Observations on the fibrous retinacula of the heel pad.

Background: The original purpose of the study was to clarify whether or not there is continuity of the Achilles tendon and the plantar fascia. Those findings have been previously published. In the course of that study, observations of the anatomy of the retinacular tethers of the heel pad were made. These observations included the discovery of the medial calcaneal retinaculum.

Methods: Ten adult cadaver feet were dissected. A longitudinal midline incision was made along the Achilles tendon and on the plantar surface of the foot. The heel pad was incised and the skin and heel pad were reflected side-to-side to reveal the calcaneal tuberosity. In this way the retinacular tethers of the heel pad could be seen.

Results: Two types of retinacular fibers were observed. Abundant small retinacula were seen coming off the plantar fascia and calcaneal tuberosity. Less abundant larger retinacula originated from the calcaneus only. Both types anchored the heel pad by branching into the fibrous stroma of the heel pad. In nine of 10 feet, a much larger retinacular structure was the principle tether of the heel pad to the medial process of the calcaneal tuberosity. We named this the medial calcaneal retinaculum.

Conclusions: The heel pad is anchored by retinacula that vary in number, location, and size. The most consistent and significant tether of the heel pad appears to be the medial calcaneal retinaculum.

Clinical Relevance: Dislocation of the fat pad of the heel is a relatively rare but potentially devastating injury. An understanding of the anatomical anchoring of the heel pad and its mechanical function can lead to a surgical procedure to restore stability to the heel pad.