Anatomy of Parotid Gland

🦷 Anatomy of the Parotid Gland

The parotid gland is the largest major salivary gland, located in the parotid bed.

• Wedge-shaped
• Weighs 20–25 g

What are the boundaries of parotid bed?

What type of acini is predominant in parotid gland?

What is accessory parotid gland?

🧩 Classification of Salivary Glands

• Major glands (paired): Parotid, Submandibular, Sublingual

• Minor glands: Numerous small glands scattered in lips, cheeks, palate, tongue

📐 Extent of Parotid Gland

• Superior: Zygomatic arch

• Inferior: Upper neck (over posterior belly of digastric + anterior SCM)

• Anterior: Masseter muscle

• Posterior: Below external auditory canal → mastoid process (over C1 lateral process)

• Medial: Between mandible (anterior) and mastoid + styloid (posterior)

🧳 Capsules of Parotid

• True capsule: From fibrous stroma of gland

• False capsule (parotid sheath): From splitting of investing layer of deep cervical fascia

What are the attachments of False capsule of parotid gland?

What is the clinical significance of attachmenent of False capsule?

🧭 Lobes of Parotid

Divided by facial nerve, retromandibular vein, external carotid artery into:

• Superficial lobe: ~80% (extends anterior & inferior to EAC → angle of mandible)

• Deep lobe: ~20% (extends into stylomandibular tunnel)

What is fasciovenous plane of Patey?

What is the clinical significance of patotid lobes?

🔎 Parts of Parotid Gland

• Apex: Over posterior belly of digastric (Carotid triangle)

• Base: Concave, related to EAC + posterior Temporo Mandibular Joint

What are the structures passing through the apex and base of parotid gland?

• Surfaces:

  • Superficial: Covered by skin → superficial fascia (platysma, great auricular nerve) → parotid fascia
  • Anteromedial: Masseter, ramus of mandible, Temporo Mandibular Joint capsule, medial pterygoid, maxillary artery
  • Posteromedial: Mastoid, Sternocleidomastoid, posterior digastric, styloid + attached muscles, ICA, IJV, last 4 cranial nerves, facial nerve entry

• Borders:

  • Anterior
  • Posterior
  • Medial

What are the structures related to the different borders of parotid gland?

🌿 Processes of Parotid gland

• Facial process
• Accessory process (accessory parotid gland)
• Pterygoid process
• Glenoid process
• Carotid process
• Pre-styloid & Post-styloid processes

🩺 Structures Passing Through Parotid

From superficial → deep (Nerve → Vein → Artery):

1. Facial nerve

   • Enters via posteromedial surface
   • Divides into temporofacial & cervicofacial trunks → 5 terminal branches (Temporal, Zygomatic, Buccal, Marginal mandibular, Cervical)

2. Retromandibular vein

   • Formed by superficial temporal + maxillary vein
   • Divides into:
     • Anterior division → joins facial vein → common facial vein
     • Posterior division → joins posterior auricular vein → external jugular vein

3. External carotid artery

   • Divides into superficial temporal + maxillary arteries
   • Also gives transverse facial artery, sometimes posterior auricular artery

What is pes anserinus?

What incision is given for drainage of parotid abscess?

🚰 Parotid Duct (Stensen’s Duct)

• Length: 5 cm, Caliber: 0.6 mm

• Formation: By union of 2 ducts within gland

• Course:

  • Emerges from anterior border → runs on masseter
  • Turns medially (1st bend) → pierces buccal fat pad, buccopharyngeal fascia, buccinator, buccal mucosa
  • Runs 1 cm within → bends again (2nd bend) → opens opposite upper 2nd molar (vestibule of mouth)

What is the surface marking of parotid duct?

What are the structures pierced by parotid duct?

What is the clinical signficance of the course of parotid duct?

🩸 Blood Supply and Lymphatic Drainage of Parotid gland

• Arterial supply: External carotid artery branches

• Venous drainage: Retromandibular vein → external & internal jugular veins

• Lymphatic drainage: Superficial & deep parotid nodes → jugulodigastric deep cervical nodes

⚡ Nerve Supply of Parotid gland

• Parasympathetic (secretomotor – watery)
• Sympathetic (mucous-rich)
• Sensory: Auriculotemporal nerve, Greater auricular nerve (C2, C3)

What is the pathway of parasympathetic innervation of parotid gland?

What is Frey’s Syndrome?