The “nerve of pain” that innervates all the teeth is ———– Group of answer choices III VII vagus trigeminal
The correct answer and explanation is:
The correct answer is trigeminal.
Explanation:
The trigeminal nerve (cranial nerve V) is the primary nerve responsible for sensory innervation to the face, including all the teeth. It is often called the “nerve of pain” in dental contexts because it carries the pain sensations from the teeth and surrounding oral structures to the brain.
Why the Trigeminal Nerve?
- Anatomy: The trigeminal nerve has three major branches:
- Ophthalmic (V1) – sensory to the upper face and scalp.
- Maxillary (V2) – sensory to the midface, including the upper teeth and maxillary sinus.
- Mandibular (V3) – sensory to the lower face, including the lower teeth, and also motor to the muscles of mastication.
- Dental Innervation:
- The maxillary nerve (V2) provides sensory fibers to the upper teeth (maxillary teeth).
- The mandibular nerve (V3) provides sensory fibers to the lower teeth (mandibular teeth).
Because these two branches cover all the teeth, the trigeminal nerve is the main sensory nerve responsible for tooth sensation, especially pain.
Why Not the Other Nerves?
- III (Oculomotor nerve): Primarily motor, controlling eye movements, no sensory function to teeth.
- VII (Facial nerve): Mainly controls muscles of facial expression and some taste sensation, but does not innervate the teeth.
- Vagus nerve (cranial nerve X): Involved in parasympathetic control of the heart, lungs, digestive tract, and some sensation in the throat, but not teeth.
Clinical Relevance:
In dental procedures, anesthetics are often targeted at branches of the trigeminal nerve to numb specific areas. For example:
- An inferior alveolar nerve block anesthetizes the mandibular teeth.
- A posterior superior alveolar nerve block targets the maxillary molars.
In summary, the trigeminal nerve is essential for transmitting pain and other sensations from the teeth, making it the “nerve of pain” for dental structures.