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 HAND SIGNS & DIAGNOSTICS:
• The hand in DOWN SYNDROME! _- Down syndrome case study 1 _- Down syndrome case study 2 • The hand in FRAGILE-X SYNDROME! _- Fragile-X syndrome case study 1 _- Fragile-X syndrome case study 2 _(In people with autism 2% to 6% have Fragile-X syndrome!) • The hand in DIABETES MELLITUS! • The hand in RHEUMATOID ARTHRITIS! • The hand in PSORIASIS! • The hand in SCHIZOPHRENIA! • The hand in EXTRAVERSION & INTROVERSION HAND TESTS:
• MARFAN SYNDROME hand test! MORE HAND DIAGNOSTICS:
• The hand lines (palmar creases) • The simian line • The Sydney line • Fingerprints (+ dermatoglyphics) • The Hypothenar whorl • What can finger length reveal? • The 5th finger (pinky) • The fingernail tutor
SEXUAL DIMORPHISM IN FINGER LENGTH & HAND SHAPE: GENDER DIFFERENCES IN THE HANDS! Sexual dimorphisms are found in dozens of hand features. Tinger length relative to palm shape is one of the typical gender related features. While women tend to have shorter fingers relative to body height (because female limbs are usually relatively short to male limbs), finger length relative to palm size shows the reversed tendency: finger length relative to palm size is typically longer in a female than in male. Despite that this feature has hardly ever been described by detail, data from studies around the world confirm that the effect-size of this sexual dimorphism in finger length is even much higher than the more well-known 2D:4D digit ratio! An overview is presented listing the typical sexual dimporphisms that are found in the hand, plus an overview about how finger length varies among the sexes around the world. The male hand is typically recognized by a muscular structure + heavier (denser/ stronger) bones, and - just like in the skull(!) - the hand shape of a man is usually wider, larger and squarer than in a woman. In men the length of the ring finger is usually larger than the length of the index finger. Hair growth is noticable and the number of hairs is higher, hairs are present on most parts of the dorsal hand except for the distal phalanges of the fingers. The skin is typically darker and redder. The density of the dermatoglyphics is smaller, and whorl fingerprints are typically more common. 
Hand characteristics in a male model - notice: this model had body hair and male facial hair removed and head hair trimmed. The female hand is typically recognized by delicate structure, and the hand shape of woman is usually more rectangular orbital with rounded corners than in a man. In women the length of the index finger is often larger than the length of the index finger. The hairs on the hand have a fine, soft structure and often hardly visible (= vellus hairs) and the number of hairs is lower and is typically found only on the dorsal + proximal phalanges at the back of the hand. The skin is typically softer, warmer and lighter. The density of the dermatoglyphics (+ the number of pain receptors) is higher, and arch & loop fingerprints are typically more common. 
Hand characteristics in a female model - notice: this model had body hair removed and head hair trimmed. around the world! The picture below displays how finger length (relative to palm length) tends to vary among males and females around the world. The average values indicate that the 'finger length index' tends to vary between men and women about 5% (women are inclined to have higher scores). In the sample from the UK the 'finger length index' numbers vary between the sexes up to almost 12%, while in the sample from Turkey the sex difference is considerably smaller: almost 2.5%. The samples from China, India, Japan & the US show numbers in between. The picture also displays that finger length in men tends to be smaller than palm breadth (confirmed in 5 out of 6 countries, with finger length is equal to palm breadth in the Japanese sample). While finger length in women tends to be larger than palm breadth (confirmed in 4 out of 6 countries). Also, finger length tends to be smaller than 79% of palm length in women (confirm by average in all six countries); and finger length tends to be smaller than 77% of palm length in men (confirmed by average in all six countries). Summarized these results indicate that in the hands of women finger length is typically long relative to palm length and palm breadth; the effect-size is more than twice as high for palm breadth (by average 7.0% difference) than for palm length (by average 3.3% difference). Finger length versus hand shape: sexual dismorphic variations in hands from China, Japan, India, Turkey, UK and the US. 
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