THE THORAX. 117 



and the longissimus dorsi externally also with its acces- 

 sory muscles ; between them superiorly, the lower por- 

 tions of the splenius colli, complexus, and transversalis 

 colli ; deepest of all, the transverso-spinales and levatores 

 costarum. 



Abscesses connected with caries of the transverse pro- 

 cesses, or laminae of the dorsal vertebrae, gravitate into 

 the inferior portion of the region, and often extend to 

 the sides of the ribs or into the axilla, instead of becom- 

 ing superficial, on account of the strong fascial lamina 

 between the superficial and deep muscles. 



A small triangular space uncovered by muscle exists 

 at the point where the trapezius and latissimus dorsi 

 diverge. The space is bounded by the two muscles just 

 named towards the spine, whilst externally it is com- 

 pleted by the inferior angle of the scapula. From the 

 fact of its being uncovered by muscle it is available for 

 auscultation. 



The vessels met with are dorsal branches from the in- 

 tercostals and the posterior scapular, and the nerves are 

 the dorsal branches of the spinal, with some few branches 

 from the cervical plexus and spinal accessory. 



With regard to the skeleton of this region, the ar- 

 rangement of the dorsal vertebrae renders their disloca- 

 tion extremely difficult, and when it does occur it would 

 seem to be invariably associated with fracture of some 

 portion of the spinal column ; the spinous processes from 

 their position are often fractured. 



The dorsal spine is very often the seat of caries of the 

 bodies of the vertebrae, or disease of the intervertebral 

 substances, inducing angular curvature and paralysis of 

 the lower limbs from pressure on the cord. "When the 



