Anatomical Variation and Morphometric Study on Foramen Transversarium of the Upper Cervical Vertebrae in the Thai Population

Abstract

Foramen transversarium (FT) and foramen arcuale (FA) of upper cervical vertebrae (C1 and C2) in the Thai population were investigated for variation and morphometry. Purpose: This study aimed to reveal the morphometry of FT and FA in the Thai population. Overview of Literature: The FT and FA are structures found in the upper spine that support the vertebral neurovascular system. Clinically, the surgical approaches to achieve upper cervical stability can be affected by spine variations. FT and FA morphometries have been documented to vary by nationality. However, such reports have been limited in the Thai population. Methods: The FT and FA of dried C1 and C2 vertebrae (identified bones; n=107, males=53 and females=54) were observed and measured using a Digital Vernier Caliper (Mitutoyo, Kawasaki, Japan). Anteroposterior (AP) and transverse diameters of the left and right FTs (n=214) were measured and compared between sexes. Variations and types of FT and FA found on the upper vertebrae were recorded and classified. Results: The FT shape of the Thai C1 was AP elliptical, while of that of C2 was transverse elliptical. Compared to females, both diameters of the upper spine were significantly greater in males except for the AP diameter of C2 on the right side. All diameters were significantly different in both sexes and sides except for the AP diameter of C1 and C2. A common type of FT classified in C1 was type 2 (male [69.81%], female [79.63%]) whereas for C2 it was type 1 (male [63.21%], female [59.26%]). Moreover, an incomplete osseous bridge was a major FA subtype observed in the Thai spine. Conclusions: FT morphometry has an elliptical shape and diameters are greater in males. The FT and FA variations identified in this study will be useful for surgeons treating vertebral neurovascular injuries of the posterior upper cervical spine in the Thai population.

DETAILED MORPHOMETRIC & MORPHOLOGICAL DESCRIPTION OF FORAMINA TRANSVERSARIUM OF ATLAS VERTEBRA

“…Our result was almost similar as study was undertaken among Thais population by Aarda et al. [26] On the other hand, among Israel & South Indian population the A-P length was much higher than our observation [6,27] (Table/ Fig 10).…”

“…Traitz et al [6] 1978 Israel 480 All 34 Nagar et al [30] 1999 Indian 1388 All 8.6 Das et al [3] 2005 Indian 132 All 1.5 Kaya et al [4] 2011 Jewish 262 All 22.7 Rekha B S et al [27] 2014 Karnataka 153 Atlas 6.54 Jawed et al [15] 2015 174 All 14.36 2.87 11.49 Rao B S et al [31] 2016 Telengana 50 Atlas 20 Srobar G et al [13] 2017 Srinagar 100 All 9 5 4 Aziz J A et al [12] 2018 Egypt 135 Atlas 17.70 Aung et al [28] 2020 Turkey All 86 Aarda et al [26] 2020…”

Morphometric Study and Anatomical Variation with its Incidence of Foramina Transversaria on the Lower Cervical Vertebrae

“…In contrast, the 13 types have been observed in South African populations, with type 1 being the most common found at C3-C6 (Taitz et al 1978). Anatomical variations on the subaxial vertebral pedicles and morphometry of the FT in the upper cervical spine have recently been documented in the Thai population (Mahiphot et al, 2019;Chaiyamoon et al, 2021). However, no morphometric study of variation in the lower cervical FTs (C3-C7) has not been conducted.…”

“…In addition, the FT variation can affect the vertebral neurovascular bundle after CPS insertion. The incidence and morphological features of C3-C7 FT variation have been well documented and differ by population (Taitz et al 1978;Kimura et al, 1985;Nagar et al, 1999;Aydinoglu et al, 2001;Das et al, 2005). For example, the FT shapes reported in Japanese, Chinese, and Indian populations have been classified into 5 types, with type 3 (elliptical with transverse direction) being the most commonly observed at C3-C5 (Kimura et al, 1985).…”