Palmar Creases In Newborns: What's Normal?

Palmar creases are the distinct lines that form on the palms of hands and soles of feet as a baby grows in the womb, usually by the 12th week of gestation. Most newborns have two major creases on the palm, neither of which extend fully from one side of the palm to the other. However, in some cases, the creases join to form a single palmar crease, which is found in around 1.5% of the world's population. While a single palmar crease is often normal, it can also be associated with various conditions that affect a person's mental and physical growth, such as fetal alcohol syndrome, Klinefelter syndrome, and Down syndrome.

Palmar creases are usually formed by the 12th week of gestation

Palmar creases are the lines on the palms of hands that help the skin stretch and squeeze. They are formed in the womb, usually by the 12th week of gestation, and are present on a baby's hands when they are born.

Most people have three prominent creases across the surface of their palms. However, some people have a single palmar crease, also known as a transverse palmar crease or simian crease. This occurs when the two palmar creases fuse together. The term "simian crease" is derived from the fact that this trait is found more frequently in non-human simians and has fallen out of favour due to its negative connotations.

A single palmar crease occurs in about 1 out of 30 people, or 1.5% of the world's population. Males are twice as likely as females to have this trait, which also tends to run in families. While it is often found in people with Down syndrome, it is not a diagnostic indicator as many people with Down syndrome do not have this crease. A single palmar crease may also be associated with other conditions that affect a person's mental and physical growth, such as fetal alcohol syndrome, Klinefelter syndrome, and pseudohypoparathyroidism.

The presence of a single palmar crease does not always indicate a problem. In some cases, it may be a normal variant with no medical significance. A healthcare provider will consider a person's family history, medical history, and physical exam results to determine if further testing is necessary.

Single palmar creases are found in about 1 out of 30 people or 1.5% of the world's population

Single palmar creases are found in about 1 out of 30 people, or 1.5% of the world's population. This condition is more common in males, who are twice as likely as females to have the trait. It is also more prevalent among Asians and Native Americans. In some families, there is a tendency to inherit the condition unilaterally, meaning it appears on only one hand.

Although single palmar creases are found more frequently in people with abnormal medical conditions, they are not predictive of any specific condition. This is because they are also found in people with no abnormal medical conditions. Single palmar creases are associated with several conditions, including Down syndrome, Aarskog syndrome, fetal alcohol syndrome, Klinefelter syndrome, and cri du chat syndrome. However, many people with these conditions do not have a single palmar crease. Therefore, it is not a reliable diagnostic indicator.

Palmar creases develop while a baby is growing in the womb, typically by the 12th week of gestation. A 1971 study refutes the hypothesis that fetal hand movement causes the crease, as the appearance of the crease occurs around the second month of gestation before the digital movement phase begins.

Single palmar creases, also known as simian creases or simian lines, were terms previously used to describe the trait. However, these terms have fallen out of favor due to their negative connotations, as they refer to monkeys or apes.

Single palmar creases are more common in males than in females

Palmar creases are epidermal flexure lines found on the palms of hands. Typically, there are three major creases: the radial longitudinal crease, the proximal transverse crease, and the distal transverse crease. However, in some individuals, the two transverse creases fuse together, resulting in a single palmar crease, also known as a transverse palmar crease or simian crease. This occurs in about 1 out of 30 people, or approximately 1.5% of the world's population.

While a single palmar crease is often considered a benign variation, it has been associated with certain medical conditions and developmental problems. For example, it is found more frequently in people with Down syndrome, fetal alcohol syndrome, Klinefelter syndrome, and other genetic disorders. However, it is important to note that the presence of a single palmar crease alone is not indicative of any specific condition, as it can also be found in people with no abnormal medical conditions.

Interestingly, single palmar creases are more common in males than in females, with males being twice as likely to have this characteristic. This trait tends to run in families, and in some cases, it may be inherited unilaterally, meaning it is present on only one hand. In addition, it is more commonly found among Asians and Native Americans compared to other populations.

The formation of palmar creases typically occurs during the early stages of fetal development, usually by the 12th week of gestation. The patterns of palmar creases are established during this period and remain unchanged throughout life. While the exact reason for the gender disparity in single palmar creases is unknown, it may be related to factors such as ethnicity, handedness, and the strength of palm flexion.

Single palmar creases are associated with Down's syndrome and other genetic disorders

A single palmar crease, also known as a transverse palmar crease, is a single line that runs across the palm of the hand. While it commonly occurs in people with Down's syndrome, it is also found in people without any abnormal medical conditions. It is present in around 1.5% of the world's population, or 1 out of 30 people, and males are twice as likely as females to have this trait.

Single palmar creases are associated with several genetic disorders, including Down's syndrome, Aarskog-Scott syndrome, fetal alcohol syndrome, Klinefelter syndrome, Wolf-Hirschhorn syndrome, and Cri du chat syndrome, among others. These disorders can affect a person's mental and physical growth and development. However, the presence of a single palmar crease alone is not a definitive indicator of any specific disorder, as many people with these disorders do not exhibit this trait.

Down's syndrome, also known as chromosome 21, is a genetic condition characterised by the presence of 47 chromosomes instead of the usual 46. It can cause a range of physical and developmental abnormalities, including intellectual disabilities, distinctive facial features, and low muscle tone. While a single palmar crease is associated with Down's syndrome, it is not a diagnostic indicator as many individuals with the syndrome do not have this crease.

Aarskog-Scott syndrome, also known as Aarskog syndrome or X-linked recessive disorder, is a genetic disease that affects a person's height, muscles, skeleton, genitals, and appearance. Fetal alcohol syndrome, meanwhile, is associated with growth, mental, and physical problems in infants born to mothers who consumed alcohol during pregnancy.

Klinefelter syndrome is a genetic condition that occurs in males with an extra X chromosome, resulting in tall stature, small testes, and a reduced level of male hormones. Wolf-Hirschhorn syndrome is a rare genetic disorder characterised by distinctive facial features, intellectual disabilities, seizures, and developmental delays.

In summary, while single palmar creases are associated with Down's syndrome and other genetic disorders, their presence alone is not sufficient for diagnosis. A comprehensive evaluation, including family history, medical history, and a complete physical exam, is necessary to determine the presence of any specific disorder.

The term simian crease is no longer used due to its negative connotations

Palmar creases are the distinct lines that form creases on the palms of hands and soles of feet. Typically, there are two or three creases on the palm, but sometimes these creases join to form just one, known as a single palmar crease or a transverse palmar crease. This occurs in about 1 out of 30 people, or 1.5% of the population, and is more common in males.

A single palmar crease is often normal, but it can also be associated with various conditions that affect a person's mental and physical growth, including Down syndrome, Aarskog syndrome, fetal alcohol syndrome, Klinefelter syndrome, and pseudohypoparathyroidism. When a newborn presents with a single palmar crease, healthcare providers will ask about family history and the mother's medical history during pregnancy.

The term "simian crease" was previously used to refer to a single palmar crease, as it resembles the usual condition of non-human simians (monkeys and apes). However, this term is no longer commonly used due to its negative or pejorative connotations. Instead, the preferred term is "single palmar crease" or "transverse palmar crease".

The shift away from using the term "simian crease" is part of a broader effort to use language that is more sensitive and respectful. By avoiding terms with negative connotations, healthcare professionals can promote a more inclusive and non-stigmatizing approach to describing medical conditions. This change in terminology reflects a recognition of the importance of language in shaping perceptions and attitudes towards different groups.

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