| Pectinate muscles | |
|---|---|
 Section of the heart showing the ventricular septum. (Pectinate muscles labeled at center left.) | |
 | |
| Details | |
| Identifiers | |
| Latin | musculi pectinati atrii dextri, musculi pectinati atrii sinistri |
| FMA | 12226 |
| Anatomical terminology | |
Thepectinate muscles (musculi pectinati) are parallel muscular ridges in the walls of theatria of theheart.
In the atria of the heart, there are two different types of walls. Behind the crest (crista terminalis) of theright atrium, also known as the posterior wall, the internal surface is smooth.[1] This is called thesinus venarum. The pectinate muscles make up the part of the anterior wall, the wall in front of the sinus venarum, theright atrial appendage.[2]
In theleft atrium, the pectinate muscles are confined to the inner surface of its atrial appendage.[1] They tend to be fewer and smaller than in theright atrium. This is due to theembryological 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.[citation needed]
Pectinate muscles of the atria are different from thetrabeculae carneae, which are found on the inner walls of bothventricles.[citation needed] The pectinate muscles originate from the crista terminalis.[citation needed]
The pectinate muscles are so-called because of their resemblance to the teeth of acomb, as inpecten.[citation needed]
This article incorporates text in thepublic domain frompage 529 of the 20th edition ofGray's Anatomy(1918)
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