Lumbricals

Diagram illustrating Lumbricals


Key Knowledge Summary

Origin

• Flexor digitorum profundus

Insertion

• Radial side of extensor expansion of corresponding finger

Innervation

• 1st & 2nd lumbricals (the most radial two) are innervated by the median nerve
• 3rd & 4th lumbricals (most ulnar two) are innervated by the deep branch of the ulnar nerve

Actions

• Flex metacarpophalangeal joints
• Extend interphalangeal joints

Video explaining the anatomy of the lumbricals