Why do Physicians check the Hand Lines of Newborn Babies?

Normal hand lines.

Why do physicians check the hand lines of newborn babies? Most newborns have two major creases on the palm, neither of which completely extend from one side of the palm to the other. However, a common variant, found in approximately 4% of western newborns, a transverse palmar crease is frequently inherited as a familial trait. Although single palmar creases are also associated with the hand in Down syndrome and other genetic disorders, the absence of other abnormalities on physical exam should reassure the examiner that no further evaluation is necessary.

 

Abnormal hand lines: a 'single palmar transverse crease', a.k.a. a simian line.

The pattern of palmar creases varies substantially within the general population. The formation of palmar creases, which occurs between the second and fifth months of prenatal development, depends e.g. on fetal movement. Once the palmar creases are formed, they remain unchanged throughout life.

More subtle normal variations of palmar creases can occur for a variety of reasons, including family background, age, and race. Many physicians are aware of the association between single transverse or bridged palmar creases, previously known as simian creases and Sydney creases, respectively, and the occurrence of Down syndrome. Although approximately 45% of patients who have Down syndrome have single transverse palmar creases, this finding occurs unilaterally (one hand) in 4% and bilaterally (both hands) in 1% of the general Caucasian population.

HAND LINES IN CHINA:

However, in the Chinese population, single transverse palmar creases may be considered a normal phenotypic variant; a recent study found that 16.8% of 3,345 healthy Chinese newborns had unilateral single transverse creases and 6.6% had bilateral single transverse creases.

Despite the high frequency of single transverse palmar creases in certain populations, aberrations in the flexion creases of the hands have the potential to signify abnormal fetal development. The association of abnormal flexion creases and various congenital disorders has been reported frequently in the literature. Studies have shown an increased incidence of single transverse palmar crease in children who have chromosome abnormalities and in low-birthweight infants. Therefore, it is reasonable to search for other congenital anomalies when evaluating an infant who has a single transverse palmar crease after taking into account the patient’s race and familial background.

When the crease occurs in isolation, however, no further evaluation is indicated.

HAND STRENGTH:

Interestingly, these is also evidence that palmar creases (hand lines) and hand motorics are directly related!

In 2010 researchers from Korea reported results which suggest that union of hand lines (palm lines) appears to correlate with hand grip strength. And interestingly, a few months later a report from France presented results which suggest that hand strenght can be predicted from hand circumference alone. So, combining both reports indicates that a talent for hand strenght could very well be found in people who have a large hand circumference + fused hand lines, such as seen in simian line! An interesting hypothesis, which is suitable to be tested for it’s accuracy in the fields of modern palm reading.

Additionally, it might be interesting to notice here that the hand lines of apes (primates) are characterized by the presence of multiple ‘fused’ transverse crease. And Gorillas who are known as the strongest species among the primates have the widest (shortest) hand shape of all apes & primates.