Retromandibular vein

Anatomy and course

The retromandibular vein arises posterior to the mandibular ramus, from the confluence of the superficial temporal and maxillary veins. Via the maxillary vein, the retromandibular vein is connected to the pterygoid venous plexus of the infratemporal fossa. The retromandibular vein runs within the substance of the parotid gland, superficial to the external carotid artery, digastric and stylohyoid muscles, and deep to the facial nerve. Along its course, the retromandibular vein drains the jaw, the lateral skull, the parotid gland and the masseter muscle. Upon reaching the inferior pole of the parotid gland, the retromandibular gland divides into an anterior and posterior branch.

• The anterior branch joins the facial vein just anteroinferior to the mandibular angle to form the common facial vein. The common facial vein continues inferiorly to reach the upper angle of the carotid triangle, where it drains into the internal jugular vein.
• The posterior branch pierces the investing layer of deep cervical fascia and joins the posterior auricular vein just below the apex of the parotid gland, forming the external jugular vein. This vein descends across the neck over sternocleidomastoid muscle to drain into the subclavian vein.

Anatomical variations

Relatively often, the retromandibular gland does not establish a connection with the posterior auricular vein to form the external jugular vein. In these cases, the external jugular vein is small, while the anterior jugular vein is reciprocally enlarged.