488 



APPLIED ANATOMY. 



The deformities seen are 



involved, atrophy, and the abolishing of the reflexes, 

 secondary results of the paralysis. 



Syringomyelia is an acquired enlargement of the central canal or the formation 

 of new canals in the gray matter. It produces motor, sensory, and trophic disturb- 

 ances which vary according to the part of the cord attacked. 



Progressive Muscular Atrophy (Duchenne's Disease). The atrophy begins 

 most often in the hands and extends to other parts of the body. Then occurs an 

 atrophy of the gray substance of the anterior horns which may extend to the brain ; 

 even the white substance of the direct and crossed pyramidal tracts may also show 

 degeneration. There is a type in which there is a lack of demonstrable cord lesions. 

 Among its various forms are those called pseudomuscular hypertrophy, progressive 

 muscular dystrophies (Erb), and primitive progressive myopathies (Charcot). 



Arthritic Muscular Atrophy. Disease of the joints often results in marked 

 disturbance of the gray matter of the cord, which in turn is followed by muscular 

 atrophy (Church: Church and Peterson, Nervous and Mental Diseases, page 38). 



Lesions Affecting Principally the White Matter of the Cord. The principal 

 lesions affecting the white matter are lateral sclerosis, locomotor ataxia, combined 

 posterolateral sclerosis, Friedreich's ataxia, and hereditary spastic paraplegia. 



Lateral sclerosis, or spastic paraplegia, is almost .unknown as a primary 

 affection. It is a sclerosis of the pyramidal tracts. It occurs as a secondary 

 degeneration, the result of cerebral disease, producing the spastic paraplegia of 

 infants Little's disease and also follows transverse lesions of the spine from tumors, 

 caries, fractures, etc. 



Locomotor ataxia, or tabes dorsalis, when advanced may affect the entire 

 portion of the cord between the posterior horns and the commissure, from the filum 

 terminale to the medulla. It begins in Clarke's column (a group of cells in the 

 posterior horn of the cord extending from the seventh cervical to the second lumbar 

 nerves) and may involve the direct cerebellar tracts and Gowers's ascending antero- 

 lateral tracts and also the posterior nerve roots. It produces both motor and sensory 

 disturbances as well as trophic changes. 



Combined Posterolateral Sclerosis (Ataxic Paraplegia of Cowers). This 

 produces symptoms combining spastic paraplegia and locomotor ataxia. The fol- 

 lowing structures are affected: columns of Burdach, Goll, crossed pyramidal tract, 

 direct pyramidal tract, and not always the ascending tract of Gowers. 



Friedreich's ataxia (family or hereditary ataxia) is a progressive paralysis 

 often appearing through many generations. There is a sclerosis of the columns of 



Goll and Burdach, crossed pyramidal tract, Gow- 

 ers's tract, direct cerebellar tract, Lissauer's tract, 

 and often atrophy of the cells of Clarke's column. 

 Hereditary Spastic Paraplegia. This is 

 a degeneration of the pyramidal tracts, columns of 

 Goll and Burdach, and direct cerebellar tract. The 

 disease has been traced through many generations. 





I"' 

 \ 



OPERATIONS ON THE SPINE. 



Spinal Puncture. Spinal puncture may be 

 performed either for diagnostic purposes, for relief 

 of accumulations of subarachnoid fluid, or for the 

 purpose of producing spinal anaesthesia. , 



The lumbar region is usually selected and the 

 puncture made just to one side of and either above 

 or below the spine of the fourth lumbar vertebra. 

 A line passing from the highest point of the crest 

 of one ilium to that of the opposite side passes 

 through the lower part of the spine of the fourth lumbar vertebra. The puncture 

 should always be made below the upper border of the second lumbar vertebra, 

 because the spinal cord extends down to that point (Fig. 490). The lumbar spines 

 are nearly or quite horizontal and do not incline downward as do those of the cervical 



Flo. 490. Lumbar puncture of the spine. 



