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

2. 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

3. Flexor carpi radialis (FCR)

4. 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

5. Palmaris longus (frequently absent)

6. 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

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

8. 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

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

10. 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

11. Flexor digitorum profundus (FDP)

12. 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 Ulnar nerve to digits 4 + 5
Spinal segments: C8, T1

13. Flexor pollicis longus (FPL)

14. 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

15. Pronator quadratus

16. 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

17. Extensor carpi radialis longus (ECRL)

18. 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

19. Extensor carpi radialis brevis (ECRB)

20. 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

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

22. 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

23. Extensor digiti minimi (EDM)

24. 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

25. Extensor carpi ulnaris (ECU)

26. 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

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

28. 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

29. Abductor pollicis longus (APL)

30. 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

31. Extensor pollicis brevis (EPB)

32. 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

33. Extensor pollicis longus (EPL)

34. 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

35. Extensor indicis (EI)

36. 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