Median Atlanto-axial joint is which type of joint –
**Core Concept**
The Median Atlanto-axial joint is a specific type of synovial joint responsible for rotational movement between the first (atlas) and second (axis) cervical vertebrae. This joint plays a crucial role in allowing the head to rotate freely from side to side.
**Why the Correct Answer is Right**
The Median Atlanto-axial joint is a pivot joint, characterized by a single bone (the dens of the axis) rotating around a single axis, allowing for rotational movements. This joint is stabilized by the transverse ligament of the atlas, which prevents the dens from being displaced. The joint capsule is reinforced by the ligaments, including the alar ligaments and the apical ligament, which provide additional stability.
**Why Each Wrong Option is Incorrect**
**Option A:** Synovial hinge joint - This type of joint allows for flexion and extension movements, but not rotational movements.
**Option B:** Fibrous joint - This type of joint is characterized by a lack of joint space and no synovial fluid, and does not allow for significant movement.
**Option C:** Cartilaginous joint - This type of joint is characterized by hyaline cartilage connecting the bones, and does not allow for rotational movements.
**Clinical Pearl / High-Yield Fact**
The Median Atlanto-axial joint is particularly vulnerable to injury, especially in cases of severe neck trauma, and can lead to conditions such as atlanto-axial rotatory subluxation.
**Correct Answer:** C. Pivot joint