Parotid Gland: The Complete Reference

Overview of article

The parotid gland is a crucial part of the human body’s salivary gland system. This almond-shaped gland is situated near the ears and extends towards the jawline. It plays a pivotal role in maintaining oral health and digestion. In this comprehensive guide, we will delve into the anatomy, function, common issues, and clinical significance of the parotid gland. Let’s get into the components of the Parotid Gland.

Components of Parotid Gland

The parotid gland is one of the major salivary glands located in the head and neck region. It plays a crucial role in the production of saliva, which aids in digestion and oral hygiene. Understanding its borders and surfaces is essential for anatomical and medical purposes.

Borders

The parotid gland has several important borders:

1. Anterior Border: This border faces forward, toward your cheek.
2. Posterior Border: It is the backside of the gland, which is closer to your ear and the jaw joint.
3. Superior Border: This upper border is near the zygomatic arch, which is part of your cheekbone.
4. Inferior Border: The lower border of the parotid gland is closer to the jawline.

Surfaces

The parotid gland has several surfaces and borders, which are important for understanding its anatomical relationships. The surfaces of the parotid gland include:

1. Superficial Surface: The outermost surface of the parotid gland is covered by the skin and subcutaneous tissue of the face. It is the surface you can feel and observe from the outside.
2. Deep Surface: The deep surface of the parotid gland is in close proximity to important structures. Like the facial nerve (cranial nerve VII), the external carotid artery, and the retromandibular vein. These structures run through or adjacent to the gland.
3. Medial Surface: The medial surface of the parotid gland is located deep within the parotid region. It is in contact with the lateral surface of the ramus of the mandible (lower jawbone).
4. Lateral Surface: The lateral surface of the parotid gland is adjacent to the masseter muscle
   (responsible for chewing). The masseter muscle separates the parotid gland from the rest of the cheek.

Parotid Duct (Stensen Duct)

The parotid duct (or Stensen duct) is a slender tube-like structure that passes through the parotid gland. Its main function is to transport saliva produced by the gland into the mouth. It aids in digestion and keeps the mouth moist.

The parotid duct has a crucial role in maintaining oral health and facilitating the digestive process. If there are any issues with this duct, it can lead to problems with salivary flow. It may result in dry mouth or other oral health concerns.

In the upcoming part, we will discuss the Arterial Supply in the Parotid Gland region.

Arterial supply of Parotid Gland 

The parotid gland is one of the major salivary glands located in the facial region. Proper functioning of the parotid gland is crucial for maintaining oral health and the digestive process. To understand its blood supply, let’s explore the arteries that contribute to nourishing this gland.

Superficial Temporal Artery

The superficial temporal artery is one of the key contributors to the arterial supply of the parotid gland. This artery is a branch of the external carotid artery, which is the main supplier of blood to the face. The superficial temporal artery courses through the scalp, running along the side of the head. As it approaches the parotid gland, it divides into several smaller branches that penetrate the gland’s superficial layers.

These branches play a vital role in providing oxygen and nutrients to the parotid gland tissue. The oxygenated blood delivered by the superficial temporal artery is essential. For the metabolic processes within the gland cells, ensure proper saliva production and secretion.

Maxillary Artery

The maxillary artery is another critical artery that contributes to the arterial supply of the parotid gland. This artery is also a branch of the external carotid artery, originating deeper within the face. It takes a more posterior route compared to the superficial temporal artery.

As the maxillary artery courses through the facial region, it sends branches toward the parotid gland. These branches supply blood to the deep portions of the gland. It ensures that all areas of the parotid receive the necessary nutrients and oxygen. This distribution helps maintain the health and functionality of the gland’s cells.

Transverse Facial Artery Branches of the External Carotid Artery

The transverse facial artery is a smaller but significant contributor to the parotid gland’s blood supply. This artery is a branch of the external carotid artery, similar to the superficial temporal and maxillary arteries. It takes a more lateral course, running across the face.

As it approaches the parotid gland, the transverse facial artery divides into smaller branches that enter the gland’s lateral aspects. These branches provide an additional source of blood to the gland, ensuring comprehensive coverage of the parotid tissue.

In the next part, we will discuss the venous drainage in the Parotid Gland, and how the various veins work.

Venous drainage of the Parotid Gland

Venous drainage refers to the system of veins responsible for carrying deoxygenated blood away from the parotid gland. Let’s discuss the venous drainage in the Parotid Gland.

Maxillary Vein

The Maxillary Vein is a significant vessel involved in the venous drainage of the parotid gland. Here’s a detailed explanation:

• Location: The Maxillary Vein is a branch of the external jugular vein and is located in the head and neck region. It plays a vital role in draining blood from several structures in the face, including the parotid gland.
• Function: The Maxillary Vein collects deoxygenated blood from the parotid gland and various other facial structures. This blood eventually travels to the internal jugular vein, which is a major vein in the neck. From there, it joins the superior vena cava and eventually returns to the heart for oxygenation.
• Importance in Parotid Gland Drainage: The Maxillary Vein is responsible for carrying away deoxygenated blood from this salivary gland. The gland’s overall function, as it ensures that waste products are removed and that the gland continues to function properly.

Superficial Temporal Vein

The Superficial Temporal Vein is another important vessel involved in the venous drainage of the parotid gland. Here’s more information:

• Location: The Superficial Temporal Vein is located on the side of the head, running in the scalp region. It is a tributary of the external jugular vein.
• Function: Drains the temporal region of the head, including the scalp, and also contributes to the venous drainage of the face.
• Importance in Parotid Gland Drainage: Drains blood from the parotid gland, along with other veins in the facial region. It’s essential for carrying away deoxygenated blood, helping to maintain the health and function of the gland.

In the upcoming section, we will understand the Lymphatic Drainage of the parotid Gland.

Lymphatic Drainage of Parotid Gland 

The parotid gland has a network of lymphatic vessels responsible for draining excess fluid and waste products. These lymphatics are divided into two sets: the superficial set and the deep set. Let’s understand both of them in detail.

Superficial Lymphatic Drainage

The superficial lymphatic drainage of the parotid gland primarily involves the lymphatic vessels and nodes. Located near the surface of the gland and the adjacent structures of the face and neck. Here are the lymphatic drainage systems:

1. Parotid Lymph Nodes: There are several parotid lymph nodes that are superficially located around the parotid gland. These nodes serve as the first line of defense for draining lymphatic fluid from the superficial aspects of the gland. They are responsible for filtering and potentially containing infections or abnormal cells that may be present in the parotid region.
2. Submandibular Lymph Nodes: Some lymphatic vessels from the parotid gland may also drain into the submandibular lymph nodes. They are located just beneath the lower jaw (mandible). This drainage pathway can provide an alternative route for lymphatic fluid from the superficial aspects of the parotid gland.

Deep Lymphatic Drainage

The deep lymphatic drainage of the parotid gland involves a more intricate network of vessels and nodes. All are located deeper within the gland and the surrounding tissues. Here are the Lympathic Drainage systems:

1. Parotid Duct Lymphatics: Lymphatic vessels within the parotid gland itself. It is referred to as the parotid duct lymphatics, which drain lymphatic fluid from the deeper regions of the gland. These vessels transport the lymph towards deeper lymph nodes.
2. Deep Cervical Lymph Nodes: For lymphatic drainage from the deeper regions of the parotid gland are the deep cervical lymph nodes. These nodes are located in the neck, deep within the sternocleidomastoid muscle. Lymphatic fluid from the parotid gland can pass through several intermediary lymph nodes before reaching these deep cervical nodes.

In the next part, we will understand the innervation in the parotid gland. It involves various nerves like the Glossopharyngeal nerve (CN IX), and the Auriculotemporal nerves.

Innervation of Parotid Gland

Proper innervation is essential for the regulation of its secretory functions. It ensures the flow of saliva into the oral cavity during digestion. Two primary nerves play a significant role in the innervation of the parotid gland. Let’s discuss the various nerves and their important functions.

Glossopharyngeal Nerve (CN IX)

The Glossopharyngeal nerve (Cranial Nerve IX), is one of the twelve cranial nerves originating from the brainstem. This nerve has several functions, including the transmission of sensory information from the oropharynx and posterior third of the tongue. Regarding the parotid gland, CN IX plays a vital role in its innervation through the following processes:

• Sensory Innervation: The glossopharyngeal nerve carries sensory fibers that provide feedback from the parotid gland. It is responsible for detecting changes in salivary composition and flow. It helps to regulate salivary secretion in response to various stimuli, such as taste or the presence of food.
• Parasympathetic Innervation: CN IX also carries parasympathetic fibers that synapse in the otic ganglion, located near the parotid gland. Postganglionic fibers from the otic ganglion then stimulate the parotid gland to secrete saliva. This parasympathetic stimulation is crucial for the digestive process, as saliva contains enzymes that initiate the breakdown of food.

Auriculotemporal Nerves

The auriculotemporal nerves are branches of the mandibular division (V3) of the trigeminal nerve (Cranial Nerve V). These nerves are primarily responsible for providing sensory innervation to various regions of the head. It includes the skin of the temporal region and the external ear. In the context of the parotid gland, they are indirectly involved in its innervation:

• Parasympathetic Innervation: They contain parasympathetic fibers that originate from the otic ganglion. As mentioned earlier, plays a role in parotid gland innervation. These parasympathetic fibers travel along the auriculotemporal nerves. It eventually reaches the parotid gland, contributing to the stimulation of saliva secretion.

In the upcoming section, we will discuss the Histology of the Parotid Gland, including serous cells, and serous asini.

Histology of the Parotid Gland

The histology of the parotid gland involves examining its structure at the cellular and tissue levels. Let’s understand the histological features of the parotid gland.

Serous Cells

Serous cells are one of the two main types of secretory cells found in salivary glands, including the parotid gland. They are responsible for producing a serous secretion, which is a thin, watery fluid rich in enzymes and electrolytes. This fluid has several important functions, including:

• Enzymatic Digestion: Serous secretions contain enzymes like amylase, which begin the digestion of carbohydrates in the mouth. Amylase breaks down starches into simpler sugars, facilitating their absorption in the digestive tract.
• Moistening and Lubrication: It helps to moisten and lubricate the oral cavity and food, making it easier to chew and swallow.
• Antimicrobial Properties: Saliva, including serous secretions, contains antimicrobial proteins and antibodies that help protect the oral cavity from pathogens.

Serous cells are characterized by their distinctive appearance under a microscope. They have a rounded, central nucleus and abundant cytoplasm filled with secretory granules.

Serous Acini

Serous acini are specialized clusters or groups of serous cells within the parotid gland. These acini are responsible for synthesizing and releasing the serous secretion. Here’s a detailed breakdown of serous acini:

• Structure: Serous acini are typically spherical or pyramidal structures composed of numerous serous cells arranged in a closely packed manner.
• Secretory Granules: There are secretory granules that store enzymes and other molecules required for the production of serous secretion.
• Duct System: After the serous acini produces the serous secretion, it is released into a network of ducts. These ducts transport the secretion towards the oral cavity.
• Control: The production and release of serous secretion from serous acini are regulated by the nervous system. Stimulation from the parasympathetic nervous system, in response to the sight or smell of food, triggers the release of saliva.

In the next part, we will understand the Embryology of the Parotid Gland.

Embryology of Parotid Gland

The embryology of the Parotid Gland gives a brief overview of its structure and various functions. So, let’s discuss it by dividing it into various sections:

1. Development of Salivary Glands: The salivary glands, including the parotid gland, originate from the ectodermal lining of the oral cavity. During early embryonic development, the primitive oral cavity goes through a series of stages. It leads to the formation of the salivary glands. These stages include the appearance of epithelial buds and their subsequent branching and differentiation into the major salivary glands.
2. Formation of Parotid Gland Primordium: The development of the parotid gland begins with the formation of a primordium or initial structure. This primordium is a localized thickening of the oral epithelium, often referred to as a “bud.” It typically emerges along the course of the Stensen’s duct, which eventually becomes the main duct of the parotid gland.
3. Proliferation and Branching: Once the initial bud forms, it undergoes rapid proliferation and branching. This stage is critical in establishing the complex, branched structure of the parotid gland. The primitive ductal system begins to take shape during this phase.
4. Role of Neural Crest Cells: Neural crest cells are a specialized group of cells originating from the neural tube during early embryonic development. They play a crucial role in the development of the parotid gland. They migrate into the developing salivary gland tissue and contribute to its growth and differentiation.
5. Interaction with Surrounding Mesenchyme: The developing parotid gland interacts with the surrounding mesenchymal tissue. This tissue provides essential signals and factors necessary for its development. This interaction is vital for proper glandular growth and function.
6. Differentiation of Acini and Ducts: As the branching continues, the epithelial cells within the gland differentiate into components. Those two components are acini (secretory units) and ducts (transportation pathways). Acini are responsible for producing saliva, while ducts transport the saliva to the oral cavity.
7. Formation of Stensen’s Duct: Stensen’s duct, also known as the parotid duct, is a significant structure within the parotid gland. It forms as a result of the ductal differentiation within the glandular tissue. It carries the saliva produced by the parotid gland. Then releases it into the oral cavity near the second upper molar.
8. Maturation and Function: As development progresses, the parotid gland matures, and its secretory function becomes operational. Saliva production begins, contributing to the digestive process by moistening food and aiding in its initial breakdown.

In the next part, we will discuss the disorders and various conditions in the Parotid Gland. Some of the conditions are Parotid gland stones (Sialolithiasis), Parotid gland inflammation (Parotitis), Suppurative sialadenitis, and Parotid gland surgery.

Functions of the Parotid Gland

The parotid gland plays several important functions related to the digestive and oral health processes. Let’s discuss the primary functions of the parotid gland.

Saliva Production

The parotid gland is one of the three major pairs of salivary glands in the human body. It plays a crucial role in saliva production. Saliva is a clear, watery fluid composed of water, electrolytes, and various enzymes. It is essential for several key functions in the oral cavity and the digestive process.

Saliva is produced by the parotid gland to maintain oral health and facilitate the initial stages of digestion. Saliva serves as a lubricant, moistening the oral mucosa, and making it easier to speak, chew, and swallow. Furthermore, it aids in the digestion of carbohydrates and lipids through the action of amylase and lingual lipase.

Enzymes and Digestion

The parotid gland secretes amylase, which is vital for the breakdown of starches (complex carbohydrates) in the mouth. Amylase starts the process of carbohydrate digestion by breaking down starches into simpler sugars like maltose. This initial digestion step begins the conversion of complex carbohydrates into forms that can be absorbed in the small intestine.

Additionally, the parotid gland contains lingual lipase, an enzyme responsible for the digestion of lipids (fats). Most fat digestion occurs in the small intestine. Lingual lipase contributes to the initial breakdown of dietary fats in the mouth. This enzyme becomes especially significant in cases where fat digestion is compromised in the small intestine.

Role in Oral Health

Saliva, produced and secreted by the parotid gland among other salivary glands, is indispensable for maintaining oral health. It serves several critical functions in this regard:

1. Lubrication: Saliva keeps the oral mucosa moist, preventing dryness and discomfort. Dry mouth, or xerostomia, can lead to oral health issues like tooth decay and gum disease.
2. Buffering: Saliva helps maintain the pH balance in the mouth. The pH balance is crucial for preventing the growth of harmful bacteria that thrive in acidic conditions. A balanced pH level is essential for overall oral health.
3. Tooth Protection: Saliva contains calcium and phosphate ions, which are important for remineralizing tooth enamel. This process helps repair and strengthen tooth enamel, protecting against decay and erosion.
4. Antibacterial Properties: Saliva contains antimicrobial proteins and antibodies that can help combat harmful bacteria and pathogens in the mouth. Thus, contributing to the prevention of oral infections.

In the upcoming part, we will discuss the Disorders of the Parotid Gland, like stones, inflammation, and vice versa.

Disorders of the Parotid Gland

The parotid gland is one of the major salivary glands located in front of and just below each ear. Disorders of the parotid gland can cause various health issues and discomfort. We will explore some common disorders and conditions associated with the parotid gland:

1. Parotid Gland Stones (Sialolithiasis)– Sialolithiasis is a condition where small, hard, calcium deposits or stones form within the ducts of the parotid gland. Thus, obstructing the flow of saliva. This blockage can lead to pain and swelling in the affected gland.
2. Parotid Gland Inflammation (Parotitis)– Parotitis is the medical term for inflammation of the parotid gland. It can result from various causes, including viral or bacterial infections, autoimmune diseases, or obstruction of the salivary ducts.
3. Suppurative Sialadenitis– Suppurative sialadenitis is a more severe form of salivary gland infection, often associated with the parotid gland. It involves the presence of pus within the gland due to a bacterial infection.
4. Parotid Gland Surgery– Parotid gland surgery is a medical procedure that addresses various conditions affecting the parotid gland. It includes the removal of tumors, treatment of recurrent infections, or the removal of obstructive stones.

Conclusion

In conclusion, the parotid gland is vital to the human body’s salivary gland system. It plays a crucial role in maintaining oral health and aiding in digestion. Understanding its anatomy, blood supply, venous drainage, lymphatic drainage, and innervation is essential for medical professionals.

The parotid gland’s embryology reveals its fascinating journey from a primordial bud to a complex, functional structure. This understanding sheds light on its development and maturation, which ultimately contributes to its role in saliva production and secretion.

However, like any other part of the body, the parotid gland is susceptible to various disorders and conditions. Like sialolithiasis (parotid gland stones), parotitis (inflammation), suppurative sialadenitis, and the need for surgical interventions. Awareness of these issues and their respective diagnostic and treatment options is crucial for maintaining overall health and well-being.

Further Reading

We express our heartfelt gratitude to our readers for their unwavering support in engaging with the Intake Learn article on Anatomy. We will continuously provide significant information you can check articles like and .

For more information on this topic, you can check other sources:

1. Wikipedia: https://en.wikipedia.org/wiki/Parotid_gland
2. Wikipedia: https://en.wikipedia.org/wiki/Maxillary_vein

Attribution

1. http://www.med.mun.ca/, CC BY-SA 3.0, via Wikimedia Commons
2. Jpogi at Wikipedia, Public domain, via Wikimedia Commons
3. Brain_human_normal_inferior_view.svg: Patrick J. Lynch, medical illustratorderivative work: Beao, CC BY 2.5, via Wikimedia Commons
4. Mikael Häggström.When using this image in external works, it may be cited as:Häggström, Mikael (2014). “Medical gallery of Mikael Häggström 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.008. ISSN 2002-4436. Public Domain.orBy Mikael Häggström, used with permission., Public domain, via Wikimedia Commons
5. Nephron, CC BY-SA 3.0, via Wikimedia Commons
6. Stapanes77, CC BY-SA 4.0, via Wikimedia Commons
7. Afrodriguezg, CC BY-SA 3.0, via Wikimedia Commons