Pronator Teres: Humeral and Ulnar heads (Median nerve passes between heads)

Flexor compartment of the forearm: Superficial layer Attachments: Proximal: Humeral head: medial epicondyle of humerus Ulnar head: coronoid process of ulna Distal: lateral mid-shaft of radius Action: pronate forearm (also; stabilize + flex elbow) PERIPHERAL NERVE + spinal cord level of origin: median nerve: C6,7,8, T1 Spinal segments: C6,7

Flexor carpi radialis (FCR)

Flexor compartment of the forearm: Superficial layer Attachments: Proximal: medial epicondyle of humerus Distal: base of 2nd metacarpal Action: flex + RD wrist jt. (also; stabilize + flex elbow)   PERIPHERAL NERVE + spinal cord level of origin: median nerve: C6,7,8, T1 Spinal segments: C6,7

Palmaris longus (frequently absent)

Flexor compartment of the forearm: Superficial layer Attachments: Proximal: medial epicondyle of humerus Distal: palmar aponeurosis Action: flex wrist (tense palmar fascia for grasp) (also; stabilize + flex elbow)   PERIPHERAL NERVE + spinal cord level of origin: median nerve: C6,7,8, T1 Spinal segments: C7,8

Flexor carpi ulnaris (FCU): Humeral and Ulnar heads (Ulnar nerve passes between the heads)

Flexor compartment of the forearm: Superficial layer Attachments: Proximal: Humeral head: medial epicondyle of humerus Ulnar head: olecranon process of ulna Distal: Humeral head: hook of hamate Ulnar head: base of 5th metacarpal Action: flex + UD wrist jt. (also; stabilize + flex elbow)   PERIPHERAL NERVE + spinal cord level of origin: ulnar nerve: C8, T1 Spinal segment: C8

Flexor digitorum superficialis (FDS): Humeral-Ulnar and Radial heads

Flexor compartment of the forearm: Intermediate layer Attachments: Proximal: Humeral-Ulnar head: medial epicondyle of humerus + coronoid process of ulna Radial head: proximal radius Distal: shaft of MIDDLE phalanx of digits 2-5 (note the split tendon) Action: flex PIP jt. of digits 2-5 (assist in MP flex + wrist flex) PERIPHERAL NERVE + spinal cord level of origin: median nerve: C6-T1 Spinal segments: C7, 8, T1

Flexor digitorum profundus (FDP)

Flexor compartment of the forearm: Deep layer Attachments: Proximal: ulna (anteromedial shaft + interosseous membrane) Distal: base of DISTAL phalanx of digits 2-5 Action: flex DIP of digits 2-5. Assist flex of PIP, MP, and wrist PERIPHERAL NERVE + spinal cord level of origin: median nerve to digits 2 + 3. Ulnar nerve to digits 4 + 5 Spinal segments: C8, T1

Flexor pollicis longus (FPL)

Flexor compartment of the forearm: Deep layer Attachments: Proximal: radius (anterior shaft + interosseous membrane) Distal: base of DISTAL phalanx of thumb Action: Flex IP of thumb. Assist flex of MP, CM   PERIPHERAL NERVE + spinal cord level of origin: median nerve: C6, 7, 8, T1 Spinal segments: C8, T1

Pronator quadratus

Flexor compartment of the forearm: Deep layer Attachments: Proximal: distal ulna (anterior) Distal: distal radius (anterior) Action: pronate forearm   PERIPHERAL NERVE + spinal cord level of origin: median nerve: C6, 7, 8, T1 Spinal segments: C8, T1

Extensor carpi radialis longus (ECRL)

Extensor compartment of the forearm: Superficial layer Attachments: Proximal: lateral supracondylar ridge of humerus Distal: base of 2nd metacarpal Action: extend + RD wrist (synergist with FCR to get pure RD)   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C6,7

Extensor carpi radialis brevis (ECRB)

Extensor compartment of the forearm: Superficial layer Attachments: Proximal: lateral epicondyle of humerus Distal: base of 3rd metacarpal Action: extend wrist (more central to axis to get pure extension)   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C6,7

Extensor digitorum (ED) (sometimes includes the term ‘communis’ – EDC)

Extensor compartment of the forearm: Superficial layer Attachments: Proximal: lateral epicondyle of humerus Distal: dorsal apparatus of digits 2-5 Action: extend MP jt. 2-5 (synergist to extend PIP + DIP + assist wrist extension)   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C6,7,8

Extensor digiti minimi (EDM)

Extensor compartment of the forearm: Superficial layer Attachments: Proximal: lateral epicondyle of humerus Distal: dorsal apparatus of digit 5 Action: extend MP jt. of 5 (synergist to extend PIP + DIP)   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C7,8

Extensor carpi ulnaris (ECU)

Extensor compartment of the forearm: Superficial layer Attachments: Proximal: lateral epicondyle of humerus + posterior ulna Distal: base of 5th metacarpal Action: extend + UD wrist (synergist with FCU to get pure UD)   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C7,8

Supinator: This muscle wraps around lateral elbow from post. to ant.

Extensor compartment of the forearm: Deep layer Attachments: Proximal: lateral epicondyle of humerus + supinator fossa of ulna Distal: proximal shaft of radius (in area of radial tuberosity) Action: supinate forearm (proximal RU jt.)   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C6

Abductor pollicis longus (APL)

Extensor compartment of the forearm: Deep layer Attachments: Proximal: radius + ulna, interosseous membrane Distal: base of 1st metacarpal Action: ABduct + extend CM jt of thumb   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C7,8

Extensor pollicis brevis (EPB)

Extensor compartment of the forearm: Deep layer Attachments: Proximal: radius, interosseous membrane Distal: base of PROXIMAL phalanx of thumb Action: extend MP jt. of thumb (assist extension of CM jt.)   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C7,8

Extensor pollicis longus (EPL)

Extensor compartment of the forearm: Deep layer Attachments: Proximal: ulna, interosseous membrane Distal: base of DISTAL phalanx of thumb Action: extend IP jt. of thumb (assist extension of MP + CM jts.)   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C7,8

Extensor indicis (EI)

Extensor compartment of the forearm: Deep layer Attachments: Proximal: ulna, interosseous membrane Distal: dorsal apparatus of index finger Action: extend MP jt. of index finger (synergist to extend PIP + DIP jts.)   PERIPHERAL NERVE + spinal cord level of origin: radial nerve: C5-T1 Spinal segments: C7,8