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Secondary Classification of Fingerprints With Small Letter Grouping: Rules and Worksheet

Secondary Classification of Fingerprints With Small Letter Grouping

Secondary Classification is a subset of Henry Fingerprint System where patterns on index fingers are assigned by capital letters. Their values are set after the primaries in the classification line. In some special cases, a special extension to secondary i.e. small-letter grouping is used.

Before jumping on how to calculate the value of a fingerprint’s secondary classification system, let’s take a look at the rules and secondary value system.

Later, I’ll show you how to calculate small letter grouping.

Rules for Secondary Classification

  • Numerator: Right Index (finger 2)
  • Denominator: Left Index (finger 7)
  • Position: placed immediately right to primary classification column.
  • Patterns: All patterns (mostly 5 common patterns)
  • Values: Capital Letter
  • Using all common patterns, 25 possible combinations.

Secondary Classification Values

Capital letters designation is used for all the commonly encountered patterns. These are listed in the following table.

S.No.PatternsSymbol/Values
1.Plain ArchA
2.Tented ArchT
3.Radial Loop R
4.Ulnar Loop (/, \) (more info)U
5.WhorlW
6.Central Pocket Loop Whorl*C
7.Double Loop *D
8.Accidental Loop Whorls*X
* Not common to secondary classification

How to Calculate Secondary Classification Value? 

Let’s calculate the value of a secondary classification number using the following example.

How to Calculate Secondary Classification Value 

Step 1: Identify Patterns

Procedure for secondary classification from step 1 to step 3

You can learn the rules for filling a 10-digit card while classifying fingerprints by following the link.

  • Right Index finger: Left Slant loop (Radial loop)
  • Left Index finger: Left Slant loop (Ulnar loop)

Step 2: Assign Values

  • Right Index finger: Radial loop= R
  • Left Index finger: Ulnar loop= U

Step 3: Representing in Henry Classification Line

  • Numerator: Right Index= R
  • Denominator: Left Index= U

This is how it looks in the henry classification system 

representation of secondary classification in henry line

Secondary Small Letter Grouping

When it comes to small letter grouping, there is always confusion while categorizing them.

Many of the authors classified small lettered groups as a part of secondary division while others considered it in the sub-secondary division of the Henry classification system of fingerprints.

Nonetheless, their values are always registered with the secondary classification number, regardless of the division in which they are classified.

Highlighting Pointers

  • Fingers Used: Other than the Index finger
  • Patterns: Plain Arches, Tented Arches, and Radial loops
  • Values: Small letter
  • Numerator: Right hand
  • Denominator: Left hand
  • Position: With secondary division number 

When Small Letter Groups are Used?

They are majorly employed when a plain arch, tented arch, or radial loop is present in fingers other than index fingers. As per the FBI database, there 7 to 10% of patterns use small letter grouping.

Moreover, when classifying fingerprints with small letter grouping, both sub secondary classification and major division are omit-out.

But…Why sub secondary and major divisions are not used with small letters grouping?

Because major and sub secondary values depend on the ridge tracing and ridge counting of fingers. This can’t be possible with arches and tented arches. However, if all of them are loops, it may be possible to include them, but again it is extremely unlikely.

That is the reason why they completely (as a whole) omitted irrespective if there is a loop or not.

Values of Small Letter Grouping Secondary Classification

In small lettered grouping, small letters are used which are given as:

  • Arches= a
  • Tented arches =t
  • Radial loops =r
  • Absence of ‘a’, ‘r’, and ‘t’ = hyphen (-)

Note 1: In other words, the appearance of ulnar loop and whorls are indicated by a hyphen (-).

Rules While Using Small Letter Fingerprint Grouping

Rules While Using Small Letter Fingerprint Grouping

There are four rules:

Rule 1: Values are assigned based on their occurrence

  • While writing the small letter, the values are placed before and after the secondary values as per their occurrence.
  • Before Secondary Value: Thumb values
  • After Secondary Value: Middle, ring, and little finger values

Rule 2: Only 3 Types of patterns are used as small letters

  • Arches= a
  • Tented arches =t
  • Radial loops =r

Rule 3: Patterns Other than 3 common types

  1. Hyphen (-) is used for the absence of ‘a’, ‘r’, or ‘t’.
  2. In other words, hyphen assigned for in-between ulnar loops and whorls i.e. ulnar loops and whorls for middle and ring finger.
  3. Thumb and little fingers with ulnar loops and whorls are omitted.
  4. If there are two consecutive ulnar loops or whorls on the middle and ring finger, they are only indicated by a single hyphen (-).
  5. If there are no in-between loops and whorls, their values are omitted.

Rule 4: For more than one Consecutive a, t, r

If more than one plain arch, tented arch, or radial loop appears consecutively, instead of writing double alphabetically, they are replaced by a number followed by a small letter. For more illustration, check practice set #2 (later in the post).

Calculation for Small Letter Grouping 

This is how small lettered grouping is calculated in accordance with secondary classification.

For example: let say, if the fingerprint has the following patterns:

Identifying Fingerprint Patterns

Right Hand

  • Thumb= Plain Arch
  • Index*= Whorl
  • Middle= Tented Arch
  • Ring= Ulnar Loop
  • Little= Ulnar Loop

Left Hand

  • Thumb= Ulnar loop
  • Index*= Ulnar loop
  • Middle= Ulnar loop
  • Ring= Plain arch
  • Little= Ulnar loop

Step 1: Writing Small Letters

Right Hand

  • Thumb= Plain Arch =a
  • Index*= Whorl = W (Secondary no.)
  • Middle= Tented Arch= t
  • Ring= omitted (rule #3.5)
  • Little= omitted (rule #3.5)

Left Hand

  • Thumb= omitted (rule #3.3)
  • Index*= Ular= U (Secondary no.)
  • Middle= Ulnar loop = – (hyphen for in-between ulnar loops and whorls)
  • Ring= Plain arch= a
  • Little= omitted (rule #3.3)

Step 2: Representing with Secondary Number

  • Numerator= aWt
  • Denominator= U-a

The following is the small lettered grouping with secondary division in Henry classification number:

KeyMajorPrimarySecondarySub SecondaryFinal
Yet to findOmitted17aWtOmittedYet to find
  1U-a  

Secondary With Small Letter Group in Amputated and Scarred Fingers

A. Scarred Fingerprints

The following table is only used for secondary and small letter grouping in case of scarred fingerprints.

Possible RuleSecondary + Small Letter Values
Rule 1: Fully Disfigured ImpressionsPatterns from corresponding opposite finger
Rule 2: Partially Scarred With Possible Pattern Type DeterminationUse the possible pattern type
Rule 3: Both Corresponding Opposite Finger are fully disfiguredWhorls pattern assigned

Note 2: If fingers are bandaged, prints are taken after healing. If healing leads to scars, the values are given by the above-scarred rules.

B. Amputated Fingers

Following table is strictly for secondary and small letter classification of fingerprints for amputated fingers.

Possible RuleSecondary + Small Letter Values
Rule 1: 1,2,3 or 4 Amputated FingersPatterns from corresponding opposite hand
Rule 2: Two Opposite Finger are AmputatedBoth fingers are assigned as whorls
Rule 3: All fingers are AmputatedW/W (no small letter values)
Rule 4: Both Hands are AmputatedFootprints are used

Worksheet for Secondary & Small Letter Groups

Practice Set #1: More than one ‘a’, ’r’, or ‘t’

Following is data extracted from a 10-digit card. Check the dedicated article on what are the rules for fill a 10-digit card.

Rt ThumbRt IndexRt MiddleRt RingRt Little
Plain archWhorlTented archTented archUlnar
Lt ThumbLt IndexLt MiddleLt RingLt Little
UlnarUlnar loopUlnar loopPlain archUlnar

Step 1: Writing Small Lettered Grouping

Rt ThumbRt IndexRt MiddleRt RingRt Little
aWttomitted
Left ThumbLeft IndexLeft MiddleLeft RingLeft Little
omittedUaomitted

Step 2: Representing them with Secondary Number

Here, except for the index finger, there is more than one small letter arch next to each other. So, instead of writing ‘tt’, ‘2t’ is registered.

  • Numerator: aW2t
  • Denominator: U-a

This is how Henry’s fingerprint number would be represented.  

KeyMajorPrimarySecondarySub SecondaryFinal
Yet to findOmitted17aW2tOmittedYet to find
  1U-a  

Note 3: If small letter grouping in the secondary is there, both sub secondary and major division is omit-out.

Practice Set #2

Following is the extracted data from the 10 digit card.

Rt ThumbRt IndexRt MiddleRt RingRt Little
WhorlRadial loopWhorlWhorlPlain Arch
Lt ThumbLt IndexLt MiddleLt RingLt Little
Plain ArchUlnar loopUlnar loopPlain archWhorl

Step 1: Writing Small Lettered Values

Right Hand

  • Thumb= Whorl = Not included (whorl and ulnar loop of thumb are omitted)
  • Index*= Radial loop = R (Secondary no.)
  • Middle & Ring = Whorl= – (single hyphen for both whorls)
  • Little= Plain arch= a

Note 4: If in the above case, little finger also has a whorl or ulnar loop, no hyphen is substituted because there is no ‘a’, ‘r’, or ‘t’ in between them.

Left Hand

  • Thumb= Plain arch = a
  • Index*= Ular= U (Secondary no.)
  • Middle= Ulnar loop = – (hyphen for in between ulnar loops and whorls)
  • Ring= Plain arch= a
  • Little= Whorl= Not included  (whorl and ulnar loop of thumb are omitted)

Step 2: Representing them with Secondary Number

  • Numerator: R-a
  • Denominator: aU-a

Practice Set #3

Following are the values extracted from the 10 digit card.

Right ThumbRight IndexRight MiddleRight RingRight Little
Plain archWhorlWhorlUlnar loopTented Arch
Left ThumbLeft IndexLeft MiddleLeft RingLeft Little
WhorlUlnar loopRadial loopWhorlTented Arch

Step 1: Writing Small Lettered Grouping

Right ThumbRight IndexRight MiddleRight RingRight Little
aW-(only one is used)t
Left ThumbLeft IndexLeft MiddleLeft RingLeft Little
omittedUrt

Step 2: Representing them with Secondary Number

  • Numerator: aW-t
  • Denominator: Ur-t

Practice Set #4

Following are the values extracted from the 10 digit card.

Right ThumbRight IndexRight MiddleRight RingRight Little
Tented archUlnar loopPlain ArchRadial loopTented Arch
Left ThumbLeft IndexLeft MiddleLeft RingLeft Little
Radial loopUlnar loopTented archPlain archWhorl

Step 1: Writing Small Lettered Grouping

Right ThumbRight IndexRight MiddleRight RingRight Little
tUart
Left ThumbLeft IndexLeft MiddleLeft RingLeft Little
rUtaomitted

Step 2: Representing them with Secondary Number

  • Numerator: tUart
  • Denominator: rUta

Frequently Asked Questions

1. What fingers are involved in secondary classification?

In secondary classification, two fingers are involved, namely finger numbers 2 and 7. They are also known as the right and left index fingers.

2. What fingers are used in small letter grouping?

All fingers except index fingers. So, fingers number 1,3,4,5,6,8,9, and 10 are used for small lettered grouping with secondary classification.

3. Where do the values of the secondary classification fall in the henry classification number?

The value of secondary classification is placed immediately after the primary classification. Additionally, small lettered values are also conjoined with secondary division.

4. What patterns are included in secondary classification?

All patterns are included here. Some common patterns such as plain arch (A), tented arch (T), ulnar loop (U), radial loop (R), and whorl (W). Uncommon patterns such as double loop (D), central pocket loop whorl (C), and accidental loops(X) are also included. 

5. What patterns are included in small lettered grouping in secondary classification?

Patterns such as plain arch (a), tented arch (t), radial loop (r) are used for small lettered grouping. In addition, for in-between whorls and ulnar loop (on middle and ring finger), hyphen (-) is used.

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