Muscles / Forearms
Lumbricals (hand)
- Forearms
- Hand
- Intermediate layer
Anatomy
- Origin
- Tendons of flexor digitorum profundus
- Insertion
- Lateral sides of the extensor expansions of digits 2-5
- Nerve
- Lumbricals 1-2: median nerve; lumbricals 3-4: deep branch of the ulnar nerve (C8-T1)
Actions
- Flex the MCP joints and extend the IP joints of digits 2-5 ("intrinsic plus" position)
Notes
- Loss of lumbricals 3-4 with ulnar nerve palsy produces clawing of the ring and little fingers.
References (4)
- Standring S, ed. Elsevier. Gray's Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed.
- Dalley AF, Agur AMR. Wolters Kluwer. Moore's Clinically Oriented Anatomy. 9th ed.
- Neumann DA. Elsevier. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed.
- Betts JG, Young KA, Wise JA, et al. OpenStax (free, openly licensed textbook). Anatomy and Physiology 2e