PROGRESSIVE MUSCULAR ATROPHY. 567 



CHAPTER VIII. 



PEOGEESSIVE MUSCULAR ATROPHY ATROPHIE MUSCULAIRE GRAIS- 

 SEUSE PROGRESSIVE PARALYSIE MUSCULAIRE PROGRESSIVE ATRO- 

 PHIQUE. 



[FriedreicJi ascribes progressive muscular atrophy to chronic in- 

 flammation of the perimysium, inducing hyperplasia of the inter- 

 stitial connective tissue and destruction of the muscular filaments. 

 But of late the more perfect means for examining the spinal cord 

 show changes in its gray anterior horns, such as atrophy, increased 

 pigmentation, or even disappearance of its ganglion-cells. Appar- 

 ently the anterior ganglion-cell columns of the spinal cord are the 

 centre of nutrition for the muscles of the trunk and limbs ; hence 

 disease in this region would cause muscular atrophy ; this disease 

 may be primary, or may be secondary to other spinal diseases, such 

 as locomotor ataxy, sclerosis of the lateral cords, central myelitis, 

 etc. The anterior nerve-roots, which are traversed by the muscular 

 nerve-filaments, and even the peripheral nerves, participate more or 

 less in the atrophy of the trophic spinal centre. The affected mus- 

 cles atrophy and become pale-red or yellowish ; in cases not far 

 advanced we may find normal, fatty, and atrophied filaments in the 

 same muscle. Sometimes, instead of fatty degeneration in the 

 primitive filaments, it occurs in the interfibrillar connective tissue ; 

 so that a division has been made into parenchymatous and inter- 

 stitial. Allied to the latter form is pseudo-muscular hypertrophy ; 

 this occurs chiefly in young males, and is due to proliferation of the 

 interfibrillar connective tissue, with deposit of numerous fat-cells 

 and atrophy of the muscular filaments ; the deposit of fat enlarges 

 the muscle and gives the appearance of hypertrophy. This affec- 

 tion comes chiefly in the lower limbs, and then in the erector spinae 

 muscles. 



Progressive muscular atrophy is most common in males between 

 thirty and fifty years. It is often hereditary, but is most frequently 

 due to continued strain of certain muscles ; sometimes also to cold, 

 excesses, certain diseases, such as typhoid, diphtheria, etc., and to 

 injuries. 



Progressive muscular atrophy and bulbar paralysis differ in the 

 location of the original disease ; the former being due to changes 

 in the motor ganglion-cells of the anterior horns, the latter to 

 changes on the floor of the fourth ventricle.] 



SYMPTOMS AND COURSE. The first symptom of progressive mus- 

 86 



