ULTRASOUND OF THE

SUBLINGUAL GLANDS - Normal

•  The glands are very small and can sometimes only be seen if there is pathology.

Sublingual Glands

• The paired sublingual salivary glands lie immediately deep to the mucous membrane under the tongue, anterior to the submandibular glands.
• They drain primarily via a duct that joins the submandibular duct.

Grays anatomy plate1024: Salivary glands

Scan plane for the sublingual glands

Ultrasound of the Sublingual Glands -Protocol

Role of Ultrasound

Intraglandular and extraglandular lesions are to be localised and differentiated.
To identify the cause of:

• A palpable lump in the gland/neck.
• The patient can sometimes palpate a stone under the mandible or under their tongue. The stone can block the duct causing infection and swelling.
• Pain
• Mumps
• Illness, including mouth or dental infections
• Mouth dryness
• Abnormality on previous xrays,CT or sialogram
• Guidance of injection, aspiration or biopsy

Limitations

• If the patient cannot lie flat with their neck extended.
• The glands are very small and can sometimes only be seen if there is pathology.

Equipment Selection

A high frequency linear probe in the 7-14 MHz range. A small footprint such as a hockey stick  is easier to manipulate.

You may need to use a lower frequency or curved linear probe (5-7MHz) to visualise the deep portion .
Good colour / power / Doppler capabilities when assessing vessels or vascularity of a structure.
Be prepared to change frequency output of probe (or probes) to adequately assess both superficial and deeper structures.

Patient position

PATIENT PREPARATION

• The patient is lying supine
  
• Low collared shirt
• May have to remove jewellery
• Towel across the chest/shoulders
• Lie the patient so their head is at the top of pillow and extended back.
• A pillow or towel can be placed under the shoulders.

Scanning Technique

It is best visualised in transverse and longitudinal planes obtained from the submental position.

The average size of the normal gland is 32 x 12mm.

The gland is obscured anteriorly by the mandible.

Usualyy the sublingual ductal system cannot be visualised.

The sublingual glands are visualised submentally.

They are deep to the mylohyoid and lateral to the geniohyoid/genioglossus.

ECHOGENICITY

Homogeneous hyperechogenicity similar to the parotid gland.

Always scan both sides for symmetry.

Have the pts head extended.

Must scan all nodal regions.

Colour Doppler may also aid in the assessment of malignancy; the lesion with a disorganised colour Doppler flow pattern and RI >0.8, PI >2 is more likely to be malignant.

Common Pathology

Acute Inflammation

Sialadenitis – heterogeneous, hypoechoic gland, micro abscesses

Inflammatory Mass – hypoechoic ,ill defined gland, ducts within lesion

Abscess- frank fluid, gas microbubbles

The ultrasound distinction of benign and malignant lesions is not precise but suspicion should be aroused when the lesion is ill defined or locally invading, when it is deep in the lobe, and when neck nodes are present.

Basic Hard Copy Imaging

Longitudinal and transverse images.

Lymph nodes.

Submandibular Glands