False about Fibrous ankylosis
**Core Concept**
Fibrous ankylosis is a type of joint ankylosis characterized by the fusion of bones due to the formation of dense fibrous tissue, usually in response to chronic inflammation or joint damage. This process can lead to a permanent loss of joint mobility.
**Why the Correct Answer is Right**
During fibrous ankylosis, the joint space is gradually obliterated by the deposition of fibrous tissue, which eventually becomes calcified. This results in a bony fusion that is less stable and more prone to pain compared to bony ankylosis. The fibrous tissue can be easily palpated as a thickened, cord-like structure.
**Why Each Wrong Option is Incorrect**
**Option A:**
In bony ankylosis, the joint space is completely obliterated by the formation of bone, resulting in a stable but immobile joint.
**Option B:**
Fibrous ankylosis can occur in any joint, but it is more common in the spine, temporomandibular joint, and sacroiliac joint.
**Option C:**
Fibrous ankylosis is often associated with chronic inflammation, trauma, or infection, which can lead to the formation of a thickened, fibrous joint capsule.
**Clinical Pearl / High-Yield Fact**
Fibrous ankylosis is a type of joint ankylosis that can be differentiated from bony ankylosis by the presence of a palpable, cord-like structure in the joint space.
**Correct Answer: D.**