**Question:** In an adult male, on per rectal examination, the following structures can be felt anteriorly except:

A. Anus
B. Rectal mucosa
C. Urethra
D. Prostate gland

**Core Concept:**
Per rectal examination is a key examination technique used in clinical practice to evaluate the rectum and its contents. In male patients, several structures are palpable during this examination, including the anus, rectal mucosa, urethra, and prostate gland.

**Why the Correct Answer is Right:**
The correct answer, D - Prostate gland, is not mentioned as a structure that can be felt anteriorly during a per rectal examination in adult males. The prostate gland is located posterior to the rectum and is usually not palpable during this examination unless there is significant enlargement or pathology.

**Why Each Wrong Option is Incorrect:**

A. Anus: While the anal verge can be felt anteriorly in female patients, in adult males, it is located posterior to the rectum and is therefore not a part of the structures that can be palpated anteriorly.

B. Rectal mucosa: The rectal mucosa is a layer of tissues lining the rectum, which can be palpated during per rectal examination. While it is not the primary focus of the question, it is essential for understanding the overall examination process.

C. Urethra: In adult males, the urethra is an integral part of the examination as it is palpable anteriorly. However, this option is incorrect because it is not specifically mentioned as an exception in the question.

**Clinical Pearl:**

Understanding the anatomy of the lower gastrointestinal tract, including the rectum, anus, urethra, and prostate gland, is crucial for accurate clinical examination. Per rectal examination is a valuable tool for assessing rectal and anorectal structures, and understanding the correct anatomy helps to avoid misinterpretation of findings.