Chewing

Question 1

What is the sensory innervation of the oral cavity?

Answer 1

Sensory innervation of the oral cavity is supplied by the branches of the trigeminal nerve (CN V).

Question 2

What is the innervation of the hard and soft palete?

Answer 2

The hard palate is innervated by the greater palatine and nasopalatine nerves, both of which are branches of the maxillary nerve (CN V2). The soft palate is innervated by lesser palatine nerve, another branch of the maxillary nerve.

Question 3

What is the innervation of the floor of the oral cavity ?

Answer 3

The floor of the oral cavity receives sensory innervation from thelingual nerve– a branch of the mandibular (V3) division of the trigeminal nerve.

Question 4

What is the innervation of the cheeks?

Answer 4

The cheeks are innervated by thebuccal nerve. It is also a branch of the mandibular division of the trigeminal nerve

Question 5

What are the boundaries of the oral cavity?

Answer 5

Roof- hard and soft palate
Walls- skin, skeletal muscle (buccinator), fascia and oral mucosa
Floor- muscular diaphragm )comprised of the bilateral mylohyoid muscles), geniohyoid muscles, tongue, salivary glands and ducts.

Question 6

Parotid, submandibular and sublingual gland location, drainage and innervation

Answer 6

Question 7

Geniglossus, hyoglossus, palatoglossus and styloglossus attachments

Answer 7

Question 8

What is the innervation of the tongue?

Answer 8

Question 9

Describe the TMJ (temporomadibular joint)

Answer 9

• The TMJ is created by the mandibular fossa and articular tubercle of the temporal bone and the condylar process of the mandible.
• It is a synovial joint.
• It contains an ‘articular disc’, an interposing plate of cartilage that increases the range of motion of the joint

Question 10

What are the movements the TMJ permits?

Answer 10

The TMJ permits multiple actions…
•Depression and elevation.
•Protraction and retraction.
•Lateral deviation.

Through two different types of movement within the joint:
•Pivoting.
•Translation.

Question 11

What muscles allow chewing?

Answer 11

Masseter
Temporalis
Medial and lateral pterygoids

Question 12

Describe the masseter muscles

Answer 12

It has two heads, a larger superficial and a smaller deep. The superficial head arises from along the inferior aspect of the zygomatic arch and inserts onto the angle of the mandible. Itsfibresare orientated obliquely and soact to elevate and protract the mandible. The deep head arises from the deep surface of the zygomaticarch. Itsfibresare arranged vertically and soact only to elevate the mandible.

Question 13

Describe the temporalis muscles

Answer 13

This muscle covers and fills the entirety of the temporal fossa. It has two sets of fibres. These converge to share a tendon (and point of insertion on the coronoid process). Vertically orientated anterior fibres which elevate the mandible. Horizontally orientated posterior fibres which retract the mandible.

Question 14

Describe the medial pterygoids

Answer 14

This muscle acts to elevate and protract the mandible. It has two heads that enclose the lateral pterygoid muscles like scissors, a superficial and a deep. Both the superficial and deep headsinsert onto the sphenomandibular ligament, labelled ‘?’. The deep head originates on themedial surfaceof thelateral pterygoid plateof the sphenoid bone. The superficial head arises from the maxillary tuberosity.

Question 15

Describe the lateral pterygoids

Answer 15

This muscle acts to protract the mandibleand open the jaw. This muscle also has two heads, both of which originate on the articular disk of the TMJ and the pterygoid fovea of the mandible. The lower head stems to the condyloid process of the mandible. This head inserts onto thelateral surface of the lateral pterygoid plateof the sphenoid bone. The upper head inserts into the roof of the infratemporal fossa.