48o 



APPLIED ANATOMY. 



that a curved rod cannot be bent laterally without twisting or rotating. Inasmuch 

 as the human spine is curved convexly backward in the dorsal region and convexly 

 forward in the lumbar region, lateral bending is accompanied by rotation of the 

 vertebrae and their attached ribs. The bodies of the vertebrae are carried toward the 

 side of the convexity of the curve and the ribs on that side project backward, pro- 

 ducing a marked hump and often an elevation of the shoulder. As a primary curve 

 forms, an attempt is made to restore equilibrium by bending the remaining portion of 

 the spine in the opposite direction, hence the curves, if of long duration, are double 

 or compound, and these secondary curves are called compensating curves. Marked 

 lumbar curves are usually accompanied by prominence of the hip on the side of the 

 convexity, but the pelvis usually remains level. Should the length of the limbs be 

 unequal, allowing tilting of the pelvis, the prominence of the hip would be on the 

 side of concavity. It is obvious that the weight of the body tends to aggravate 

 these pathological curves. The treatment of scoliosis is directed to correcting these 

 faulty curves by exercises and appliances intended to support and stretch the body 

 on the contracted or depressed side and restore the tone and power to the relaxed 

 muscles and tissues of the opposite side. 



Spina Bifida. The spinal canal is formed by the laminae of the vertebrae 

 arching over and uniting posteriorly. This union begins in the dorsal region and 



progresses towards the head and sacral regions. 

 Failure of union constitutes spina bifida. It is 

 most frequent in the lumbar and sacral regions. 

 Usually a sac formed of the spinal membranes 

 protrudes and contains the spinal cord flattened 

 out like a strap passing down on its posterior sur- 

 face, but sometimes the sac contains no nervous 

 elements. Frequently the sac is so thin that it 

 soon inflames, ruptures, and allows escape of the 

 cerebrospinal fluid, and death ensues from menin- 

 gitis. The parts below are not infrequently para- 

 lyzed and hydrocephalus may coexist. Operative 

 procedures have been frequently successful in 

 mild cases, but in extensive lesions they have 

 been quite fatal, and even when primarily suc- 

 cessful may be followed by the development of 

 hydrocephalus. 



AFFECTIONS OF THE SPINAL 

 COLUMN. 



Caries of the Spine. While caries of any 

 part of the vertebrae may occur from injury, it is 

 almost always the result of tuberculous disease 

 in the bodies ; the pedicles, laminae, and proc- 

 esses remain unaffected. As the bodies become 

 destroyed the anterior portion of the spine col- 

 lapses, and this causes a projection of the spines 

 of the affected vertebrae posteriorly or kyphosis. 

 This projection of one or more spinous processes 

 is the surest indication of spinal caries or Pott's 

 disease. 



There is also rigidity of the affected region. 

 This is recognized by the attitude assumed and 

 by having the patient, if an adult, bend the back 

 anteroposteriorly. Small children should be 

 placed flat on a table, face down, and then gradu- 

 ally raised by the feet. If the spine is normal the child will readily bend in the lumbar 

 and lumbodorsal regions. The movable regions, embracing the cervicodorsal and dor- 

 solumbar vertebrae, are the sites most frequently affected. Distention of the abdomen 



FIG. 482. Psoas abscess originating from 

 spinal caries of the dorsolumbar vertebra: 

 and following the psoas muscle to the groin. 

 (From a sketch by the author of a specimen 

 in the Mutter Museum of the College of 

 Physicians). 



