Details of rare and novel anatomical variations in a case with bilateral long styloid processes.

Anatomical vascular variants are frequently reported; however, their broader anatomical context and potential associations with additional variations are often overlooked. This case report presents a unique combination of multiple rare and novel cervical vascular anatomical variants identified in a single patient, thereby highlighting the importance of comprehensive anatomical assessment. A 64-year-old female patient underwent a computed tomography angiography, during which several unexpected anatomical variants were identified: bilaterally elongated styloid processes, with differing ossified segments; bilateral internal jugular vein (IJV) compression at the atlas transverse processes, consistent with jugular nutcracker syndrome; and bilateral Launay's external carotid veins, which drained into the IJVs and communicated via the prevertebral venous plexus. Additionally, a bilateral overlap of the mastoid and transverse processes of the atlas was observed. The right lingual artery exhibited an unusual sinuous course, perforating the hyoglossus muscle. The left IJV displayed a 2.78 cm longitudinal fenestration, with distinct anterior and posterior arms. Complex venous communications were also noted, including a left anterior jugular vein (AJV)-superior thyroid vein connection, a bilateral AJV prelaryngeal anastomosis, and evidence of a drainage pathway from the left IJV to the right AJV. Furthermore, a left posterior external jugular vein (EJV) was observed, continuing the left occipital vein and draining into the left EJV. This case illustrates that the presence of a specific anatomical variant should prompt careful evaluation for additional, potentially unexpected variations. A thorough anatomical assessment can reveal complex interrelationships among vascular structures, which may have significant clinical and surgical implications.