FASCIAL CANAL CONSISTENTLY IDENTIFIED FOR PASSAGE OF MEDIAL PLANTAR CUTANEOUS NERVE OF THE GREAT TOE

Abstract

To describe a discrete fascial canal containing the medial plantar cutaneous nerve of the great toe in operations of the great toe. Clinical Relevance: The medial plantar cutaneous nerve of the great toe is one of the terminal branches of the medial plantar nerve which itself is the anterior division of Posterior tibial nerve. This branch provides sensation to the dorsomedial aspect of the distal phalanx of the great toe.

Motor branches of the medial branch are given off proximal to the first metatarsophalangeal joint. A medial incision centred over the first metatarsophalangeal and creation of distally based capsular flap is employed in number of operations of the Hallux, e.g. Modified Silver’s McBride, Chevron Osteotomy, Replacement of the MTP Joint. The medial plantar cutaneous nerve is prone to injury if it is not identified and protected, leaving the patient with loss of sensation to the medial surface of the great toe. After dissection of the skin and superficial fascia over the medial side of the 1st MTP joint, a discrete layer of dense connective tissue is seen passing from the medial sesamoid to the medial plantar aspect of the first metatarsal. The closed blades of dissecting scissors can be inserted under this layer proximally to distally and the medial plantar cutaneous nerve can be seen to enter the canal at its proximal end. This fascial layer can then be opened and the underlying nerve thus identified and protected. Opening the tunnel proximally and identifying the nerve ensures nerve is not divided with plantar arm of distally based capsular flap. Identification and protection of this nerve prevents the complication of loss of sensation and the development of a painful neuroma, giving the patients a better outcome following surgery.