RADIO-ANATOMY

PAROTID GLANDAND

SUBMANDIBULAR GLAND

OVERVIEW OF ANATOMY

1)- DEVELOPMENTAL AND GROSS ANATOMY2)- ULTRASOUND FEATURES3)- X RAY4)- CT AND MRI ANATOMICAL LOCATION

PAROTID GLANDDevelopment

• Appear early - sixth week of prenatal age.• The epithelial buds of these glands are located on the inner

part of the cheek, near the labial commissures of the primitive mouth

• Grow posteriorly toward the otic placodes of the ears and branch to form solid cords with rounded terminal ends near the developing facial nerve.

• 10 weeks of prenatal development, these cords are canalized and form ducts, with the largest becoming the parotid duct for the parotid gland.

• Secretion by the parotid glands via the parotid duct begins at approximately 18 weeks of gestation.

Location• Inferior and anterior to the external acoustic meatus and

posterior to the mandibular ramus and anterior to the mastoid process of temporal bone.

Draining• The vestibule of oral cavity through Stensen duct or parotid

duct that emerges from the anterior border of the gland, superficial to the masseter muscle pierces the buccinator muscle, then opening up into the oral cavity on the inner surface of the cheek, usually opposite the maxillary second molar.

• The parotid papilla is a small elevation of tissue that marks the opening of the parotid duct.

Surfaces and borders

• The gland has four surfaces superficial or lateral,superior, anteromedial and posteromedial.

• The gland has three borders anterior, medial and posterior.

• The Parotid gland has two ends: superior end in the form of small surface and an inferior end (apex).

Structures that pass through the gland

These are from lateral to medial:

(1) Facial nerve (2) Retromandibular vein (3) External Carotid artery (4) Superficial temporal artery (5) branches of the great auricular nerve

Blood SupplyThe gland is mainly irrigated by External Carotid artery via the posterior auricular artery and the transverse facial.

Venous DrainageVenous return is to the Retromandibular vein.

Lymphatic drainageThe gland is mainly drained into the preauricular or parotid lymph nodes which ultimately drain to the deep cervical chain.

SUBMENDIBULAR GLAND

• Develop later than the parotid glands and appear late in the sixth week of prenatal development.

• They develop bilaterally from epithelial buds in the sulcus surrounding the sublingual folds on the floor of the primitive mouth.

• Arise of solid cords branch from the buds and grow posteriorly, lateral to the developing tongue. The cords of the submandibular gland later branch and then become canalized to form the ductal part.

• The submandibular gland acini develop from the cords’ rounded terminal ends at 12 weeks, and secretory activity via the submandibular duct begins at 16 weeks. Growth of the submandibular gland continues after birth.

LOCTION• Lying superior to the digastric muscles, divided into

superficial and deep lobes, which are separated by the mylohyoid muscle.

• The superficial lobe comprises most of the gland, with the mylohyoid muscle runs under it. The deep lobe is the smaller part.

Indications• Indications include:• In the evaluation of the functional integrity of the salivary glands• In case of obstructions• To evaluate the ductal pattern• In case of facial swellings, to rule out salivary gland pathology• In case of intra-glandular neoplasms.

Containdications • Persons who are allergic to iodine and/or contrast medium.• Cases where there is acute infection,• patients with thyroid function tests• When calculi are located in anterior part of the salivary gland duct

Sialography

It is a fatty glandular tissue that is encased in a dense capsule. Because of this, the parotid gland on CT is consistently more lucent (-25 to 10 Hounsfield units [H]) than surrounding muscles (35-60 H) and likewise is distinctly more radiodense than adjacent fat in the subcutaneous tissues, infratemponal fossa, and lateral pharyngeal space(-125 to -50 H)(figs. 1A, 1B, and 2B).

CT OF SLIVERY GLAND