Salivary stones represent grit blocking salivary ducts, thus preventing saliva drainage and causing gland enlargement.
Usually occurs in middle-aged adults, with a slight male preponderance.
Anatomy & Physiology
The parotid gland consists of a superficial (outer) and a deep
(inner) part, which are separated by the tree-like terminal branches of
the facial nerve, responsible for facial movement. Lymph nodes are
present within the gland.
Saliva leaves the gland through Stensen's duct, which pierces the
facial muscles and enters the mouth through the cheek opposite the
second upper molar tooth. Saliva flow is stimulated by chewing and the
presence of food in the mouth, particularly sour substances. The
stimulus is mediated via parasympathetic nerve fibres carried on the
auriculotemporal nerve to the parotid gland.
The submandibular gland consists of superficial and deep parts
separated by the myelohyoid muscle. The duct leaves the deep part of the
gland and enters the floor of the mouth, meeting its opposite partner.
The deep part of the gland is intimately related to the hypoglossal
nerve, which moves the tongue, and the lingual nerve, which provides
sensation to the front half of the tongue.
Saliva flow is stimulated via parasympathetic (chorda tympani) nerve fibres carried along the lingual nerve.
80% of stones occur in the submandibular gland, with 20% occurring in
the parotid gland. In most cases, multiple stones are found, but
multiple gland involvement only occurs in about 3% of patients.
Submandibular stones are thought to be more common because its saliva is
more alkaline and has a higher concentration of calcium and phosphate,
as well as a higher mucous content. Furthermore, the duct is longer and
has an antigravity flow.
The cause is unknown, but stones commonly occur in patients with
chronic sialoadenitis. These stones are predominantly made of calcium
phosphate on an organic matrix. Gout predisposes to stones made of uric
Recurrent pain and swelling of the involved glands is often
associated with eating. Infection may occur with repeated episodes of
obstruction and swelling. Stones may be palpable in the involved duct
and the gland may be tender.
Complications of Disorder
Complications include acute suppurative sialoadenitis and duct narrowing (stricture).
These may include:
- Plain X-rays to identify radioopaque stones. Despite their similar
chemical makeup, 90% of submandibular stones are radioopaque, but only
10% of parotid stones are radioopaque.
- Sialography, which involves injecting dye into the salivary duct
openings in the mouth to identify non-radioopaque stones and strictures
in the ducts, is 100% reliable in making the diagnosis if duct entry is
- Computed tomographic scanning +/- sialography
Conservative treatments give adequate relief for many patients and include:
- Sour foods (Sialogogues) to stimulate saliva flow.
- Massaging the affected salivary gland to promote saliva flow.
- Artificial saliva products and/or frequent small drinks.
- Antibiotics are required for episodes of acute inflammation.
Stones near the duct opening may be removed through the mouth. Stones
along the length of the duct can either be removed with small
endoscopes, with a basket to retrieve the stones, or can sometimes be
removed by cutting down on the duct with surgical instruments. Both
procedures carry the risk of scarring the duct and causing further
Stones within the gland traditionally are treated by removing the affected gland, but can now be shattered using a li