Organs - The Salivary Glands

Question 1

What are the different salivary glands?

Answer 1

1) Parotid
2) Sublingual
3) Submandibular

Question 2

Parotid gland overview

Anatomical divisions?

Location?

Answer 2

Bilateral.

Anatomically divided into deep and superficial lobes, that is separated by the facial nerve.

Located within the parotid region.

Question 3

Parotid region - borders

Answer 3

Superiorly - zygomatic arch

Inferiorly - inferior border of the mandible

Anteriorly - masseter muscle

Posteriorly - sternocleidmastoid muscle and external ear.

Question 4

What is the parotid duct called?

Location?

Opening?

Answer 4

The Stensen duct - transports secretions of the parotid gland to the oral cavity.

It traverse along the masseter muscle, pierces the buccinator, moving medially and opens up near the second upper molar.

Question 5

Parotid gland - anatomical relationships?

Answer 5

1) Facial nerve - gives rise to five terminal branches within the parotid gland - these branches innervate the muscles of facial expression.
2) External carotid artery (ECA) - ascends through the parotid gland. Within the gland, the ECA gives rise to the posterior auricular artery. The ECA then divides into two terminal branches: the maxillary artery and superficial temporal artery.
3) Retromandibular vein - formed by convergence of the maxillary and superficial temporal veins. One of the major structures responsible for venous drainage of the face.

Question 6

Parotid gland - vasculature

Answer 6

Supplied by branches of the ECA:

1) Posterior auricular artery
2) Superficial temporal artery

Venous drainage by the retromandibular vein.

Question 7

Parotid gland - innervation

Answer 7

Receives sensory and autonomic innervation.

Sensory - auriculotemporal nerve

Autonomic (parasympathetic) - begins with the glossopharyngeal nerve (lesser petrosal nerve) which synapes onto the otic ganglion. The auriculotemporal nerve then carries the parasympathetic fibres from the otic ganglion to the parotid gland.

Parasympathetic innervation increases the amount of saliva production.

Autonomic (sympathetic) - originates with the superior cervical ganglion. Fibres travel from this ganglion along the ECA to reach the parotid gland.

Sympathetic innervation inhibits saliva production, via vasoconstriction.

Question 8

Clinical relevance - parotid gland tumours

Type?

Treatment?

Surgical complications?

Answer 8

Most common site of salivary gland tumour.

Usually benign, such as an adenolymphoma.

In contrast, tumours of the sublingual and submandibular gland tend to be malignant.

Treatment - surgical excision of tumour and parotid gland, known as parotidectomy. It is critical to identify the branches of the facial nerve in this procedure.

Surgical complications - damage to the facial nerve can cause paralysis of the facial muscles. These muscles will lose tone and sag. The inferior eyelied is particularly affected, falling away from the eyeball (known as an ectropion).

Question 9

Clinical relevance - parotitis

Answer 9

Inflammation of the parotid gland, usually as a result of an infection.

Parotid gland is enclosed in a tough connective tissue capsule. Where swelling is produced, this will cause pain.

Pain can be referred to the external ear since the external ear is also supplied by sensory innervation of the auriculotemporal nerve.