INTRINSIC MUSCLES OF THE HAND-LUMBRICALS

SUMMARY

FIRST & SECOND LUMBRICALS
1. O: lateral 2 FDP tendons.
 2. I: tendons pass through a fibrous lumbrical canal to insert into the lateral side of the extensor expansion of digits 2 & 3. 
3. NS: digital branches of the median n.
4. BS: superficial & deep palmar arches.
5. A: extend the interphalangeal joints, flex the MCPJ.

THIRD & FOURTH LUMBRICALS
6. O: medial 2 FDP tendons. 
7. I: tendons pass through a fibrous lumbrical canal to insert into the lateral side of the extensor expansion of digits 4 & 5.
8. NS: deep branch of the ulnar n. 
9. BS: superficial & deep palmar arches.
10. A: extend the interphalangeal joints, flex the MCPJ.


Image: Case courtesy of OpenStax College, Radiopaedia.org. From the case rID: 44017 [Accessed 18 Nov. 2018].

Reference(s)

R.M.H McMinn (1998). Last’s anatomy: regional and applied. Edinburgh: Churchill Livingstone.
Gray, H., Carter, H.V. and Davidson, G. (2017). Gray’s anatomy. London: Arcturus.