Upper limb

Flexor Pollicis Brevis, Superficial Head

Musculus flexor pollicis brevis, caput superficiale

Origin

Trapezium bone and the flexor retinaculum

Insertion

Base of the proximal phalanx of the thumb

Function

Flexion of the metacarpophalangeal joint of the thumb

Innervation

Median nerve (C8–T1)

Movement & chain

Works together with the deep head (usually innervated by the ulnar nerve) and with flexor pollicis longus during gripping movements of the thumb, and with opponens pollicis and abductor pollicis brevis during opposition.

Palpation

Palpable on the thenar eminence, medial to abductor pollicis brevis, during resisted thumb flexion.

Clinical

In an isolated median nerve lesion proximal to the wrist, the deep head (often innervated via the ulnar nerve) remains functional, so thumb flexion at the MCP joint may be partly preserved.

Segmental innervation

C8–T1.

In clinical practice

Focus on hand function and edema prevention; ensure IV cannulas and splints maintain functional hand position to prevent joint contractures.

Region in the model

Upper limb