Medical Jurisprudence, Forensic medicine and Toxicology. Vol. 1 by R. A. Witthaus et al.
4. Changes in color due to
1113 words | Chapter 60
(_a_) Cadaveric ecchymoses.
(_b_) Putrefaction.
COOLING OF THE BODY.
Immediately after death there is a slight rise of temperature, supposed
to be due to the fact that the metabolic changes in the tissues still
continue, while the blood is no longer cooled by passing through the
peripheral capillaries and lungs.
The body gradually cools and reaches the temperature of the surrounding
air in from fifteen to twenty hours; this is the ordinary course,
but the time may be influenced by a variety of causes, such as the
condition of the body at the time of death, manner of death, and
circumstances under which the body has been placed.
In certain diseases, as yellow fever, rheumatism, chorea, and tetanus,
the temperature of the body has been known to rise as high as 104° F.
and remain so for a time. Again, it has been observed that when death
has taken place suddenly, as from accident, apoplexy, or acute disease,
the body retains its heat for a long time. The bodies of persons dying
from hanging, electrocution, suffocation, or poisoning by carbon
dioxide, do not generally cool for from twenty-four to forty-eight
hours, and cases are recorded where three days have elapsed before the
body was completely cold. On the other hand, bodies dead from chronic
wasting diseases or severe hemorrhage cool very rapidly, even in four
or five hours.
In determining the temperature of a dead body the hand is not a
reliable guide: the thermometer should always be used.
FLACCIDITY.
The first effect of death from any cause is general relaxation of the
entire muscular system. The lower jaw drops, the eyelids lose their
tension, the limbs are flabby and soft, and the joints become flexible.
In from five to six hours after death, and generally while the body is
in the act of cooling, the muscles of the limbs are observed to become
hard and contracted, the joints stiff, and the body unyielding. Muscles
which are contracted in the death-agony do not necessarily become
relaxed at any time.
The muscular tissues in the dead body can be considered as passing
through three stages: (1) flaccid but contractile, (2) rigid and
incapable of contraction, (3) relaxed and incapable of further
contractility.
RIGOR MORTIS.
This is sometimes called cadaveric rigidity and occurs generally within
six hours after death and disappears within sixteen to twenty-four
hours. Many theories have been advanced to account for it, but the most
probable one is that the rigidity is due to the coagulation of the
myosin in the muscles by the weak acids which are no longer removed
from the system; the muscles always give an acid reaction and are
opaque instead of transparent; after putrefaction has set in ammonia is
developed, the myosin dissolved, and so flaccidity results.
Rigor mortis occurs first in the muscles of the eyelid, next the
muscles of the lower jaw and neck are affected, then the chest and
upper extremities; afterward it gradually progresses from above
downward, affecting the muscles of the abdomen and lower limbs. The
rigidity disappears in the same sequence. The period after death
when rigor mortis manifests itself, together with its duration, is
chiefly dependent upon the previous degree of muscular exhaustion.
Brown-Séquard has demonstrated that the greater the degree of muscular
irritability at the time of death, the later the cadaveric rigidity
sets in and the longer it lasts. He has also shown that the later
putrefaction sets in, the more slowly it progresses.
The more robust the individual and the shorter the disease, the more
marked and persistent is this muscular rigidity. It has been noticed
that the bodies of soldiers killed in the beginning of an engagement
become rigid slowly, and those killed late quickly. This explains the
reason why bodies are sometimes found on the battle-field in a kneeling
or sitting posture with weapons in hand.
If the rigidity of rigor mortis after it is once complete is overcome,
as in bending an arm, it never returns; but if incomplete it may
return. This will serve at times to distinguish real death from
catalepsy and its allied conditions. While the _average_ duration of
rigor mortis has been given as sixteen to twenty-four hours, it must
be remembered that in some cases it has been known to last only a few
hours, as in death by lightning or by electrocution. In other cases it
has persisted for seven and fourteen days.
This long continuance of rigor mortis has been noted in death from
strychnine and other spinal poisons, in suffocation, and in poisoning
by veratrum viride.
Atmospheric conditions modify to a large extent the duration of rigor
mortis. Dry, cold air causes it to last for a long time, while warm,
moist air shortens its duration. Also immersion in cold water brings on
rigor mortis quickly and lengthens its duration.
CADAVERIC ECCHYMOSIS—CADAVERIC LIVIDITY OR HYPOSTASIS.
Within a few hours after death the skin of the body, which is of a
pale, ashy-gray color, becomes covered by extensive patches of a bluish
or purple color, which are most pronounced and are first seen on the
back part of the trunk, head extremities, ears, face, and neck, and are
due to the blood, before coagulating, settling in the most dependent
parts of the body, producing a mottling of the surface with irregular
livid patches. There is also a stagnation of blood in the capillary
vessels, especially in those in the upper layer of the true skin or in
the space between the cuticle and cutis. The discoloration continues to
increase until the body is cold, when it is entirely arrested. Later
on, just before putrefaction begins, the color deepens, and the change
appears to proceed from an infiltration of blood pigment into the
dependent parts of the body.
At the same time the discolorations are appearing on the surface of the
body, _internal hypostasis_ is also taking place, most marked in the
dependent portions of the brain, lungs, intestines, kidneys, and spinal
cord.
This condition in the brain may be mistaken for so-called congestive
apoplexy; in the lungs, for pulmonary apoplexy or the first stage
of lobar pneumonia; in the intestines and spinal meninges, for the
beginning of inflammatory changes.
The position of these hypostases will afford the best correction for
this possible error. The appearances presented by cadaveric ecchymoses
have often been mistaken for the effects of violence applied during
life. Innocent persons have been accused and tried for murder or
manslaughter on charges afterward proved to be groundless. Therefore it
is of the utmost importance that the medical jurist should be able to
distinguish between ante-mortem and post-mortem ecchymoses.
The following are the points of difference:
Reading Tips
Use arrow keys to navigate
Press 'N' for next chapter
Press 'P' for previous chapter