Upper 1st molar is supplied hy:
**Core Concept**
The question is testing the knowledge of the dental pulp nerve supply, specifically the upper first molar. The dental pulp is a highly innervated structure that receives both sensory and autonomic nerve fibers. The nerve supply of the dental pulp is crucial for diagnosing and managing dental pain.
**Why the Correct Answer is Right**
The upper first molar is supplied by the inferior alveolar nerve (IAN), which is a branch of the mandibular division of the trigeminal nerve (CN V3). The IAN enters the mandibular canal and divides into several branches that innervate the lower teeth. However, the upper first molar receives its nerve supply from the buccal and palatal branches of the maxillary nerve (CN V2), which is the primary nerve supply for the upper teeth. The buccal branch of the maxillary nerve provides sensory innervation to the buccal aspect of the upper first molar, while the palatal branch provides sensory innervation to the palatal aspect.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the inferior alveolar nerve (IAN) primarily supplies the lower teeth, not the upper first molar.
**Option B:** This option is incorrect because the lingual nerve is a branch of the mandibular division of the trigeminal nerve (CN V3) that provides sensory innervation to the tongue and the floor of the mouth, not the upper first molar.
**Option C:** This option is incorrect because the auriculotemporal nerve is a branch of the mandibular division of the trigeminal nerve (CN V3) that provides sensory innervation to the temporomandibular joint and the external auditory meatus, not the upper first molar.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the nerve supply of the upper teeth is primarily provided by the maxillary nerve (CN V2), while the nerve supply of the lower teeth is primarily provided by the inferior alveolar nerve (IAN).
**Correct Answer: C. The buccal and palatal branches of the maxillary nerve (CN V2) supply the upper first molar.**