This article discusses the anatomy, variations, function, and clinical significance of the retromandibular vein.
Anatomy
The retromandibular vein is formed by the joining of the superficial temporal vein with the maxillary vein. It then passes through the parotid gland (the largest of the salivary glands) behind the mandible (jawbone).
After it emerges from the parotid gland, the retromandibular vein forms two branches: the anterior and the posterior. Venous blood from the retromandibular veins drains into the internal jugular vein and external jugular vein:
The anterior retromandibular vein joins with the anterior facial vein. It forms the common facial vein, which drains into the internal jugular vein. The posterior retromandibular vein joins with the posterior auricular vein and forms the external jugular vein. The external jugular eventually drains into the subclavian vein.
The retromandibular vein is a deep vein, meaning it is far from the surface of the body. Unlike superficial veins, deep veins usually have a nearby artery with similar naming. Deep veins are larger and surrounded by muscle.
Anatomical Variations
In some people, the retromandibular vein follows different paths on the different sides of the face.
One 2018 study outlines four different retromandibular vein variations that may increase the risk of damage during certain facial surgeries.
Even rarer is when the retromandibular vein is entirely absent. When it’s not present, it can make surgery more difficult. It also changes how blood drains from the head and neck.
Function
The retromandibular vein drains venous blood from several areas around the head, including the:
Jaw Parotid gland Lateral skull Masseter muscle (a large muscle on the side of the head used during chewing)
Deep veins like the retromandibular vein are larger than superficial veins because they transport large amounts of blood back to the heart.
Clinical Significance
Potential anatomical variations of the retromandibular vein can make surgery in the facial area more difficult. By being aware of potential variations, surgeons can better prepare themselves for tricky facial surgeries.
In the rare case the retromandibular vein is absent, it poses a problem for surgeons who use the vein as a guidepost during certain facial surgeries such as a parotidectomy.
A study from 2018 outlines several case studies where anatomical variations of the vein were discovered during parotidectomies. Researchers explain that the variations may increase bleeding and nerve injury risk.
The location and variations of the retromandibular vein are also a concern during sagittal split ostomy surgery. This is one of the most common jaw surgeries. It is used to correct malformations of the lower jaw or improve overbite or underbite. Major bleeding or nerve damage can occur if the surgeon is not vigilant for variations.
Summary
The retromandibular vein is a deep facial vein that drains structures of the face, including the lateral (side) of the skull, jaw, parotid gland, and masseter muscle. It drains into the jugular veins. Its location and variation are essential to note when surgeons perform procedures on the parotid gland or jaw.
