Glandulae salivariae
The equine salivary glands include three major paired glands: the parotid (largest, located below the ear), the mandibular/submaxillary (medial to the mandible), and the sublingual (beneath the tongue). The parotid gland wraps around the base of the ear and is traversed by the facial nerve and external carotid artery. Horses are unique in that salivation is entirely reflexive, triggered by chewing, and does not occur in anticipation of food. The large volume of bicarbonate-rich saliva is essential for buffering the continuously secreting gastric acid.
Salivary gland disease is uncommon but can include sialoliths, sialadenitis, or trauma. The parotid region is relevant in evaluations of facial nerve function and guttural pouch disease. Reduced salivation can contribute to dental or oral problems.
## Overview A salivary mucocele (sialocele) is a collection of saliva in the tissues after rupture of a salivary duct or gland. In horses it most often involves the sublingual or parotid region and a
## Overview Parotid gland melanoma is a melanocytic tumor in the region of the parotid salivary gland, common in older gray horses. It appears as a firm nodular mass. Large tumors can affect the faci
## Overview Parotitis or sialadenitis is inflammation of the salivary glands, most often the parotid or mandibular. It may be infectious or secondary to blockage of the duct by a sialolith (salivary
Excessive drooling, facial swelling below the ear, or difficulty eating should be evaluated. Normal salivation occurs mainly during chewing.
## Overview A salivary mucocele (sialocele) is a collection of saliva in the tissues after rupture of a salivary duct or gland. In horses it most often involves the sublingual or parotid region and appears as a soft, fluctuant, painless swelling under the jaw or near the ear. Aspiration yields thick, mucus-like saliva. It may slowly enlarge. ## Causes Trauma or obstruction leading to duct rupture. ## Diagnosis Clinical appearance and aspiration of viscous saliva. Ultrasound helps define the extent. ## Treatment Surgical removal of the affected gland or duct ligation in many cases. Simple drainage often leads to recurrence. ## Recovery and Prognosis Good with appropriate surgery. ## Prevention None specific. Signs include: soft fluctuant painless swelling in the intermandibular space or parotid region; may slowly enlarge; aspiration yields viscous saliva
## Overview Parotid gland melanoma is a melanocytic tumor in the region of the parotid salivary gland, common in older gray horses. It appears as a firm nodular mass. Large tumors can affect the facial nerve (causing lip droop) or interfere with swallowing. Biopsy shows dark pigmented tissue. ## Causes Genetic predisposition of gray horses to melanoma. ## Diagnosis Physical examination and biopsy. Staging for internal spread if the mass is large. ## Treatment Surgical excision when feasible, local chemotherapy, or monitoring. Systemic options are limited. ## Recovery and Prognosis Good for local control of accessible masses. The overall melanoma tendency in gray horses is progressive. ## Prevention None. Regular monitoring of gray horses. Signs include: firm nodular mass near the parotid; possible lip droop from facial nerve involvement; dysphagia if large; dark cut surface
## Overview Parotitis or sialadenitis is inflammation of the salivary glands, most often the parotid or mandibular. It may be infectious or secondary to blockage of the duct by a sialolith (salivary stone). Signs include painful swelling, fever, difficulty chewing, and excessive salivation. ## Causes Bacterial infection, viral disease, or duct obstruction. ## Diagnosis Palpation, ultrasound, and sometimes sialography or endoscopy of the duct. ## Treatment Antibiotics, anti-inflammatories, and removal of any stone. Abscesses may need drainage. ## Recovery and Prognosis Good once the obstruction or infection is resolved. ## Prevention None specific. Signs include: painful swelling in the parotid or mandibular region; fever; difficulty chewing; excessive salivation; reluctance to eat
Salivary gland disease is uncommon but can include sialoliths, sialadenitis, or trauma. The parotid region is relevant in evaluations of facial nerve function and guttural pouch disease. Reduced salivation can contribute to dental or oral problems.
Excessive drooling, facial swelling below the ear, or difficulty eating should be evaluated. Normal salivation occurs mainly during chewing.
See the Salivary Glands on our interactive 3D horse model. Open 3D Model