A Handy Landmark (Triangle Technique) for Identification of the Facial Nerve during Parotid Surgery

Abstract

The parotid glands are paired major salivary glands located in front of the tragus and below the ear lobule at the retromandibular area (behind the mandibular ramus and in front of the mastoid process of the temporal bone) on each side of the upper neck. The facial nerve is one of the most important structures encountered during parotidectomy. The neurovascular structures that pass through the parotid gland from lateral to medial are facial nerve, retromandibular vein, external carotid artery, superficial temporal artery and maxillary artery. Branches of the great auricular nerve enter the gland from the neck and remains superficial. Parotid surgery is indicated in certain pathological conditions namely benign and malignant neoplasm, chronic inflammatory diseases, sialolithiasis, intra-parotid cysts/sinuses and lymphadenopathy; and many more. The importance of the facial nerve and methods of identification are enumerated by the multiple anatomical landmarks during parotidectomy. The triangle landmark is one of these anatomical landmarks considering the base of the styloid process, tragal cartilage to tragal pointer and the origin of the posterior belly of the digastric muscle at the mastoid tip. Facial Nerve and the Parotid Gland: The intra-temporal facial nerve exits from the stylomastoid foramen slightly posterior to the styloid process and anteromedial to the mastoid process. The main trunk is approximately 1.3 cm in length enters into the parotid gland and divides into cervico-marginal and zygomatico-temporal branches; and of course, buccal branches (upper and lower buccal) remain common in both the divisions. The cervico-marginal branches supply the muscles of the mouth and neck; and zygomatico-temporal branches supply the muscles of the forehead and eye. The facial nerve arbitrarily divides the gland into superficial and deep lobes.Aim of the Study: The aim of this study was to locate the facial nerve trunk (FNT) very easily. Quickly and accurately at the point where the long axis along the tragal pointer from the tragus and posterior belly of the digastric from the mastoid tip meets over the styloid process.