BACK AND POSTERIOR CERVICAL REGION. 127 



processes, and supra-spinous ligament of from four to eight 

 of the dorsal, those of all the lumbar, and two of the sacral 

 vertebrae, from the posterior third of the crest of the ilium, 

 and from three or four of the lower ribs, by serrations which 

 indigitate with similar processes of the external oblique 

 muscle of the abdomen; the fibres pass upward and for- 

 ward to be inserted by a strong flat tendon into the floor 

 of the bicipital groove of the humerus. In their course 

 upward they overlap the inferior angle of the scapula, and 

 beneath them, at this point, a synovial bursa may some- 

 times be found. A distinct fleshy slip is sometimes given 

 off from the lower angle of the scapula, and a muscular 

 band often stretches across the axilla to terminate in either 

 the pectoralis major or the coraco-brachialis muscle. 



Cutaneous nerves, branches of the posterior divisions of 

 the spinal nerves, will be observed perforating the spinal 

 tendons of both the last-described muscles. 



A triangular space will sometimes be found intervening 

 between the latissimus dorsi and external oblique, only 

 remarkable as having been erroneously supposed to be a 

 point at which intestinal hernia was liable to occur. 



The latissimus dorsi is covered in its dorsal region by 

 the trapezius muscle and, at its lower part, by a layer of the 

 fascia lumborum ; this fascia consists of three layers; the 

 superficial, lying upon the latissimus and blending with 

 its aponeurosis is attached to the two lower ribs, and the 

 spines of the lumbar vertebrae ; the middle passes beneath 

 the latissimns, between the erector spinae and quadratus 

 Inmborum, and is attached to the tips of the lumbar trans- 

 verse processes ; the internal passes in front of the quadratus 

 lumborum, and is attached to the bases of the lumbar trans- 

 verse processes. These three Ia3 7 ers constitute the posterior 

 origin of the transversalis abdominis muscle. 



The trapezius and latissimus are now to be divided through the 

 middle of their muscular portions and reflected. In doing this, care 

 must be taken not to push too far the separation between them and 

 the muscles beneath at their spinal attachments, inasmuch as their 

 tendons are united and confounded with those of the next layer. In 

 removing the trapezius, branches of the supra-scapular artery will be 

 divided. 



The RHOMBOIDEUS MINOR MUSCLE is a narrow band 

 arising from the spinous processes, and supra-spinous liga- 

 ment of the last cervical and first dorsal vertebrae, and in- 



