49 - An Anomalous Septum Situated Between the Atrial Septal Wall in a Male Cadaver

Poster Board Number: 49
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Co-authors:

Shyanne Craggs - D'Youville University; Megan Gervasi - D'Youville University

Abstract Body : Atrial septal defects (ASD) are a congenital heart defect characterized by an abnormal opening in the atrial septum, which separates the right and left atria of the heart. ASDs are one of the most commonly observed congenital heart defects, observed in 25% of live births. The atrial septum forms from a series of structural changes that occur between the 27^th and 38^th days of development. The atrial septum is composed of two septal structures, septum primum and septum secundum, that allow some blood to flow directly from the right atrium to the left atrium via the foramen ovale and ostium secundum. This is an important feature of development that leads to a reduction in the amount of blood flowing to the developing lungs. Following birth, breathing results in an increase in pressure in the left atrium which prevents the flow of blood between the right and left atria. Eventually the septum primum and septum secundum fuse to form a continuous atrial septum.



There are 5 recognized types of ASDs, and they are classified based on their size and location. The most common ASD, secundum ASD, involves a defect of the fossa ovalis due to malformation or defects of the septum primum. This defect results in a persistent opening in the atrial septum following birth. Secundum ASDs account for 75% of all observed ASDs and has a female predominance of approximately 2:1.



During a routine cadaver dissection of the heart in a gross anatomy course, a secundum ASD was observed in a 77-year-old male cadaver. Measurements of the orifice showed a depth of 0.6cm and an opening of 0.3cm. Three fenestrations were visible in a portion of the atrial septum derived from the septum primum. A review of the literature for photographic images of atrial septal defects revealed that there was limited access to images. Photographing atrial septal defects could improve understanding of the defects and the underlying mechanisms in student populations. It can also provide clinicians with insight into possible treatment of ASDs.