[Location] Localized in supine position or the erect sitting position and with the foot putting flatly, on the medial aspect of the foot, in the depression distal and inferior to the base of the first metatarsal bone. ( Fig. 30 )
 
[Regional Anatomy] Skin→subcutaneous tissue→abductor hallucis→flexor hallucis brevis→flexor hallucis longus tendon. Superficial layer, there are the medial branches of the foot from saphenous nerve and the the tributaries of the dorsal venous arch of the foot; deep layer, the branches or the subordiantial ramus of the medial plantar artery and vein, and the branches of the medial plantar nerve.