Abstract
The nutrient arteries of the bilateral supraspinatus muscles in 10 Japanese adults were examined, and the findings are reported hereunder. The supraspinatus muscle was classified in accordance with the origin and intramuscular pattern of distribution of the supplying arteries into a total of 10 types. Additional classifications were combinations of the following three types. The Type I muscle was supplied by the transverse cervical (Tc) and suprascapular (Ss) arteries arising from the subclavian artery (S), and Type II by the circumflex scapular artery (Cs) from the axillary artery (Ax) in addition to the arteries found in the Type I muscle. Subtypes A and B represent the sites at which Ss originates from the first part of S, and from either the third part of S or from Ax, respectively, while Subtype C demonstrated two Ss arteries. Subtypes B and C were further divided into two types, s and a, which respectively indicate the site from which Ss arose from the third part of S and from Ax. The most frequently observed type of supraspinatus muscle was Type IB-s (40% of all examined muscles), followed by Type IA (25%), and then Type IIA (15%). This latter was the only observed example of Type II. Moreover, in Type IB-s, Ss supplied 82.4% of the area, while Tc supplied 17.4% of the entire muscle. The number of arteries counted was two in 75% of examples and three in 25%. The site at which the innervating branch of the supraspinatus muscle arose from the suprascapular nerve, and the form of the scapular notch also are described, and the interrelationship between the muscle types in regard to the arteries and the above two factors are discussed. NOTE: An explanation as to what is mean by "the first part" or "the third part" of an artery would help.
