ABSTRACT
Using the angiography and the corrosion methods we studied the arterial distribution of the papillary muscles of the left ventricle in llo dog hearts, according to the peculiarities of vasculature, disscused the influence of obstruction of coronary artery upon the papillary muscle.The anterior and posterior papillary muscles in dog all are tethered type. The average length and width of anterior papillary muscle are 1.96 cm. and 1.10cm, respectively, while those in the posterior papillary muscle are 2.04 cm. and 1.20 cm. respectively.The origins of arterial blood supply of anterior papillary muscle may be classiffied into 4 types, type Ⅰ, in which the arterial branehes are from the anterior descending artery, is in leading position(71%); type Ⅱ, in which branches are both from the anterior descending and left circumflex arteries, is in the next place(18%). Origins of arterial branches of posterior papillary muscle are classed under 2 types: type Ⅰ, in which all arterial branches are from the left circumflex artery, is the most, 91%, among them 65% from the posterior branch of the left ventricle.The peculiarities of arterial distribution in papillary muscles are as follows: 1. All artery branch entering the papillary muscle are of Class B. 2. All are segmental distribution in papillary muscles. Each muscle recieyes 2-9 branches, mostly 5 or 6 branches. 3. Each half of one papillary muscle recieves several branches symmetrically. 4. The arrangement of hrauches may be classiffied into several types; mixed type is the most, then comes the transverse type. 5. The branches anastomose each other to form the subendocardial plexus, which is most evident in the middle and upper third of the papillary muscle.