Parotid gland

 

**Parotid Gland: Anatomy, Nerve Supply, and Arterial Supply**

The parotid gland is the largest salivary gland located in the face. It plays a crucial role in producing saliva, which aids in the initial digestion of food and lubrication of the oral cavity. Let's explore the anatomy, nerve supply, and arterial supply of the parotid gland in this short lecture.

**Anatomy:**

The parotid gland is a bilateral, pyramidal-shaped gland situated in front of the ear, between the skin and the masseter muscle. It extends from the zygomatic arch superiorly to the angle of the mandible inferiorly. The gland is partially covered by the parotid fascia, which provides a protective layer.

**Nerve Supply:**

The parotid gland receives its parasympathetic innervation from the glossopharyngeal nerve (CN IX) via the lesser petrosal nerve. The lesser petrosal nerve carries the parasympathetic fibers from the glossopharyngeal nerve to the otic ganglion, located just below the foramen ovale. From the otic ganglion, the postganglionic parasympathetic fibers reach the parotid gland and stimulate salivary secretion.

The parotid gland also receives sympathetic innervation from the superior cervical ganglion. Sympathetic stimulation causes vasoconstriction in the blood vessels supplying the gland.

**Arterial Supply:**

The arterial blood supply to the parotid gland is mainly derived from the external carotid artery, which is one of the major branches of the common carotid artery. The external carotid artery gives rise to several branches that supply the parotid gland:

1. **Superficial Temporal Artery:** This artery gives off the transverse facial artery, which supplies the anterior part of the parotid gland.

2. **Maxillary Artery:** The maxillary artery gives rise to the deep auricular artery and anterior tympanic artery, both of which contribute to the blood supply of the parotid gland.

3. **Superior Temporal Artery:** This artery also contributes to the arterial supply of the gland.

**Clinical Significance:**

The parotid gland is susceptible to various conditions, including inflammation, infections (such as mumps), and tumors. Infections of the parotid gland can lead to painful swelling, which is a characteristic symptom of mumps. Tumors in the parotid gland can be benign (e.g., pleomorphic adenoma) or malignant (e.g., mucoepidermoid carcinoma). Surgical procedures involving the parotid gland require careful consideration of its nerve supply to avoid damage to the facial nerve, which runs through the gland.

In conclusion, the parotid gland is an important salivary gland located in the face. It receives parasympathetic innervation from the glossopharyngeal nerve and sympathetic innervation from the superior cervical ganglion. The arterial blood supply to the parotid gland is mainly derived from the external carotid artery, through its various branches. Understanding the anatomy and functions of the parotid gland is essential for diagnosing and managing conditions affecting this gland in clinical practice.

MCQs on Parotid Gland

Q1. The parotid gland is located between the skin and which muscle?

Q2. The parotid gland receives parasympathetic innervation from which cranial nerve?

Q3. Which nerve carries parasympathetic fibers to the parotid gland?

Q4. The arterial blood supply to the parotid gland is mainly derived from which artery?

Q5. The parotid gland extends from the zygomatic arch to which structure?

Q6. The parotid gland is partially covered by which protective layer?

Q7. Which branch of the external carotid artery contributes to the blood supply of the parotid gland?

Q8. The parotid gland is located in front of which anatomical structure?

Q9. The parotid gland is susceptible to various conditions, including inflammation and infections. Which condition is characterized by painful swelling of the parotid gland?

Q10. The parotid gland receives sympathetic innervation from which ganglion?