Anatomy: Arms
Arm
Muscle | Attachements | Nerve Supply | Actions |
Biceps Brachii | O: Coracoid process of scapula, Supraglenoid tubercle of scapula I: Tuberosity of radius | Musculocutaneous Nerve | – Supinate forearm – Flexes forearm – Flexes shoulder |
Brachialis | O: Distal half of anterior surface of humerus I: Coronoid process and tuberosity of ulna | Musculocutaneous Nerve | – Flexes forearm |
Coracobrachialis | O: Coracoid process I: Middle third of medial surface of humerus | Musculocutaneous Nerve | – Flex arm – Adduct arm |
Triceps Brachii | O: Infraglenoid tubercle of scapula, posterior surface of humerus, | Radial Nerve | – Extends arm -Extends forearm |
Forearm Flexors
Muscle | Attachements | Nerve Supply | Actions |
Flexor Carpi Radialis | O: Medial epicondyle of radius I:Base of 2nd metacarpal | Median Nerve | – Flexes hand -Abducts hand |
Flexor Carpi Ulnaris | O: Olecranon I: Pisiform, Hook of hamate, 5th metacarpal | Ulnar Nerve | – Flexes hand -Adducts hand |
Flexor Digitorum Superficialis | O: Medial epicondyle of humerus, Coronoid process of ulna, Oblique line of radius I:Shafts of middle phalanges of medial four digits | Median Nerve | – Flexes proximal interphalangeal joints of middle four digits |
Pronator Teres | O: Coronoid process of ulna, Medial epicondyle of humerus I: Lateral surface of radius | Median Nerve | – Pronate forearm -Flexes forearm |
Palmaris Longus | O: Medial epicondyle of humerus I: Distal half of flexor retinaculum | Median Nerve | – Flexes hand -Tenses palmar aponeurosis |
Forearm Extensors
Muscle | Attachements | Nerve Supply | Actions |
Brachioradialis | O: Proximal 2/3s of lateral supra-epicondylar ridge of humerus I: Lateral surface of distal end of radius proximal to styloid process | Radial Nerve | – Weak forearm flexion – Maximal forearm flexion when midpronated |
Extensor Carpi Radialis Longus | O: Lateral supra-epicondylar ridge of humerus I: Dorsal aspect of base of 2nd metacarpal | Radial Nerve | – Extend wrist – Abduct wrist |
Extensor Carpi Radialis Brevis | O: Lateral epicondyle of humerus I: Dorsal aspect of base of 3rd metacarpal | Deep Branch of Radial Nerve | – Extend wrist – Abduct wrist |
Extensor Digitorum | O: Lateral epicondyle of humerus I:Extensor expansions of medial four digits | Posterior Interosseous Nerve | – Extends medial four fingers |
Extensor Digiti Minimi | O: Lateral epicondyle of the humerus I:Extensor expansion of 5th finger | Posterior Interosseous Nerve | – Extends 5th finger |
Extensor Carpi Ulnaris | O: Lateral epicondyle of the humerus I: Dorsal aspect of base of 5th metacarpal | Posterior Interosseous Nerve | – Extends wrist – Adducts wrist |
Adductor Pollicis Longus | O: Posterior surface of proximal half of ulna and radius I:Base of 1st metacarpal | Posterior Interosseous Nerve | – Abducts thumb – Extends thumb |
Extensor Pollicis Longus | O: Posterior surface of middle third of ulna and interosseous membrane I: Dorsal aspect of base of distal phalanx of thumb | Posterior Interosseous Nerve | – Extends distal phalanx of thumb |
Extensor Pollicis Brevis | O: Posterior surface of distal third of radius and interosseous membrane I: Dorsal aspect of base of proximal phalanx of thumb | Posterior Interosseous Nerve | – Extends proximal phalanx of thumb |