AnatomyDeck

Muscle

Lumbricals (hand)

Flex MCP, extend IP joints

Upper limbMuscular system

High-yield

Flex MCP + extend IP joints; lateral two median, medial two ulnar. Loss → clawing tendency.

Overview

Four small muscles arising from the FDP tendons that flex the MCP and extend the IP joints, producing the 'lumbrical position'. Split median/ulnar supply.

Reference facts

  • Origin

    Tendons of flexor digitorum profundus

  • Insertion

    Lateral bands of the extensor expansions of the medial four fingers

  • Action

    Flex the MCP joints and extend the IP joints of the fingers

  • Innervation

    Lateral two: median nerve (C8, T1). Medial two: deep branch of ulnar nerve (C8, T1)

  • Blood supply

    Superficial and deep palmar arches

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