Navicular Tuberosity: A Surface Landmark for the Masterknot of Henry.

Background: Medial aspect of foot is unexplored due to its complex anatomy. Masterknot of Henry is an important landmark in this region, which plays a key role during tendon transfer procedures especially in those involving the flexor hallucis longus and flexor digitorum longus. We aim to determine the exact anatomical location of masterknot of Henry with respect to the bony prominences of the medial aspect of the foot and compare these measurements to the length of the foot.

Methods: Twenty cadaveric below-knee specimens were dissected. Structures on the medial side of the foot were exposed. Distance of the masterknot of Henry from surrounding bony landmarks was measured. Depth of the masterknot from skin of the plantar aspect was also measured. Means of all parameters were calculated. Relation between measurements and the foot length was determined using correlation and regression analysis. P value of less than 0.05 was considered significant.

Results: Distance of masterknot of Henry from navicular tuberosity was found to be fairly constant of 19.965 mm. Foot length was found to be correlating with the distance between masterknot of Henry and medial malleolus, navicular tuberosity and its depth from the skin.

Conclusions: Navicular tuberosity can be considered an important surface landmark for the location of masterknot of Henry. Correlation of length of the feet with various measurements helps to find the masterknot considering the foot length to be an important variable. Good knowledge of surface anatomy leads to shorter operating time and less morbidity during procedures involving the flexor hallucis longus and flexor digitorum longus.