The muscles of upper limb are divided into:
shoulder
arm
forearm
hand
Muscles of shoulder
Deltoid
Supraspinatus
Infraspinatus
Teres minor
Teres major
Subscapularis
Deltoid
Origin:
lateral one-third of clavicle, acromion, and spine of scapula
Insertion: deltoid tuberosity of humerus
Action: abducts the arm; anterior part may flexes and medically rotates the arm and the posterior part extends and laterally rotates arm
Supraspinatus
Origin:
the supraspinous fossa of the scapula
Insertion: upper of the three facets on the greater tubercle of the humerus.
Action: stabilizes shoulder joint and abducts the arm
Infraspinatus
Origin:
the infraspinous fossa of the scapula
Insertion: middle facets on the greater tubercle of the humerus.
Action: stabilizes shoulder joint and laterally rotates the humerus.
Teres minor
Origin:
the upper two-thirds of lateral border of the scapular on the dorsal surface.
Insertion: the lowest facet on the greater tubercle of the humerus.
Action: laterally rotates and adducts the humerus.
Teres major
Origin:
the dorsal surface near the inferior angle of the scapular.
Insertion: the crest of lesser tubercle of humerus.
Action:acts with the latissimus dorsi in addicting, extending and medial rotating the humerus.
Subscapularis
Origin: subscapular fossa
Insertion: lesser tubercle of humerus
Action: medially rotates the humerus and stabilizes the shoulder joint.
Antererior group
Biceps brachii
Coracobrachialis
Brachialis
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
Coracobrachialis
Origin: coracoid process
Insertion: the middle part of the medial border of humerus.
Action: adducts and weakly flexes the arm at the shoulder joint.
Brachialis
Origin:
the distal half of the front of the humerus
Insertion:
coronoid process and tuberosity of the ulna.
Action: main flexor of elbow joint.
Posterior group
Triceps brachii
Origin:
long head, infraglenoid tubercle; lateral head, above groove for radical n., medial head, below groove for radical n.
Insertion: olecranon of ulna
Action: extends elbow joint), long head can extend and adduct shoulder joint
Muscles of forearm
Anterior group
Superficial layer
Brachioradialis
Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor carpi ulnaris
Pronator teres
Origin:
medical epicondyle of humerus and deep fascia of forearm
Insertion: middle of lateral surface of radius
Action:
pronation of forearm
Second layer
-flexor digitorum superficials
Third layer
Flexor digitorum profundus
Flexor pollicis longus
Fourth layer
- pronator quadratus
Action: flex radiocarpal joint and fingers, pronate forearm
Posterior group
Superficial layer
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
Deep layer
Supinator
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
Extensor indicis
Action: extend radiocapral joint and fingers, and supinate forearm
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 hand
Lateral group-thenar
Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis
Adductor pollicis
Action: flex, abduct, adduct and oppose thumb
Medial group-hypothenar
Abductor digiti minimi
Flexor digiti minimi brevis
Opponens digiti minimi
Action: flex, abduct , and oppose little finger
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