Salivary gland ultrasound is a high-yield small parts study. The glands are superficial, accessible, and ultrasound is often the first — and sometimes only — imaging needed to answer the clinical question. Understanding what to look for separates a good scan from a great one.

Major Salivary Glands: Anatomy

Parotid Gland

Largest of the three major glands. Lies in the preauricular region, anterior and inferior to the ear, extending into the retromandibular region.

Structure: Two lobes (superficial and deep) separated by the facial nerve — the nerve is not directly visible on ultrasound, but its course (from the stylomastoid foramen through the gland) determines surgical approach. Stensen's duct drains anteriorly into the oral cavity at the upper second molar.

Normal echogenicity: Isoechoic to slightly hyperechoic compared to adjacent muscle. Homogeneous.

Intraparotid lymph nodes: Normal — the parotid is the only major salivary gland that contains lymph nodes. These are often visible as small oval hypoechoic structures within the gland.

Submandibular Gland

Located in the submandibular triangle (floor of mouth, below the mandible). Wharton's duct opens at the sublingual papilla near the frenulum.

Normal echogenicity: Similar to parotid — homogeneous, moderate echogenicity.

Size: Roughly 3 × 2 × 2 cm (variable).

Sublingual Gland

Smallest of the major glands. Located in the floor of the mouth. Not always well-visualized on standard neck ultrasound.

Scanning Technique

Probe: 12–15 MHz linear transducer — high frequency for these superficial glands.

Patient position: Supine, head extended slightly, turned away from the side being examined.

Protocol:

Survey the gland in transverse — sweep through the entire gland
Long axis — measure length
Identify the duct — Stensen's (parotid) or Wharton's (submandibular) — look for any dilation or calculus
Doppler — color flow to characterize vascularity of any mass
Compare to contralateral side — asymmetry is significant

Normal Measurements

Gland	Approximate Size
Parotid	5–6 × 3–4 × 2–3 cm
Submandibular	3–5 × 2–3 × 2–3 cm

Document if you can't visualize a gland or if it appears atrophic.

Inflammatory Conditions

Acute Sialadenitis

Bacterial infection of a salivary gland — usually parotid or submandibular. Common organism: Staphylococcus aureus. May follow dehydration, post-surgical period, or dental work.

Sonographic findings:

Gland enlargement
Decreased echogenicity (edema) — diffuse or focal
Increased vascularity on color Doppler — hypervascular gland
Thickened overlying skin/subcutaneous tissue
± Reactive periparotid/submandibular lymphadenopathy

Abscess formation: Focal anechoic or hypoechoic collection within the gland; complex, with internal echoes. Doppler: absent flow centrally; rim vascularity.

Chronic Sialadenitis / Sialolithiasis

Ductal obstruction from calculi (stones) → chronic inflammation.

Submandibular gland: Most common site for calculi (80–90%) — Wharton's duct has a longer, tortuous course.

Parotid: Less common calculi but still occurs (Stensen's duct calculi).

Sonographic findings of calculi:

Echogenic focus within the duct or gland parenchyma
Posterior acoustic shadowing (as with gallstones — the higher the calcium content, the more shadowing)
Small calculi (< 3 mm) may not shadow
Ductal dilation proximal to the stone

Always trace the duct: Start at the gland hilum and follow the duct distally. A dilated duct with an echogenic focus at any point = calculus until proven otherwise.

Sjögren's Syndrome

Autoimmune destruction of salivary and lacrimal glands. Bilateral parotid and submandibular involvement.

Sonographic findings:

Heterogeneous echotexture — classic "Swiss cheese" or geographic hypoechoic areas
Lobulated, irregular appearance
Multiple cystic (anechoic) foci within parenchyma
Hypervascularity on Doppler
Normal or enlarged glands early; atrophic in chronic disease
Associated cervical lymphadenopathy

Clinical note: Increased lymphoma risk in Sjögren's — any dominant mass within the gland deserves further evaluation.

Benign Tumors

Pleomorphic Adenoma (Benign Mixed Tumor)

Most common salivary gland tumor (70% of all salivary tumors). Most common in the parotid gland (superficial lobe).

Sonographic appearance:

Well-defined, oval or rounded mass
Hypoechoic relative to normal gland parenchyma
Homogeneous (small) or heterogeneous (larger — may have cystic areas)
Smooth, well-defined capsule
Posterior acoustic enhancement (due to soft tissue vs surrounding gland)
Low to moderate vascularity on Doppler

Important: Pleomorphic adenoma has a small but real risk of malignant transformation (carcinoma ex pleomorphic adenoma) — especially if untreated > 10–15 years or if growing rapidly.

Reporting: Document size, location within the gland (superficial vs deep lobe), and proximity to the facial nerve (deep lobe masses may require total parotidectomy).

Warthin's Tumor (Papillary Cystadenoma Lymphomatosum)

Second most common benign parotid tumor. Almost exclusively in the parotid gland, particularly the inferior pole (tail of parotid). Associated with smoking.

Sonographic appearance:

Well-defined
Heterogeneous — mixed solid and cystic components; "honeycomb" or mixed architecture
Hypoechoic to anechoic cystic areas within a predominantly solid mass
Often bilateral or multifocal (10–15% bilateral, 10–15% multiple)
Doppler: moderate vascularity

Malignant Tumors

Malignant salivary gland tumors are uncommon but important to recognize.

Types: Mucoepidermoid carcinoma (most common), adenoid cystic carcinoma, acinic cell carcinoma, carcinoma ex pleomorphic adenoma.

Concerning ultrasound features:

Irregular, ill-defined margins
Heterogeneous internal architecture
Infiltrative growth (poorly demarcated from surrounding gland)
Adjacent lymphadenopathy (with loss of hilum, rounded nodes)
Marked vascularity (disorganized, peripheral pattern)
Fixation to surrounding structures

If any of these features are present → MRI (or CT) is recommended. Ultrasound alone cannot reliably diagnose malignancy in salivary gland tumors.

Key Images to Capture

Parotid gland — long and transverse views with measurements
Submandibular gland — long and transverse views with measurements
Stensen's duct / Wharton's duct — document if dilated or obstructed
Any mass — two planes, three dimensions, Doppler
Periparotid / submandibular lymph nodes
Contralateral gland for comparison

Reporting Language

Normal: "Bilateral parotid glands are symmetric, homogeneous, and of normal echogenicity. No focal mass, ductal dilation, or calculus. Small oval intraparotid lymph nodes noted bilaterally — within normal limits. Bilateral submandibular glands: normal size, echogenicity, and homogeneous parenchyma."

Calculus: "Dilated Wharton's duct identified within the right submandibular gland measuring 4 mm in diameter. A 5 mm echogenic focus with posterior acoustic shadowing is identified within the proximal right submandibular duct, consistent with a sialolith. The right submandibular gland parenchyma is mildly heterogeneous with increased echogenicity, consistent with chronic sialadenitis."

Mass: "2.4 × 1.8 × 2.1 cm well-defined, oval hypoechoic mass in the superficial lobe of the right parotid gland. The mass has a thin echogenic capsule, posterior acoustic enhancement, and moderate internal vascularity. No adjacent lymphadenopathy. Sonographic features are most consistent with a pleomorphic adenoma. MRI of the parotid is recommended for pre-operative characterization."

SonoBuddy's small parts protocols include thyroid, salivary gland, lymph node, and soft tissue ultrasound guides.

Salivary Gland Ultrasound: Parotid, Submandibular, and Pathology