**Question:** Ankylosis of TMJ can be best viewed in:

The temporomandibular joint (TMJ) is a synovial joint that connects the mandible to the temporal bone of the skull, allowing for mandibular movement. Ankylosis of TMJ refers to the fusion of the articular surfaces of the joint, which can be caused by trauma, infection, or other factors.

**Core Concept:** Ankylosis is the fusion of joint surfaces, which can lead to impaired joint mobility and function. In the context of the TMJ, it presents with limited mouth opening and pain on jaw movement.

**Why the Correct Answer is Right:** The correct answer, **Option C: X-rays**, is chosen due to its ability to visualize the fusion of joint surfaces caused by ankylosis. X-rays, particularly orthopantomograms or OPGs, are effective in demonstrating the loss of joint space and calcification in the TMJ area, which are key features of ankylosis.

**Why Each Wrong Option is Incorrect:**

A. **Option A: Computed tomography (CT)** is often used to visualize bony structures, but it is less effective in assessing soft tissue changes like joint space loss, which is crucial in diagnosing ankylosis.

B. **Option D: Magnetic resonance imaging (MRI)** is a valuable imaging modality for soft tissue evaluation; however, ankylosis primarily involves the bony structures, making X-rays more appropriate for diagnosing this condition.

C. **Option B: Ultrasound**: While ultrasound is valuable in assessing soft tissues, it is less effective in visualizing the bony changes associated with ankylosis compared to X-rays.

**Clinical Pearl:** Ankylosis of TMJ can be easily misdiagnosed if proper imaging modality is not chosen. X-rays are crucial for detecting the characteristic features of ankylosis, ensuring accurate diagnosis and management.