Neck Anatomy: Triangles, Swellings, and Diagnosis

The Neck

• Includes compartments, triangles, trachea, vessels, and lymph nodes
• Anatomical knowledge of the neck area is essential for safe clinical and surgical practice

Triangles of the Neck

• The sternomastoid muscle divides the neck into anterior and posterior triangles
• The digastric muscle & superior belly of omohyoid muscle divide the anterior triangle into sub-mental, digastric, carotid, and mascular sections

DD of Neck Swellings

• General neck swellings can be related to the skin, subcutaneous tissue, vessels, nerves, lymphatics, or muscles
• General neck swellings are present everywhere

Examples of General Swellings:

• Sebaceous cyst
• Lipoma
• Hemangioma
• Neurofibroma
• Lymphangioma
• Tumors
• Midline neck swellings include:
  • Submental abscess
  • Ludwig's angina
  • Plunging ranula
  • Sequestration dermoid cyst (submental or suprasternal)
  • Enlarged lymph nodes (submental, prelaryngeal, or pretracheal)
  • Swelling in suprasternal (Burns's) space
    • Cystic:
      • Dermoid cyst: Aspiration differentiates it from a cold abscess
      • Aortic arch aneurysm: Presents with expansile pulsation
    • Solid: Lipoma or lymph nodes
• Lateral neck swellings include:
  • Submandibular triangle:
    • Salivary gland enlargement
    • Lymph node enlargement
    • Plunging ranula
    • Jaw tumors
  • Posterior triangle:
    • Lymph node enlargement (most common)
    • Cystic hygroma
    • Prominent cervical ribs
    • Subclavian aneurysm
    • Pharyngeal diverticulum
    • Pneumatocele
  • Carotid & muscular triangle:
    • Lymph node enlargement (most common)
    • Thyroid lobe enlargement (next common)
    • Branchial cyst
    • Branchiogenic carcinoma
    • Aneurysm of the carotid vessels
    • Carotid aneurysm
    • Carotid body tumor
    • Swellings of SCM muscle (e.g., hematoma or tumor)
    • Laryngocele

Rule of 7 in the Neck

• Based on the average duration of a patient's symptoms:
  • 7 days suggests inflammation
  • 7 months suggests neoplasm
  • 7 years suggests a congenital defect

Rule of 80 in the Neck

• 80% of nonthyroid neck masses are neoplastic
• 80% of neoplastic neck masses are seen in males
• 80% of neoplastic neck masses are malignant
• 80% of malignant neck masses are metastatic
• 80% of metastatic neck masses have a primary source above the clavicle

Fistulae & Sinus of Neck

• Thyroglossal fistula:
  • Site: Middle line
  • Opening: Crescent shaped
  • Track: Can be traced
• Tuberculous sinus:
  • Number & Site: Multiple over T.B. adenitis
  • Edge: Undermined
  • Margin: Cyanotic
  • Discharge: Thin serous discharge
• Sinus of hyoid bursitis:
  • Site: At the hyoid level
  • Shape: Oval
  • Discharge: Pus
• Cervicofacial actinomycosis:
  • Number: Multiple
  • Discharge: Yellowish Sulphur granules (colonies)
• Other types
  • Branchial fistula
  • Osteomyelitis of mandible
  • Salivary fistula

Number of Swellings

• Can be single or multiple
• Single Swelling:
  • Anterior Triangle:
    • In presence of swallowing movement:
      • Solid: Thyroid gland nodule or rare Lymph nodes
      • Cystic: Thyroglossal cyst
    • In absence of swallowing movement:
      • Solid: Carotid body tumor, Salivary gland tumor, rare Lymph nodes
      • Cystic: Dermoid cyst, Parapharyngeal lesions
• Posterior Triangle:
  • Solid: Lymph nodes
  • Cystic: Cystic Hygroma
  • Pulsatile: Subclavian artery aneurysm
• In the case of multiple swellings, generally consist of Lymph Nodes

Thyroglossal Cyst

• ETIOLOGY Midline tubulodermoid cyst due to patency of thyroglossal duct.
• LOCATION
  • Just below hyoid bone (most common)
  • Lies in the midline
  • Except at the level of thyroid cartilage where it is pushed to the left.
• STRUCTURE
  • Lining: Stratified columnar, cubical or squamous epithelium
  • Content: Clear viscid or mucoid fluid
  • Wall: Thin & may contain thyroid tissue
  • Narrow fibrous band extending from cyst wall to hyoid bone, potentially upwards to the tongue
• COMPLICATIONS
  • Recurrent infection
  • Thyroglossal fistula
  • Malignancy (1%)
    • Commonly papillary carcinoma, occasionally squamous cell carcinoma, and never medullary carcinoma.
• CLINICAL PICTURE
  • Number: Single
  • Site: Midline
  • Shape: Rounded or oval
  • Surface: Smooth
  • Edge: Well-defined
  • Consistency: Cystic
  • Movement: Moves up & down with deglutition (A) & protrusion of tongue (B) while the mouth is open, but not vertically
  • Tenderness: Not tender unless complicated
  • Track: may be palpable (Thyroglossal tug)
• SPECIAL TESTS
  • Hold track between 2 fingers & ask the patient to protrude his tongue, creating a special tugging sensation.
• DIAGNOSTIC STEPS
  • History and clinical examination, investigation, endoscopy & biopsy
• TREATMENT
  • Thyroid ultrasound or scan (to ensure thyroid gland is in place) then Sistrunk Operation with Horizontal elliptical incision placed over cyst or enclosing fistulous opening. Cyst or fistula + the whole track + central part of the hyoid bone + part of the base of the tongue may be excised.

Thyroglossal Fistula

• ETIOLOGY
  • Resulting from rupture or incision of thyroglossal abscess
  • Incomplete excision of thyroglossal track are always acquired
• PATHOLOGY
  • Track is lined with columnar epithelium connecting an external opening to the hyoid bone,connected to wall of cyst OR remnant
  • Near the midline
  • Crescentric & convexity directed upwards
  • Discharge viscid fluid or pus
• CLINICAL PICTURE
  • History of abscess followed by small opening, which discharge viscid fluid or pus.
  • External opening moves up: with deglutition & protrusion of the tongue, and overlying hood sign is characteristic

Cystic Hygroma (Hydrocele of the Neck) = (Cavernous Lymphangioma)

• ETIOLOGY
  • Caused by sequestration of a portion of the jugular lymph sac
• SITE
  • Posterior triangle of the neck (75%) “Most common”
  • Axilla (20%)
  • Cheek, Tongue, Groin, Mediastinum
  • Extension across two or more lymphatic regions
• STRUCTURE
  • Multilocular
  • Containing an aggregation of cysts looking like soap bubbles
  • Does not communicate with lymphatics, filled with clear mucous
  • Fluid does not coagulate
• CLINICAL FEATURES
  • Age: Present at birth (may be obstructed labor) or Occasionally present in early infancy
  • Surface: Smooth
  • Consistency: Soft & cystic (fluctuant)
  • Special: brilliantly transilluminant partially compressible, not reducible
  • Size Increase during crying
• COMPLICATIONS
  • Disfigurement of face (more worrying for parents)
  • Rapid increase in size → Respiratory obstruction (dangerous sign)
  • Infection → Abscess (warm – tender – soft)
  • Septicemia (life threatening)
  • Rupture (chylous fistula – chylothorax)
  • Recurrence of cyst (15%)
• DIAGNOSTIC STEPS
  • History and clinical examination, investigation, endoscopy & biopsy
• TREATMENT
  • Preoperative MRI and Aspiration of the contents is essential. Then Preoperative injection of sclerosants with excision of entire aggregation of cysts
  • NB: meticulous dissection across all planes including deeper muscular one to clear entire cyst wall to prevent recurrence
  • If abscess develops they are Drained under proper antibiotics or later excised and If respiratory obstruction, perform Aspiration and tracheostomy are done

Branchial Cyst

• ORIGIN
  • Branchial cyst arises from 2nd branchial cleft remnants rarely 1st, 3rd, 4th
• SITE
  • Anterior border of upper ⅓ of SCM muscle
• AGE
  • Congenital with presentation during late adolescents & early 3rd decade
• SEX
  • Equal in both sexes
• SIDE
  • In 3% cases, it is bilateral (may be familial)
• PAIN
  • Usually painless unless it is infected
• SURFACE
  • Smooth
• CONSISTENCY
  • Often tense, cystic, and transilluminant
• SPECIAL
  • NOT compressible or reducible
• PATHOLOGY
  • Contains Cholesterol crystals
  • Contains toothpaste like material that is typical of histologically identifiable Squamous epithelium with the occasional presence of ciliated columnar epithelium
• COMPLICATIONS
  • Recurrent infection
  • Rupture may cause acquired branchial fistula
  • Brachiogenic carcinoma "Very rare”
• DIAGNOSTIC STEPS
  • CT scan (to differentiate () it and chemodectoma if the cyst feels solid)
  • Aspiration (To differentiate () it and cold abscess by high cholesterol content)
• TREATMENT
  • Always required, performed under General anesthesia (G/A) because Cyst is near to carotids, 12th, 9th, 11th nerves, posterior belly of digastric, and pharyngeal wall and the posterior pillar of tonsils causing Complications such as injury to major structures, recurrent infection or fistula formation due to incomplete removal of track

Branchial Fistula

• CONGENITAL (A) -MCQ with Failure of fusion between 2nd & 5th branchial arches leading to Lies on lower ⅓ of SCM
• ACQUIRED (B)
  • Infection of branchial cyst & Incomplete excision, Lies on upper part of anterior border of sternomastoid from High in lateral wall of pharynx behind tonsil (Supratonsillar fossa of Rosenmuller) & Passes bifurcation of carotid.
• PATHOLOGY
  • congenital Pass() bifurcation of carotid with Lineage composed of ciliated columnar epithelium Surrounded by lymphoid tissue and mucus
• ACQUIRED
  • High in the lateral wall of the pharynx behind the tonsil (Supratonsillar fossa of Rosenmuller), and passes bifurcation of carotid.
  • Lineage formed by ciliated columnar epithelium, mucus or pus if infected
• CLINICAL PICTURE
  • Congenital
    • Usually presents at birth
      • It is common in children & early adolescent period that is connected to the pharynx
  • ACQUIRED
    • There is a history of infected branchial cyst, followed by a small opening
    • The opening discharges mucoid fluid rich in cholesterol or pus
• TREATMENT - Through a 2-3 transverse incision and higher skin incision to completely open and dissect a path.

Pharyngeal (Zenker's) Diverticulum

• Develops as midline mucosal herniation on the posterior aspect of the pharyngo-esophageal junction through Killian dehiscence.
• Failure of relaxation of the cricopharyngeal muscle will lead to Herniation of the pharyngeal mucosa. It increases intraluminal pressure or acquired pulsion diverticulum
• Limited by spine and when enlarged comes to a) lie to the side (usually left) or b) as well as behind the esophagus
• Is composed of, A,B,&C and lined by Mucosa – Submucosa, that form Incomplete muscular coat
• CLINICAL PICTURE
  • Includes regurgitation of non acidic material
• has at first a globular pouch form or Bleeding (rare) and may lead to Pneumonitis, Lung abscess or Pulmonary collapse and is known to predispose Carcinoma.
• Signs include Barium appearance or perforations, and endoscopy for perforation risk.
• The treatment follows special incisions

Carotid Body Tumor / Paragangliomas

• Chemoreceptor tissue in carotid body Chemodectoma
• Shape Oval
• Always encased in the adventitia, nonhormonally active and unilateral with the nerve traveling through the Glossopharyngeal nerve
• The external blood supply consist mainly of carotid, high levels of pressure or hypoxia (2–10 centimeters)
• Special incisions, and well placed high SCM levels will require vertixal and close attention to each patients complications
• The behavior It is benign or could be locally malignant, and is located in front of the anterior
• located in the level hyoid to be specific and in patients with high blood pressure can cause headaches or create syncope
• Theblood supply is from the artery and does not secrete anything
• Thetreatment in and will be require an incisions along anterior margin