Inferior Calcaneal Nerve (Baxter Nerve)

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Baxter nerve.jpg
Baxter nerve is the nerve labelled nerve to abductor digiti quinti.
Inferior Calcaneal Nerve (Baxter Nerve)
Nerve Type Mixed nerve
Origin First branch of lateral plantar nerve. L4-S4 ventral rami from the sciatic nerve.
Course Passes between Abductor Hallucis and Quadratus Plantae, and along the medial border of the long plantar ligament.
Sensory innervation Long plantar ligament, calcaneal periosteum, and anterior calcaneal tubercle. No cutaneous innervation.
Motor innervation Abductor Digiti Minimi (Foot), Quadratus Plantae, Flexor Digitorum Brevis
Conditions Baxter's Nerve Entrapment

The first branch of the lateral plantar nerve is also known as the inferior calcaneal nerve or Baxter's nerve.

Proximal and Related Structures

The L4-S4 ventral rami form the sciatic nerve. The sciatic nerve divides in the distal thigh into the tibial nerve and peroneal nerve. The tibial nerve passes through the deep posterior compartment of the leg.

The tibial nerve ramifies into the medial plantar nerve, lateral plantar nerve, and medial calcaneal nerves. The nerves exit the tarsal tunnel and continue to the plantar aspect of the foot.

The medial plantar nerve runs anterior to the lateral plantar nerve. It supplies sensory information to the medial two thirds of the plantar foot, and motor innervation to the flexor digitorum brevis, abductor hallucis, flexor hallucis brevis, and first lumbrical.

The lateral plantar nerve supplies sensation to the lateral plantar aspect of the foot, 5th toe, and lateral half of the 4th toe. It supplies motor innervation to the remaining foot muscles that aren't innervated by the medial plantar nerve.

Course

Baxter's nerve is first branch of the lateral plantar nerve. It arises from the lateral plantar nerve at various levels under the deep fascia of the Abductor Hallucis muscle. It runs vertically in between the Abductor Hallucis and Quadratus Plantae and then makes a sharp 90 degree turn horizontally. It passes laterally under the Calcaneus to supply the Abductor Digiti Minimi muscle.

Innervation

It is a mixed nerve.

Motor supply is to the Abductor Digiti Minimi, and occasionally to the Flexor Digitorum Brevis and lateral half of the Quadratus Plantae

Sensory supply is to the calcaneal periosteum, long plantar ligament, and adjacent vessels.

Variation

It can originate directly from the Posterior Tibial Nerve