**Question:** Source of aerial supply to testis:

A. Internal iliac artery
B. External iliac artery
C. Profunda femoris artery
D. Umbilical artery

**Core Concept:**
The testis is supplied with blood from two main sources: the internal iliac artery and the external iliac artery. The testis requires a constant supply of oxygen and nutrients, as well as a good drainage for waste products, which is provided by the testicular artery and vein.

**Why the Correct Answer is Right:**
The correct answer, B (external iliac artery), is the direct continuation of the common iliac artery. The external iliac artery then gives rise to the testicular artery, which supplies blood to the testis. The testicular artery is a branch of the external iliac artery and is responsible for delivering oxygen, nutrients, and other essential substances to the testis.

**Why Each Wrong Option is Incorrect:**
A. The internal iliac artery is incorrect because it branches off the common iliac artery and supplies blood to the pelvic organs and the internal genital organs. It does not directly supply the testis.
C. Profunda femoris artery is incorrect because it is a branch of the femoral artery and does not directly supply the testis.
D. Umbilical artery is incorrect as it is present in the umbilical cord and is not involved in the supply of blood to the testis.

**Clinical Pearl:**
The testis is a crucial organ in male reproduction and requires a constant supply of oxygen, nutrients, and removal of waste products. Understanding the arterial supply is essential for appreciating the pathophysiology of testicular ischemia, which can lead to infertility and testicular damage.