The angle between medial wall and lateral wall of orbital cavity is
**Core Concept**
The orbital cavity is a complex anatomical space that houses the eye and its associated structures. The angle between the medial and lateral walls of the orbital cavity is a critical anatomical landmark that is essential for understanding the spatial relationships of the orbital contents.
**Why the Correct Answer is Right**
The correct answer is the result of the anatomical orientation of the orbital cavity. The medial wall of the orbit is formed by the lamina papyracea of the ethmoid bone, the lacrimal bone, and the orbital plate of the palatine bone. The lateral wall is formed by the orbital surface of the maxilla and the zygomatic bone. The angle between these two walls is approximately 90 degrees, allowing for a wide range of motion of the eye in the orbit.
**Why Each Wrong Option is Incorrect**
* **Option A:** The angle between the medial and lateral walls of the orbital cavity is not 60 degrees, as the medial wall is not directly opposed to the lateral wall in this orientation.
* **Option B:** The angle between the medial and lateral walls of the orbital cavity is not 120 degrees, as this would result in an excessively wide orbital cavity.
* **Option C:** The angle between the medial and lateral walls of the orbital cavity is not 30 degrees, as this would result in an excessively narrow orbital cavity.
**Clinical Pearl / High-Yield Fact**
The angle between the medial and lateral walls of the orbital cavity is a critical anatomical landmark that is essential for understanding the spatial relationships of the orbital contents. A thorough knowledge of this angle is essential for surgical procedures such as orbital surgery and ophthalmic surgery.
**Correct Answer:** **D**. 90 degrees.