Morphological variation of the caudal fossa of domestic cat skulls assessed with CT and geometric morphometrics analysis

Abstract

Objectives This study aimed to investigate differences and demonstrate a normal range of morphological variation of the caudal fossa of the cranium of domestic cats. Methods CT scans of 32 domestic cat heads of 11 breeds were included. Isosurfaces from skulls were characterised through three-dimensional geometric morphometrics using geographical landmarks placed on the internal surface of the caudal fossa and foramen magnum. Raw data was transformed with a Procrustes fit and coordinate covariance was analysed by principal components to establish breed- and sex-level differences. Skulls were also classified according to the number of concavities along the mid-sagittal vermiform impression. Differences were investigated between breed groups and sex, and correlation was sought with age. Results Analyses revealed size-independent differences in occipital bone morphology across breeds and sex; however, no clustering was evident. Most variability was observed at the exoccipital bones, ventral portion of the supraoccipital bone, dorsum sellae of the basisphenoid and the osseous tentorium cerebelli. No statistically significant differences were identified via two-sample t-tests between breed groups or sexes. No statistically significant correlation using Spearman rho correlation coefficient was identified with age. Conclusions and relevance The feline caudal fossa displays a wide range of intra- and inter-breed variation, not linked to age or sex. Concavities along the vermiform impression have not previously been described. As advanced imaging modalities are becoming more frequently used for domestic felids, an established range of normality is important for discriminating pathological changes from anatomical variances.

Examination of the morphometric features and three-dimensional modelling of the skull in Van cats by using computed tomographic images

“…Also, the skull indices obtained from these cranial measurements are quite effective in distinguishing or identifying morphological types (21). For this reason, various craniometric measurements have been used in the studies in determining the morphological variations between the domestic and wild cat species (6,8,14,30,(35)(36)(37).…”

“…The measurements obtained from skull using computed tomography (CT) and three -dimensional modelling software may be mostly used in revealing the biometric differences between sexes (34). For this purpose, many studies have been conducted in the veterinary medicine (8,20,37). No study was found on skull of Van cats in the literature reviews.…”

A lateral approach to the feline cerebellar fossa: case report and identification of an external landmark for the tentorium ossium

“…The veterinary literature contains few descriptions of the cranial morphology in cats, with none being focused on the attachment of the tentorium ossium. [18][19][20] Although cats can be divided into three phenotypic skull shapes, round-shaped, triangular and cuneiform, the impact that parameters such as skull length, width and height have on the position of the Figure 4 The same post-acquisition processing was applied to the postoperative CT images of a 17-year-old cat. (a) As in the other cats, the line that demarks the tentorial attachment (red) and nuchal crest (green) is seen on the right side.…”

“…The veterinary literature contains few descriptions of the cranial morphology in cats, with none being focused on the attachment of the tentorium ossium. 18–20 Although cats can be divided into three phenotypic skull shapes, round-shaped, triangular and cuneiform, the impact that parameters such as skull length, width and height have on the position of the tentorium ossium within the cranial cavity remains unknown. 19 In European cats, one external morphological feature that may be important is the squamous portion of the occipital bone, which approximates either the shape of an isosceles triangle or a semi-oval shape from a caudal viewpoint.…”

New Genomic Insights into the Conformation of Lipizzan Horses

“…Furthermore, a GWAS of joint angles from the horse shape space model applied to FM and Lipizzan horses revealed novel QTL for poll angle and elbow joint angle 12 . Two-dimensional (2D) geometric morphometric data have been already used to explore the genetic architecture of morphological differences in mollusks 13 , sorghum 14 , or house ies 15 , while three-dimensional (3D) data has been used to study facial traits in humans (summarized in 16 ), cats 17 and dogs 18 .…”