Polite Dissent

Iron Man #28 “Haunted”
Daniel and Charles Knauf, writers
Roberto de la Torre, penciler

I’ve picked on the Knaufs more than a few times during their run on Iron Man, but this time, they have it right — or at least mostly right

Tony Stark: Target pencil-laser to bisect calcaneus diagonally from tendo calcaneus to tibialis posterior tendon.

In order to remove the device around his ankle that’s stopping him from accessing his Extremis suit, Tony Stark has decided to cut off his heel.
The calcaneus is the large bone that makes up the heel.
The tendo calcaneus is an older term for the Calcaneal Tendon, better known as the Achilles Tendon.
The tibialis posterior tendon comes off the (wait for it) tibialis posterior muscle — one of the deep muscles of the lower leg. It wraps around the calcaneus on the inside of the ankle before inserting on the navicular bone (wih smaller insertions on some of the other foot bones).

Based on the art, it looks like Tony is cutting the calcaneus from the point where the Achilles Tendon first meets the calcaneus to the point where the posterior tibial tendon inserts on the navicular, which more or less matches what he is saying — though if I were cutting part of my anatomy with a laser I’d be very specific about where to cut so mistakes weren’t made.