This fact is from Head Neck Nerve Supply in Oral Anatomy & Histology. It is a commonly tested concept in NEET MDS examinations. Understanding this fact is crucial for answering MCQs correctly.
Trigeminal V = main sensory nerve head face
V1 Ophthalmic = sensory only forehead
V3 Mandibular = only division with motor and sensory
Lingual nerve = taste anterior two-thirds via chorda tympani from VII
IAN block anesthetizes V3 = IANB
Facial nerve VII = motor muscles of facial expression
Marginal mandibular branch = important surgical landmark.