The first lumbrical is the only foot lumbrical innervated by the medial plantar nerve. It arises from the medial aspect of the first FDL tendon and inserts into the extensor hood of the second toe, producing the intrinsic-plus position. It is the most medially placed and most reliably present of the four lumbricals.
| Origin | Medial border of the first FDL tendon slip (unipennate) |
|---|---|
| Insertion | Medial base of the proximal phalanx of the second toe and extensor hood |
| Nerve Supply | Medial plantar nerve (S2, S3) |
| Blood Supply | First plantar metatarsal artery |
| Actions |
|
|---|
It flexes the MTP joint and extends the interphalangeal joints of the second toe, helping keep the toe flat against the ground during push-off.
The first lumbrical is preserved in lateral plantar nerve injuries but lost with medial plantar nerve damage. Its function is assessed by the ability to flex the second MTP joint while extending the PIP joint (intrinsic-plus test). Transfer of the first lumbrical is used in second toe crossover deformity correction. In claw toe surgery, lumbrical advancement restores the intrinsic-plus position at the second MTP joint.
Not directly palpable due to deep plantar position. Assessed functionally by second MTP flexion with PIP extension testing.
Medial deviation and dorsal subluxation of the second toe from loss of first lumbrical MTP flexion and extensor hood stability, requiring lumbrical transfer or plantar plate repair.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
