Behind the Knife ABSITE 2026: Head and Neck Review

High-Yield Head and Neck Anatomy

• 📌 Thoracic Outlet Anatomy: From anterior to posterior, the structures are the subclavian vein, phrenic nerve, anterior scalene, subclavian artery, brachial plexus, and middle scalene.
• 💡 Neck Triangles: The anterior triangle is bounded by the midline, sternocleidomastoid, and mandible, containing the carotid sheath. The posterior triangle is bounded by the sternocleidomastoid, trapezius, and clavicle, containing the spinal accessory nerve.
• 🧠 Recurrent Laryngeal Nerve: Innervates all laryngeal muscles except the cricothyroid (innervated by the superior laryngeal nerve). It branches from the vagus nerve, looping behind the subclavian artery on the right and the aortic arch on the left.

Head and Neck Cancers

• 🎯 Most Common: Squamous cell carcinoma is the most common head and neck cancer, affecting men 5:1, with risk factors including alcohol, tobacco (synergistic effect), and HPV.
• 📈 Staging and Treatment: Stage 1 & 2 cancers are local disease, treated with surgery or radiation depending on location and morbidity. Stage 3 & 4 cancers are locally aggressive or have distant metastases, treated with a multimodal approach: wide local excision, modified radical neck dissection, followed by radiation +/- chemotherapy.
• ⚠️ Oral Squamous Cell Cancer: Cancers over 4 cm require resection with modified radical neck dissection and post-operative radiation.

Salivary Gland Tumors

• 🔬 Malignancy Risk: Smaller salivary glands have a higher malignancy risk (sublingual > submandibular > parotid).
• 🥇 Most Common Malignant: Mucoepidermoid carcinoma, treated with resection (total parotidectomy with facial nerve preservation if in parotid) and +/- radiation.
• 🐌 Adenoid Cystic Carcinoma: Slow-growing, tends to invade nerves; treatment is resection with +/- radiation, but surgical aggressiveness may be tempered by sensitivity to radiation.
• 🥈 Most Common Benign: Pleomorphic adenoma, treated with superficial parotidectomy. Recurrent or multifocal cases may be treated with radiotherapy. Avoid enucleation due to recurrence risk.
• 🧐 Warthin Tumor (Papillary Cystadenoma Lymphomatosum): More common in male smokers >60, can be bilateral; treatment is watchful waiting.

Unknown Primary Head and Neck Cancer

• 🔍 Workup: Thorough head and neck exam (including fiber optic exam), FNA or biopsy of regional node, CT of head/neck/chest +/- PET scan, followed by OR for direct laryngoscopy, esophagoscopy, and ipsilateral tonsillectomy with directed biopsies.
• 📍 Most Common Primary Sites: Tonsils, followed by the base of the tongue.
• 🔄 If Primary Still Unknown: Ipsilateral modified radical neck dissection and bilateral radiation.

Melanoma of the Head and Neck

• 📝 Diagnosis: Full-thickness biopsy (excisional, incisional, or punch); avoid shave biopsies.
• 📏 Treatment Margins: Resect with margins similar to other body sites (1 cm for <1mm depth, 2 cm for >2mm depth).
• 🤝 Lymph Node Management: Clinically positive nodes require lymphadenectomy. Sentinel lymph node biopsy is indicated for melanomas <8mm with ulceration or >=8mm depth.
• ↔️ Anterior vs. Posterior Drainage: Melanomas anterior to the tragus-to-tragus line drain to the parotid basin (superficial parotidectomy, selective anterior neck dissection). Posterior melanomas require a selective posterior neck dissection.

Quick Hits

• 🦴 Torus Palatinus: Painless bony overgrowth on the palate; usually asymptomatic, resect if interfering with dentures.
• ☀️ Oral Cavity Cancer: Most common site is the lower lip (sun exposure); flap reconstruction needed if > half the lip is resected.
• 🦠 EBV-Related Head and Neck Cancer: Classic nasopharyngeal squamous cell carcinoma, highly sensitive to radiation.
• 💧 Frey's Syndrome: Gustatory sweating after parotidectomy due to injury/cross-innervation of the auriculotemporal nerve.
• 😷 Suppurative Parotitis: Postoperative fever, pain, swelling at jaw angle; caused by Staphylococcus aureus; treated with hydration, antibiotics, and I&D if abscessed.
• 🗣️ Vocal Cord Dysfunction: Post-emergent surgical airway may cause thyroid cartilage fracture.
• 🩸 Tracheostomy Bleeding: Small bleeds: bronchoscopy to rule out fistula. Large bleeds: finger pressure against sternum, OR for innominate artery resection, primary tracheal closure, and buttress coverage.
• 🛡️ Preventing Tracheostomy Fistula: Place tracheostomy between 2nd and 3rd tracheal rings; lower placement (3rd-5th rings) increases risk.