Head & Neck: MRCEM Primary questions with answers

The Head & Neck topic belongs to the anatomy section of MRCEM Primary, which carries 60 of the 180 questions. It covers the muscles of the neck, the anterior and posterior triangles, the thyroid gland, the structure of the eyeball and eyelid, and the visual pathway. Airway problems, neck wounds, eye injuries and visual field defects all depend on knowing exactly what lies where.

5 free questions below, each with the answer and the full explanation · 226 in the full bank · Last updated after the 27 October 2026 MRCEM Primary sitting.

1. Question 1 · Structure of the Eyeball and Eyelid

   A male aged 25 presents to the emergency department after being struck under the chin during a basketball game. He reports severe pain in front of his ears and has his jaw locked in a closed position. On physical examination, his jaw appears to be displaced posteriorly. Which ligament is most likely compromised by this injury?

   1. AStylomandibular ligament
   2. BLateral pterygoid muscle
   3. CTemporomandibular ligament
   4. DSternoclavicular ligament
   5. ESphenomandibular ligament
   Show answer and explanation

   Answer: C. The temporomandibular ligament lateral to the joint resists posterior displacement of the mandible, so a blow under the chin can injure it.

   • A: Stylomandibular ligament is an accessory ligament, not the main restraint.
   • B: Lateral pterygoid is a muscle, not a ligament.
   • D: Sternoclavicular ligament belongs to the shoulder girdle, not the jaw.
   • E: Sphenomandibular ligament is an accessory ligament, not the main restraint.

   Full explanation

   The Temporomandibular joint (TMJ):

   The temporomandibular joint (TMJ) is a hinge type synovial joint that connects the mandible to the temporal bone of the skull. It is responsible for the movement of the jaw, allowing functions such as chewing, speaking, and yawning.

   Movements of the temporomandibular joint (TMJ)

   • Hinge movement: Opening and closing the mouth.
   • Gliding movement: Forward (protrusion) and backward (retrusion) movements of the jaw.
   • Lateral movements: Side-to-side jaw motion.

   Muscles Involved:

   • Temporalis: Elevates and retracts the jaw.
   • Masseter: Elevates the jaw.
   • Medial and Lateral Pterygoid: Assist in side-to-side movements and protrusion.

   Ligaments of the temporomandibular joint (TMJ):

   • Lateral capsular (Temporomandibular) ligament: Prevents posterior and inferior dislocation of the TMJ. It is the strongest ligament in the joint and reinforces the lateral side of the joint capsule.
   • Sphenomandibular ligament originates from the sphenoid spine, and attaches to the mandible. Acts as a passive support to the mandible, especially when the mouth is wide open.
   • Stylomandibular ligament: Provides stability and limits excessive jaw movements. Overstretching can result in hypermobility of the jaw, increasing the risk of dislocation.
   • Innervation: The TMJ is primarily innervated by the mandibular branch of the trigeminal nerve (V3).

   Clinical pearls:

   Temporomandibular joint (TMJ) Dislocation:

   Anterior dislocation: The most common form, where the condyle slips forward over the articular eminence, locking the mouth open. Trauma or excessive opening of the mouth (e.g., yawning, dental procedures) can stretch or tear ligaments, resulting in dislocation.

   Posterior dislocation: Posterior temporomandibular joint (TMJ) dislocation is a rare condition compared to anterior dislocation. In this type of dislocation, the mandibular condyle is displaced backward, towards the external auditory canal and the base of the skull. Jaw locked in a closed position, In contrast to anterior dislocation, Patients are unable to close their mouths.

2. Question 2 · Head & Neck

   Which one of the following nerves supplies sensory innervation to the nasopharynx?

   1. AFacial nerve
   2. BMandibular nerve
   3. CMaxillary nerve
   4. DVagus nerve
   5. EGlossopharyngeal nerve
   Show answer and explanation

   Answer: C. The nasopharynx is supplied by the maxillary nerve.

   • A: Facial nerve is not the pharyngeal sensory nerve.
   • B: The mandibular nerve does not supply the pharynx.
   • D: Vagus supplies the laryngopharynx.
   • E: Glossopharyngeal supplies the oropharynx.

   Full explanation

   Each subdivision of the pharynx has different sensory innervation:

   • The nasopharynx is supplied by the maxillary nerve
   • The oropharynx is supplied d by the glossopharyngeal
   • The laryngopharynx is supplied by the vagus nerve.

3. Question 3 · Anterior and Posterior Triangle of Neck

   A boy aged 18 presents to the ED with a nosebleed. On examination, you suspect the site of bleeding to be in little’s area. Which of the following blood vessels are likely to be involved?

   1. AAnterior ethmoidal and posterior superior alveolar arteries
   2. BDescending palatine and anterior ethmoidal arteries
   3. CSphenopalatine and superior labial arteries
   4. DAscending pharyngeal and descending palatine arteries
   5. EDescending palatine and ascending pharyngeal arteries
   Show answer and explanation

   Answer: C. Little's area (Kiesselbach's plexus) is formed by the sphenopalatine, superior labial, greater palatine and anterior ethmoidal arteries.

   • A: Posterior superior alveolar artery supplies the maxillary molars.
   • B: Descending palatine is a component, but this pair omits the sphenopalatine and superior labial.
   • D: Ascending pharyngeal does not contribute to Little's area.
   • E: Ascending pharyngeal does not supply the anterior septum.

   Full explanation

   Little’s area also known as Kieselbach's plexus is formed by:

   • Superior labial artery
   • Sphenopalatine artery
   • The greater palatine artery
   • The anterior ethmoidal artery

4. Question 4 · Muscles of the Neck

   A man aged 30 attends the emergency department with limited mouth opening after a mandibular fracture. Which of the following muscles is mainly responsible for opening the mouth?

   1. ALateral pterygoid
   2. BMedial pterygoid
   3. CSternothyroid
   4. DMasseter
   5. ETemporalis
   Show answer and explanation

   Answer: A. Lateral pterygoid pulls the condyle forward, opening the mouth; the other listed jaw muscles close it.

   • B: Medial pterygoid mainly elevates the mandible.
   • C: Sternothyroid is an infrahyoid strap muscle, not a main jaw opener.
   • D: Masseter is a powerful elevator that closes the mouth.
   • E: Temporalis elevates and retracts the mandible.

   Full explanation

   Summarizing the muscles involved in mouth opening and closing, along with their functions:

5. Question 5 · Thyroid Gland

   During a skull examination, a medical student is asked to identify the structure that passes through the foramen spinosum. Which of the following structures passes through the foramen spinosum?

   1. AOptic nerve
   2. BMeningeal branch of the mandibular nerve >
   3. CHypoglossal nerve
   4. DInternal carotid artery
   5. EMeningeal branch of mandibular artery
   Show answer and explanation

   Answer: B. The foramen spinosum transmits the meningeal branch of the mandibular nerve, plus the middle meningeal artery and vein.

   • A: The optic nerve passes through the optic canal.
   • C: The hypoglossal nerve passes through the hypoglossal canal.
   • D: The internal carotid artery passes through the carotid canal.
   • E: The artery is the middle meningeal, from the maxillary artery, not the mandibular.

   Full explanation

   The structures that pass through the foramen spinosum are:

   • Meningeal branch of the mandibular nerve
   • Middle meningeal artery
   • Middle meningeal vein