What is the most likely cause of unilateral pain during chewing in a patient with no facial tenderness?

Unilateral pain during chewing, particularly in the absence of facial tenderness, most strongly suggests an issue with the temporomandibular joint (TMJ). Temporomandibular joint syndrome, or TMJ disorder, encompasses a variety of problems related to the jaw joint and surrounding muscles that control jaw movement. Chewing involves significant movement and stress on the TMJ, which can lead to pain if there is dysfunction, such as inflammation, misalignment, or muscle strain on one side of the joint.

The key here is recognizing that TMJ disorders often manifest as pain localized to the jaw region, especially during activities that involve the jaw, like chewing. The lack of facial tenderness can also help to differentiate TMJ-related pain from other conditions that may cause facial discomfort or pain due to systemic issues, infections, or other musculoskeletal causes.

The other conditions listed are not commonly associated with unilateral pain during chewing. Rotator cuff tears are related to shoulder pain and typically do not cause jaw symptoms. A scaphoid fracture primarily affects the wrist and hand, leading to wrist pain, not jaw pain. An acromioclavicular joint separation involves injury to the shoulder, which again wouldn't typically present as unilateral chewing pain. Thus, the specific symptom of