## Distinguishing Feature: Facial Nerve Relationship **Key Point:** The facial nerve (CN VII) passes through the substance of the parotid gland, dividing it into superficial and deep lobes. This is the single most important anatomical discriminator between parotid and submandibular glands. ### Comparative Anatomy Table | Feature | Parotid Gland | Submandibular Gland | | --- | --- | --- | | **Nerve within gland** | Facial nerve (CN VII) | Lingual nerve (CN V₃) passes medial, not through gland | | **Type of secretion** | Serous (watery) | Mucoserous (mixed) | | **Duct opening** | Opposite upper 2nd molar | Opposite lower 2nd molar | | **Location** | Superficial to mandibular ramus | Deep to mandibular ramus, in submandibular fossa | | **Size** | Larger (~25 g) | Smaller (~15 g) | | **Lymph nodes** | Intraparotid nodes present | Submandibular nodes present | **High-Yield:** The facial nerve divides the parotid into: - **Superficial lobe** (lateral to nerve) - **Deep lobe** (medial to nerve, extends into lateral pharyngeal space) This anatomical relationship is clinically critical for parotid surgery — the nerve must be identified and preserved during dissection. ### Clinical Pearl Bell's palsy or facial nerve paralysis following parotid surgery indicates iatrogenic nerve injury. The submandibular gland has no such nerve traversing it, making it safer to dissect without risk of motor nerve injury. **Mnemonic:** **PENS** = **P**arotid has **E**xternal carotid and **N**ervus **S**eventh (facial nerve) 
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