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: Anatomy
Infection of thenar space is drained by incision at? 
Select and explain. 
A. 1st Webspace, B. 2nd Webspace, C. Just above flexor retinaculum, D. 3rd Webspace
A: 1st Webspace
Answer: A: 1st Webspace 
Explanation: Thenar space communicates with fascial sheath of 1st Lumbrical. Mid palmar space communicates with fascial sheath of 2nd, 3rd & 4th Lumbrical. 2nd space cannot be incised in palmar space infection due to risk of damaging intermediate septum. Infections of  thenar space is drained by incising 1st webspace.