Atlas

Ankle

The ankle joint is a synovial hinge joint, primarily formed by the tibiotalar articulation between the inferior articular surface of the tibia, the medial malleolus, the lateral malleolus of the fibula, and the trochlea of the talus. This joint is essential for locomotion, allowing mainly plantar flexion and dorsiflexion movements of the foot.
Stability is ensured by a complex ligamentous system that includes the medial and lateral collateral ligaments, the tibiofibular syndesmosis, and several accessory ligaments.
The joint is surrounded by tendon sheaths and synovial bursae that facilitate the movement of the tendons of the extrinsic foot muscles. In hemophilic arthropathy, the ankle is one of the most frequently affected joints, with manifestations that can significantly impair lower limb function.

Projections

In musculoskeletal ultrasound, images are acquired through different projections that allow visualization of the ankle structures from various angles.

Anterior

Anterior

The anterior projection allows visualization of the structures located at the front of the ankle, such as the anterior joint capsule, the articular surface of the distal tibia, and the trochlea of the talus. This view is particularly useful for assessing joint effusions, synovial thickening, marginal osteophytes, and cartilage alterations that characterize the acute and chronic phases of hemophilic arthropathy.
Lateral

Lateral

The lateral projection focuses on the outer part of the ankle, visualizing the fibular malleolus, the anterior and posterior talofibular ligaments, and the calcaneofibular ligament. This perspective is essential for diagnosing ligament instability, chronic sprains, and for assessing structural alterations of the lateral compartment, which is frequently involved in hemophilic arthropathy.
Medial

Medial

The medial projection provides a view of the inner part of the ankle, allowing observation of the tibial malleolus, the deltoid ligament, and the posterior tibial tendon. This projection is essential for evaluating medial tendinopathies, alterations of the deltoid ligament, and manifestations of hemophilic arthropathy, which often shows a preferential involvement of the medial compartment.
Posterior

Posterior

The posterior projection allows exploration of the structures located behind the joint, including the Achilles tendon, the retrocalcaneal bursa, and the posterior recess of the ankle. This view is crucial for identifying Achilles tendinopathies, retrocalcaneal bursitis, posterior impingements, and fluid collections within the posterior synovial recess — all conditions that may be associated with hemophilic arthropathy.