This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Spos Injury, Subject name: Orthopaedics
Sudden dorsiflexion of foot may lead to which of the following injuries: 
Select and explain. 
A. Anterior talofibular ligament injury, B. Tendo Achilles avulsion injury, C. Rupture of deltoid ligament, D. Tarsal tunnel syndrome
B: Tendo Achilles avulsion injury
Answer: B: Tendo Achilles avulsion injury 
Explanation: Most Tendoachilles(TA) tears occurs 2-6 cm above the calcaneal inseion (watershed zone) M/C mechanism of injury - sudden forced plantar flexion of foot, unexpected dorsiflexion of foot and violent dorsiflexion of plantar flexed foot. Test for TA rupture - Thompson test/ Simmonds test/O'Brien needle test. Simmond's Test: