Origin and Course
The tibial nerve (n. tibialis) divides into two terminal branches: the medial and lateral plantar nerves. The resulting medial and lateral neurovascular bundles pass through the tarsal tunnel (canalis calcaneus) and continue into the sole of the foot.
Throughout its course, the lateral plantar nerve travels adjacent to the lateral plantar artery (a. plantaris lateralis).
Branches
In the deep fascial layers of the sole, the lateral plantar nerve divides into the following branches:
- Superficial branch (r. superficialis n. plantaris lateralis).
- Deep branch (r. profundus n. plantaris lateralis) — running alongside the deep plantar arch (arcus plantaris profundus).
- Proper plantar digital nerves (nn. digitales plantares propriae) — providing cutaneous sensory innervation to the digits.
Muscle Innervation
The lateral plantar nerve provides motor innervation to the muscles of the 5th digit, adductor hallucis, quadratus plantae, lumbricals II through IV, plantar and dorsal interossei, and the lateral part of the flexor hallucis brevis.
Specific muscles innervated by the n. plantaris lateralis include:
- Muscles of the 5th digit, including the abductor digiti minimi (m. abductor digiti minimi).
- Adductor hallucis (m. adductor hallucis) — both its transverse and oblique heads.
- Quadratus plantae (m. quadratus plantae).
- Lumbricals (mm. lumbricales) — digits II–IV.
- Plantar interossei (mm. interossei plantares) — 3 muscles.
- Dorsal interossei (mm. interossei dorsales) — 4 muscles.
- The lateral part of the flexor hallucis brevis (m. flexor hallucis brevis).
Cutaneous Innervation
Sensory branches of the lateral plantar nerve supply the following areas of the foot skin:
- Lateral part of the sole.
- 5th digit.
- Lateral half of the 4th digit.
For comparison: the heel region is innervated by the tibial nerve (n. tibialis), the medial margin and center of the sole by the medial plantar nerve, and a narrow strip of the medial surface by the saphenous nerve (n. saphenus).