Name

# Flexor Pollicis Brevis

Pronunciation

(FLEK-sur POL-uh-sus BREV-is)

Origin/Proximal Attachment

Distal border of flexor retinaculum & trapezium

Insertion/Distal Attachment

Base of proximal phalanx of thumb

+/- to lateral sesamoid bone at MCP joint

Action/Relevance

Flexes thumb (at MCP joint)

Innervation

Superficial Head: Median nerve - recurrent branch (C8, T1)

Deep Head: Ulnar nerve - deep branch (C8, T1)

Notes

Muscle for flexion and adduction of the thumb. Origin: flexor retinaculum, trapezium and trapezoid. Insertion: base of the proximal phalanx of hand of the thumb.