1. Fingerprint Patterns & Minutiae

2. Big Men in Fingerprinting History
Sir Francis Galton – performed the first serious study of fingerprinting and published Finger Print in 1892
Sir Edward Henry – developed classification system based on patterns of ridges. Still used in most English speaking countries today.

3. How are fingerprints formed?
Only found on hairless parts of body
Formed by papillary ridges by the fourth month of pregnancy

4. How are fingerprints formed?
Sweat glands secrete sweat to skin surface
Sweat necessary to form latent prints

5. Types of Fingerprints Latent – the most frequently found
invisible to the eye
formed by sweat, oil on surfaces of finger ridges
must be treated with chemicals, powders, etc. to be visible

6. Types of Fingerprints Visible – easily seen by the unaided eye
most common when fingers are blood stained
can also be made by ink or other similar medium staining fingers of person leaving print
rarely found at crime scenes since perpetrators would attempt to wipe away easily seen evidence of this type

7. Types of Fingerprints Plastic – a.k.a. molded print
made by impression of fingerprint in soft material
soft material might be drying paint, putty, soap and cheese (most often the bane of dairy thieves the world over!)

8. Fingerprint Principles
Immutable – the patterns of ridges do not change over the course of a person’s life. The patterns begin to form on the skin surface during the third month of pregnancy.
Unique – the patterns of ridges are specific to the person. Even identical twins have unique fingerprints.

9. Fingerprint Patterns - Arches
Made up of ridges lying one above the other in a general arching formation
Least common of the general patterns of fingerprints.
Two types of arches: plain, like shown here

10. Fingerprint Patterns - Arches
Tented arch
Sharp upthrust of sides of arch results in an angle that is less than 90°

11. Fingerprint Patterns - Loops
Consists of one or more free-recurving ridges and one delta
Radial loop – loop comes from thumb side of hand
Ulnar loop – loop comes from pinkie finger side of hand
NOTE: Perpetrators rarely leave Post-it notes telling you which hand they used during a crime!

12. Loops
Loops must have one delta and one or more ridges that enter and leave on the same side. These patterns are named for their positions related to the radius and ulna bones.
Radial Loop (Right Thumb)
Loop opens toward the left or the radial bone.
Ulnar Loop (Right Thumb)
Loop opens toward right or the ulna bone
NOTE: On the left hand, a loop that opens to the left would be an ulnar loop, while one that opens to the right would be a radial loop.

13. Fingerprint Patterns - Whorls
Whorls have at least one ridge that makes (or tends to make) a complete circuit.
They also have at least two deltas. If a print has more than two deltas, it is most likely an accidental.

14. Fingerprint Patterns - Whorls
Double loop pattern
Two loop formations that are separate and apart
2 deltas

15. Fingerprint Patterns - Whorls
Central pocket loop consists of one or more free recurving ridges and two points of delta
“Lollipop” effect with one delta and its ridge lines

16. Fingerprint Patterns - Whorls
Central pocket loop
“Lollipop” effect with one delta and its ridge lines

17. Fingerprint Patterns - Whorls
Accidental pattern –doesn’t fit into other category.

18. Fingerprint Patterns
Describes the shapes that are produced by the black or colored portions of the fingerprint, NOT the white or uncolored portions
The black portions are called ridges

19. Minutiae Patterns Whorls, Loops, & Arches are class evidence.
A suspect could be excluded based on the type of print
To individually identify, details of print must be examined.
Minutiae Pattern: The shape, pattern, and position of a ridge pattern that make it unique.
These usually places where the ridge changes.

20. Fingerprint Patterns
Ridge ending – a ridge that ends abruptly

21. Fingerprint Patterns
Bifurcation – a single ridge that divides into two ridges.

22. Fingerprint Patterns
Lake or enclosure – a single ridge that bifurcates and reunites a short time after to form a single ridge

23. Fingerprint Patterns
Short ridge, island or independent ridge – a ridge that starts, travels a short distance and then ends

24. Fingerprint Patterns
Dot – an independent ridge with approximately equal length and width

25. Fingerprint Patterns
Spur – a bifurcation with a short ridge branching off a longer ridge

26. Fingerprint Patterns
Crossover or bridge – a short ridge that runs between two parallel ridges

27. Points of Identification
The same minutiae are present
The minutiae flow in the same direction
The minutiae occupy the same relative positions to each other

28. Classification system based on the presence of whorl pattern in
Henry Classification
Classification system based on the presence of whorl pattern in
the fingerprint.
R. Index
(16)
R. Ring
(8)
L. Thumb
(4)
L. Middle
(2)
L. Little
(1)
R. Thumb
R. Middle
R. Little
L. Index
L. Ring
Approximately 25% of the population falls into the 1/1 category