Myology

Myology

SHANDONG UNIVERSITY

Liu ZhiyuLiu 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 neckSuprahyoid 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


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


★ 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 BackTrapezius 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 ( Ⅺcranial 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

Posterior layerMiddle layer

Anterior layer

Trapezius

Deltoid

Ausculatory triangle

Latissimus dorsiThoracolumbar fascia

Levator scapular

Rhomboideus

Inferior lumbar triangle

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.


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


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

T12

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

Diaphragm

Action: Contraction: the dome moving

downward, increases the volume of thoracic cavity which results in inspiration, at the same time the intra-abdominal 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 5th-7th 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 forearmAntererior group (9) Second layer (1)

Flexor digitorum

superficialis Third layer (2)

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 forearmPosterior 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.


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.


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


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.


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.

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Myology