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AN28.1-10 | Face & parotid region — Part 2

Facial Vessels, Deep Facial Vein & Lymph Drainage (AN28.3, AN28.5, AN28.8)

Facial Artery (AN28.3):
- Origin: External carotid artery (in the carotid triangle)
- Grooves the submandibular gland, then hooks around the inferior border of mandible (anterior to masseter) → pulsation palpable here
- Runs tortuously across the face to the medial angle of eye as the angular artery
- Branches: inferior labial, superior labial (anastomoses across midline to form labial arcade), lateral nasal, angular
- Anastomoses with the ophthalmic artery (ICA territory) at the medial canthus

Facial Vein:
- Begins as the angular vein at medial canthus (drains forehead via supratrochlear/supraorbital veins)
- Runs less tortuous than artery (straight downwards, posterior to artery)
- Drains into internal jugular vein below angle of mandible
- No valves — key property enabling retrograde flow toward cavernous sinus

Deep Facial Vein (AN28.8):
- Connects the facial vein to the pterygoid venous plexus (in the infratemporal fossa)
- Pterygoid plexus → emissary veins → cavernous sinus
- Surgical importance: Provides a second intracranial communication route; dental infections can spread via pterygoid plexus to cavernous sinus. Damage during operations in the infratemporal fossa can cause significant haemorrhage.

Lymph Drainage of Face & Neck (AN28.5):
The face drains via named nodes along predictable pathways:

• Parotid nodes → drain scalp, temporal region, upper face
• Buccal (facial) nodes → drain cheek, nose, lower eyelid
• Submandibular nodes → drain cheek, nose, upper/lower lip, anterior tongue, floor of mouth
• Submental nodes → drain tip of tongue, lower incisor region, central lower lip
• All ultimately drain to the deep cervical nodes (jugular chain along IJV)

Cervical node levels (important for cancer staging):
Levels I–VI; Level I = submental + submandibular; Level II/III/IV = upper/middle/lower jugular; Level V = posterior triangle; Level VI = central compartment.

Parotid Gland (AN28.9)

The parotid gland is the largest salivary gland, purely serous.

Parts: Has a superficial lobe and a deep lobe separated by the facial nerve (CN VII) as it passes through the gland — there is no true capsular division; the "lobes" are a surgical description.

Borders: Anteriorly: masseter and ramus of mandible; Posteriorly: mastoid process, SCM, posterior belly of digastric; Superiorly: zygomatic arch; Inferiorly: extends to angle of mandible.

Parotid duct (Stensen's duct): Emerges from the anterior border → runs horizontally on masseter (palpable when masseter is contracted) → pierces buccinator → opens into oral cavity opposite the upper 2nd molar tooth.

Contents (structures within the parotid — deep to superficial):
1. External carotid artery (divides into superficial temporal + maxillary arteries within gland)
2. Retromandibular vein
3. Facial nerve (CN VII) — most superficial of the major contents; divides into five branches
(Mnemonic: "Some Rascals May Find Answers" from deep to superficial)

Nerve supply of parotid: Secretomotor (parasympathetic) = auriculotemporal nerve (CN V3) carrying secretomotor fibres from the otic ganglion (preganglionic from glossopharyngeal CN IX via the lesser petrosal nerve). Sensory = auriculotemporal nerve.

Surgical importance: In parotidectomy, the facial nerve must be identified and preserved. The nerve is found at the stylomastoid foramen using landmarks (tragal pointer, posterior belly of digastric). Superficial parotidectomy (removes the superficial lobe while preserving CN VII) is the standard operation.

Frey's Syndrome (AN28.10):
After parotidectomy or parotid injury, aberrant regeneration of parasympathetic fibres from the auriculotemporal nerve into the sympathetic nerves of the overlying sweat glands and skin vessels occurs. Result: gustatory sweating — the patient sweats and flushes on the affected cheek when eating (stimulation of salivation also activates the misdirected sweat glands). Treated with topical anticholinergics (glycopyrrolate cream) or botulinum toxin injection.