MICROANATOMY

Detailed explanation-1: -A blood drop striking a smooth surface at a 90° angle will result in an almost circular stain; there is little elongation, and the spines and satellites are fairly evenly distributed around the outside of the drop.

Detailed explanation-2: -When a droplet of blood strikes a surface perpendicular (90 degrees) the resulting bloodstain will be circular. Blood that strikes a surface at an angle less than 90 degrees will be elongated or have a tear drop shape.

Detailed explanation-3: -Because blood demonstrates surface tension, or cohesive forces that act like an outer skin, a drop of blood dropped at a 90° angle forms a near-perfect spherical shape.

Detailed explanation-4: -Blood forms a spherical shape (perfect circular shape) almost immediately upon separating from the blood source. The spherical shape is caused by the surface tension of the blood. Surface Tension causes the blood drop to pull itself in; both horizontally and vertically.

Detailed explanation-5: -The shape of the stain tends to change depending upon the angle of impact, which caused the stain. The steeper the impact, the more elliptical or elongated, the blood drop. The more acute the angle of impact, the more elongated the stain. 90-degree angles are perfectly round drops.