The Achilles tendon is an obvious vertical axis on the posterior ankle area, stretching from the insertion on the calcaneum to the musculotendonous junction, a variable distance above. By convention, the distal 2cm are the insertional zone, from 2-7cm from the insertion is the mid-portion, and above that the musculotendonous zone. Patients with pain in the insertion tend to be older and less physically active. Insertional pain may be accompanied by pain in an inflamed retrocalcaneal bursa, and the patient may complain of swelling on each side of the Achilles due to retrocalcaneal bursitis. General used swelling around the tendon is likely to be due to paratendonitis, while a localised swelling in the mid portion is usually tendonopathy. Older patients with insertional tendonopathy often complain of painful, generalised swelling of the insertion that rubs on their shoes - this is often bony ingrowth into the tendon (spurs). Younger patients tend to have more localised posterolateral prominences (Haglund's deformity) without tendonopathy.

Lateral to the Achilles tendon lie the peroneal tendons, running down the back of the fibula and distally. Patients may complain of pain (usually tendonopathy) or swelling (paratendonitis) in the peroneal area. They may describe true dislocation of the peroneal tendons (often brevis only); this is sometimes described as "something coming out of place" in the ankle. Some people complain of clicking in the peroneal area. This may be due to dislocation or to a split, usually in peroneus brevis.

The sural nerve courses from the midline of the Achilles laterally to run lateral and below the peroneal tendons. It may be injured by a direct blow, stretch or surgery.

On the medial side of the Achilles tendon, the long plantar flexors of the ankle and the neuromuscular bundle run on the back of the tibia. From medial they are: tibialis posterior, flexor digitorum longus (remember this is medial at this level), the neuromuscular bundle and then, in the midline of the ankle posteriorly and deep to the Achilles, flexor hallucis longus. Tibailis posterior tendonopathy is usually presented as medial pain, while FHL pain is often felt deeply in the ankle posteriorly.

In this deeper layer of the posterior ankle region, the posterior ankle joint line is an invisible horizontal axis. Posterior ankle pain is often felt deeply in the ankle, and may be worse in plantar flexion, such as when up in tiptoes or, in dancers, on pointe. Such posterior impingement pain may be due to synovitis, FHL tendonopathy or an enlarged posterior talar process or os trigonum.