Microsurgical anatomy of the third segment of vertebral artery

Objective To accumulate the morphological data of the third segment of vertebral artery and to provide the basis of microvascular anatomy for clinical treatment. Method Ten adult cadaver heads (20 sides)were used in the study. The morphology of the third segment of vertebral arteries was observed and their dimensions were measured with the aid of an operating microscope. Results The third segments of the vertebral arteries were tortuous. The external diameters of left vertebral arteries(4. 01 ±1.12)mm were larger than that of the right ones (3.45± 0. 32) mm. The length of the third segment of the vertebral artery was(50. 93 ±8. 23)ram. There was no significant anatomic variation. Conclusions The third segment of vertebral artery is tortuous to enable the movements of neck. The far-lateral approach is often used to expose the third segment of vertebral artery. The suboccipital triangle may be an anatomic marker for the third segment of vertebral artery. Key words: Vertebral artery;  Anatomy;  Suboccipital triangle