HLTH1008 Chap.7 Ankle and Foot Complex
Ankle and Foot Complex
The ankle and foot turn a single hinge into an adaptable platform. This chapter covers the talocrural mortise, its range and its medial and lateral ligaments, then reads ankle injuries from their mechanism: inversion with plantarflexion tears the anterior talofibular ligament, while eversion with dorsiflexion fractures the malleolus.
It explains coupled pronation and supination at the subtalar and transverse tarsal joints, the longitudinal and transverse arches and their supports, the tarsal tunnel and its contents, and the blood supply of the talus. A decision path for ankle injuries and a worked identification of the tarsal tunnel turn the anatomy into exam-ready answers.
Ligament strength, rather than force alone, decides whether a ligament tears or a bone breaks.
What this chapter covers
- 01
Talocrural joint, mortise and range
- 02
Deltoid and lateral ligaments
- 03
Inversion sprains and eversion fractures
- 04
Subtalar joint and coupled movements
- 05
Transverse tarsal joint and foot rigidity
- 06
Medial and lateral longitudinal arches
- 07
Tarsal tunnel and tibial nerve entrapment
- 08
Talar blood supply and plantar fascia
Worked example · free
Reading an ankle injury from its mechanism
- +1Inward rolling with the toes pointed is inversion with plantarflexion.
- +1That stretches the lateral ligament, whose weakest band, the anterior talofibular ligament, tears first.
- +1Outward and upward forcing is eversion with dorsiflexion, which stretches the medial side.
- +1The deltoid ligament is so strong that the medial malleolus tends to fracture instead.
Key terms
- Talocrural joint
- The ankle hinge between the tibia, fibula and talus.
- Deltoid ligament
- The strong four-part medial ligament of the ankle.
- Anterior talofibular ligament
- The weak lateral ankle band most often torn in inversion sprains.
- Spring ligament
- The plantar calcaneonavicular ligament that supports the talar head.
- Flexor retinaculum
- The roof of the tarsal tunnel behind the medial malleolus.
- Pes planus
- A low or flat medial longitudinal arch.
- Subtalar joint
- The composite joint between talus and calcaneus that produces pronation and supination.
- Plantar aponeurosis
- The fibrous sheet from the calcaneus to the toes that supports the arch.
- Pes cavus
- An abnormally high medial arch that causes callosities and pain.
Ankle and Foot Complex FAQ
What passes through the tarsal tunnel?
From front to back, the lecture lists tibialis posterior, flexor digitorum longus, the posterior tibial artery with its veins, the tibial nerve and flexor hallucis longus. The flexor retinaculum forms the roof and the medial surface of the calcaneus forms the floor of the tunnel.
Why is the talus at risk of avascular necrosis?
No muscle or tendon attaches to the talus, and its main blood supply enters behind its neck. The foot lecture splits the supply between the anterior tibial, posterior tibial and perforating fibular arteries, and a fracture that cuts the supply to the body leaves it without blood.
What does supination do to the foot?
At the subtalar joint supination couples plantarflexion, inversion and adduction. In weight-bearing the medial arch rises, and the transverse tarsal joint becomes close-packed; pronation reverses each component, flattens the arch and leaves the transverse tarsal joint loose-packed.
Why are inversion sprains more common than eversion injuries?
The lateral ligament is weaker than the deltoid ligament, and its anterior talofibular band is flat and weak, so inversion with plantarflexion tears it readily. The deltoid ligament is so strong that eversion tends to break the medial malleolus instead of tearing the ligament.
What causes tarsal tunnel syndrome?
Entrapment of the tibial nerve or its branches under the flexor retinaculum. The course lists calcaneal fracture, arthritis, severe pronation, varicosities, diabetes and masses as causes, and notes that heel sensation is usually preserved because the medial calcaneal branch leaves before the tunnel.
Exam move
Draw the ankle from the front and side and label the deltoid and the three lateral bands. Practise the injury pathway aloud for inversion and eversion. Learn the coupled movement table one axis at a time, then add the weight-bearing differences. Finish with the arches, writing the bones, summit, pillars and weakest point for each, and list the tarsal tunnel contents in order.
Add the talar blood supply and plantar fasciitis to your summary, and practise identifying the fifth metatarsal tuberosity and the navicular tuberosity with the tendons that insert on them.
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