The Relationship of the Posterior Cranial Fossa, the Cerebrum, and Cerebellum Morphometry with Tonsiller Herniation

Abstract

Background: Tonsillar herniation is a condition that manifests as herniation of the brain parts, originating from the hindbrain and progressing through the foramen magnum into the cervical vertebral canal. Although the etiology of tonsillar herniation is unclear, it has been suggested that it may be congenital or acquired. In particular, there is speculation that primary mesodermal insufficiency may affect the size of the posterior cranial fossa.

Impact of morphological measurements on symptoms in Chiari malformation type 1

“…In their study, Taştemur et al [14] stated that in individuals with tonsillar herniation, foramen magnum sagittal diameter, cerebellum height, and cerebellum sagittal diameter increases, whereas the maximum cranial height, supraocciput length, clivus length, and fossa cranii posterior height decreases. It has been stated that the cranium would bend forward and the tonsils would be lower in the case of short villus and hypoplastic condyle [6].…”

“…Previous studies show that the narrowness of PCF or the excess in parenchyma plays a role in herniation [6,11,14]. An earlier study stated that a 2-mm change in the intracranial distance can cause considerable differences in the patient's symptoms [11].…”

“…Various studies describe that CM1 has a higher prevalence among women than among men [6,14,16]. Arnautovic et al [15] reported that CM1 is more prevalent among women, and suggested that the cause for this is the coincidental identification of lesions in women while determining the cause of headaches.…”

“…CM1 herniation can be as small as 3 mm and as large as 25 mm [11]. Taştemur et al [14] reported the average herniation amount in individuals with tonsillar herniation of 4.85 (3.09) mm. Lei et al [16] reported the amount of tonsil ectopia in patients to be 13.6 mm.…”

“…Tonsillar herniation (TH): is the distance between the tip of the cerebellar tonsils and opisthion -basion line ( Figure 3) [14]. All measurements were performed by the same observer.…”