Bony landmark · Ankle

Calcaneal tuberosity

Tuber calcanei

The calcaneal tuberosity is the back and underside of the heel bone — the part that strikes the ground and the part you stand on. It is where two great systems meet from opposite ends. Behind, the Achilles tendon inserts on it, so every contraction of the gastrocnemius and soleus pulls here, with a bursa cushioning the tendon against the bone. Underneath, the plantar fascia takes origin from its inner process, along with the first layer of small foot muscles — the abductor hallucis, flexor digitorum brevis and abductor digiti minimi. The calf pulling from behind and the arch pulling from in front both anchor at this single point.