Tarsal bone interposed between the proximal and distal rows is
**Core Concept**
The tarsal bones are a group of seven bones in the foot that form the tarsal tunnel. The tarsal bones are divided into two rows: the proximal row (scaphoid, lunate, and calcaneus) and the distal row (cuboid and navicular). The tarsal bones play a crucial role in weight-bearing, shock absorption, and maintaining the arch of the foot.
**Why the Correct Answer is Right**
The correct answer is the bone that is located between the proximal and distal rows of tarsal bones. The **cuboid** bone serves as a keystone, holding the two rows together and maintaining the stability of the foot. The cuboid bone articulates with the calcaneus (proximal row) and the fourth and fifth metatarsals (distal row), allowing for a wide range of motion.
**Why Each Wrong Option is Incorrect**
* **Option A:** The **scaphoid** bone is part of the proximal row and does not interpose between the two rows.
* **Option B:** The **lunate** bone is also part of the proximal row and does not fit the description.
* **Option C:** The **calcaneus** bone is a large, single bone in the proximal row and is not interposed between the two rows.
**Clinical Pearl / High-Yield Fact**
The cuboid bone is often involved in injuries such as cuboid syndrome, which can lead to pain and swelling in the lateral aspect of the foot.
**Correct Answer: C. Cuboid**