TOC Dissector Quiz Index Help Upper Extremity Previous Page Next Page Overview
Laboratory 8. Palm of the Hand
Step 12. Lumbrical Muscles of the Hand

Previous Image Next Image

Click for Full Screen
Click image to view full screen

Orientation Icon

Retract the tendons of the flexor digitorum superficialis muscle distally, and identify the four small lumbrical muscles . Each lumbrical muscle arises from the radial side of a tendon of flexor digitorum profundus muscle. Distally, each lumbrical muscle inserts into the extensor expansion of the same finger. (The extensor expansions will be dissected in the next laboratory exercise).

The lumbrical muscles act to flex the metacarpophalangeal (m/p) joint and extend the proximal and distal interphalangeal (i/p) joints of the finger. The first and second lumbrical muscles are innervated by the median nerve, whereas the third and fourth lumbrical muscles are innervated by the ulnar nerve.

Links and References:
Grant's: 6.91, 6.93, and 6.100
Netter (1ed.): 433-437 (2ed.): 429-433
Rohen/Yokochi: 367 and 399