MUSCLES-THENAR EMINENCE

SUMMARY

1. ABDUCTOR POLLICIS BREVIS - arises from the flexor retinaculum & scaphoid tubercle. Inserts into base of proximal phalanx of thumb & tendon of EPL.
 
2. FLEXOR POLICIS BREVIS - arises from the flexor retinaculum & trapezium. Inserts into radial sesamoid of thumb. 

3. OPPONENS POLLICIS - deepest of the thenar muscles. Arises from the flexor retinaculum & trapezium. Inserted into the radial border of the whole 1st MC. 

4. Thenar eminence is supplied by the recurrent branch of the median n. Remember that FPB is subject to more variation than any other muscle in the body! It may be supplied by the ulnar n. instead or have double supply.

Image: Case courtesy of OpenStax College, Radiopaedia.org. From the case rID: 44017 [Accessed 18 Apr. 2020].

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.