200 MUSCLES OF THE UPPER LIMB. 



MUSCLES ATTACHING THE UPPER LIMB TO THE TRUNK POSTERIORLY. 



The trapezius muscle (cucullaris) arises by a thin aponeurosis from tho 

 protuberance of the occipital bone, and the inner third of its superior 

 curved line, from the ligamentum nuchse, and from the spines of the last 

 cervical and all the dorsal vertebrae, as well as from the supraspinous 

 ligaments. From this extended line of oiigin the fibres converge to their 

 insertion : the superior fibres, descending and turning forwards in the neck, 

 are inserted into the external third of the clavicle at its posterior border ; 

 the succeeding fibres pass transversely to the inner border of the acromiou 

 process and upper border of the spine of the scapula, while the inferior 

 fibres ascending terminate in a flat tendon which glides over the triangular 

 area at the base of the spine of the scapula, and is inserted into the rough 

 mark at the root of the spine. The greater part of the origin becomes 

 immediately muscular, but opposite the seventh cervical spine, and for the 

 distance of several vertebrae above and below that point, a flat tendon 

 extends outwards, widest at the middle of the space, and narrowing towards 

 the upper and lower ends, so that the aponeuroses of the two muscles taken 

 together have an elliptical form. The fibres of origin from the occipital 

 bone have no tendinous lustre, and resemble rather a strong fascia. The 

 muscles of the two sides, regarded together, have the form of a four- sided 

 figure, or shawl, pointing downwards : hence the names which have been 

 given to it. 



The trapezius is superficial in its whole extent : it covers the splenius, the greater 

 part of the complexus above the splenius, the levator anguli scapulae, the rhomboidei, 

 the supraspinatus, and small portions of the infraspinatus, latissimus dom, and 

 lumbar aponeurosis. The spinal accessory nerve, and the superficial cervical artery, 

 pass into it from its deep surface. 



The trapezius is not unfrequently shorter than above described, and the number of 

 dorsal vertebras with which it is connected is sometimes diminished even to six or 



The latissimus dorsi arises by tendinous fibres from the spiuous processes 

 of the six or seven lowest dorsal vertebrae, and from the posterior layer of 

 the lumbar apoueurosis, through the medium of which it is attached to 

 the lumbar and upper sacral spines and back part of the iliac crest ; it also 

 arises by fleshy fibres for an inch or more from the iliac crest in front of the 

 outer margin of the lumbar aponeurosis, and from the last three or four 

 ribs by fleshy slips which iuterdigitate with the attachments of the external 

 oblique muscle. The fibres at the upper part are the shortest, and pass 

 almost horizontally outwards over the lower angle of the scapula, from which 

 they frequently receive a fasciculus of fleshy fibres ; those lower down 

 become longer and incline from below upwards, gradually increasing in the 

 degree of their obliquity ; finally, those which are attached to the ribs 

 ascend almost vertically. By this convergence the fibres of the muscle 

 eoine to form a narrow band of some thickness, which, accompanying the 

 teres major towards the axilla, winds round the lower and outer border of 

 that muscle so as finally to be placed in front of it. At this place it 

 terminates in a flat tendon of about two inches in length, which generally 

 becomes adherent to that of the teres major, but is again detached from it 

 at the insertion. The tendon is inserted in the floor of the bicipital groove 

 of the humerus, a little higher than the insertion of the teres major. From 

 this twisting of the muscle upon itself, the anterior surface of the tendon 

 is continuous with the posterior surface of the rest of the muscle. 



