From which branch of the trigeminal nerve (CN V) does the TMJ receive sensory innervation?

The temporomandibular joint (TMJ) receives its sensory innervation primarily from the mandibular branch of the trigeminal nerve (CN V3). This branch is responsible for transmitting sensory information from the lower jaw, as well as providing motor innervation to the muscles of mastication.

The mandibular branch sends branches that innervate the TMJ, allowing it to relay sensations such as pain, pressure, and proprioception, which are essential for proper jaw function and movement. The intimate relationship between the TMJ and the mandibular branch underscores why this branch is the correct answer regarding sensory innervation.

In contrast, while the maxillary (CN V2) and ophthalmic (CN V1) branches of the trigeminal nerve do provide sensory innervation to other facial regions, they do not have a direct role in innervating the TMJ. The facial nerve (CN VII) predominantly innervates muscles of facial expression and does not contribute to sensory fibers in the TMJ. Therefore, the identification of the mandibular branch as the source of sensory innervation is vital in understanding the anatomy and functionality of the TMJ.