Fourth Lumbrical of Foot (Musculus lumbricalis pedis quartus)
Educational content only — not medical advice.
Anatomy
The most lateral, bipennate vermiform muscle, arising from the adjacent sides of the third and fourth tendons of flexor digitorum longus and running to the fifth toe. It is the smallest of the four and is sometimes absent.
Origin & insertion
From the adjacent sides of the third and fourth tendons of flexor digitorum longus, into the lateral aspect of the extensor hood and metatarsophalangeal capsule of the fifth toe.
Action
Flexes the metatarsophalangeal joint of the fifth toe and extends its interphalangeal joints.
Innervation
Lateral plantar nerve (S2–S3).
Clinical notes
Its tendon, like the other lumbricals, sits plantar to the deep transverse metatarsal ligament — a detail that decides whether a lesion at the web space affects the lumbrical or the interosseous first.
Related structures
Educational references
FAQ
What is the role of the Fourth Lumbrical of Foot?
The most lateral, bipennate vermiform muscle, arising from the adjacent sides of the third and fourth tendons of flexor digitorum longus and running to the fifth toe. It is the smallest of the four and is sometimes absent.
Why is the Fourth Lumbrical of Foot clinically important?
Its tendon, like the other lumbricals, sits plantar to the deep transverse metatarsal ligament — a detail that decides whether a lesion at the web space affects the lumbrical or the interosseous first.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details