Background: We investigated diameters of prevertebral — V1, and atlantic — V3
parts of extradural segment of vertebral artery (VA). Variable results from the literature
about VA diameters reflect variety of diagnostic and imaging methods, various sample
sizes, different levels of measurements, and lack of possible specific ethnic, regional or
genetic data. Additionally, the data are often without distinctions of left-right or of sex.
Materials and methods: For this computed tomography (CT) angiographic
study 91 adult people (182 VAs) of both sexes (47 males and 44 females) and of
age between 33 and 75 years were selected. Diameters were measured at fixed
predefined points of VA, marked as inferior (A) point (at V1 part in region of VA
origin), as middle (B) point (the end of V1 part), and superior (C) point, at V3
part — 5 mm before VA penetrated the dura. Inferior (A) and middle (B) points
actually represent locations at beginning (A) and at terminal (B) regions of V1 part
of VA, and superior point C represents terminal part of V3.
Results: In total sample ipsilateral (both left [L] and right [R] sided) diameters on
investigated levels of VA showed progressive and highly significant decreases. The
mean values were on the right side at point A — 3.63 mm, at B point — 3.31 mm,
and at C point — 3.08 mm. On the left side, mean values were at point A —
3.76 mm, at B point — 3.50 mm, and at point C — 3.21 mm. Pattern of increasing
sex differences in diameters of VA, was ranging from no differences (point A),
trough significant (point B), to highly significant differences (point C). For inferior
point (A) we did not find significant differences in VA diameters between males
(R 3.78 mm; L 3.89 mm) and females (R 3.50 mm; L 3.62 mm), in middle (B)
point sex differences were significant (males: R 3.44 mm, L 3.66 mm; females:
R 3.18 mm, L 3.33 mm) and in most superior point (C) differences were highly
significant (males: R 3.278 mm, L 3.39 mm; females: R 2.88 mm, L 3.01 mm).
However, we did not find significant intrasex (in males or in females) left-right
differences in mean values of VA diameters for all three investigated levels.
Conclusions: Our findings, as the first data about diameters of VA systematically obtained by CT angiography in the population of western Balkans and wider, suggest that
in design of future studies of VA diameters is necessary to analyse separately the data
for sex, as well as to use defined standard levels. (Folia Morphol 2019; 78, 3: 494–500)