124 THE NERVOUS SYSTEM. 
muscle fibres may become smaller than normal or split up into longitud- 
inal fibrillze or transversely into discoid fragments. 
Describe the lesion atrophia musculorum lipomatosa. 
There may be a growth of new connective tissue between the muscle 
fibres, which tissue is in turn replaced by fat-cells. The muscle fibres 
retain their normal appearance or may appear to be increased in size. 
What other degenerations are seen in muscle ? 
Fatty and hyaline degenerations, showing the changes that have 
been described as occurring with these forms of degeneration elsewhere. 
What tumors occur in muscle ? 
Fibromata, chondromata, lipomata, myxomata and sarcomata may 
occur as primary growths springing from the interstitial connective 
tissue. Carcinomata and sarcomata oceur by extension from adjacent 
parts 
THE NERVOUS SYSTEM. 
BRAIN. 
What are some of the gross pathological changes in the dura 
mater? 
There may be hemorrhage in the membrane itself, between it and 
the cranium, or between the dura and pia mater. Thrombi may form 
in any of the venous sinuses. 
What is pachymeningitis ? 
It is an inflammation of the dura mater. 
Name the different inflammations of the dura mater. 
Pachymeningitis, interna acuta. 
Pachymeningitis, externa acuta. 
Chronic pachymeningitis. 
Tubercular pachymeningitis. 
Syphilitic pachymeningttis. 
What are the causes of and changes in acute pachymeningitis 
externa ? 
It is usually caused by disease of or by injury to the cranial bones. 
The membrane is swollen, soft and congested. There may be a sup- 
purative inflammation with the formation of pus. 
What are the causes of and changes in acute pachymeningitis 
interna ? 
It may be secondary to inflammation of the external surface of the 
dura, or may occur as a complication of pyzemia, chronic diffuse 
