This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Orthopaedics
Thomas test detects 
Select and explain. 
A. Shortening of lower limb, B. Flexion deformity of hip, C. Lengthening of lower limb, D. Intractness of tendoachillis tendon
B: Flexion deformity of hip
Answer: B: Flexion deformity of hip 
Explanation: None