Muscles of Anterior Forearm

Anterior muscles of forearm (8)

3 categories: Superficial (4) = flexor carpi ulnaris, flexor carpi radialis, palmaris longus and pronator teres. All originate from the common felxor tendon from the medial epicondyle of humerus. FLEX digits/wrist + PRONATE forearm. MEDIAN NERVE and ULNAR NERVE Intermediate (1): ONLY flexor digitorum superficialis. Between superficial and deep layers. 5 Superficial and intermediate muscles cross elbow joint. 3 deep don't. Deep(3): Flexor digitorum profundus, flexor pollicis longus and pronator quadratus In general: anterior compartment of forearm = flexion at wrist and fingers and pronation.

Flexor digitorum profundus

DEEP Attachments: Originates from ulna and associated interosseous membrane. At wrist, splits into 4 tendons, that pass through the carpal tunnel and attach to distal phalanges of the 4 fingers Actions: ONLY muscles that FLEXES the DIPJs of fingers. Also flexes MCPJs at wrist. Innervation: Medial half acts on the little and 1/2 ring fingers - ULNAR NERVE Lateral half: 1/2 ring, middle, index and 3/4 thumb = anterior interosseous branch of MEDIAN NERVE

Flexor pollicis longus

Deep to FDP Attachments: from anterior surface of radius and surrounding interosseous membrane. Attaches to base of distal phalanx of thumb. Actions: FLEXES IPJs and MCPJs of thumb Innervation: MEDIAN NERVE (anterior interosseous branch, C8-T1)

Flexor digitorum superficialis

INTERMEDIATE Good anatomical landmark in forearm - median nerve and ulnar artery pass between it's 2 heads and then travel posteriorly. Attachments: 2 heads, medial epicondyle of humerus and radius. Splits into 4 tendons at wrist, travel through carpal tunnel and attaches to the middle phalanges of the 4 fingers. Action: FLEXES MCPJs + PIPJs at the 4 fingers and FLEXES wrist Innervation: MEDIAN NERVE (C7-T1)

Palmaris longus

Most SUPERFICIAL of the anterior superficial compartment. Absent in 15% of pop. Median nerve underneath it. Attachments: originates medial epicondyle and attaches to distal half of flexor retinaculum of wrist. Action: FLEXION at the wrist Innervation: MEDIAN NERVE (C7-8)

Pronator teres

SUPERFICIAL Attachments: 2 origins: -Humeral head: medial epicondyle -Ulnar head: coronoid process Attaches laterally to midshaft of the radius. Action: PRONATES +FLEXES forearm Innervation: MEDIAN NERVE (C6-7)

Flexor carpi radialis

SUPERFICIAL Attachments: originates from medial epicondyle and attaches to the base of metacarpals II and III. Actions: FLEXION and ABduction at wrist Innervation: MEDIAN NERVE (C6-7)

Flexor carpi ulnaris

SUPERFICIAL Attachments: 2 heads originates from medial epicondyle. Long origin from olecranon and attaches to the pisiform, hook of hamate and 5th MCP. Actions: Flexion and ADduction at wrist Innervation: ulnar nerve (C7-8)

Pronator Quadratus

Square shaped muscle, deep to tendons of FDP and FPL. Attachments: From anterior surface of ulna attaches to anterior surface of radius. Actions: Pronates forearm Innervation: MEDIAN NERVE (anterior interosseous branch, C8-T1)

Nerve supply of hand

Ulnar nerve (C8-T1) Median nerve (C5-8) Radial superficial nerve (C6-8)