The concavity on the medial side of kidney is known as

Options

A. Renal pelvis
B. Hilum
C. Calyces
D. Pyramid

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure of the Kidney**: The kidney is an organ located in the abdominal segment of the body and is divided into two main parts: the outer cortex and the inner medulla.

2. **Identifying the Medial Side of the Kidney**: The medial border of the kidney is characterized by its shape. It is concave in the center and convex towards the ends. This means that the middle part of the kidney curves inward while the ends bulge outward.

3. **Describing the Orientation of the Kidney**: The kidney is positioned such that its medial border is directed forward and slightly downward. This orientation is important for understanding its anatomical relationships with other organs.

4. **Recognizing the Central Feature**: In the central part of the kidney, there is a deep longitudinal fissure. This fissure is a significant anatomical feature that divides the kidney.

5. **Naming the Fissure**: The longitudinal fissure is bounded by prominent overhanging lips, both anterior and posterior. This fissure is specifically known as the hilum.

6. **Understanding the Function of the Hilum**: The hilum serves an important function as it transmits vessels, nerves, and the ureter into and out of the kidney. This makes it a crucial point for the kidney's connection to the rest of the body.

7. **Final Answer**: Therefore, the concavity on the medial side of the kidney is known as the hilum.

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