She must not have been strangled because she did not have petechiae.β -Defense Attorney (name omitted)
The above quote identifies a common myth surrounding strangulation. Petechiae, tiny red spots resulting from burst capillaries, does not always occur in strangulation. The presence or absence of petechiae in strangulation is widely misunderstood. Here are some facts about petechiae:
1. Petechiae results from arterial pressure being built up faster than the body can accomplish venous return. (Blood is flowing into the area faster than it can flow out). In strangulation this results from blockage of venous blood flow.
2. Petechiae can result from activities other than strangulation, such as childbirth, skydiving, vomiting, vigorous coughing, any type of mechanism that results in the build-up of arterial pressure. I have some interesting photos from colleagues who experienced, childbirth, food poisoning, or sickness, and sent me their petechiae photos.
3. Petechiae characteristics:
- Non-palpable (flat as opposed to a raised area on the skin, cannot be felt on exam)
- Non-tender (no discomfort when touched)
- Do not blanch when touched
- Usually appear in crops or clusters (may be diffuse)
- Petechiae occurs upstream from the area of compression.
4. Petechiae, if present, represents a significant finding because it confirms neck compression for at least 20-30 seconds. This indicates compression for a life-threatening period of time.
5. While petechiae may be present, a victim can be fatally strangled without any petechiae. In studies, approximately 78% of strangled patients lacked
observable petechiae.
β