Version July 2025
| Muscle | Proximal attachment | Distal attachment | Innervation* | Main action |
| Superficial (first) layer | ||||
| Pronator teres | Middle of convexity of lateral surface of radius | Median nerve (C6, C7) | Pronates and flexes forearm (at elbow) | |
| Ulnar head | Coronoid process | |||
| Humeral head | Medial epicondyle of humerus (common flexor origin) | |||
| Flexor carpi radialis (FCR) | Base of second metacarpal | Flexes and abducts hand (at wrist) | ||
| Palmaris longus | Distal half of flexor retinaculum and apex of palmar aponeurosis | Median nerve (C7, C8) | Flexes hand (at wrist) and tenses palmar aponeurosis | |
| Flexor carpi ulnaris (FCU) | Flexes and adducts hand (at wrist) | |||
| Humeral head | Pisiform, hook of hamate, fifth metacarpal | Ulnar nerve (C7, C8) | ||
| Ulnar head | Olecranon and posterior border (via aponeurosis) | |||
| Intermediate (second) layer | ||||
| Flexor digitorum superficialis (FDS) | Medial epicondyle (common flexor origin and coronoid process) | Shafts (bodies) of middle phalanges of medial four fingers | Median nerve (C7, C8, T1) | Flexes middle phalanges at proximal interphalangeal joints of middle four fingers; acting more strongly, it also flexes proximal phalanges at metacarpophalangeal joints |
| Humeroulnar head | ||||
| Radial head | Superior half of anterior border | |||
| Deep (third) layer | ||||
| Flexor digitorum profundus (FDP) | Proximal three quarters of medial and anterior surfaces of ulna and interosseous membrane | Bases of distal phalanges of fourth and fifth fingers | Ulnar nerve (C8, T1) | Flexes distal phalanges four and five at distal interphalangeal joints |
| Medial part | ||||
| Lateral part | Anterior interosseous nerve, from median nerve (C8, T1) | Flexes distal phalanges two and three at distal interphalangeal joints | ||
| Flexor pollicis longus (FPL) | Anterior surface of radius and adjacent interosseous membrane | Base of distal phalanx of thumb | Flexes phalanges of first digit (thumb) | |
| Pronator quadratus | Distal quarter of anterior surface of ulna | Distal quarter of anterior surface of radius | Pronates forearm; deep fibers bind radius and ulna together | |
