Umbilical artery is a branch of
**Core Concept**
The umbilical artery is a vital structure involved in fetal development, playing a crucial role in the exchange of gases, nutrients, and waste products between the fetus and the mother. It is a branch of the internal iliac artery, supplying blood to the fetus's placenta through the umbilical cord.
**Why the Correct Answer is Right**
The internal iliac artery gives rise to several branches, including the umbilical artery, which arises from the anterior division of the internal iliac artery. This artery then descends through the pelvis, passing through the inguinal canal to reach the umbilicus, where it becomes the medial umbilical ligament after birth. The umbilical artery is responsible for carrying deoxygenated blood from the fetus to the placenta, where it is oxygenated and nutrient-rich blood is returned to the fetus.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the umbilical artery does not arise from the common iliac artery, which is a larger artery that supplies blood to the lower extremities and external genitalia.
**Option B:** This option is incorrect because the superior mesenteric artery is a branch of the aorta that supplies blood to the small intestine, and it is not directly related to the umbilical artery.
**Option C:** This option is incorrect because the external iliac artery is a branch of the common iliac artery that supplies blood to the lower extremities, and it is not involved in the formation of the umbilical artery.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the umbilical artery becomes the medial umbilical ligament after birth, and its remnant can be palpated in the midline of the abdomen, serving as a significant anatomical landmark.
**Correct Answer: D. Internal iliac artery**