Part of spine, involved in Rheumatoid arthritis is:
**Core Concept**
Rheumatoid arthritis (RA) is a chronic autoimmune disorder that affects multiple joints, including those in the spine. The disease involves an inflammatory process that targets the synovial membrane, leading to cartilage and bone destruction. In the spine, RA can affect the cervical, thoracic, and lumbar regions.
**Why the Correct Answer is Right**
The correct answer is related to the cervical spine, which is often involved in RA due to its high mobility and the presence of synovial joints. The cervical spine's involvement in RA is due to the inflammatory process that targets the synovial membrane, leading to cartilage and bone destruction. This can result in symptoms such as neck pain, stiffness, and limited range of motion.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because RA can involve other parts of the spine, such as the thoracic and lumbar regions, but the cervical spine is a more common site of involvement.
**Option B:** This option is incorrect because RA is not typically associated with the sacrum or coccyx.
**Option C:** This option is incorrect because while RA can affect the facet joints in the spine, it is not the primary site of involvement.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that RA can affect any joint in the body, including those in the spine. The cervical spine is a common site of involvement, and early recognition and treatment are crucial to prevent long-term damage and disability.
**Correct Answer: C. The cervical spine.**