Anatomic Sciences: Head, Neck, and Craniofacial Development
Core regional anatomy
Head and neck questions reward a regional approach. Trace the trigeminal nerve from its three divisions to their exits: V1 through the superior orbital fissure, V2 through the foramen rotundum, V3 through the foramen ovale. Know that the lingual nerve (V3) carries general sensation from the anterior two-thirds of the tongue, while the chorda tympani (VII) carries taste; the posterior third is supplied by the glossopharyngeal nerve for both modalities. The four muscles of mastication are masseter, temporalis, medial pterygoid, and lateral pterygoid - all elevate except the lateral pterygoid, which protrudes and depresses the mandible.
Development and histology
Branchial arch derivatives are high-yield: the first arch gives the mandible, malleus, incus, and muscles of mastication; the second arch gives the stapes, styloid process, and muscles of facial expression; the third gives the greater horn of the hyoid and stylopharyngeus. Tooth formation passes through bud, cap, and bell stages, with enamel arising from ectoderm (ameloblasts) and dentin, pulp, and cementum from ectomesenchyme.
Traps
Questions frequently swap the foramen rotundum and ovale, or ask which muscle opens the jaw. Others test whether a tissue is ectodermal or neural-crest derived, or blur the line between the nerve for general sensation and the nerve for taste. Lymphatic drainage of the tongue (tip to submental, body to submandibular/deep cervical) is another common distractor.
Rule of thumb
Link each nerve to its foramen and its function in one sentence. If an answer choice pairs a structure with a foramen that breaks your sentence, it is the distractor. For muscles, remember that the lateral pterygoid is the one that lowers and protrudes.