Anatomy and Physiology of the Salivary Glands and Sialography

Types of salivaryglands

The Major Salivary Glands

• Parotid
• Submandibular
• Sublingual

The Minor SalivaryGlands

 

Embryology

• 6th-8th Weeks ofGestation
• Parotid
• First to develop
• Last to becomeencapsulated
• Autonomic NervousSystem Crucial

Anatomy of ParotidGland

• Wedge shaped with 5processes
• 3 Superficial
• 2 Deep
• Parotid Compartment
• Superior – Zygoma
• Posterior – EAC
• Inferior – Styloid,ICA, Jugular Veins
• 80% overlies
• Masseter &Mandible
• 20% Retromandibular
• Stylomandibular,Tunnel,Isthmus of Parotid
• Tail of Parotid

Parapharyngeal Space

• Prestyloid Compartment
• PoststyloidCompartment (Paragangliomas)

Stensen’s Duct

• Arises from anteriorborder
• 1.5 cm inferior toZygomatic arch
• Pierces Buccinator at2nd Molar
• 4-6 cm in length
• 5 mm in diameter

Parotid Capsule

• Superficial layer DeepCervical Fascia
• Superficial layer
• Deep layer

 

CN VII-Facial nerve

• 2 Surgical zones
• 3 Motor branches
• immediately
• Pes Anserinus – 1.3 cm
• Temperofacial Division
• Cervicofacial Division
• 5 Terminal branches

Localization of CN VII

• Tragal pointer
• Tympanomastoid suture
• Posterior bellyDigastric
• Styloid process
• Retrograde dissection
• Mastoidectomy

• Great Auricular nerve
• Auriculotemporal nerve
• Superficial Temporalvessels
• Frey’s Syndrome

Neural compartment-VII, Great Auricular,Auriculotemporal

Venous compartment-Retromandibular vein

Arterial compartment-SuperficialTemporal/Transverse Facial

Lymphatics

• Paraparotid &Intraparotid nodes
• Superficial & DeepCervical nodes

Submandibular Gland-Anatomy

 

• The ‘Submaxilla’
• Submandibular Triangle
• Mylohyoid ‘C’
• Marginal Mandibular branch
• Capsule fromsuperficial layer of Deep Cervical fascia

Wharton’s duct

• Exits medial surface
• Between Mylohyoid &Hyoglossus
• 5 cm in length
• Lingual nerve & CNXII

Innervation

Superior CervicalGanglion (symp)

Submandibular Ganglion(para)

Artery: Submentalbranch of Facial a.

Vein: Anterior Facial Vnerve.

Lymphatics: DeepCervical and Jugular chains

Facial artery nodes

Between Mandible &Genioglossus

No capsule

Ducts of Rivinus +/-Bartholin’s duct

Sialogram not possible

Innervation: Same asSubmandibular

Artery/Vein: Sublingualbranch of Lingual & Submental branch of Facial

Lymphatics:Submandibular nodes

Minor Salivary Glands

• 600-1,000
• Simple ducts
• Buccal, Labial,
• Palatal, Lingual
• Tumor sites:
• Palate, upper lip,cheek
• Lingual & Palatinenn.

Imaging of SalivaryGland-Important things to remember

• CT – Inflammatory
• MR – Tumor
• Children: U/S & MR
• NO sialogram duringactive infection
• Parotid is fatty

The Secretory Unit

• Acinus (serous, mucous,mixed)
• Myoepithelial cells
• Intercalated duct
• Striated duct
• Excretory duct

Microanatomy of Salivary glands

• Striated &Intercalated ducts well developed in serous, NOT mucous glands
• Striated duct: HCO3into, Cl from lumen
• Intercalated duct: Kinto lumen, Na from lumen, producing hypotonic fluid
• Excretory ducts do NOTmodify saliva

 

The Bicellular Theory

• Intercalated duct
• Excretory duct

The Multicellular Theory

Parotid: serous &fatty

Submandibular: mixed serous

Sublingual: mixed mucous

Stroma: Plasma cells

Function of Saliva

1. Moistens oral mucosa
2. Moistens & cools food
3. Medium for dissolvedfood
4. Buffer (HCO3)
5. Digestion (Amylase,Lipase)
6. Antibacterial (Lysozyme, IgA, Peroxidase, FLOW)
7. Mineralization
8. Protective Pellicle

 

Effects of Salivaryhypofunction

• Candidiasis
• Lichen Planus
• Burning Mouth
• Aphthous ulcers
• Dental caries
• Xerostomia not reliable

 

Production of Saliva

• Primary secretion
• Ductal secretion
• The “secretory potential”
• (hyperpolarizes)
• Increased flow rate yieldsdecreased
• hypotonicity & K

Autonomic Innervation

Parasympathetic

• Abundant, waterysaliva
• Amylase down

Sympathetic

• Scant, viscous saliva
• Amylase up

Salivary Flow

• 1-1.5 L/day (1 cc/min)
• Unstimulated state
• Submandibular
• Stimulated state
• Parotid
• Sublingual & minor
• Mucin

Effects of Aging

Total salivary flowindependent of age

Acinar cellsdegenerate with age

Submandibular glandmore sensitive to metabolic/physiologic change

Unstimulated salivaryflow more greatly affected by physiologic changes

Sialography

Radiologic examinationof the salivary glands

The submandibular andparotid glands are investigated by this method

The sublingual glandis usually not evaluated this way-Difficulty incannulation

Indications

• Ductal obstruction-Stonesor tumors
• Inflammation of a ductor gland

Contraindications

• Severe infection of agland
• Known allergies tocontrast media

Equipment

• Fluoroscopic unitw/spot film capabilities
• Cannula forintroducing contrast
• Connecting tubing
• Lemons
• Dilators for duct
• 5 mL syringe
• Overhead light
• Gauze
• Contrast

Preliminary andProcedure Radiographs

• Parotid-Tangential
• Perpendicular tocassette, directed to lateral surface of mandibular ramus
• Submandibular-Lateral
• Perpendicular tocassette, directed to 1 in. superior to mandibular angle to demonstrate parotidgland

• Inferior margin ofmandibular angle to demonstrate the submandibular gland

Patient Preparation

1. Thorough explanationof examination
2. Any removable dentalwork, jewelry, and other artifact causing opaque items must be removed
3. Consent must be signed

Procedure

• The patient firstsucks on a lemon wedge to open the ducts
• An overhead lamp isused to provide adequate light
• The duct iscannulated, not punctured, and contrast is introduced with fluoroscopicguidance
• Radiographs are obtained
• After the radiographs,the patient then sucks on a lemon wedge to evacuate the contrast
• Obtain post-procedureradiographs as indicated

Lateral Parotid GlandRadiograph

 

Lateral SubmandibularGlands