated by the radial nerve. These are the
extensors of the wrist, hand, and digits.
The radial nerve also innervates the SUPINATORS.
The BRACHIORADIALIS MUSCLE is innervated by the
radial nerve. It is a flexor of the forearm. This muscle lies
outside of the compartments.
 The extensor muscles include: extensor carpi ulnaris,
extensor digitorum lateralis, extensor digitorum communis,
extensor carpi radialis brevis, and extensor carpi radialis
longus. They all use the radial nerve.
 The flexors and anterior compartment muscles are
innervated by the median nerve EXCEPT for the flexor
carpi ulnaris and the flexor digitorum profundus.


 There are 20 muscles in the hand.
 The have both origin and insertion in hand.
Therefore, they are called INTRINSIC
MUSCLES.
 They allow us to have an opposable thumb.
 All of the intrinsic muscles are innervated by the
ULNAR NERVE, except for 5. These 5 are
innervated by the median nerve.
The median nerve innervates these 5 exceptions:
Three of them control the THENAR (thumb)
area.
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If a nerve is cut, we can do tests to determine where the damage
is.
If the cut is at the wrist, we fear damage to the median nerve.
This test is done with a pin on the palm and dorsum of the hand.
Since the median nerve also serves the intrinsic muscles of the
thumb, the person should have lost the ability to oppose the
thumb. Clinically, this is called “Ape hand” since apes can’t
oppose their thumbs.
 If the radial nerve is damaged higher up, then
the extensors will not work. This caused a
“Dropped Wrist”.
 If the ulnar nerve is damaged in the wrist, we get
a “claw hand”. The intrinsic muscles will not
work. The thumb will work because it is
innervated by the median nerve.
The Rotator Cuff
 These muscles are often torn in baseball and
tennis.
 They all originate on the scapula and insert on
the humerus. More specifically, they insert on
the head of the humerus.
 The SUBSCAPULARIS MUSCLE (subscapular
nerve) originates on the deep side of the scapula
in the subscapular fossa.
The subscapularis muscle comes across and inserts on
the medial-anterior surface of the humerus (lesser
tuberosity).
 This make the subscapularis a medial rotator (pronator)


Posteriorly (dorsally), the INFRASPINATUS MUSCLE
(suprascapularis nerve) and TERES MINOR (axillary
nerve) are lateral rotators (supinators) of the humerus.
 The infraspinatus originates on the infraspinous
process and inserts on the greater tuberosity of
the humerus.
 The teres minor originates on the axillary border
of the scapula between the infraspinatus and the
long head of the triceps. It inserts just dorsal to
the infraspinatus on the greater tuberosity of the
humerus.
These two have the same action and are antagonistic to
the subscapularis muscle.
 The SUPRASCAPULARIS MUSCLE (suprascapular
nerve) originates on the supraspinous fossa, passes
ventral to the acromion and cranial to the shoulder joint.
It inserts on the greater tuberosity of the humerus. It is
an abductor and weak lateral rotator of the arm.

Muscles of the Rotator Cuff
All INSERT on the humerus
Muscle
Origin
Subscapularis
Subscapular fossa Medial rotator of
the humerus
Infraspinous fossa Lateral rotator of
the humerus
Lateral border of
Lateral rotator of
scapula (upper 2/3) the humerus
Supraspinous
Abducts the
fossa
humerus
infraspinatus
Teres minor
supraspinatus
Action
Moving the Scapula
 These muscles all insert on the scapula.
Since
they insert on the scapula, by definition they
move it.
 The clavicle braces the scapula through its
articulation with the acromion laterally and the
manubrium medially. This is the only bony
attachment to the axial skeleton on humans.
(THERE IS NO BONY ATTACHMENT IN CATS)
This brace is important since humans use their upper
limb as a tool.
 Since the mooring muscles move the scapula, they can
also stabilize it.
 The trapezius muscle (spinal accessory nerve) is one
muscle in humans. The SPINO portion stabilizes and
depresses. The CLAVO portion elevates it and the
ACROMIO portion abducts and retracts.

Muscles of the Scapula
*All these muscles INSERT on the scapula
Muscle
Origin
Action
Trapezius
Ligamentum nuchae and
C7-T12
Elevates, adducts, rotates,
and depresses the scapula
Levator Scapulae ventralis
C1-C4
Elevates the scapula,
flexes neck laterally
Rhomboids
C7-T5
Adduct, elevate, and rotate
the scapula
Pectoralis minor
Ribs 3-5
Depresses and rotates the
scapula
Serratus anterior
Ribs 1-9
Protracts and rotates the
scapula
Muscles that Move the Arm
These muscles all insert on the humerus.
 The DELTOID (axillary nerve) has three parts:
anterior portion has origin on the lateral third of the clavicle.
middle fibers have origin on the lateral border of the acromion
process
posterior fibers originate from the lower border of the spine of
the scapula.
 The insertion for the deltoid is on the middle of the lateral surface
of the shaft of the humerus. Its action is primarily as a flexor,
while it also can abduct and extend the humerus.

 The PECTORALIS MAJOR (medial and lateral
pectoral nerves) has its origin on the medial half
of the clavicle, from the sternum, and from the
upper six costal cartilages.
 It inserts on the lateral lip of the bicepital groove
of the humerus.
 Its action is at adduct, medially rotate, and flex
the humerus.
 The LATISSIMUS DORSI MUSCLE
(thoracodorsal nerve) has its origin from the
posterior part of the iliac crest, lumbar fascia,
and the spines of the lower six thoracic vertebra,
and lower three or four ribs.
 It inserts on the bicepital groove of the humerus.
 Its action is to extend, adduct, and medially
rotate the humerus.
 The TERES MAJOR muscle (lower subscapular
nerve) orginates from the lower third of the
posterior surface of the lateral border of the
scapula.
 It inserts on the medial lip of the biceptal groove
of the humerus.
 Its action is extension, adduction, and medial
rotation of the humerus.
 The CORACOBRACHIALIS MUSCLE
(musculocutaneous nerve) has its origin at the
tip of the coracoid process and inserts on the
middle of the medial side of the humerus.
 Its action is to flex and adduct the humerus.
Muscles of the Upper Limb
*All INSERT on the humerus
Muscle
Origin
Action
Deltoid
Lateral ½ of clavicle, acromion Prime flexor, abducts and
and spine of scapula
extends the humerus.
Laterally and medially rotates
arm.
Pectoralis major
Sternum and ribs 2-6
Adducts, flexes, and medially
rotates humerus
Latissimus dorsi
Iliac crest, T7-T12 and lumbar
fascia
Extends, adducts, and
medially rotates the humerus
Teres major
Lateral border of scapula
(lower 1/3)
Extends, adducts, and
medially rotates the humerus
Coracobrachialis
Coracoid process
Flexes and adducts the
humerus.
1.
Pectoantebrachialis
2.
Pectoralis Major
3.
Pectoralis Minor
4.
Xiphihumeralis
5.
Linea Albea
6.
Epitrochlearis
7.
Triceps (Long Head)
8.
Teres Major
9.
Subscapularis
10.
Serratus Ventralis
11.
Latissimus Dorsi
1.
Rectus Thoracis
2.
Rectus Abdominis
3a.
Scalenus Anterior
3b.
Scalenus Medius
3c.
Scalenus Posterior
4.
Serratus Ventralis
5.
Subscapularis
6.
Teres Major
7.
Coracobrachialis
8.
Latissimus Dorsi
1.
Latissimus Dorsi
6.
Spinodeltoid
2.
Spinotrapezius
7.
Acromiodeltoid
3.
Acromiotrapezius
8.
Clavodeltoid
4.
Clavotrapezius
9.
Triceps Lateral Head
5.
Levator Scapulae Ventralis
10. Triceps Long Head
1. Clavotrapezius
2.
3.
4.
5.
6.
7.
8.
(Reflected)
Acromiotrapezius
Supraspinatus
Infraspinatus
Triceps (Long Head)
Triceps (Lateral Head)
Acromiodeltoid
Clavodeltoid
9.
Rhomboideus
Capitis
10.
Splenius Capitis
11.
Rhomboideus
Minor
12.
Rhomboideus
Major
13.
Spinotrapezius
14.
Latissimus Dorsi
15.
Longissimus
Anterior
Posterior
Muscles Crossing the Elbow
Muscle
Origin
Insertion
Action
Triceps Brachii
(radial nerve)
Infraglenoid tubuercle
and shaft of humerus
Olecranon process of
ulna
Forearm extensor
Anconeus
(radial nerve)
Lateral epicondyle of
humerus
Lateral aspect of
olecranon process of
ulna
Abducts ulna during
forearm pronation
Biceps Brachii
(musculocutaneous
nerve)
Supraglenoid tubercle
and coracoid process
Radial tuberosity
Flex forearm and
supinate hand
Brachialis
(musculocutaneous
nerve)
Anterior surface of
humerus
Coronoid process of
ulna and capsule of
elbow
Forearm flexor and hand
supinator
Brachioradialis
(radial nerve)*
Supracondylar ridge of
the humerus
Styloid process of radius
Synergist in forearm
flexion
*Exception: radial nerve usually serves extensor muscles
Muscles of the Forearm
Muscle
Origin
Insertion
Action
Pronator Teres
(median nerve)
Humerus
Coronoid process of
ulna
Lateral raidus
Pronate forearm
Weak flexor of elbow
Base of 2nd and 3rd
metacarpals
Flexor of wrist, abduct
hand
ANTERIOR
Superficial Muscles
Flexor Carpi Radialis Humerus-medial
epicondyle
(median nerve)
Palmaris Longus
(median nerve)
Humerus-medial
epicondyle
Palmar fascia
Weak wrist flexor
Flexor Carpi Ulnaris
(ulnar nerve)
Humerus-medial
epicondyle
Olecranon process
Pisiform and hamate
bones, base the 5th
metacarpal
Powerful flexor of wrist,
adductor of hand
Flexor Digitorum
Superficialis
(median nerve)
Humerus-medial
Four tendons into
epicondyle, coronoid
middle phalange of
process of ulna, shaft of fingers 2-5
radius
Flexes wrist
ANTERIOR
Deep Muscles
Muscles of the Forearm
Muscle
Origin
Insertion
Action
Flexor Pollucis
Longus
(median nerve)
Radius and
interosseous
membrane
Distal phalanx of
thumb
Flexes distal
phalanx of thumb
Flexor Digitorum
Profundus
(ulnar and median
nerves)
Ulna and
interosseous
membrane
Four tendons into
distal phalanges of
fingers 2-5
Flexor of the
fingers
Pronator
Quadratus
(median nerve)
ulna
radus
Forearm pronation
POSTERIOR Superficial Muscles
Muscles of the Forearm
Muscle
Origin
Insertion
Action
Extensor Carpi Radialis
Longus
(radial nerve)
Humerus-lateral
epicondyle
Base of 2nd metacarpal
Extends and abducts
wrist
Extensor Carpi Radialis
Brevis
(deep branch of radial
nerve)
Humerus-lateral
epicondyle
Base of 3rd metacarpal
Extends wrist
Extensor Digitorum
(radial nerve)
humerus
Four tendons into
extensor expansions and
distal phalanges of
fingers 2-5
Prime mover of finger
extension
Extensor Carpi Ulnaris
(posterior interosseous
nerve)
Humerus-lateral
epicondyle and ulna
Base of fifth metacarpal
Extends wrist and
adducts wrist
POSTERIOR Deep Muscles
Muscles That Move the Forearm
Muscle
Origin
Insertion
Action
Supinator
(post. Interosseous
nerve)
Humerus, ulna
Radius proximal end
Supinate forearm
Abductor Pollucis
Longus
(post. Inter. Nerve)
Post. Radius and ulna
Base of 1st metacarpal
and trapezium
Abducts and extends
thumb
Extensor Pollucis Brevis
and longus
(post. Inter. Nerve)
Shaft of radius and ulna, Base proximal phalanx
interosseous membrane (brevis) and distal
phalanx (longus) of
thumb
Extends thumb
Extensor Indicis (post.
Inter. Nerve)
Distal ulna, interosseous Extensor expansion of
membrane
index finger
Extends index finger
Intrinsic Muscles of the Hand
Thenar Eminence
Muscle
Origin
Insertion
Action
Abductor Pollucis
Brevis
(median nerve)
Flexor retinaculum,
Carpal bones
Base of first proximal
phalanx
Abducts thumb
Flexor Pollucis Brevis
(median nerve)
Same as above
Same as above
Flex thumb
Opponens Pollucis
(median nerve)
Flexor retinaculum
and trapezium
Anterior side of first
metacarpal
Oppostion
Adductor pollucis
(ulnar nerve)
Capitate bone and
bases of metacarpals
2-4
Medial side of base of
first proximal phalanx
Adducts and opposes
the thumb
Intrinsic Muscles of Hand
Hypothenar Eminence
Muscle
Origin
Insertion
Action
Abductor Digiti
Minimi
(ulnar nerve)
pisiform
Medial side of
proximal phalanx of
5th finger
Abducts little finger
at MPJ.
Flexor digiti minimi
brevis
(ulnar nerve)
Hamate and flexor
retinaculum
Same as above
Flexes little finger
Opponens digiti
minimi
(ulnar nerve)
Same as above
Medial side of
metacarpal 5
opposition
Muscles of the Hand
Midpalmar Muscles
Muscle
Origin
Insertion
Action
Lumbricals
(median and ulnar
nerve)
Lateral side of each
tendon of the deep
flexor
Lateral edge of
extensor expansion
of fingers 2-5
Flex the MPJ
Extend IPJ’s
Palmar Interossei
(ulnar nerve)
Midaxial side of each Extensor expansion
metacarpal except of
met. #3
Dorsal interossei
(ulnar nerve)
Sides of metacarpals Extensor expansions Abduct fingers
Adduction of fingers
Cubit, Wrist, and Hand
The CUBITAL FOSSA is the concavity on the anterior
surface of the elbow.
 Boundaries: draw a line from the medial to lateral
epicondyles and extend from each epicondyle distally to
the pronator teres and brachioradialis.
 Inside this fossa we find the BICIPITAL
APONEUROSIS, a broad tendon expansion from the
biceps. This structure merges with the fascia over the
flexor muscles in the forearm.

The BRACHIAL ARTERY passes deep to the bicipital
aponeurosis and then divides into the ULNAR and RADIAL
ARTERIES.
 Blood pressure is measured at the brachial artery.
 The MEDIAN NERVE lies with the brachial artery. It runs
deep to the aponeurosis.
 Superficial to the aponeurosis we have a superficial vein,
the MEDIAL CUBITAL VEIN. It drains the skin of the hand,
forearm, and arm. If you cause the arm and forearm
muscles to contract, the veins should stand out more (they
do the same with a tourniquet). These superficial veins are
the sites of IV’s.

 The CEPALIC VEIN comes up the lateral side of
the arm, goes in-between the deltoid and
pectoral muscles where it joins the AXILLARY
VEIN. The AXILLARY VEIN then becomes the
SUBCLAVIAN VEIN.
 The BASILIC VEIN is on the medial side of the
forearm and is connected to the CEPHALIC vein
by the MEDIAN CUBITAL VEIN.
In the wrist, the PALMARIS LONGUS MUSCLE has short
muscle fibers and a long tendon. Approx. 10% of the
people don’t have this muscle.
 Its tendon runs superficial to the flexor retinaculum. You
can palpate this tendon by making a fist and flexing it. It is
the cord-like structure in the middle aspect of the wrist.
 Since this is weak flexor, and there are many other flexors
in the wrist, this tendon can be spared and used for tendon
transplants.

 Medial to palmaris longus is the FLEXOR CARPI
ULNARIS. It goes to the wrist. On the lateral
side of the palmaris longus is the FLEXOR
CARPI RADIALIS. (remember, we are talking
about anatomical position).
 The most lateral muscle is the
BRACHIORADIALIS MUSCLE.
 The median nerve lies with the radial artery in
the forearm, but they separate at the level of the
wrist. The radial nerve lies lateral to the other
tendons with the brachioradialis muscle.
 Medially, the ulnar nerve and ulnar artery lie
together. To cut the arteries on the ventral side,
you need to go through the tendons first.
 The “anatomical snuff box” is formed by the tendons
of the extensor pollicis brevis and longus and the
abductor pollicis longus.
 On the ventral side of the wrist, we find the
FLEXOR RETINACULUM, which acts in holding the
tendons close to the wrist. This insures the greatest
mechanical advantage. There is a similar band of
tissue at each knuckle joint as well.
Tendons run deep to these retinacula. There is one
exception in the human: Palmaris Longus.
 The tendons slide under the retinacula. Friction at
these sites is reduced due to BURSAE. In the wrist, the
bursae encircles the tendons forming a synovial sheath.
This bursa is invaginated twice to surround two rows of
tendons: Flexor Digitorum Superficialis and the Flexor
Digitorum Profundus.

The thumb has its own synovial sheath for its flexor
tendon- FLEXOR POLLICIS LONGUS.
 A growth from a tendon sheath is called a GANGLION.
A ganglion is like a cyst that is filled with a very thick
fluid. These ganglia can reduce mobility of the tendon
within the sheath.
 The FLEXOR RETINACULUM (Carpal Ligament)
attaches to the HAMATE (medially) and the
TRAPEZIUM (laterally).

 On the extensor side (posterior side), the
EXTENSOR RETINACULUM attaches medially to
the HAMATE. The flexor and extensor retinacula do
not connect to each other.
 Between the carpal bones and the flexor
retinaculum is the CARPAL TUNNEL.
 If one gets an infection in this tunnel, it can affect the
median nerve – which in turn affects 3 intrinsic
muscles. A person can lose the ability to oppose the
thumb, it may become weak and a tingling sensation
(parathesias) may occur. This group of symptoms is
called a SYNDROME.
 But pressure within the tunnel may cause the
same set of symptoms.
 Therefore, carpal tunnel syndrome must be
differentiated from an infection.
 Treatment for carpal tunnel syndrome is surgical
release of the retinaculum to relieve pressure.
The Lower Extremity
Very similar to the upper extremity
 Some definitions:
a. Thigh – part from the hips to knees
b. Leg – part from the knee to the ankle
 Note that the hip joint is a ball and socket joint. It allows
movement in all direction. The knee only allows flexion
and extension – not circumduction. It is never normal
for hyperextension of knee (genu recurvatum)

 The nerves of the lower extremity are simpler
than the upper limb. There are three nerves
entering the thigh. Their lateral branches serve
the gluteal muscles.
femoral nerve
obturator nerve
sciatic nerve
L2,3,4
anterior compartment
L2,3,4
medial compartment
L4,5,S1,2,3 (sacral plexus) posterior compartment
 The only one of the three that travel below the
knee is the sciatic nerve.
 The sciatic nerve branches into two nerve:
1. tibial nerve
2. common peroneal nerve
a. Superficial peroneal nerve
b. Deep peroneal nerve
Anterior compartmentExtensors of the knee
Femoral Nerve
lateral
medial
femur
Medial compartmentAdductors of the knee
Obturator Nerve
Posterior
compartmentFlexors of the
knee
Sciatic Nerve
 The anterior compartment of the thigh is
homologous to the posterior compartment of the
arm.
 The posterior compartment of the thigh is
homologous to the anterior compartment of the
arm.
The leg has three compartments
Anterior compartment
- dorsiflexors (flexors) of the foot
- deep peroneal nerve
2. Posterior compartment
- plantarflexors (extensors) of the foot
- tibial nerve
3. Lateral compartment
- extensors of the foot
- superficial peroneal nerve

1.
Muscle
Origin
Insertion
Action
Psoas major
FEMORAL NERVE
Transverse processes
and bodies of T12-L5
femur
Prime flexor of thigh and
trunk.
Iliacus
FEMORAL NERVE
Iliac fossa
femur
Same as psoas major
Gluteus Maximus
GLUTEAL NERVES for
all gluteal muscels
Outside of ilium, sacrum,
and coccyx
Iliotibial tract and femur
Extends the thigh
Gluteus Medius
- Part exposed and part
covered by maximus.
Shots given here.
Outside of ilium
Lateral surface of femur
Abducts thigh. Pelvic tilt
to allow opposite limb to
clear ground during gait.
Muscle
Gluteus
Minimus
Tensor
Fascia Latae
Origin
Insertion
Outer
surface of
ilium
Iliac crest
Lateral side
of femur
Action
Abductor of
thigh
Iliotibial tract Extends
(lateral side knee,
abducts, and
of femur)
medially
rotates
 The FASCIA LATA (not to be confused with the
muscle of similar name) is connective tissue on
the lateral side of the femur. This forms the
ILIOTIBIAL BAND. This band connects the ilium
and tibia and is the site of inflammation in
runners – iliotibial band syndrome.
Muscles of the Medial Compartment of the Thigh
Obturator Nerve
Muscle
Adductor
Femoris
(magnus and
brevis)
Adductor
Longus
Gracilis
Origin
Insertion
Action
Os coxae
Posterior
medial femur
Adduct thigh at
hip
Body of pubis –
medial side
Medial surface
of pubis and
ischium
Posterior medial
femur
Medial surface
of tibia
Adduct thigh
and hip
Adduct thigh,
flex leg
Muscles of the Posterior Compartment of the Thigh
Tibial portion of Sciatic Nerve
Muscle
Origin
Insertion
Action
Biceps Femoris
ischium
fibula
Flex leg and
extend thigh
semitendinosis
ischium
tibia
Flex leg and
extend thigh
semimembranosis
ischium
tibia
Flex leg and
extend thigh
Muscles of Anterior Thigh
*Femoral Nerve
Muscle
Origin
Insertion
Action
Pectineus
pubis
Linea aspera of femur
Adduct, flex, and
laterally rotate thigh
sartorius
ASIS
Medial side of tibia
shaft
Flex, abduct, and
laterally rotate hip.
Flex leg
Vastus lateralis
Femoral shaft
Patella/tibial
tuberosity
Extend leg
Vastus medialis
Femoral shaft
Patella/tibial
tuberosity
Extend leg
Vastus intermedius
Femoral shaft
Patella/tibial
tuberosity
Extend leg
Rectus femoris
AIIS
Patella/tibial
tuberosity
Extend leg and flex
thigh




The rectus femoris cross two joints, therefore it has actions on
the two joints involved.
The patella is articulates with the FEMUR, not the tibia.
The patella is attached to the femur and tibia by the PATELLAR
LIGAMENT. When this ligament is pulled, the patella is lifted
superiorly and brings the leg into an extended position.
In the posterior leg, the GASTROCNEMIUS muscle is
responsible for plantarflexion. It originates at the femur and
inserts on the posterior surface of the calcaneus. It crosses two
joints so it can flex the knee and plantarflex (extend) the foot. It
is innervated by the tibial nerve.
Motor Branches of the
L2
Femoral Nerve
L3
L4
Rectus
femoris
iliopsoas
pectineus
sartorius
Vastus
lateralis
Vastus
Vastus
intermedius medialis
Motor Branches of the
Obturator Nerve
Adductor
brevis
Adductor
longus
gracilis
Adductus magnus
Motor Branches of the
L4
L5
S1
Sciatic Nerve
S2
Hamstrings
S3
Semitendinosis
Biceps femoris
semimembranosus
Tibial
nerve
Gastrocnemius
and posterior
compartment of
the leg and foot
Common
peroneal
nerve
Superficial peroneal
nerve
Lateral
compartment of leg
Deep peroneal
nerve
Anterior
compartment of
leg
Anterior Leg Structures - Superficial
Identify the Following:
Tibialis Anterior
Peroneus Longs
Peroneus Brevis
Extensor Digitorum Longus
Patellar Tendon
Patella
Tibia
Peroneus Tertius
Extensor Hallucis Longus
Popliteus Tendon
Sartorius Tendon
Posterior Leg Structures Superficial
Identify the Following:
Femur
Tibia
Fibula
Soleus
Achilles Tendon
Plantaris
Popliteus
Calcaneus
Posterior Leg Structures Deep
Identify the Following:
Achilles Tendon
Flexor Hallucis Longus
Flexor Digitorum Longus
Calcaneus
Talus
Tibia
Fibula
Femur
Intrinsic Muscles of the Foot
These muscles all originate and insert on foot bones.
 They help to flex, extend, abduct, or adduct the toes.
 All the intrinsic muscles of the foot are found on the
plantar surface (except the one on the dorsal aspect).
 The plantar muscles are arranged in 4 layers, from
superficial to deep.

Intrinsic Muscles of the Foot
Muscle
Origin
Insertion
Action
Layer
Extensor Digitorum
Brevis
(deep fibular nerve)
Anterior part of
calcaneus
Base of proximal
phalanx 1, extensor
expansions of toes
2-4
Extend the MPJ
Only one on dorsum
of foot
Flexor Digitorum
Brevis
(medial plantar
nerve)
Calcaneal tuber
Middle phalanx of
toes 2-4
Flex toes
1
Abductor Hallucis
(medial plantar
nerve)
Tuber calcanei and
flexor retinaculum
Proximal phalanx of
hallux
Abducts hallux
1
Abductor digiti
minimi
(lateral plantar
nerve)
Tuber calcanei
Lateral side base of
little toe proximal
phalanx
Abducts little toe
1
Muscle
Origin
Insertion
Action
Layer
Quadratus Plantae
(lateral plantar nerve)
calcaneus
Tendon on FDL
Straightens the pull of
FDL
2
Lumbricales
(medial and lateral
plantar nerve)
Tendons of FDL
Extensor expansion of
proximal phalanx of
toes 2-5 on medial side
Flex at MPJ and extend
at IPJ
2
Flexor Hallucis Brevis
(medial plantar nerve)
Lateral cuneiform and
cuboid bones
Base of proximal
phalanx of hallux. Each
tendon of this muscle
has an associated
sesamoid bone
Flex hallux at MPJ
3
Adductor Hallucis
(lateral plantar nerve)
Bases of metatarsals 24,
Base of proximal
phalanx of great toe
Weak adductor of great
toe
3
Flexor Digiti Minimi
Brevis
(lateral plantar nerve)
Base of 5th metatarsal
Base of 5th toe proximal
phalanx
Flexes little toe
3
Plantar and Dorsal
Interossei
(lateral plantar nerve)
Same as interossei of
hand
Same as interossei of
hand
Same as interossei of
hand
4
The Neck
 When dissecting the neck from the anterior
surface, you will come across the HYOID BONE.
 The hyoid bone is the only bone in the body that
does not articulate with other bones.
 The base of the tongue is attached to the hyoid
bone.
 The hyoid bone is attached by muscles to the
skull, providing for flexibility for speech.
 It also attaches to the styloid process of the
TEMPORAL BONE.
 The muscles in the neck are named for their
points of attachment.
 From the STERNUM to the THYROID
CARTILAGE lies the STERNOTHYROID
MUSCLE. This muscle lies lateral and deep to
the STERNOHYOID MUSCLE.
 From the STERNUM to the MASTOID
PROCESS lies the STERNOMASTOID
MUSCLE.
 From the CLAVICLE to the MASTOID
PROCESS lies the CLEIDOMASTOID MUSCLE.
 In humans, the STERNOMASTOID and the
CLEIDOMASTOID are one muscle called the
STERNOCLEIDOMASTOID MUSCLE.
 The DIGASTRIC MUSCLE opens the jaw and
attaches to the mastoid process and the inner
border of the mandible at the central portion
(midline fusion area).
stylohyoid
digastric
sternohyoid
omohyoid
thyrohyoid
sternocleidomastoid
trapezius
clavicle
Cadaver
Specimen of
Lateral Neck
1.
Digastric
2.
Mylohyoid
3.
Geniohyoid
4.
Sternohyoid
5.
Sternomastoid
6.
Clavotrapezius
7.
External Jugular Vein
Regions of the Neck
 Anterior Triangle
-bounded by sternohyoid muscle, the digastric
muscle, and the sternomastoid muscle.
 Posterior Triangle
- bounded by the cleidomastoid muscle, the
clavotrapezius muscle, and the clavicle.
Anterior Triangle


Thyroid Gland
-bilobate
-endocrine gland
Common Carotid Arteries and Branches
- cranial thyroid artery
- muscular branch (lateral to the CTA)
- cranial laryngeal artery
- lingual artery (sublingual artery)
- internal (brain) and external carotid arteries (passes deep to the
digastric muscle
INTERNAL JUGULAR VEIN runs with the common
carotid artery in the anterior triangle.
 The HYPOGLOSSAL NERVE (cranial nerve XII) runs
with the sublingual artery.
 The SPINAL ACCESSORY NERVE (cranial nerve XI)
innervates the cleidomastoid and trapezius muscles.
 The nerve that runs with the common carotid artery is
the VAGUS NERVE (cranial nerve X) which is joined by
the SYMPATHETIC TRUNK.

Posterior Triangle
 The EXTERNAL JUGULAR VEIN runs obliquely
across this triangle.
 The SPINAL ACCESSORY NERVE runs from
the cleidomastoid and clavotrapezius. This
nerve is the only structure found in both
triangles.
 The SUBCLAVIAN ARTERY and VEIN are found
deep to the clavicle.
 Deep to the clavicle you will find the BRACHIAL
PLEXUS. This complex of nerves are VENTRAL
RAMI from
C5-T1. It innervates the muscles and provides
sensation to the upper extremity.
Muscles of the
Posterior Neck
Identify the Following:
Splenius capitis
Rhomboid major
Rhomboid minor
Supraspinal ligament
Trapezius
Semispinalis capitis
Splenius cervicis
Sternocleidomastoid
The Abdominal Muscles

RECTUS ABDOMINIS MUSCLE
- 4 segments on each side
- obvious during sit-ups (lateral margin)
- segments separated by tendinous intersections
a. Level at umbilicus
b. Inferior to the xiphoid
c. Midway between a and b
 The rectus abdominis muscle lies within the
aponeurosis of the abdominal muscles.
 The linea alba is the union of all the
aponeuroses.
 There are three layers of abdominal
musculature:
a. External oblique
b. Internal oblique
c. Tranversus abdominis
 The fibers of the external and internal oblique
muscles are perpendicular to each other.
 External oblique muscle fibers run superolateral
from their tendinous insertion.
 The internal oblique muscle fibers run
inferolateral.
 Deep to these muscles lie the transverse
abdominis muscle. In the human, these fibers
are transverse.
 The rectus abdominis muscle run superior to
inferior. It attaches in some places to the
aponeurosis of the internal oblique.
 External Oblique
origin: lower 8 ribs
inserts: xiphoid process, linea alba, pubic
symphysis, pubic tubercle, and iliac crest
 Internal Oblique
origin: lumbar fascia, iliac crest, inguinal
ligament
inserts: lower 3 ribs and costal cartilage,
xiphoid, linea alba, pubic symphysis
 Transverse Abdominis
origin: 6 lower costal cartilages, lumbar fascia,
iliac crest.
inserts: xiphoid, linea alba, pubic symphysis
ALL OF THESE MUSCLES COMPRESS THE
ABDOMINAL CONTENTS, SUPPORT
VISCERA, and ROTATE THE TRUNK.
 On the dorsal wall of the abdomen, we find the
PSOAS MAJOR and PSOAS MINOR muscles.
 These originate on the transverse process of
T12-L5 and insert on the lesser trochanter of the
femur.
 They flex the thigh and the trunk
 The QUADRATUS LUMBORUM originates on
the iliac crest and transverse processes of L5.
 It inserts on rib 12 and L1-4.
 Its action is to depress the rib cage and act as a
lateral flexor.




The ILIACUS MUSCLE
originates on the iliac fossa
and inserts on the lesser
trochanter of the femur.
It forms a muscle sheet with
the psoas. This is
commonly called the
iliopsoas.
It flexes the thigh and the
trunk.
Filet Mignon is the psoas
major.
Muscles of the
Anterior
Abdominal Wall
The Inguinal Region
 The inguinal ligament is formed by the
aponeurosis of the abdominal muscles. This is
attached at the ASIS and pubic tubercle.
 Anything going from the abdominal cavity to the
testes must go through this ligament.
 The area of the ligament that allows these
structures to pass through is called the
INGUINAL CANAL.




The inguinal canal is composed of an internal and external
INGUINAL RING.
The internal inguinal ring is displaced laterally from the external
ring.
An empty space connects these rings and forms the INGUINAL
CANAL. Blood vessels, nerves, lymphatics, and the vas
deferens to the testes fill this canal.
Part of the viscera can pass through the canal and become a
HERNIA. If the herniated organ becomes stuck or “strangled”,
blood supply is compromised and death to the tissue can result.
Abdominal Quadrants



The abdominal cavity can be divided into 9 areas called
quadrants.
The quadrants are separated by imaginary lines.
The lines are:
a. Subcostal plane – drawn transversely at the level of L3
vertebra.
b. Transpyloric Line (TPL)
c. Intertubercular Line – drawn through the iliac tubercle.
The Nine
Abdominal Regions
d. 2 vertical lines from a point on the superior margin of the
diaphragm at the level of midclavicular to the inguinal ligament.
The boundaries of the abdomen:
superior: diaphragm
inferior: pelvic inlet (beginning of pelvic cavity
anterior: abdominal muscles
posterior: lumbar vertebrae, diaphragm, rib 12
lateral: some ribs, muscles, diaphragm, iliac fossa
The Transpyloric Line
At the level of rib 9 at the lateral margin of the rectus
abdominis muscle.
 It crosses the S1 vertebra.
 It lies superior to the subcostal line and passes through
the right and left hypochondral and epigastric spaces.
 The duodenal-jejunal junction, kidneys, liver,
gallbladder, stomach, pancreas, spleen, and both colic
flexures lie on or touch the TPL.
