Salivary glands
General
Anatomy
Topic Completed: 1 September 2015
Minor changes: 6 December 2020
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PubMed Search: Salivary glands[TI] anatomy[TIAB]
Table of Contents
Definition / general | Embryology | Diagrams / tables | Radiology images | Clinical images | Microscopic (histologic) images | Additional referencesCite this page: Tanakchi S, Aly FZ. Anatomy. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/salivaryglandsnormalanatomy.html. Accessed January 23rd, 2021.
Definition / general
- Parotid gland:
- Largest salivary gland (15 - 30 g), 6 x 3 cm
- It is wrapped around the mandibular ramus, has broad superficial lobe and smaller deeper lobe, with facial nerve usually between both lobes
- Provides only 25% of the total salivary volume but on stimulation, the parotid secretion rises to 50%
- Stensen duct (main duct) empties into the oral cavity opposite crown of second maxillary molar
- 20% have accessory parotid gland and duct, usually overlying the masseter muscle
- Parotid gland has its own fascia (capsule), which is continuous with superficial layer of deep cervical fascia
- Contains 3 - 24 lymph nodes (not all with complete structural organization), usually lateral to facial nerve in superficial lobe
- Blood supply: external carotid artery and its terminal branches
- Venous return: retromandibular vein
- Lymphatic drainage: preauricular lymph nodes that drain to the deep cervical chain
- Nerve supply: mainly autonomic through the glossopharyngeal nerve
- Vascular bundle (retromandibular vein, external carotid artery, superficial temporal artery and maxillary artery) lies medial to facial nerve
- Submandibular gland:
- Divided into superficial and deep lobes, separated by the myelohyoid muscle
- In submandibular triangle formed by anterior and posterior bellies of digastric muscle and inferior margin of mandible
- Weighs 50% of parotid gland (7 - 15 g)
- Provides 60 - 65% of the total salivary volume
- Wharton duct (submandibular duct) empties into the floor of mouth on both sides of the tongue frenulum at sublingual caruncla
- Lingual nerve wraps around Wharton duct, CN XII runs inferior and parallel to Wharton duct
- Has its own capsule, which is continuous with superficial layer of deep cervical fascia
- No lymph nodes within the capsule but 3 - 6 adjacent lymph nodes in submandibular triangle
- Blood supply: sublingual and submental arteries
- Venous return: anterior facial vein
- Lymphatic drainage: submandibular nodes to upper deep cervical nodes
- Nerve supply: direct by sympathetic nervous system (facial artery plexus) and indirect by parasympathetic nervous system (chorda tympani)
- Sublingual gland:
- Smallest of major salivary glands (2 - 4 g)
- Lies deep to the floor of oral mucosa between mandible and genioglossus muscle
- Has no true fascial capsule
- Has no single dominant duct but is drained by 10 small ducts (ducts of Rivinus)
- Occasionally, several of more anterior ducts may join to form a common duct (Bartholin duct), which typically empties into Wharton duct
- Bartholin duct unites with the submandibular duct just prior to its opening into the oral cavity at the sublingual caruncula on both sides of tongue frenulum
- Blood supply: sublingual and submental arteries
- Venous return: sublingual vein
- Lymphatic drainage: submandibular lymph nodes
- Nerve supply: lingual and chorda tympani nerve (from facial nerve) provides parasympathetic supply
- Minor salivary glands:
- Except for the gingiva and anterior hard palate, minor salivary glands (500 - 1000, 1 - 5 mm each) are located throughout the submucosa of the oral cavity
- More numerous in posterior hard palate
- Each salivary unit has its own simple duct
- Most of these minor salivary glands are mucinous with the main exception of Ebner glands, which are serous glands located in the circumvallate papillae of the tongue
Embryology
- Parotid gland primordia (anlage) arises in weeks 5 - 6 from ectoderm, followed by submandibular gland primordia in week 6 from endoderm, then sublingual gland primordia in weeks 7 - 8 from endoderm
- Intraoral minor salivary glands (including von Ebner gland) develop during the third month from endoderm
- Primordia develop from primitive oral cavity (stomodeum) as buds, which proliferate as cords, form terminal bulbs, develop clefts and further proliferate as branches from original cord; then the process is repeated
- Lumens form in epithelial cords and progress to terminal bulbs; cells differentiate into various ducts and acini
- Connective tissue diminishes with maturation
- Parotid buds may penetrate intraparotid lymph nodes; rare with submandibular or sublingual structures
- Secretion by the parotid glands via the parotid duct begins at about 18 weeks of gestation, while secretion by the submandibular gland begins at 16 weeks of gestation
Diagrams / tables
AFIP images
Drawing of
the oral cavity
of a 9 week
old embryo
Parotid gland lymph nodes
Horizontal section
through lateral
portion of pharynx
Lateral view of
the head shows
anatomic position
Medial surface
of the mandible
and mylohyoid
muscle
Radiology images
Images hosted on other servers:
Figures 1a and 3a: normal anatomy
Clinical images
AFIP images
Right and left submandibular ducts
Microscopic (histologic) images
AFIP images
Proliferative
epithelial cord
of the developing
parotid gland
Moderately cellular,
fibrous stroma
in a 25 week old fetus
At high magnification,
the terminal tubules
are a double layer
of epithelial cells
Additional references
