In rheumatoid ahritis which pa of spinal column is most commonly involved ?
**Core Concept**
Rheumatoid arthritis (RA) is a chronic autoimmune disorder that primarily affects the joints, leading to inflammation, pain, and degeneration. The **cervical spine** is particularly vulnerable due to its high mobility and complex anatomy.
**Why the Correct Answer is Right**
The cervical spine is the most commonly involved part of the spinal column in RA, particularly the **atlantoaxial joint**. This is because the cervical spine has a high range of motion, making it more susceptible to inflammatory damage. The **synovial joints** in this region can become inflamed, leading to pain, stiffness, and potentially life-threatening complications.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because, although the lumbar spine can be involved in RA, it is not the most common site of spinal involvement.
**Option B:** Incorrect as the thoracic spine is less frequently affected than the cervical spine in RA.
**Option D:** Incorrect because, while the entire spine can be involved in severe cases, the cervical spine is the most commonly affected region.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **atlantoaxial subluxation** is a serious complication of cervical spine involvement in RA, which can lead to spinal cord compression and neurological deficits.
**Correct Answer:** C. Cervical spine.