Learning Objective: By the end of this lesson, the learner will be able to describe the anatomical position, relations, neurovascular supply, and clinical relevance of the parotid gland and apply this understanding to basic and clinical problem-solving.
The parotid gland is the largest bilateral salivary gland located in the face. It produces serous, enzyme-rich saliva, which enters the oral cavity to lubricate food and begin chemical digestion.
Anatomical Position
The gland has an irregular, lobulated shape with superficial and deep lobes, separated by the facial nerve. It occupies the parotid region, bounded by:
- Superior: Zygomatic arch
- Inferior: Mandibular angle
- Anterior: Masseter
- Posterior: External ear & sternocleidomastoid
Its secretion travels through the Stensen duct, which crosses the masseter, pierces the buccinator, and opens near the upper second molar.
Anatomical Relationships
The parotid gland is surgically important due to key structures passing through it:
- Facial nerve (CN VII): gives five terminal branches
- External carotid artery: gives the posterior auricular artery; divides into the superficial temporal & maxillary arteries
- Retromandibular vein: formed from the superficial temporal + maxillary veins
Activity
Vasculature
- Arterial supply: posterior auricular & superficial temporal arteries (branches of external carotid)
- Venous drainage: retromandibular vein
Innervation
Sensory:
- Auriculotemporal nerve (gland)
- Great auricular nerve (fascia)
Parasympathetic (↑ saliva):
- Origin: Glossopharyngeal nerve (CN IX)
- Synapse: Otic ganglion
- Postganglionic fibers: via auriculotemporal nerve
Sympathetic (↓ saliva):
- Origin: superior cervical ganglion
- Travel: along the external carotid artery
Activity
Clinical Relevance
Parotid Tumours
The parotid is the most common site of salivary gland tumours, often benign (e.g., pleomorphic adenoma). Parotidectomy risks injury to the facial nerve → resulting in muscle paralysis and facial droop.
Parotitis
Inflammation of the parotid gland, often infectious. Because the gland is enclosed in a tight capsule, swelling is painful. Pain may refer to the external ear due to auriculotemporal nerve overlap.
