[=Notice=: 1. _External characters_—shape; measurement; amount of fat,
etc. 2. _Contents_—serum; quantity; color; how affected by heat;
blood; quantity; character; source. 3. _Internal surface_—adhesions;
their position, extent and character; as firm, soft, etc.]
The pericardium is subject to the same affections as other serous
membranes, including _inflammation_, _adhesions_, _effusions_ or _morbid
growths_.
=Inflammation= of the pericardium or _pericarditis_, is characterized by
an unusual dryness of the surface, with injection of the vessels in the
early stage, while at a later period a layer of plastic lymph will be
found adhering to the surfaces. The deposit may be limited to some small
portion, or be distributed over the whole inner surface of the membrane
and upon the exterior of the heart, giving them the appearance of having
been smeared over with some sticky substance. Often the surfaces are
rough or villous in appearance, like the mucous membranes of the
intestines. Irregular calcareous patches are sometimes found in old
chronic cases, developed within the thickened portions of the membrane.
=Adhesions= may also form between the surfaces in contact. The whole
cavity may in this manner become obliterated, or bands of adhesion may
be found here and there.
=Effusions= may be found in the pericardium, as in other serous
cavities. When the result of _pericarditis_, the fluid will often
contain floating shreds of lymph. Sometimes the fluid will be found
highly albuminous, and again bloody or mixed with pus. This effusion may
have taken place so early as to have prevented any adhesion of parts; or
it may not have commenced until union had taken place at certain parts,
when, from the distension of the sac, these bands may be found greatly
elongated, and stretching across the cavity in various directions. When
the effusion is but part of a _general dropsy_, it will be clear, while
the surfaces of the membrane will be smooth and destitute of evidences
of inflammation. In quantity, the fluid found in these cases may vary
from a few ounces to a pint or more.
_Blood_ may sometimes be found filling the pericardium, either from a
wound of its walls, rupture of the heart, or from the bursting of an
aneurism. In scurvy, purpura, etc., small patches of extravasated blood
may be found in its walls.
=Morbid Growths.= The more common of these, found in connection with the
pericardium, are _cancers_. They are usually secondary in their
appearance, and generally will have first developed in the mediastinum.
_Fibrous_ or _cystic_ tumors have been noticed in a few rare cases,
while _tubercles_ of the miliary form, are not uncommon within this
membrane.