A Study of Morphology, Morphometry, Symmetry and Development of External Opening of Carotid Canal With Comparison in Male, Female and Foetus

Abstract

Introduction: The Carotid Canal is an important structure at the base of skull as it conveys the internal carotid artery, along with a sympathetic nerve plexus and a venous plexus. Previous researches done on carotid canal suggest that abnormalities to this canal, such as fractures of carotid canal and carotid sympathetic plexus schwannoma have their effect on the internal carotid artery and the structures passing through it. Cases of absence of carotid canal have also been reported, which causes variations of the internal carotid artery. Attempt has been made in this study to give a detailed view of the 'external opening of carotid canal' (EOCC) which is the gateway of the carotid canal at the skull base. This study shall be useful for Surgeons, Radiologists, Anatomists, Forensic Experts, Anthropologists, etc. Aim: This study aims at measuring the various dimensions of the external openings of the carotid canal pair present at the base of skull, and to observe the age changes, sexual dimorphism, and symmetry of the external opening of the carotid canal from the analysis of these measurements. Materials and methods: Total 235 dry skulls that included 181 adolescent to adult skulls of known age and sex (age ranging from 13 years up to old age skulls of 60 years or above) and 54 foetal skulls were studied for this purpose. The longest & shortest diameter of each carotid canal, was measured using a screw adjusted compass and a Vernier Calliper. Their distance from pharyngeal tubercle and from the X axis and Y axis was measured. Observations and Results: In the present study, it was observed that external opening of each carotid canal was unique in its morphology and morphometry. The dimensions of external opening of carotid canal progressively increased from foetal age to 25 years of age, however after 25 years of age, it did not show any age change within same sex, but it showed age changes when adolescent female skulls of age less than 25 years were compared with adult male skulls of age above 25 years. It was also observed that the external opening of carotid canal showed sexual dimorphism when compared within same age group (that is, between adolescent male and female skulls below 25 years age, and between adult male and female skulls above 25 years age. Further it was also observed that EOCC did not show any asymmetry in foetal age, however it showed asymmetry in female skulls below age 25 years (adolescent).

Morphological and Morphometric Analysis of the External Aperture of the Carotid Canal in Serbian Population

“…According to the results of our study there were no statistically significant differences of the length and width of the EACC between sides and sexes except for the parameter AP which was statistically significant (p = 0.017) between the right and left side on the female skulls. These results are in contrast with those of Aoun et al (2013), and Shaikh & Kulkarni (2014), who found statistically significant differences between male and female skulls in relation to the side. This, the different results of the studies may be related to population differences.…”

Identification of Sex from Carotid Canal in South Indian Population

“…These findings were more or less in agreement with previous studies [6][7][8] (Table 3). No literature is available in English to confirm these variations between two sexes.…”

“…The probable reason could be the haemodynamic pressure is more in male crania as compared to female crania [9], moreover haemodynamic pressure on right side of the brain, hence diameter of the right CC are more than left side in both sexes. The increased diameter of male CC than female CC is paedomorphic tendency of human skull [8].…”

The anatomical relation of the extracranial internal carotid artery in the parapharyngeal space

“…We assume that this is caused by the symmetry of the external carotid canal openings in the skulls of both men and women, hence the artery is forced by their position to change its position in relation to the medial line, and thus to the pharyngeal wall. 14 Men presented no asymmetry in any of the abovementioned measurements.…”