Expiratory Blood Stains

 

Source of blood - one or more of the following:

(1) lung

(2) trachea or bronchus

(3) mouth or oropharynx

(4) nares

 

Patterns of expiration that may impart more energy to the exhaled blood:

(1) coughing

(2) sneezing

(3) gasping

 

Features:

(1) The greater the force at exhalation the smaller the droplets. A forceful exhalation can generate a fine mist.

(2) Blood mixed with saliva will have a lighter color.

(3) Blood coughed from the lungs may contain small air bubbles.

(4) Expiratory blood stains may be mixed with stains from blood dripping from the mouth or nose.

 

Differential diagnosis:

(1) atomized blood from a high velocity gunshot

(2) high velocity splatter