What clinical sign might you expect in a dog with trigeminal neuritis affecting the mandibular branch?

In a dog with trigeminal neuritis affecting the mandibular branch, one would expect to see a dropped jaw as a clinical sign. The mandibular branch of the trigeminal nerve is responsible for motor function to the muscles of mastication (chewing). If this nerve is compromised, the muscles that support the jaw become weak or lose function, resulting in the jaw being unable to remain closed properly. This manifests as a dropped jaw, where the lower jaw hangs open, leading to drooling and difficulty in eating or drinking.

Understanding this specific condition and its impact on muscle control helps establish why this sign is particularly indicative of trigeminal neuritis. Other clinical signs, such as seizures or facial droop, are not directly linked to the function of the mandibular nerve and are associated with other neurological conditions. Excessive salivation might occur as a secondary consequence of the inability to properly close the mouth, but it is not the primary clinical sign indicating involvement of the mandibular branch of the trigeminal nerve.