The Parotid Gland

The parotid gland consists of two lobes; the superficial lobe and the deep lobe. The parotid duct is a salivary duct that emerges from the parotid gland, and it runs along the lateral side of the masseter muscle, and opens into the vestibule of the mouth, between the cheek and the gums, at the parotid papilla, which lies across the second upper molar tooth. It deposits saliva into the mouth.

The Seventh Cranial Nerve

Parotid gland removal is one of the most challenging and complex procedures in Head and Neck surgery. The seventh cranial nerve, which stimulates all of our facial movement, runs directly through the parotid gland. The cranial nerve arises from the brain stem and extends posteriorly to the abducens nerve and anteriorly to the vestibulocochlear nerve. It courses through the facial canal in the temporal bone and exits through the stylomastoid foramen after which it divides into branches at the back edge of the parotid gland.[i]

A portrait of woman’s face, showing the seventh cranial nerve, and the different branches, which run through the parotid gland.

The Facial Nerve Branches.

All of our facial movement is stimulated by the cranial nerve: the muscles of facial expression, the left forehead wrinkle, left eyelid closure and movement of the left half of our face including our nose, mouth and eyebrows. The five branches of the 7^th cranial nerve are;

• The temporal branch –innervating the muscles in the upper part of the face.
• The zygomatic branch- innervating the middle part of the face.
• The buccal branch- innervating the cheek muscles, including the buccinators muscle.
• The mandular branch- innervating muscles of the lower part of the face.
• The cervical branch- innervating the muscles below the chin and the platysma muscle.[i]

The 7^th cranial nerve is miniscule, and when a surgeon performs either a partial or a complete parotidectomy, they have to carefully isolate the facial nerve, so that it can be preserved during surgery. This is an intricate procedure – even with the most careful pair of hands, the facial nerve can get accidentally nipped or cut. If there is a tumour over the nerve, then the nerve has to be cut, but the patient is made aware of this before surgery.

Surgeons will test the facial nerve during surgery to check its functionality. However, f it gets nipped, the patient can end up with facial nerve damage, either permanent or temporary. Even if the nerve is fully preserved, the patient can still be left with temporary facial nerve damage, which can be caused from bruising or pulling of the nerve.

Minimally Invasive Procedures.

Due to the complexities of parotid gland surgery, salivary gland removal is reserved as a last resort when treating salivary gland disease, such as Sialadentis and parotitis. In order to preserve the facial nerve, minimally invasive procedures are tried first. Sialoendoscopy is a therapeutic procedure, which is used to remove salivary gland stones and treat salivary gland inflammation. Ductoplasties are another minimally invasive procedure to treat benign salivary gland obstruction. These can repair a damaged duct, which has thinned, (stenosis), by using angioplasty balloon. Both of these minimally invasive procedures were tried in 2015. I found the saline irrigation of my gland to be therapeutic. In summary, the relief that these procedures brought me, was only short-term. That is why I had a superficial parotidectomy in 2018.

This image shows a clinician carrying out a sialendoscopy on a patient, who suffers with parotid gland disease.

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Foot Notes

[i] Myckatyn TM, Mackinnon SE; A Review of Facial Nerve Anatomy. Semin Plast Surg. 2004, Feb. A Review of Facial Nerve Anatomy- PubMed (nih.gov)

[i] Dominika Dulak; Imama A. Naqvi. Neuroanatomy, Cranial Nerve 7 (Facial); National Library of Medicine National Centre for Biotechnology Information. Stat Pearls Publishing; 2023, January.

Neuroanatomy, Cranial Nerve 7 (Facial) – PubMed (nih.gov)