MFDS Head and Neck Anatomy 2 — Questions and Answers
Question 1: An inferior alveolar nerve block fails to anaesthetise which structure, necessitating a separate injection?
- Mandibular molars pulps
- Buccal gingiva of mandibular molars (Correct answer)
- Lower lip and chin
- Mandibular premolar pulps
Correct answer: Buccal gingiva of mandibular molars
The buccal (long buccal) nerve, a separate branch of CN V3, supplies the buccal gingiva and mucosa of the mandibular molar region and is not blocked by a standard inferior alveolar nerve block.
Question 2: Which muscle protracts the mandibular condyle during mouth opening?
- Masseter
- Medial pterygoid
- Lateral pterygoid (Correct answer)
- Temporalis
Correct answer: Lateral pterygoid
The inferior head of the lateral pterygoid contracts during mouth opening, pulling the condyle and articular disc anteriorly (protraction), while the posterior fibres of temporalis retract the condyle on closing.
Question 3: The mylohyoid nerve, which supplies the mylohyoid muscle, arises from which parent nerve?
- Lingual nerve
- Buccal nerve
- Inferior alveolar nerve (Correct answer)
- Mental nerve
Correct answer: Inferior alveolar nerve
The mylohyoid nerve is a branch of the inferior alveolar nerve arising just before it enters the mandibular foramen; it runs in the mylohyoid groove to supply the mylohyoid muscle and the anterior belly of the digastric.
Question 4: The maxillary teeth receive their primary arterial supply from branches of which artery?
- Facial artery
- Maxillary artery (Correct answer)
- Infraorbital artery
- Buccal artery
Correct answer: Maxillary artery
The posterior superior alveolar and anterior superior alveolar arteries, both branches of the maxillary artery, supply the maxillary teeth and their supporting structures.
Question 5: The pterygomandibular raphe serves as the key landmark for which local anaesthetic technique?
- Mental nerve block
- Infraorbital nerve block
- Inferior alveolar nerve block (Correct answer)
- Posterior superior alveolar nerve block
Correct answer: Inferior alveolar nerve block
The pterygomandibular raphe marks the medial boundary of the pterygomandibular space; the needle for an inferior alveolar nerve block is directed lateral to this raphe, towards the mandibular foramen.
Question 6: Which bones form the floor of the orbit?
- Zygomatic, maxillary, and palatine bones (Correct answer)
- Frontal, zygomatic, and sphenoid bones
- Maxillary, lacrimal, and ethmoid bones
- Zygomatic, frontal, and lacrimal bones
Correct answer: Zygomatic, maxillary, and palatine bones
The floor of the orbit is formed by the orbital surface of the maxilla (largest contribution), the orbital surface of the zygomatic bone (anterolaterally), and the orbital process of the palatine bone (posteriorly).
Question 7: Which cranial nerve exits the skull through the stylomastoid foramen?
- Glossopharyngeal nerve (CN IX)
- Facial nerve (CN VII) (Correct answer)
- Accessory nerve (CN XI)
- Hypoglossal nerve (CN XII)
Correct answer: Facial nerve (CN VII)
The facial nerve (CN VII) exits the skull through the stylomastoid foramen before entering the parotid gland, where it divides into its five terminal branches (temporal, zygomatic, buccal, marginal mandibular, cervical).
MFDS Head and Neck Anatomy 2
An inferior alveolar nerve block fails to anaesthetise which structure, necessitating a separate injection?