Anatomy of Salivary Glands

Anatomy of Salivary Glands

• The parotid gland is the largest, situated below the ear and enclosed by a capsule formed by the deep cervical fascia.
• It is divided into a superficial part (80%) and a deep part (20%).
• An accessory parotid gland might be present, extending along the parotid duct.
• The parotid gland receives its parasympathetic innervation from the auriculotemporal nerve and its sympathetic innervation from the plexus around the external carotid artery.
• Structures within the parotid gland from deep to superficial:
  • External carotid artery, maxillary artery, superficial temporal artery, posterior auricular artery
  • Retromandibular vein
  • Facial nerve and its branches

Submandibular Salivary Gland

• Located below the mandible.
• Duct: Wharton’s duct opens into the floor of the mouth at the sublingual papilla.
• Nerve supply: Parasympathetic from the chorda tympani nerve (branch of the facial nerve), sympathetic from the superior cervical ganglion.
• Blood supply: Facial artery.

Minor Salivary Glands

• Approximately 450 minor salivary glands are distributed in the lips, cheeks, palate, and floor of the mouth.
• They contribute about 10% of the total salivary volume.

Salivary Flow & Disorders

• Salivary flow originates primarily from the submandibular salivary gland.
• Sialorrhoea is increased salivary flow, often caused by drugs, cerebral palsy, or psychiatric conditions.
• Xerostomia is decreased salivary flow, seen in postmenopausal women, depression, dehydration, medication side effects, and radiation therapy.

Salivary Calculus

• Sialography is used for diagnosing and treating salivary issues.
• Sialography should not be performed in acute inflammation.
• It is important to inject only 1 ml of dye during sialography, to avoid extravasation and chemical sialadenitis.

Acute Sialadenitis

• Inflammatory condition of the salivary glands.
• Can be caused by stasis (dehydration, duct obstruction), lack of oral hygiene, major surgery, radiotherapy, or infection (bacterial or viral).
• Mumps, a viral infection, commonly affects the parotid gland.

Parotitis

• Viral parotitis (mumps) is characterized by painful parotid enlargement and fever.
• Bacterial parotitis is often caused by Staphylococcus aureus.
• Endemic parotitis may result from parasitic infestations and protein malnutrition.

Submandibular Gland Pathology

• Causes for submandibular gland swelling include:
  • Stones or strictures within the submandibular gland duct.
  • Sialectasis (grape-like cluster appearance)
  • Masses
• Salivary colic, an intense pain associated with meals, might be a symptom of submandibular gland stones.
• A tender, firm swelling below the mandible that increases with meals is a common sign of submandibular gland disease.

Treatment of Salivary Gland Disorders

• Acute sialadenitis is managed with hot fomentations, analgesics, and antibiotics.
• Drainage under general anesthesia is indicated for localized, severe cases.
• Submandibular stones are removed intraorally if located in the duct or require excision of the gland if located within it.
• Conservative management is usually preferred for sialosis (benign salivary gland enlargement) but excision may be considered in complicated cases.

Parotid Fistula

• A fistula is a connection between the parotid gland or its ducts and the skin or oral cavity.
• It can be internal, external, or arise from the gland or duct.
• Commonly caused by abscess drainage, surgery, trauma, or tumors.
• Fistula from the duct usually produces profuse discharge, while fistula from the gland has a minimal discharge.

Parotid Tumor

• Most common tumor of the parotid gland is pleomorphic adenoma.
• Pleomorphic adenomas are slow-growing, usually painless, and can gradually increase in size.
• They do not typically affect the facial nerve, although long-standing tumors can develop into carcinomas.
• Adenolymphoma, another parotid tumor, is characterized by a "hot spot" on technetium scans and does not become malignant.
• Facial nerve paralysis is a concerning sign, indicating possible tumor involvement.

Surgical Complications

• Parotid surgery complications include bleeding, infection, nerve injuries (marginal mandibular, lingual, hypoglossal), and fistula formation.

Submandibular Salivary Gland Tumours

• Tumors in the submandibular gland can be treated with surgery, but careful attention is needed due to proximity to crucial nerves.
• Tumours often manifest as unilateral, painless, firm, smooth, mobile swellings in front of the parotid gland.

Key Considerations:

• The parotid and submandibular glands are crucial for salivary production.
• Salivary gland diseases are common and varied, impacting daily activities and overall health.
• Understanding anatomy, physiology, and pathology of the salivary glands is essential for diagnosing and treating these conditions effectively.
• Consult a healthcare provider if you suspect any salivary gland issues.

This quiz explores the anatomy and innervation of the major salivary glands, focusing on the parotid and submandibular glands. It covers their locations, structural components, and nerve supply. Test your knowledge on this essential topic in human anatomy.