Parietal foramen: incidence and topography

Abstract

The parietal foramen (PF) is a small inconsistent aperture located at the border of the middle 1 /3 and posterior 1 /3 of the parietal bone near the sagittal suture and is considered an emissary foramen. Cranial emissary foramina are of utmost importance due to the structures that traverse the foramen. Variations in these foramina are common. Knowledge of the PF is important when performing neurosurgical procedures as the emissary vessels are at risk. The present study used 100 dry adult calvaria to determine the frequency of PF, the diameter of the PF, as well as topography of the PF (using the sagittal suture as an anatomical landmark). A total of 32% of calvaria had PF present bilaterally; whilst 35% of calvaria had unilateral PF. The study also reports 5% calvaria in which PF were present on the sagittal suture. The mean diameter recorded was 1.55mm [0.74-3.08mm], and the mean distance between the lateral margin of the PF and the sagittal suture was 9.02mm [4.44-18.20mm]. Knowledge of the incidence and topography of the PF may aid neurosurgeons in creating and adjusting techniques and procedures in order to mitigate the risk of injury to emissary veins and other structures emerging from the PF.

Osteological Study of the Parietal Foramen in the Adult Human Skull Bones and its Clinical and Surgical Correlations

“…Depending on whether the third fontanel shuts, the PF might be unilateral or bilateral (Yılmaz et al, 2014;Agarwal et al, 2015) . This statement is consistent with the increased prevalence found in this current study, which found a 35.1 % existence of bilateral PF, that is higher than those of Naidoo et al (2021) 32 % andDebbarma et al (2015) (30 %) (Debbarma et al, 2015;Naidoo et al, 2021) . But, this discovery is less than those of Murlimanju et al (2015) (55.2 %) and Gangmei et al (2018) (62.5 %).…”

“…According to this study, mean incidence of unilateral PF is 43.3 % of cases (right: 23 %, left: 20.3 %), this finding is higher than the findings of Naidoo et al (2021) (35 %) and Berge & Bergman (2001) (30 %). The recognition of emissary foramina, like the PF, is critical for clarification of regional vasculature and differentiating these foramina from variation anatomy (Shantharam & Manjunath, 2018).…”

“…In this area, the parietal foramina are located on both sides of the sagittal suture and the area is named as "the obelion". The name is derived from the Greek symbol "obelos%" that appears similar to the arrangement of the sagittal suture and the bilateral parietal foramina (Naidoo et al, 2021). Apart from the transmission of vessels, no satisfactory explanation has been given regarding the PF's function; therefore, its function remains unclear and is still being investigated (Agarwal et al, 2015;Mahakkanukrauh et al, 2021).…”

Trigonocephaly and Cranium Bifidum Occultum Treated Simultaneously Using the Split-Bone Technique and Piezosurgery

“…CBO has been given other designations, such as enlarged parietal foramina (if more than 5 mm in diameter), foramina parietalia permagna, fenestrae parietals symmetricae, or Catlin mark (due to the high incidence of this bone defect in the Catlin family, as described by Goldsmith, who observed this malformation in 16 members across five generations [ 1 - 4 , 11 , 12 ]. Its etiology has been attributed to an abnormality in intramembranous ossification during the fifth month of gestation, and several gene mutations have been described that make this condition hereditary in nature, such as loss of function mutations in human homeobox genes MSX2 in chromosome 5 and ALX4 in chromosome 11 [ 3 , 5 , 11 , 12 ].…”

Emissary veins and foramina: topography, incidence, and clinical significance

“…It had a mean diameter of 1.55 mm and was located at a mean distance of 9.02 mm lateral to the sagittal suture. 7 Enlarged parietal foramina may be identified in addition to the ordinarily sized and positioned parietal emissary foramina. 8 In South Indian skulls, the parietal emissary foramen was present at the junction of middle and posterior thirds of the parietal bone in 71.5% of skulls, at a mean distance of 6.7 mm (right) and 6.8 mm (left} lateral to the sagittal suture: solitary in 62.9%, double in 6.9%, triple in 1.7%, unilaterally absent in 32.7%, and bilaterally absent in 12.1% of skulls.…”