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
During incision & drainage of ischiorectal abscess, which nerve is/are affected/injured: 
Select and explain. 
A. Superior rectal nerve, B. Inferior rectal nerve, C. Superior gluteal nerve, D. Inferior gluteal nerve
B: Inferior rectal nerve
Answer: B: Inferior rectal nerve 
Explanation: B i.e. Inferior rectal nerveThrough a posterior horse shoe shaped recess both ischiorectal fossae are connected behind the anal canal; so a unilateral abscess may become bilateral.During dissection of ischio rectal fossa, inferior rectal, pudendal, posterior scrotal or labial nerve & vessels along with perforating branches of S2-S3 and perineal branches of S4 nerve may get damaged.