Pear-shaped Aperture

Pear-shaped aperture (lat. apertura piriformis) is an anatomical formation at the base of the skull. It is an irregular pear-shaped hole located between the large wings of the main bone. The jugular vein emerges from the cranial cavity through the pyriform aperture, and the nerves innervating the olfactory region of the nasal cavity also pass through.

The piriform aperture is bounded anteriorly by the sphenoid bone, posteriorly by the greater wing of the sphenoid bone, and superiorly by the body of the sphenoid bone. At the bottom, the aperture opens into the fossa of the base of the skull. The shape and size of the pear-shaped aperture can vary.

Thus, the pyriform aperture is an important anatomical formation of the base of the skull, through which nerves and blood vessels pass, connecting the cranial cavity with the facial skeleton. Knowledge of its structure is necessary for surgical interventions and diagnosis of pathologies in this area.

The pyriform aperture is the small anal fold at the site of its transition into the rectal opening.

The anterior gluteal ligament, attaching to the intermuscular field in the area of ​​the deepening of the semilunar line, lies under the ventral edge of the lesser anal fold, and then, before covering the intermuscular field, reaches the lower gluteal line. Posterior to it lies the presacral fascia. The pyriform apertures lie on the anterior border of the anus. One pear-shaped pair of apertures was noted - usually in the front and less often (in 32% of cases) in the back, two at a time. In the presence of two pyriform apertures, the urethral opening, the lateral sphincter of the rectum, the pyriform opening, the remains of the sigmoid colon and the vagina open into the anus.