Narrowing and obliteration of the uterine ca vity. Atresia.—The defects which come under this head may be either congenital or ac quired. They inay consist in a simple nar rowing, or stricture of the cavities of the uterus, or of the apertures leading to them, or in a complete obliteration of some or all of these. Probably most of the cases of atresia which do not originate in the malformations already described, have resulted from the or ganisation of the products of inflanimation affecting these parts.
Obliteration of the external os uteri, either partial or complete, is the most common of these conditions. In minor degrees, where the form of the parts is not lost in adhesions with adjacent structures, the os is found closed by narrow metnbranous threads or bands. If the closure is not complete, pregnancy may ensue, hut labour is obstructed, and the original seat of the os is then with difficulty traced, or it cannot be found.
The cervical canal may be entirely oblite rated by the formation of fibrous tissue, in which smooth muscular fibres have been some times found.
Obliteration, or narrowing of the inner ute rine orifice, may occur in the progress of senile atrophy, or as a result of the same processes that cause obliterations lower down. All the foregoing atresiw may result in the collections of fluids within the uterine cavity recently de scribed.
Lastly, the cavity of the uterine body may be so completely closed that no trace of it can be found. Such an example is delineated in Pl. 13. of Boivin's and Doges' Atlas, which contains also the figure of another uterus, the original seat of whose cavity is indicated only by a narrow triangular band of white tissue nearly as hard as cartilage.
Pathologic conditions which may involve se veral of the uterine tissues.
Cancer. —The two main disorganising pro cesses hy which the structure of the uterus is metamorphosed or disintegrated and ultimately more or less destroyed, are those under which cancer and fibroid are respectively developed in its tissues. Of these, regarded as destruc tive agents, cancer ranks second in point of frequency, but first in potency.
Cancer occurs in the uterus as in the ovaries, under the three principal varieties of encepha loid, scirrhous, and colloid. But while in the latter organ colloid as a primary disease is certainly more common than either of the other two ; in the uterus, on the other hand, both scirrhous and colloid are rare, while ence phaloid constitutes the chief form under which cancer is found.
The development of cancer may undoubt edly commence in any portion of the uterus, but the number of instances in which it occurs, first, in the cervix, and especially in the va ginal portion, is so preponderating, that this may be regarded as mainly the seat of origin of uterine cancer.
The comparative rarity of opportunities for examining uterine cancer in the incipient stage, has limited to a certain extent our knowledge of this part of the subject.
The cervix in the incipient stage, smooth, tense and hard, or exhibiting upon its surface here and there knotty projections, is found upon section to have its tissues infiltrated in parts by the cancerous structure, which differs in the character and relative proportions of its elements, according to the form which the cancer assumes. In the medullary variety a white cream-hke or lardaceous semi-fluid mat ter, composed of the usual cancer constituents, is found interspersed among the meshes of a loose reticulum, in the softer portions of which few if any of the normal uterine fibres can be traced. The larger preponderance of the en cephaloid matter, compared with the fibrous strorna, occasions that semi-elastic feel which the part early acquires, and at the same time constitutes the main difference between en cephaloid and scirrhous cancer.
In the scirrhous or fibrous variety the greater hardness of the structures is depend ent upon the presence of a large proportion of a coarser fibrous stroma, composed of dense white fibres, the minute interspaces of which are occupied by a greyish or reddish softer and often pulpy substance, which may be obtained by scraping, or may be squeezed from the part. In the harder forms of scirrhous but little fluid is so obtainable ; but in some specimens here and there, softer portions are found from which a fluid cream-like matter exudes, dif fering in no respect from the pulp of ence phaloid cancer. These and the softer portions obtained by scraping are composed of cancer cells with molecules, granules, and disinte grated fibrous tissue.