Exam category: Procedures → Extremity
Why it matters: The ankle carries the most-tested naming trap in the lower limb — the "mortise" view — and it only makes sense once you know why a plain AP ankle fails. Around it sit the joint classifications the registry asks by name and a foot-and-toe routine where the oblique rotates one direction for the whole foot and the opposite direction for some individual digits.
Work distal to proximal: toes → foot → calcaneus → ankle. A true AP ankle doesn't open the joint, so the ankle gets a rotation ladder instead of one frontal projection, and the amount of rotation is the whole discriminator. First, though, the lesson names the lower limb's joints and the conditions attached to each region. The limb continues in Knee & femur.
The foot's 26 bones split into 14 phalanges, 5 metatarsals and 7 tarsals — and the registry's region-ID questions on the foot and ankle draw from the metatarsals and four of the tarsals by name.
Metatarsals are numbered 1 to 5 from the medial (great-toe) side to the lateral (little-toe) side, the same convention as the digits. The first metatarsal sits medially; the fifth metatarsal sits laterally, and its base carries a prominent tuberosity — a common fracture site.
Four tarsals show up by name on region-ID questions:
Memory cue: medial/lateral splits the tarsals the same way it splits the metatarsals — navicular is medial, cuboid is lateral, just like first metatarsal medial, fifth metatarsal lateral.
Answer this to keep going. 15 more sections unlock below.
A patient has point tenderness over the prominent tuberosity at a metatarsal base on the lateral side of the foot. Which metatarsal is it?
Section 1 of 16. Answer the check to keep going.