98th Annual Meeting DOG 2000

K 99

The course of the occipital artery – An anatomical investigation into the location of the biopsy in suspected vasculitis

D. Schmidt1; G. Adelmann2

Background: The occipital artery can become inflamed in giant cell arteritis. For biopsy purpose it is essential to know the precise cource of this vessel.

Methods: In 6 randomly selected specimens of the head, the occipital artery and vein were identified and followed in the cranial direction after their emergence from under the splenius capitis muscle. In addition, their topographical relationship to the greater occipital nerve was observed.

Results: Course of the vessels: The occipital artery followed a tortuous course including an occasional hairpin bend, in four out of the 6 specimens. Lateral distance of the occipital artery from the external occipital protuberance: The occipital artery ran at a mean distance of 3.92 cm from the midline on the right side and at a mean distance of 4.4 cm on the left.

Variations in the course: A comparison between the right and left side showed a marked difference in the course of the vessels. The extent of the tortuosity varied considerably. The angle between upper nuchal line and occipital arteries: In most of the cases, this angle was 90°, which means a fairly straight upward course for the artery. External diameter: The average external diameter of the occipital artery (in the region where it crosses the upper nuchal line) was on the right side 2.3 mm and on the left 2.7 mm.

Discussion: Recommended site for biopsy: Because the greater occipital nerve enters below the external protuberance of the occiput into the subcutis and crosses the occipital artery afterwards, we recommend carrying out biopsies of the occipital artery between 1 and 3 cm above and between 4 and 5 cm lateral to the external occipital protuberance.

1Univ.-Augenklinik, Killianstr. 5,79106 Freiburg; 
Anatomisches Institut der Universität, Albertstr. 17, 79104 Freiburg