CMT Orofacial Anatomy & Physiology 3 — Questions and Answers
Question 1: The orbicularis oris muscle is classified as which type of muscle?
- Pennate muscle
- Sphincter muscle (Correct answer)
- Fusiform muscle
- Bipennate muscle
Correct answer: Sphincter muscle
The orbicularis oris acts as a sphincter, encircling the mouth opening to compress and close the lips.
Question 2: Which structure separates the oral cavity from the nasal cavity?
- Soft palate only
- Hard palate only
- Both hard and soft palate (Correct answer)
- Velum only
Correct answer: Both hard and soft palate
Both the hard palate (anterior bony portion) and soft palate (posterior muscular portion) together form the roof of the mouth and floor of the nasal cavity.
Question 3: The hypoglossal nerve (CN XII) provides motor innervation to all tongue muscles EXCEPT which one?
- Genioglossus
- Hyoglossus
- Palatoglossus (Correct answer)
- Styloglossus
Correct answer: Palatoglossus
The palatoglossus is innervated by the vagus nerve (CN X) via the pharyngeal plexus, making it the exception among tongue muscles.
Question 4: In the context of orofacial myology, the 'nasolabial fold' is formed by which landmark?
- Junction of nasal bone and cartilage
- Crease between cheek and upper lip (Correct answer)
- Base of the columella
- Philtrum ridge
Correct answer: Crease between cheek and upper lip
The nasolabial fold is the groove running from the sides of the nose to the corners of the mouth, formed where cheek tissue meets the upper lip.
Question 5: Which muscle elevates the hyoid bone and assists in swallowing?
- Thyrohyoid
- Sternohyoid
- Mylohyoid (Correct answer)
- Omohyoid
Correct answer: Mylohyoid
The mylohyoid elevates the hyoid bone and floor of the mouth, assisting in the oral and pharyngeal phases of swallowing.
Question 6: The Stensen's duct (parotid duct) opens into the oral cavity opposite which tooth?
- Upper first premolar
- Upper first molar
- Upper second molar (Correct answer)
- Upper canine
Correct answer: Upper second molar
Stensen's duct opens on the buccal mucosa of the cheek opposite the maxillary second molar.
Question 7: Which anatomical structure marks the posterior boundary of the oral cavity?
- Uvula
- Posterior pharyngeal wall
- Anterior tonsillar pillars (Correct answer)
- Posterior tonsillar pillars
Correct answer: Anterior tonsillar pillars
The anterior tonsillar pillars (palatoglossal arches) mark the transition between the oral cavity and the oropharynx.
CMT Orofacial Anatomy & Physiology 3
The orbicularis oris muscle is classified as which type of muscle?