Rasha M. Salama; Hamad Alsaykhan & Walaa A. Fadda

The occipital emissary foramen (OEF) represents an important anatomical channel that transmits the occipital emissary vein, forming a venous communication between the extracranial suboccipital tissues and the intracranial occipital sinus. The prevalence and morphological variability of the OEF differ considerably across populations, reflecting developmental, genetic, and geographical influences. This descriptive observational study aimed to determine the incidence, laterality patterns, and morphometric characteristics of the OEF in 92 adult human dry skulls and to clarify its potential clinical implications. Skulls were systematically examined to document the presence or absence of the foramen, its position relative to the external occipital crest, side distribution, and total number of foramina per specimen. The study revealed that most skulls (81.5 %) exhibited at least one OEF, predominantly located on the squamous part of the occipital bone. Bilateral presentation represented the most frequent pattern, followed by unilateral and midline forms. A single OEF occurred most commonly, whereas double and multiple foramina were less frequent. This substantial variability underscores the relevance of understanding OEF anatomy, particularly in neurosurgical and neurointerventional procedures involving the posterior fossa and suboccipital region, where unanticipated emissary veins may increase the risk of bleeding or facilitate the spread of infection. These findings reinforce the importance of careful preoperative planning to minimize complications associated with emissary venous channels.

KEY WORDS: Occipital emissary foramen; Occipital emissary vein; Prevalence; Skulls; External occipital crest.

SALAMA, R. M.; ALSAYKHAN, H. & FADDA, W. A. Prevalence of occipital emissary foramen and its clinical relevance in human adult skulls. Int. J. Morphol., 44(2):610-616, 2026.