Anatomic Alert: Spinal accessory nerve traversing a fenestrated internal jugular vein

Area of Science:

• Neurosurgery
• Anatomy
• Vascular Anatomy

Background:

• The spinal accessory nerve (cranial nerve XI) and internal jugular vein (IJV) are critical structures in the upper neck.
• Variations in the anatomical course of these structures can impact surgical procedures.

Observation:

• A unique case is presented where the spinal accessory nerve coursed through a fenestrated segment of the internal jugular vein.
• This fenestration represents an unusual anatomical variant.

Findings:

• The spinal accessory nerve demonstrated an atypical pathway by traversing a fenestrated internal jugular vein.
• This finding highlights a previously undocumented anatomical variation.

Implications:

• Awareness of this spinal accessory nerve and IJV variant is essential for neurosurgeons.
• Understanding this variant can prevent iatrogenic injury during upper cervical spine and neurosurgical interventions.