Anatomy of Paranasal Sinuses

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Questions and Answers

What is the primary function of the paranasal sinuses in relation to the voice?

To produce sound waves

To regulate breathing

To produce mucus

To act as resonators (correct)

What is the main reason why the maxillary sinus is prone to infection?

Its drainage orifice is located near the roof of the sinus. (correct)

Its drainage orifice is located near the floor of the sinus.

The apices of the roots of the teeth in the maxilla are far from the floor of the maxillary sinus.

The sinus is too small to drain effectively.

What is the function of the motor root of the trigeminal nerve?

It forms the trunk of the mandibular nerve. (correct)

It supplies the medial pterygoid muscle.

It supplies the buccinator muscle.

It supplies the sensory root of the trigeminal nerve.

Which nerve branch is responsible for supplying the temporomandibular joint?

Auriculotemporal nerve Signup and view all the answers

What is the function of the buccal nerve?

It supplies the skin and mucous membrane of the cheek. Signup and view all the answers

What is the function of the meningeal branch of the mandibular nerve?

It supplies the dura mater. Signup and view all the answers

Which of the following is NOT a branch of the posterior division of the mandibular nerve?

Nerve to the lateral pterygoid muscle Signup and view all the answers

What is the relation between the apices of the roots of the teeth in the maxilla and the floor of the maxillary sinus?

The apices are close to the floor of the maxillary sinus. Signup and view all the answers

Which of the following muscles is NOT supplied by the mandibular nerve?

Buccinator muscle Signup and view all the answers

Which nerve is responsible for conveying postganglionic parasympathetic secretomotor fibers to the parotid salivary gland?

Auriculotemporal nerve Signup and view all the answers

Where does the lingual nerve cross the submandibular duct?

In the mouth Signup and view all the answers

What type of muscle forms the substance of the lips?

Orbicularis oris muscle Signup and view all the answers

What is the name of the shallow vertical groove seen in the midline on the outer surface of the upper lip?

Philtrum Signup and view all the answers

Which muscle is supplied by the mylohyoid nerve?

Mylohyoid muscle Signup and view all the answers

What is the function of the preganglionic fibers that originate in the glossopharyngeal nerve?

Convey secretomotor fibers to the submandibular ganglion Signup and view all the answers

What is the name of the space that communicates with the exterior through the oral fissure between the lips?

Vestibule Signup and view all the answers

What is the name of the muscle that forms the lateral wall of the vestibule?

Buccinator muscle Signup and view all the answers

What is the location of the otic ganglion relative to the mandibular nerve?

Medial to the mandibular nerve Signup and view all the answers

Where does the duct of the parotid salivary gland open into the vestibule?

Opposite the upper second molar tooth Signup and view all the answers

What is the potential consequence of clumsy extraction of an impacted third molar?

Damage to the lingual nerve Signup and view all the answers

Which nerve is responsible for supplying the skin of the chin?

Mental nerve Signup and view all the answers

What is the name of the part of the mouth that lies between the lips and the cheeks externally and the gums and the teeth internally?

Vestibule Signup and view all the answers

What is the purpose of the communicating branch that runs from the inferior alveolar nerve to the lingual nerve?

To facilitate communication between the two nerves Signup and view all the answers

What is the name of the fold that forms the entrance into the pharynx?

Palatoglossal fold Signup and view all the answers

What forms the roof of the mouth?

Hard palate in front and soft palate behind Signup and view all the answers

What is the main function of the superior retrodiscal layer in the TMJ joint?

To connect the articular disc to the tympanic plate of the temporal bone Signup and view all the answers

Which of the following arteries is NOT a main supplier of the TMJ?

Posterior tympanic artery Signup and view all the answers

What is the main function of the lateral pterygoid muscle in the TMJ?

To pull the neck of the mandible and the articular disc forward Signup and view all the answers

Which of the following movements is NOT possible in the TMJ?

Translation of the mandible along the articular tubercle Signup and view all the answers

What is the function of the synovial membrane in the TMJ?

To line the capsule in the upper and lower cavities of the joint Signup and view all the answers

Which nerve branches are responsible for the nerve supply to the TMJ?

Auriculotemporal and masseteric branches of the mandibular nerve Signup and view all the answers

What is the venous drainage of the TMJ?

Via the superficial temporal vein and the maxillary vein Signup and view all the answers

What is the position of the teeth in the rest position?

The teeth are slightly apart Signup and view all the answers

Study Notes

Paranasal Sinuses

Each frontal sinus is roughly triangular in shape and extends upward above the medial end of the eyebrow and backward into the medial part of the roof of the orbit.
Frontal sinuses open into the middle meatus of the nose through the infundibulum.
Sphenoidal sinuses are located within the body of the sphenoid bone and open into the sphenoethmoidal recess above the superior concha.
Ethmoidal sinuses are contained within the ethmoid bone, between the nose and the orbit, and are separated from the latter by a thin plate of bone.
Anterior ethmoidal sinuses open into the infundibulum; middle ethmoidal sinuses open into the middle meatus on or above the bulla ethmoidalis; and posterior ethmoidal sinuses open into the superior meatus.

Drainage of Mucus and Functions of Paranasal Sinuses

Mucus produced by the mucous membrane is moved into the nose by ciliary action of the columnar cells.
Drainage of mucus is also achieved by the siphon action created during the blowing of the nose.
The function of the sinuses is to act as resonators to the voice and to reduce the weight of the skull.
When the apertures of the sinuses are blocked or they become filled with fluid, the quality of the voice is markedly changed.

Mandibular Nerve

The mandibular nerve is a mixed nerve with both motor and sensory functions.
The sensory root leaves the trigeminal ganglion and passes out of the skull through the foramen ovale to enter the infratemporal fossa.
The motor root of the trigeminal nerve also leaves the skull through the foramen ovale and joins the sensory root to form the trunk of the mandibular nerve.
The mandibular nerve divides into a small anterior and a large posterior division.
Branches from the main trunk of the mandibular nerve include:
- Meningeal branch
- Nerve to the medial pterygoid muscle, which supplies the medial pterygoid muscle and the tensor veli palatini muscle
Branches from the anterior division of the mandibular nerve include:
- Masseteric nerve to the masseter muscle
- Deep temporal nerves to the temporalis muscle
- Nerve to the lateral pterygoid muscle
- Buccal nerve to the skin and the mucous membrane of the cheek
Branches from the posterior division of the mandibular nerve include:
- Auriculotemporal nerve, which supplies the skin of the auricle, the external auditory meatus, the temporomandibular joint, and the scalp, and conveys postganglionic parasympathetic secretomotor fibers from the otic ganglion to the parotid salivary gland
- Lingual nerve, which descends in front of the inferior alveolar nerve and enters the mouth to run forward on the side of the tongue and crosses the submandibular duct
- Inferior alveolar nerve, which enters the mandibular canal to supply the teeth of the lower jaw and emerges through the mental foramen to supply the skin of the chin

Clinical Notes

Injury to the lingual nerve may occur during clumsy extraction of an impacted third molar.
The otic ganglion is a parasympathetic ganglion that is located medial to the mandibular nerve just below the skull, and it is adherent to the nerve to the medial pterygoid muscle.

Oral Cavity

The lips are two fleshy folds that surround the oral orifice and are covered on the outside by skin and lined on the inside by mucous membrane.
The substance of the lips is made up of the orbicularis oris muscle, the muscles that radiate from the lips into the face, labial blood vessels and nerves, connective tissue, and many small salivary glands.
The philtrum is the shallow vertical groove seen in the midline on the outer surface of the upper lip.
Median folds of mucous membrane (the labial frenulae) connect the inner surface of the lips to the gums.

Temporomandibular Joint

The temporomandibular joint is composed of the condyle of the mandible and the articular fossa of the temporal bone.
The joint is divided into upper and lower cavities by the articular disc.
The superior retrodiscal layer of the TMJ joint is a lamina composed of connective tissue and elastic fibers that continues the posterior part of the articular disk and connects the disc to the tympanic plate of the temporal bone.
The inferior retrodiscal layer of the TMJ joint is a lamina composed of collagen fibers that continues the posterior part of the articular disk and inserts into the condylar neck.
The synovial membrane lines the capsule in the upper and lower cavities of the joint.
The nerve supply of the TMJ is from the auriculotemporal and masseteric branches of the mandibular nerve.
The vascular supply of the TMJ is mainly from the deep auricular artery, the superficial temporal artery, and the anterior tympanic artery.
The venous drainage of the TMJ is via the superficial temporal vein and the maxillary vein.
The movements of the TMJ include depression, elevation, protrusion, retraction, and rotation.
In the position of rest, the teeth of the upper and lower jaws are slightly apart. On closure of the jaws, the teeth come into contact.

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Description

This quiz covers the anatomy and location of paranasal sinuses, including frontal, sphenoidal, and ethmoidal sinuses.