Background: Internal carotid artery (ICA) is a major source of blood supply to the brain. Awareness of
the petrous and cavernous parts of ICA is significant for radiological diagnosis and surgical interventions
on skull base. Though several angiographic studies and few endoscopic skull base studies have been done
on the artery, there are very few cadaveric dissection studies available in the literature on both the parts.
Aims: To study the morphology and morphometry of the petrous and cavernous parts of the ICA.
Materials and Methods: The study was conducted on fifty, formalin fixed head and neck specimens in the
department of Anatomy, Pushpagiri Institute of Medical Sciences and Research Centre, Thiruvalla, Kerala,
India. The petrous and cavernous parts of the ICA were dissected. The appearance of their curvatures were
studied, and any deviations from the normal were noted down. Their length and diameter were measured
in cms, and analyzed using mean, standard deviation and ‘t’ test.
Results: No abnormal curvatures were noted in the petrous part, but redundant curvature was observed in
the cavernous part in 30%, and was more frequent on the right side. Aneurysms were noted in 4% and 10%
of the petrous and cavernous parts respectively. The mean length and diameter of the petrous part were 3.8
± 0.39 cm and 0.49 ± 0.24 cm respectively, and those of the cavernous part were 3.59 0.46cm and 0.48
± 0.1cm respectively.
Conclusion: Petrous part of ICA is fairly constant in appearance, whereas redundant curvature can affect
the cavernous part (30%), and was more frequent on the right side. Aneurysms were less common, but
observed in both the parts. There is no significant difference between the length and diameter of both the
parts, which measured approximately 3.5 – 4 cm and 0.5 cm respectively.
Petrous part, Cavernous part, Internal carotid artery, Aneurysm, Redundant curvature, Variations.