Joint involved in movement of head from left to right.
**Core Concept**
The movement of the head from left to right involves the coordinated action of multiple joints in the cervical spine. This movement is known as lateral flexion, which requires the combined effort of several cervical vertebrae and their associated muscles and ligaments.
**Why the Correct Answer is Right**
The correct answer is the atlanto-axial joint (C1-C2), which is a synovial joint that allows for rotational movement between the first (atlas) and second (axis) cervical vertebrae. This joint is responsible for the movement of the head from left to right, as well as from right to left. The atlanto-axial joint is unique in that it is the only joint in the human body that allows for rotational movement in all directions. This is due to the presence of the odontoid process (dens) of the axis, which serves as a pivot point for rotation.
**Why Each Wrong Option is Incorrect**
* **Option A:** The atlanto-occipital joint (C0-C1) is primarily involved in flexion and extension of the head, not lateral flexion.
* **Option B:** The C3-C4 and C4-C5 joints contribute to lateral flexion, but they are not the primary joints involved in the movement of the head from left to right.
* **Option D:** The C6-C7 joint is not typically involved in lateral flexion of the head.
**Clinical Pearl / High-Yield Fact**
The atlanto-axial joint is also the site of a condition known as atlanto-axial rotatory subluxation, where there is a partial dislocation of the joint due to a rotatory force. This condition can be caused by trauma or congenital anomalies and can lead to neurological deficits if left untreated.
**Correct Answer:** C.