Left atrium

LEFT ATRIUM

  • The left atrium forms the posterior part of the base of the heart.
  • It lies behind the pulmonary artery and aorta and above the ventricle.
  • It consists of a sinus and an auricle.
  • The later extends on the left side and its blind end lies behind the origin of the pulmonary artery.
  • The sinus receives the pulmonary veins, about 4 to 7 in number in two groups.
  • The following features are seen in the interior
    • The endocardium.
    • The openings of pulmonary veins about 4 to 7 in number into the sinus.
    • The musculi pectinate as in the right auricle.
    • The left atrio-ventricular orifice.

Last modified: Wednesday, 2 May 2012, 7:11 AM