Muscles of scapula 1 Deltoid Origin lateral third

ⅠMuscles of scapula 1. Deltoid三角肌 • Origin: lateral third of clavicle, acromion, and spine of scapula • Insertion: deltoid tuberosity of humerus • Action: abducts，flexes and medially rotates (anterior part), extends and laterally rotates (posterior part) arm

Supraspinatus 冈上肌 Infraspinatus 冈下肌 Teres minor小圆肌 Teres major大圆肌

Subscapularis 肩胛下肌

ⅡMuscles of arm 1. Anterior group Biceps brachii 肱二头肌 n. Origin: long head, supraglenoid tubercle; short head, coracoid process n. Insertion: radical tuberosity n. Action: flexor of elbow joint, supinator of forearm, weak flexor of shoulder joint

– Coracobrachialis 喙肱肌 – Brachialis 肱肌

2. Posterior group – triceps brachii 肱三头肌 • Action: extends elbow joint, long head can extend adduct shoulder joint

Muscles of forearm • Anterior group • Superficial layer – Brachioradialis 肱桡肌 – Pronator teres 旋前圆肌 – Flexor carpi radialis 桡侧腕屈肌 – Palmaris longus 掌长肌 – Flexor carpi ulnaris 尺侧腕屈肌

• Second layer – flexor digitorum superficials 指浅屈肌

• Third layer – Flexor digitorum profundus 指深屈肌 – Flexor pollicis longus 拇长屈肌 • Fourth layer – Pronator quadratus 旋前方肌 Action: flex radiocarpal joint and fingers, pronate forearm

Ⅳ Muscles of hand 1. Lateral group－thenar 鱼际 (4) – Abductor pollicis brevis拇短展肌 – Flexor pollicis brevis 拇短屈肌 – Opponens pollicis 拇对掌肌 – Adductor pollicis 拇收肌 • Action: abduct, flex, oppose and adduct thumb

2. Medial group－hypothenar (3) – Abductor digiti minimi 小指展肌 – Flexor digiti minimi brevis 小指短屈肌 – Opponens digiti minimi 小指对掌肌 • Action: abduct , flex, and oppose little finger

3. Intermedial group • Lumbricales 蚓状肌(4) －flex fingers at MP joints; extend fingers at IP joints • MP=metacarpophalangeal joint • IP=interphalangeal joint

• Palmar interossei 骨间掌侧肌(3)－ adduct fingers towards middle finger at MP joints • Dorsal interossei 骨间背侧肌(3)－abduct fingers away from middle finger at MP joints