Review Note

What is the action and innervation of the lumbricals?

Flex the metacarpophalangeal (MCP) joints and extend the interphalangeal (IP) joints. Innervated by the median nerve (lateral two) and the deep branch of the ulnar nerve (medial two).

The lumbricals flex the metacarpophalangeal (MCP) joints and extend the interphalangeal (IP) joints. The lateral two lumbricals are innervated by the median nerve, while the medial two are innervated by the ulnar nerve. [Source: ECE-Wk05-Lab 1-GAL-StuGuide-Anatomy of the Upper Limb II.pdf].