Muscle
Lumbricals (hand)
Flex MCP, extend IP joints
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
Frequently asked questions
What does the lumbricals (hand) do?
The lumbricals (hand) flex the MCP joints and extend the IP joints of the fingers.
What nerve innervates the lumbricals (hand)?
Lateral two: median nerve (C8, T1). Medial two: deep branch of ulnar nerve (C8, T1).
Where does the lumbricals (hand) attach?
The lumbricals (hand) originates from the tendons of flexor digitorum profundus and inserts on the lateral bands of the extensor expansions of the medial four fingers.
What is the blood supply of the lumbricals (hand)?
The lumbricals (hand) is supplied by the superficial and deep palmar arches.