1. Ankle anatomy

2. Common ankle injuries: Lateral ankle sprain-- from inversion injury. Most likely to damage anterior talofibular ligament. Sometimes calcaneofibular as well, which results in significant ankle instability. Rarely is the posterior talofibular ligament injured in inversion injuries. Swelling, erythema, pain, mild to moderate functional impairment, no deformity. Pain to palpation anterior of lateral malleolus. 

3. Common ankle injuries: peroneal tendon tear. From inversion injury, can happen concomitantly with lateral ankle sprain. There may or may not be swelling. Can also be due to repetitive trauma. 

4.  Common ankle injuries: fibular fracture usually from high-velocity/high-impact injuries, like fall or car accident. Severe pain, swelling, inability to ambulate, deformity. 

5.  Common ankle injuries: Talar dome fracture. may occur concomitantly with lateral ankle sprain. Presents with severe or persistent pain beyond normal lateral ankle sprain. Worry about this because it may compromise the blood supply and lead to avascular necrosis of the talus. 

6. Common ankle injuries: Subtalar dislocation. Can be either lateral or medial, will present with deformity. Talus subluxes off calcaneus/navicular bone 

7. Common ankle injuries: Medial sprain actually not super common, since it usually results from forced everson and dorsiflexion, and the deltoid ligament on the medial side of the ankle is a very strong ligament. 

8. Common ankle injuries: Syndesmotic sprain, generally involves anterior inferior tibofibular ligament and interosseus membrane. High impact injury. Pain and disability out of proportion. Positive ankle squeeze test: squeeze tibia and fibula together, then release; pain on release indicates sprain of anterior inferior tibulofibular ligament. 

9. Ankle sprain grades:

-Grade I: stretched tendon, minor tear. Mild pain, swelling. Little to no functional compromise, no mechanical instability. No excessive stretching of joint. 

-Grade II: incomplete tear. Pain to palpation over involved structure(s). Mild to moderate pain, swelling, ecchymosis. Moderate functional compromise. Loss of motor function, mild to moderate mechanical instability. Some stretching of joint with stress, but with stopping point. 

-Grade III: complete tear. Severe pain, swelling, ecchymosis, functional compromise. Inability to bear weight, mechanical instability. Stretching of joint with no stopping point. 

10. When to x-ray? The Ottowa ankle rules: 

Weight bearing=able to walk 4 steps unsupported.