Myology SHANDONG UNIVERSITY Liu Zhiyu Myology n Morphology

Myology SHANDONG UNIVERSITY Liu Zhiyu

Myology n Morphology of skeletal muscle Muscle belly q Tendon aponeurosis Classification q Long muscle q Short muscle q Broad muscle q Orbicular muscle q n

Myology n n Origin －the fixed attachment Insertion － the movable attachment Action q Agonist q Antagonist q Synergist q Fixators Nomenclature of mucles : q shape q size q Location q their points of attachment

Myology Accessory structures n Fascia q q n Superficial fascia Deep fascia Synovial bursa

Myology n Tendinous sheath q q Fibrous layer Synovial layer: n n Mesotendon vincula tendinum

Synovial cyst of wrist

Muscles of head

Facial muscles n Epicranius q q q n n Frontal belly Occipital belly Galea aponeurotica Orbicularis oculi Buccinator Orbicularis oris Nasalis

Facial muscles

n n Temporalis Masseter lateral pterygoid Medial pterygoid

n Temporalis q q q n Origin－temporal fossa Insertion－coronoid process of mandible Action－elevates and retracts mandible Masseter q q q 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 n Lateral pterygoid n Medial pterygoid

Muscles of the neck

Muscles of the neck Superficial group n n Platysma 颈阔肌 Sternocleidomastoid 胸锁乳突肌

Muscles of the neck Suprahyoid muscles n n Digastric Mylohyoid Stylohyoid Geniohyoid Elevate (raise) hyoid bone and depress mandible.

Muscles of the neck Infrahyoid muscle n Sternohyoid n Sternothyroid n Thyrohyoid n Omohyoid Depress hyoid or larynx after elevation

Muscles of the neck Deep group n Lateral q q q n Scalenus anterior Scalenus medius Scalenus posterior Medial q q longus capitis longus colli Flex the head, bends the neck forward

Major muscles of the neck ★ Sternocleidomastoid n n n 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 n n n Origin: transverse processes of C 3 -C 6. 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 n n 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 n Trapezius n Levator scapulae n Rhomboideus n Latissimus dorsi n Thoracolumbar fascia

The Muscles of Back Deep group n Splenius n Erector spinae

Major Muscles of Back Trapezius n n 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 n n Origin: q Spinous processes of lower six thoracic and all lumbar vertebrae q Median sacral crest q 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 Latissimus dorsi Inferior lumbar triangle Rhomboideus Thoracolumbar fascia

Muscles of thorax Muscles connecting the upper n n n limb to the thoracic wall Pectoralis major Pectoralis minor Serratus anterior

Muscles of thorax n Intrinsic muscles q q Intercostales externi Intercostales intimi Transverses thoracis

Major muscles of thorax Pectoralis Major n n 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 n n 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 n n Origin: superior border of rib below Insertion: inferior border of rib above Replaced posteriorly by internal intercostals membrane. Action: depress ribs forced expiration

Diaphragm n n Shape and position: dome-shaped between thorax and abdomen, consists of a peripheral muscular part and a central tendon Origin q Sternal part: arising from xiphoid process q Costal part: arising from lower six and costal cartilages q Lumbar part: arising by two crura from upper 2 -3 lumbar vertebrae Insertion: central tendon Weak areas: q Lumbocostal triangle q Sternocostal triangle

Diaphragm Openings in the diaphragm n n n Aortic hiatus lies anterior to the body of the 12 th thoracic vertebra between the crura and transmits the aorta, thoracic duct Esophageal hiatus lies at level of T 10. It transmits esophagus and vagus nerves Vena cava foramen lies at T 8 level in the central tendon. It transmits the inferior vena cava. T 8 T 10 T 12

Diaphragm Action: n n 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 n n Obliquus externus abdominis Obliquus internus abdominis Transversus abdominis Rectus abdominis

Obliquus externus absominis n General direction of fibers: downward, forward and medially (run down and inward)

Obliquus externus absominis Structures n n n 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 n n Deep to obliquus externus abdominis General direction of fibres: upwards, forwards and medially

Transversus abdominis n n Deep to obliquus internus General direction of fibers: run horizontally forward.

Transversus abdominis n Inguinal falx q q n 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 q q Dirived from the lower fibers of the obliquus internus abdominis and transversus abdominis Around the spermatic cord and testis

Rectus abdominis n Position: lie on to either of n Origin: pubic crest and n Insertion: xiphoid and 5 th-7 th n Tendinous intersections 3 n linea semiluaris midline symphysis costal cartilages -4

Similar functions for above four pairs of muscles n n 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 n Formed by fusion of aponeurosis of obliquus externus abdominis and anterior leaf of aponeurosis of obliquus internus abdominis

Sheath of rectus abdominis Posterior layer n n n Formed by fusion of posterion leaf of aponeurosis of obliquus internus abdominis and aponeurosis of transversus abdominis Absent in about 4 -5 cm 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 n Linea alba －tendinous raphe between right and left recti from xiphoid to pubic symphysis

Landmarks and surface anatomy n n n Linea alba Rectus abdominis Tendinous intersections Linea semilunaris Umbilicus: at the level of L 3 ~ L 4 Inguinal ligament

Muscles of abdomen Posterior group n n Quadratus lumborum Psoas major

Muscles of upper limb

Muscles of shoulder n Deltoid n Supraspinatus n Infraspinatus n Teres minor n Teres major n Subscapularis

Muscles of arm n Antererior group q q q n Biceps brachii Coracobrachialis Brachialis Posterior group q Triceps brachii

Muscles of forearm Antererior group (9) n Superficial layer (5) q Brachioradialis q Pronator teres q Flexor carpi radialis q Palmaris longus q Flexor carpi ulnaris

Antererior group (9) n Second layer (1) q n Third layer (2) q Flexor digitorum profundus Flexor pollicis longus q Pronator quadratus q n Flexor digitorum superficialis Fourth layer (1) Action: flex radiocarpal joint and fingers, pronate forearm

Muscles of forearm Posterior group (10) n Superficial layer (5) q Extensor carpi radialis longus q Extensor carpi radialis brevis q Extensor digitorum q Extensor digiti minimi q Extensor carpi ulnaris

Muscles of forearm Posterior group (10) n n Deep layer (5) q Supinator q Abductor pollicis longus q Extensor pollicis brevis q Extensor pollicis longus q Extensor indicis Action: extend radiocapral joint and fingers, and supinate forearm

Muscles of hand n Lateral group－thenar (4) q q Abductor pollicis brevis Flexor pollicis brevis Opponens pollicis Adductor pollicis n Action: flex, abduct, adduct and oppose thumb n Medial group－hypothenar 小鱼际（3） q q q n Abductor digiti minimi Flexor digiti minimi brevis Opponens digiti minimi Action: flex, abduct , and oppose little finger

Muscles of hand n Intermedial group q Lumbricales (4) flex fingers at MP joints; extend fingers at IP joints q Palmar interossei (3) adduct fingers towards middle finger at MP joints q Dorsal interossei (4) abduct fingers away from middle finger at MP joints

Major muscles of upper limb Deltoid n n n 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 n Teres major Origin: dorsal surface of inferior angle of scapula q Insertion: crest of lesser tubercle of humerus q Action: medially rotates and adducts arm

Major muscles of upper limb n Trilateral and quadrilateral foramina q q 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 n n 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 n n n 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 adduct shoulder joint

Major muscles of upper limb Pronator teres n n 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 n Origin: lateral epicondyle of humerus and upper part of lateral border of ulna n Insertion: upper third of anterior surface of radius n Action: supination of forearm

Muscles of lower limb

Muscles of lower limb The muscles of lower limb are divided into: n n Muscles of hip Muscles of thigh Muscles of leg Muscles of foot

Muscles of hip Anterior group n Iliopsoas q Iliacus q Psoas major n Psoas minor n Tensor fasciae latae

Muscles of hip Posterior group n Gluteus maximus n Gluteus medius n Gluteus minimus n Piriformis n Obturator internus n Obturator externus n Quadratus femoris

Muscles of thigh Anterior group n Sartorius n Quadricep q Rectus femoris q Vastus lateralis q Vastus intermedius q Vastus medialis n Blood supply: femoral artery n Nerve supply: femoral nerve

Muscles of thigh Medial group Pectineus n Adductor longus n Adductor brevis n Adductor magnus n Gracilis Action: adduct thigh at hip joint Blood supply: q Deep femoral a. q Obturator a. Nerves supply: obturator n. n

Muscles of thigh Posterior group n Biceps femoris n Semitendinosus n Semimembranosus Action q Flex the leg at knee joint q Extend the thigh at hip joint

Muscles of leg Anterior group n n 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 n Peroneus longus n Peroneus brevis n Action: plantar flex and evert the foot n Blood supply: branches from the peroneal artey n Nerve supply: superficial peroneal n.

Muscles of leg Posterior group n Superficial lager q triceps surae n Gastrocnemius n Soleus

Muscles of leg Posterior group n Deep layer q Popliteus q Flexor digitorum longus q Tibialis posterior Flexor hallucis longus Nerve supply: tibial n. q n

Muscles of foot n n Muscles on dorsum: extensor digitorum brevis Muscles in sole: medial, lateral and intermediate groups

Muscles of hip Iliopsoas n n Origin: q Psoas major: transverse processes and lateral surface of bodies of lumbar vertebrae q Iliacus: iliac fossa Insertion: lesser trochanter of femur Action: flexes thigh on trunk Nerve supply: lumbar plexus

Muscles of hip Gluteus maximus n n 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 n n 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 n Origin: q q n n n 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 n n Origin: lateral surface of tibia Insertion: medial cuneiform and base of 1 st metatarsal Action: dorsiflexes and inverts foot Nerve supply: deep peroneal n.

Muscles of leg Triceps surae n n Origin: q Gastrocnemius: medial and lateral condyles of femur q 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 n n 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.