**Core Concept**
The deep perineal pouch is a fascial space in the perineum that contains the urethral sphincter, the deep transverse perineal muscle, and the nerves and vessels that innervate and supply the pelvic floor. Understanding the contents of the deep perineal pouch is essential for identifying the correct answer.

**Why the Correct Answer is Right**
The deep perineal pouch contains the following structures: the external urethral sphincter, the deep transverse perineal muscle, the urethral crest, the prostatic utricle, and the bulbourethral glands. The correct answer is one of the options listed below, which is not a content of the deep perineal pouch.

**Why Each Wrong Option is Incorrect**
**Option A:** The external urethral sphincter is actually located in the superficial perineal pouch, not the deep perineal pouch. It plays a crucial role in voluntary control of urination.
**Option B:** The deep transverse perineal muscle is indeed a content of the deep perineal pouch and helps to stabilize the pelvic floor and support the pelvic organs.
**Option C:** The urethral crest is a ridge of tissue in the urethra and is not a content of the deep perineal pouch. However, this option is not the correct answer, as we are looking for the option that is NOT a content of the deep perineal pouch, and we have not identified the correct answer yet.
**Option D:** The bulbourethral glands are actually located in the deep perineal pouch and secrete pre-ejaculate fluid to lubricate the urethra during ejaculation.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the superficial and deep perineal pouches are two distinct fascial spaces in the perineum, each containing different structures. The superficial perineal pouch contains the external urethral sphincter, the ischiocavernosus muscle, and the bulbospongiosus muscle, among others.

**Correct Answer:** A.