Name Flexor pollicis brevisPronunciation (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) |