The pectinate muscles (musculi pectinati) are parallel muscular ridges in the walls of the
atria of the
heart
The heart is a muscular Organ (biology), organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as ca ...
.
Structure
Behind the crest (
crista terminalis) of the
right atrium
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two at ...
the internal surface is smooth.
Pectinate muscles make up the part of the wall in front of this, the
right atrial appendage
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two at ...
.
In the
left atrium
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two at ...
, the pectinate muscles are confined to the inner surface of its atrial appendage.
They tend to be fewer and smaller than in the
right atrium
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two at ...
. This is due to the
embryological origin of the auricles, which are the true atria. Some sources cite that the pectinate muscles are useful in increasing the power of contraction without increasing heart mass substantially.
Pectinate muscles of the atria are different from the
trabeculae carneae, which are found on the inner walls of both
ventricles. The pectinate muscles originate from the crista terminalis.
Name
The pectinate muscles are so-called because of their resemblance to the teeth of a
comb
A comb is a tool consisting of a shaft that holds a row of teeth for pulling through the hair to clean, untangle, or style it. Combs have been used since prehistoric times, having been discovered in very refined forms from settlements dating ba ...
, as in
pecten.
References
External links
*
*
* - "Right atrium, internal structure, anterior view"
Cardiac anatomy
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