Spina vestibuli, or vestibular spine, is a bony structure, in anatomical terms a 'mesenchymal condensation', which extends from the mediastinum of the heart and covers the leading edge of the primary
atrial septum
The interatrial septum is the wall of tissue that separates the right and left atria of the heart.
Structure
The interatrial septum is a that lies between the left atrium and right atrium of the human heart. The interatrial septum lies at angle ...
; its origin is outside of the heart. Below the opening of the orifice of the
coronary sinus
The coronary sinus () is the largest vein of the heart. It drains over half of the deoxygenated blood from the heart muscle into the right atrium. It begins on the backside of the heart, in between the left atrium, and left ventricle; it begi ...
they fuse to form a triangular thickening — the spina vestibuli. It is believed to play a formative role in atrial septation, which is how the common
atrium of the heart divides into two during
gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...
. Its lack of development is thought to contribute to the
morphogenesis
Morphogenesis (from the Greek ''morphê'' shape and ''genesis'' creation, literally "the generation of form") is the biological process that causes a cell, tissue or organism to develop its shape. It is one of three fundamental aspects of deve ...
of
atrioventricular septal defect
Atrioventricular septal defect (AVSD) or atrioventricular canal defect (AVCD), also known as "common atrioventricular canal" or "endocardial cushion defect" (ECD), is characterized by a deficiency of the atrioventricular septum of the heart that c ...
(AVSD) in
Down syndrome.
References
External links
"Development and structure of the atrial septum", at bmjjournals.com
Embryology of cardiovascular system
{{Developmental-biology-stub