Head and Neck, NEET PG & INI-CET Anatomy MCQs

Explanation

The three trigeminal divisions exit in order from front to back and top to bottom: V1 through the superior orbital fissure, V2 through foramen rotundum and V3 through foramen ovale. Foramen spinosum carries the middle meningeal artery, not a nerve division. Remembering the sequence rotundum then ovale for V2 then V3 covers most questions on the topic.

Explanation

Foramen ovale transmits the mandibular division, V3, along with the accessory meningeal artery and the lesser petrosal nerve. V3 is the only trigeminal division carrying motor fibres, which is why a lesion here weakens the muscles of mastication. The facial nerve leaves through the stylomastoid foramen instead.

Explanation

The jugular foramen transmits cranial nerves IX, X and XI along with the internal jugular vein. Glossopharyngeal loss removes the afferent limb of the gag reflex, vagal loss gives hoarseness through the recurrent laryngeal branch, and accessory loss weakens trapezius and sternocleidomastoid. The hypoglossal canal carries only CN XII, so tongue deviation without these features points there instead.

Explanation

The superior orbital fissure carries the three ocular motor nerves, III, IV and VI, the branches of V1 and the superior ophthalmic vein. The optic nerve takes a separate route through the optic canal, accompanied by the ophthalmic artery. That separation explains why an optic canal lesion can spare eye movements while abolishing vision.

Explanation

The trochlear nerve is unique in leaving the brainstem dorsally, just below the inferior colliculus, and it decussates before doing so. It therefore supplies the superior oblique of the opposite side and has the longest intracranial course, which makes it vulnerable in head injury. Superior oblique depresses and intorts the adducted eye, so patients complain of vertical diplopia going down stairs.

Explanation

Cranial nerves III, IV, V1 and V2 run within the lateral wall of the cavernous sinus, while the abducent nerve runs free in the sinus alongside the internal carotid artery. Being surrounded by blood rather than protected by dura, it is the first to suffer when pressure rises. The result is a lateral rectus palsy with failure of abduction.

Explanation

Three structures pass through the parotid, and their depth is fixed: the facial nerve is most superficial, the retromandibular vein lies deep to it, and the external carotid artery is deepest. The nerve divides within the gland into its five terminal branches without supplying the gland itself. Its superficial position is why superficial parotidectomy carries a real risk of facial weakness.

Explanation

The recurrent laryngeal nerve runs in the tracheo-oesophageal groove and has a variable relationship to the branches of the inferior thyroid artery, passing in front, behind or between them. Ligating that artery close to the gland rather than on the main trunk keeps the dissection away from the nerve. The superior thyroid artery has the same problem with the external laryngeal nerve, which is why it is ligated close to the upper pole.

Explanation

The posterior triangle is bounded in front by the posterior border of sternocleidomastoid, behind by the anterior border of trapezius, and below by the middle third of the clavicle. The inferior belly of omohyoid crosses it and subdivides it into occipital and supraclavicular parts. The accessory nerve crosses the triangle superficially and is at risk during lymph node biopsy here.

Explanation

The carotid sheath contains the common and internal carotid arteries, the internal jugular vein and the vagus nerve, with the vein lateral, the artery medial and the nerve between and behind them. The sympathetic chain lies behind the sheath, embedded in prevertebral fascia, not inside it. That separation is why a sheath lesion need not cause Horner syndrome.

Explanation

The lingual nerve loops under the submandibular duct, passing from lateral to medial as it descends and then ascending on its medial side to reach the tongue. It is one of the few places where a nerve spirals around a duct rather than running alongside it. The relationship matters in surgery for submandibular calculi, where the nerve lies directly in the operative field.