Anatomy: Arms


Arm

MuscleAttachementsNerve SupplyActions
Biceps BrachiiO: 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 BrachiiO: Infraglenoid tubercle of scapula, posterior surface of humerus, Radial Nerve – Extends arm
-Extends forearm

Forearm Flexors

MuscleAttachementsNerve Supply Actions
Flexor Carpi RadialisO: Medial epicondyle of radius
I:Base of 2nd metacarpal
Median Nerve– Flexes hand
-Abducts hand
Flexor Carpi UlnarisO: 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 TeresO: Coronoid process of ulna, Medial epicondyle of humerus
I: Lateral surface of radius
Median Nerve– Pronate forearm
-Flexes forearm
Palmaris LongusO: Medial epicondyle of humerus
I: Distal half of flexor retinaculum
Median Nerve – Flexes hand
-Tenses palmar aponeurosis

Forearm Extensors

MuscleAttachementsNerve SupplyActions
BrachioradialisO: 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 LongusO: Lateral supra-epicondylar ridge of humerus
I: Dorsal aspect of base of 2nd metacarpal
Radial Nerve– Extend wrist
– Abduct wrist
Extensor Carpi Radialis BrevisO: Lateral epicondyle of humerus
I: Dorsal aspect of base of 3rd metacarpal
Deep Branch of Radial Nerve– Extend wrist
– Abduct wrist
Extensor DigitorumO: Lateral epicondyle of humerus
I:Extensor expansions of medial four digits
Posterior Interosseous Nerve– Extends medial four fingers
Extensor Digiti MinimiO: Lateral epicondyle of the humerus
I:Extensor expansion of 5th finger
Posterior Interosseous Nerve– Extends 5th finger
Extensor Carpi UlnarisO: Lateral epicondyle of the humerus
I: Dorsal aspect of base of 5th metacarpal
Posterior Interosseous Nerve– Extends wrist
– Adducts wrist
Adductor Pollicis LongusO: Posterior surface of proximal half of ulna and radius
I:Base of 1st metacarpal
Posterior Interosseous Nerve– Abducts thumb
– Extends thumb
Extensor Pollicis LongusO: 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 BrevisO: 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

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