Which nerve supplies the temporomandibular joint (TMJ)?

The auriculotemporal nerve is a branch of the mandibular nerve (V3), which is one of the three major branches of the trigeminal nerve (cranial nerve V). It plays a crucial role in supplying sensory innervation to the temporomandibular joint (TMJ). This nerve not only provides sensory fibers to the joint itself but also innervates the surrounding structures, including parts of the ear and the parotid gland, which are significant in relation to TMJ function and pathology.

The auriculotemporal nerve's role is particularly important when considering pain or discomfort in the region of the TMJ, as it conducts pain sensations from the joint. This is critical for diagnosing TMJ disorders, as the symptoms may often involve pain that is referred along the auriculotemporal nerve.

The other options are associated with different functions and do not specifically supply sensory input to the TMJ. The nerve to masseter primarily innervates the masseter muscle, the facial nerve mainly serves muscles of facial expression and does not supply the TMJ, and while the mandibular nerve is indeed a part of its pathway, it does not directly innervate the TMJ itself. Therefore, the auriculotemporal nerve is