Myology
SHANDONG UNIVERSITY
Liu Zhiyu
Myology

Morphology of
skeletal muscle
Muscle belly
 Tendon
aponeurosis
Classification
 Long muscle
 Short muscle
 Broad muscle
 Orbicular muscle


Myology




Origin －the fixed attachment
Insertion － the movable attachment
Action
 Agonist
 Antagonist
 Synergist
 Fixators
Nomenclature of mucles :
 shape
 size
 Location
 their points of attachment
Myology
Accessory structures
 Fascia



Superficial fascia
Deep fascia
Synovial bursa
Myology

Tendinous sheath


Fibrous layer
Synovial layer:


Mesotendon
vincula tendinum
Synovial cyst of wrist
Muscles of head
Facial muscles

Epicranius







Frontal belly
Occipital belly
Galea aponeurotica
Orbicularis oculi
Buccinator
Orbicularis oris
Nasalis
Facial muscles
★Masticatory muscles




Temporalis
Masseter
lateral pterygoid
Medial pterygoid
★ Masticatory muscles

Temporalis




Origin－temporal fossa
Insertion－coronoid process of
mandible
Action－elevates and retracts
mandible
Masseter



Origin－inferior border and medial
surface of zygomatic arch
Insertion－lateral surface of ramus
of mandible and angle of mandible
Action－elevates mandible
★ Masticatory muscles

Lateral pterygoid

Medial pterygoid
Muscles of the neck
Muscles of the neck
Superficial group


Platysma 颈阔肌
Sternocleidomastoid 胸锁乳突肌
Muscles of the neck
Suprahyoid muscles




Digastric
Mylohyoid
Stylohyoid
Geniohyoid
Elevate (raise) hyoid bone and
depress mandible.
Muscles of the neck
Infrahyoid muscle

Sternohyoid

Sternothyroid

Thyrohyoid

Omohyoid
Depress hyoid or larynx after
elevation
Muscles of the neck
Deep group

Lateral




Scalenus anterior
Scalenus medius
Scalenus posterior
Medial


longus capitis
longus colli
Flex the head, bends the neck
forward
Major muscles of the neck
★ Sternocleidomastoid



Origin: manubrium and
sternal end of clavicle
Insertion: mastoid process of
temporal bone
Action: contraction of one
muscle draws head toward the
same side, and turn face to
opposite side; both muscles
act together to draw head
backward
Major muscles of the neck
Scalenus anterior



Origin: transverse
processes of C3-C6.
Insertion: tubercle for
scalenus anterior
Action: unilateral, bends
neck laterally; bilateral,
elevate first rib, an
accessory muscle of
inspiration; if rib is fixed,
flex neck anteriorly
Major muscles of the neck
★ Scalene fissure


Above the first rib, there
is a triangular space
between scalenus
anterior and medius.
The brachial plexus and
the subclavine a.
emerge from this space.
Muscles of trunk
The Muscles of Back
Superficial group

Trapezius

Levator scapulae

Rhomboideus

Latissimus dorsi

Thoracolumbar fascia
The Muscles of Back
Deep group

Splenius

Erector spinae
Major Muscles of Back
Trapezius




Origin: superior nuchal line, external
occipital protuberance, ligamentum
nuchae and spinous processes of
seventh cervical and all thoracic
vertebrae
Insertion: lateral third of clavicle,
acromion, and spine of scapular
Acton: upper fibers elevate scapula,
lower fibers depress scapula; if scapula
is fixed, one side acting along, draws
head toward the same side, and turn
face to opposite side; both sides
together, draw head directly backward
Nerve supply: accessory nerve (Ⅺ
cranial nerve)
Major Muscles of Back
Latissimus dorsi




Origin:
 Spinous processes of lower six thoracic
and all lumbar vertebrae
 Median sacral crest
 Posterior part of iliac crest
Insertion: floor of intertubercular groove of
humerus.
Action: trunk fixed, extends, adducts and
medially rotates arm ; arm fixed, elevates
trunk.
Nerve supply: thoracodorsal nerve
Thoracolumbar Fascia
Anterior layer
Middle layer
Posterior layer
Trapezius
Levator scapular
Deltoid
Ausculatory triangle
Rhomboideus
Latissimus dorsi
Inferior lumbar triangle
Thoracolumbar fascia
Muscles of thorax
Muscles connecting the upper
limb to the thoracic wall
 Pectoralis major
 Pectoralis minor
 Serratus anterior
Muscles of thorax

Intrinsic muscles




Intercostales externi
Intercostales interni
Intercostales intimi
Transverses thoracis
Major muscles of thorax
Pectoralis Major




Origin: medial half of clavicle,
sternum, upper six costal cartilages.
Insertion: lateral lip of the bicipital
groove of humerus
Action: adducts the arm and rotates
it medially; the clavicular fibers also
flex the arm; with the arm above the
head, raise the body as in climbing
Nerve supply: lateral pectoral n.
Major muscles of thorax
Intercostales externi




Origin: inferior border of rib
above
Insertion: superior border of
rib below
Replaced anteriorly by
external intercostals
membrane
Action: raise ribs adding in
forced inspiration
Major muscles of thorax
Intercostales interni




Origin: superior border of rib
below
Insertion: inferior border of rib
above
Replaced posteriorly by internal
intercostals membrane.
Action: depress ribs for forced
expiration
Diaphragm




Shape and position: dome-shaped
between thorax and abdomen, consists of
a peripheral muscular part and a central
tendon
Origin
 Sternal part: arising from xiphoid
process
 Costal part: arising from lower six and
costal cartilages
 Lumbar part: arising by two crura from
upper 2-3 lumbar vertebrae
Insertion: central tendon
Weak areas:
 Lumbocostal triangle
 Sternocostal triangle
Diaphragm
Openings in the
diaphragm



Aortic hiatus
lies
anterior to the body of the 12th
thoracic vertebra between the
crura and transmits the aorta,
thoracic duct
Esophageal hiatus
lies at level of T10. It transmits
esophagus and vagus nerves
Vena cava foramen
lies at T8 level in the central
tendon. It transmits the inferior
vena cava.
T8
T10
T12
Diaphragm
Action:


Contraction: the dome moving
downward, increases the volume of
thoracic cavity which results in
inspiration, at the same time the intraabdominal pressure is increased
assists in defecation, vomiting or child
birth.
Relaxation: the dome returns to the
former position, reduces the volume
to the thoracic cavity, resulting in
expiration.
Muscles of abdomen
Anterolateral group




Obliquus externus
abdominis
Obliquus internus
abdominis
Transversus abdominis
Rectus abdominis
Obliquus externus absominis

General direction of fibers:
downward, forward and
medially (run down and inward)
Obliquus externus absominis
Structures



Inguinal ligament
Lacunar ligament
Superficial inguinal
ring
－
triangular-shaped
defect in aponeurosis
of obliquus externus
abdominis above
pubic tubercle
Superficial inguinal ring
Obliquus internus abdominis


Deep to obliquus externus
abdominis
General direction of fibres:
upwards, forwards and
medially
Transversus abdominis


Deep to obliquus internus
General direction of fibers: run
horizontally forward.
Transversus abdominis

Inguinal falx



Obliquus internus abdominis
has a lower, free border that
arches over spermatic cord
Inserted with transversus
abdominis fiber into medial
part of pecten of pubis
Cremaster


Dirived from the lower fibers of
the obliquus internus
abdominis and transversus
abdominis
Around the spermatic cord and
testis
Rectus abdominis

Position: lie on to either of
midline

Origin: pubic crest and
symphysis

Insertion: xiphoid and 5th7th costal cartilages

Tendinous intersections
3-4

linea semiluaris
Similar functions for
above four pairs of muscles




Support and compress the abdominal viscera
Increase intra-abdominal pressure, aid in expulsive
efforts-vomiting, coughing, sneezing, defecation,
urination and childbirth.
Depress ribs, assist in (the act of force(4)expiration.
Flex, lateral flex, and rotate vertebral column
Sheath of rectus abdominis
Anterior layer

Formed by fusion of
aponeurosis of obliquus
externus abdominis and
anterior leaf of aponeurosis of
obliquus internus abdominis
Sheath of rectus abdominis
Posterior layer



Formed by fusion of posterion
leaf of aponeurosis of obliquus
internus abdominis and
aponeurosis of transversus
abdominis
Absent in about 4-5cm below
the umbilicus, where
aponeuroses of all three
muscles form anterior layer the
lower free border named
arcuate line
Below this line rectus
abdominis in contact with
transverse fascia
Muscles of abdomen

Linea alba
－tendinous raphe
between right and left
recti from xiphoid to
pubic symphysis
Landmarks and surface anatomy






Linea alba
Rectus abdominis
Tendinous intersections
Linea semilunaris
Umbilicus: at the level of L3 ~ L4
Inguinal ligament
Muscles of abdomen
Posterior group


Quadratus lumborum
Psoas major
Muscles of upper limb
Muscles of shoulder

Deltoid

Supraspinatus

Infraspinatus

Teres minor

Teres major

Subscapularis
Muscles of arm

Antererior group




Biceps brachii
Coracobrachialis
Brachialis
Posterior group

Triceps brachii
Muscles of forearm
Antererior group (9)

Superficial layer (5)

Brachioradialis

Pronator teres

Flexor carpi radialis

Palmaris longus

Flexor carpi ulnaris
Muscles of forearm
Antererior group (9)

Second layer (1)


Third layer (2)



Flexor digitorum
superficialis
Flexor digitorum
profundus
Flexor pollicis longus
Fourth layer (1)

Pronator quadratus
Action: flex radiocarpal joint
and fingers, pronate
forearm
Muscles of forearm
Posterior group (10)

Superficial layer (5)

Extensor carpi radialis longus

Extensor carpi radialis brevis

Extensor digitorum

Extensor digiti minimi

Extensor carpi ulnaris
Muscles of forearm
Posterior group (10)


Deep layer (5)

Supinator

Abductor pollicis longus

Extensor pollicis brevis

Extensor pollicis longus

Extensor indicis
Action: extend radiocapral joint and
fingers, and supinate forearm
Muscles of hand

Lateral group－thenar (4)




Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis
Adductor pollicis

Action: flex, abduct, adduct and oppose thumb

Medial group－hypothenar 小鱼际（3）




Abductor digiti minimi
Flexor digiti minimi brevis
Opponens digiti minimi
Action: flex, abduct , and oppose little finger
Muscles of hand

Intermedial group

Lumbricales (4)
flex fingers at MP joints; extend fingers at IP joints

Palmar interossei (3)
adduct fingers towards middle finger at MP joints

Dorsal interossei (4)
abduct fingers away from middle finger at MP joints
Major muscles of upper limb
Deltoid



Origin: lateral third of
clavicle, acromion, and spine
of scapula
Insertion: deltoid tuberosity
of humerus
Action: abducts the arm，
anterior fibers flex and
medially rotate arm;
posterior fibers extend and
laterally rotate arm
Major muscles of upper limb

Teres major Origin: dorsal
surface of inferior angle of
scapula
 Insertion: crest of lesser
tubercle of humerus
 Action: medially rotates
and adducts arm
Major muscles of upper limb

Trilateral and quadrilateral
foramina


Between the subscapularis and teres
major, there is a long triangular
space whose lateral side is surgical
neck of humerus.
The long head of triceps brachii
subdivides this space into a medial
trilateral foramen and a lateral
quadrilateral foramen.
Major muscles of upper limb
Biceps brachii




Origin: long head, supraglenoid
tubercle; short head, coracoid
process
Insertion: radical tuberosity
Action: supinator of forearm,
flexor of elbow joint, weak flexor
of should joint
Nerve supply:
Musculocutaneous n.
Major muscles of upper limb
Triceps brachii



Origin: long head,
infraglenoid tubercle; lateral
head, above groove for
radical n., medical head,
below groove for radical n.
Insertion: olecranon of ulna
Action: extends elbow joint,
long head can extend and
adduct shoulder joint
Major muscles of upper limb
Pronator teres




Origin: medical epicondyle of
humerus and deep fascia of
forearm
Insertion: middle of lateral
surface of radius
Action: pronation of forearm and
flexion of elbow
Nerve supply: median n.
Major muscles of upper limb
Supinator

Origin: lateral epicondyle of
humerus and upper part of
lateral border of ulna

Insertion: upper third of
anterior surface of radius

Action: supination of forearm
Muscles of lower limb
Muscles of lower limb
The muscles of lower limb are divided into:




Muscles of hip
Muscles of thigh
Muscles of leg
Muscles of foot
Muscles of hip
Anterior group

Iliopsoas

Iliacus

Psoas major

Psoas minor

Tensor fasciae
latae
Muscles of hip
Posterior group

Gluteus maximus

Gluteus medius

Gluteus minimus

Piriformis

Obturator internus

Obturator externus

Quadratus femoris
Muscles of thigh
Anterior group

Sartorius

Quadricep

Rectus femoris

Vastus lateralis

Vastus intermedius

Vastus medialis

Blood supply: femoral artery

Nerve supply: femoral nerve
Muscles of thigh
Medial group
Pectineus
 Adductor longus
 Adductor brevis
 Adductor magnus
 Gracilis
Action: adduct thigh at hip joint
Blood supply:
 Deep femoral a.
 Obturator a.
Nerves supply: obturator n.

Muscles of thigh
Posterior group

Biceps femoris

Semitendinosus

Semimembranosus
Action

Flex the leg at knee joint

Extend the thigh at hip joint
Muscles of leg
Anterior group




Tibialis anterior
Extensor hallucis longus
Extensor digitorum longus
Peroneus tertius
Blood supply: Anterior tibial a.
Nerve supply: Deep peroneal n.
Muscles of leg
Lateral group

Peroneus longus

Peroneus brevis

Action: plantar flex and evert the
foot

Blood supply: branches from the
peroneal artey

Nerve supply: superficial peroneal n.
Muscles of leg
Posterior group

Superficial lager

triceps surae

Gastrocnemius

Soleus
Muscles of leg
Posterior group

Deep layer

Popliteus

Flexor digitorum longus

Tibialis posterior
Flexor hallucis longus
Nerve supply: tibial n.


Muscles of foot


Muscles on dorsum: extensor
digitorum brevis
Muscles in sole: medial, lateral
and intermediate groups
Muscles of hip
Iliopsoas




Origin:
 Psoas major: transverse
processes and lateral
surface of bodies of
lumbar vertebrae
 Iliacus: iliac fossa
Insertion: lesser trochanter
of femur
Action: flexes thigh on trunk
Nerve supply: lumbar
plexus
Muscles of hip
Gluteus maximus




Origin: gluteal surface of ilium
and dorsal aspect of sacrum
Insertion: gluteal tuberosity of
femur and iliotibial tract
Action: extends and laterally
rotates thigh at hip joint; raises
trunk when the lower limb is
fixed
Nerve supply: inferior gluteal
n.
Muscles of thigh
Sartorius




Origin: anterior superior
iliac spine
Insertion: upper medial
surface of tibia
Action: flexes hip and knee
joints; rotates flexed knee
medially
Nerve supply: femoral n.
Muscles of thigh
Quadriceps femoris

Origin:







Rectus femoris: anterior inferior iliac spine
Vastus medialis: medial lip of linea aspera
Vastus lateralis: lateral lip of linea aspera
Vastus intermedius: anterior surface of
femur
Insertion: tibial tuberosity via patellar
ligament
Action: extends leg at knee joint; rectus
femoris also flexes thigh at hip joint
Nerve supply: femoral n.
Muscles of leg
Tibialis anterior




Origin: lateral surface of
tibia
Insertion: medial
cuneiform and base of 1st
metatarsal
Action: dorsiflexes and
inverts foot
Nerve supply: deep
peroneal n.
Muscles of leg
Triceps surae




Origin:
 Gastrocnemius: medial and
lateral condyles of femur
 Soleus: soleal line of tibia and
upper third of fibula
Insertion: calcaneum via tendo
calcaneus
Action: flexes knee joint and
plantar flexes foot at ankle joint;
steadies leg on foot during
standing
Nerve supply: tibial n.
Muscles of leg
Tibialis posterior




Origin: posterior surface of
tibia and fibula and
interosseous membrane
Insertion: tuberosity of
navicular, all cuniforms
Action: plantar flexes and
inverts foot
Nerve supply: tibial n.