http://valdosta.sgaonline.com/2010vdt/pdfs/KJohnson_second_autopsy.pdf
Dr. Anderson gave this case a much needed reality check.
The bruising and damage to the right side of the neck is corroborated by at least one autopsy photo and the EMS report.
The evidence in this case supports that
Kendrick Johnson died of homicidal asphyxiation. KJ had prominent petechiae on the forehead (between the eyes) and blood red eyes. None of this was reported in the AR. The lab/crime report did document it.
A closer look at strangulation cases | Texas District & County Attorneys Association
Visible evidence
Some of the best evidence of strangulation comes in the form of post-mortem examinations (autopsies)
where the tissues of the neck and the brain can be evaluated.
Other visible injuries to look for are swelling of the neck (edema), lips, or tongue.
Petechiae, which is the rupturing of capillaries (small blood vessels near the surface of the skin) is present in a very few cases. When petechiae is lacking, defense attorneys seem to want to hang their hat on its absence as evidence that no strangulation occurred.
Petechiae occurs in moments
where the jugular vein (which is closest to the surface of our skin and is thus obstructed with less pressure)
is blocked and prevented from sending blood down to the heart but
the carotid artery (which is deeper than the jugular vein and sends blood to the head) is open. This blockage of blood causes the capillaries to burst.
This is significant because for petechiae to occur, some pressure was placed on a certain part of the victim’s neck that occluded the jugular vein. In other words,
petechiae is caused when only the most superficial part of the anatomy is blocked.
This is not to say that the presence of petechiae isn’t important—
it certainly helps to prove strangulation in that it is evidence of impeding the blood flow of the jugular vein—but
it can also support the argument that a struggle took place or that the suspect released and/or varied the pressure he used during the assault. At the same time, the absence of petechiae shouldn’t be a concern for a prosecutor. Even in cases where petechiae might be present, it is easily missed as it sometimes presents itself as a single pin-point dot on the earlobe, in the eye, on the eyelid, or behind the ear.
Like many other visible injuries consistent with strangulation, it is such a small injury that
it is often overlooked and can be easily covered by freckles,
dark skin, make-up, or lighting.