| Waist | |
|---|---|
 The human waist | |
| Identifiers | |
| FMA | 228775 |
| Anatomical terminology | |
The waist is the part of the abdomen between the rib cage and hips. Normally, it is the narrowest part of the torso.
Waistline refers to the horizontal line where the waist is narrowest, or to the general appearance of the waist.
Because of this and because the waist is often synonymous with the stomach, one can become confused as to the exact location of the waist. Another confusing factor is that the waistline differs on different people. A study showed that self-reported measurements, as opposed to measurement done by a technician, underestimated waist circumference and this underestimation increased with increased body size. In the study, waist circumference measured at the level of the umbilicus was larger than that measured at the natural waist. [1]
To locate the natural waistline, one need simply stand upright and then tilt over to the side, keeping the legs and hips straight. Where the torso creases is the natural waistline.[ citation needed ]
The waist is usually measured at the smallest circumference of the natural waist, usually just above the belly button. [2] Where the waist is convex rather than concave, as in pregnancy and obesity, the waist may be measured at a vertical level 1 inch above the navel. [3]
Strictly, the waist circumference is measured at a level midway between the lowest palpable rib and the iliac crest, [4] respectively typically 60% and 64% of total height. [5] It can be predicted as 72% of the neck height; [5] an alternative approximation, very relevant in anthropometry, is Small of the Back (SOB) + 2cm. [5]
Variables such as posture significantly influence the measurement of the waist, and therefore any measurements for a group need to maintain a constant posture between the subjects. [6]
Waist size (waist circumference) is an indicator of abdominal obesity and is one of the criteria for diagnosing the metabolic syndrome. Excess abdominal fat is a risk factor for developing heart disease and other obesity related diseases. A study published in the European Heart Journal in April 2007 [7] showed that waist circumference and waist–hip ratio (defined as waist circumference divided by hip circumference) were predictors of cardiovascular events. The National Heart, Lung, and Blood Institute [8] classifies the risk of obesity-related diseases as high if men have a waist circumference greater than 102 cm (40 in) and women have a waist circumference greater than 88 cm (35 in). Further, whether waist circumference or body mass index (BMI) is a better predictor of adverse health outcomes is debatable. For example, those who lift weights may have high BMI but are at relatively low risk for cardiovascular consequences. For these people, waist circumference may be a better indicator of overall health. Some research suggests waist circumference can be predicted from brain function, therefore capturing the neurobehavioral pathophysiology of obesity. [9]
An extremally high waist circumference can lead to falsely low estimates of bone health when using the trabecular bone score. [10]
Waist–hip ratio is the ratio of the circumference of the waist to that of the hips. It measures the proportion by which fat is distributed around the torso. [11]
In modern clothing, the region referred to as the waist is considerably below the waist as defined anatomically. With the advent of pants and skirts that do not require support from above, the clothing waist moved down to a position where the body starts to expand to form the buttocks and a support is therefore available. However, the waist region remains a highly important measurement and anthropometric landmark in garment construction. [6]
Jewellery, such as a belly chain, may be worn around either the clothing or anatomical waist.
Waist reduction or waist training refer to the act of wearing a corset or other constricting garment to reduce or alter the waistline. The four floating ribs may be permanently compressed or moved by such garments. A girdle may also be used to alter the appearance of the waist.
Waist reduction may be used simply to reduce the width of the waist. This change can be permanent or temporary.
Waist training may be used to achieve a certain permanent waist shape, such as a pipe-stem waist.
Definition: "middle part of the body," also "part of a garment fitted for the waist, portion of a garment that covers the waist" (but, due to fashion styles, often above or below it), probably from Old English *wæst 'growth', hence, 'where the body grows', from Proto-Germanic *wahs-tu- (cognates: Old English wæstm, Old Norse vöxtr, Swedish växt, Old High German wahst 'growth, increase', Gothic wahstus 'stature', Old English weaxan 'to grow'. [12]
Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms (kg) and height in metres (m).
Abdominal obesity, also known as central obesity and truncal obesity, is the human condition of an excessive concentration of visceral fat around the stomach and abdomen to such an extent that it is likely to harm its bearer's health. Abdominal obesity has been strongly linked to cardiovascular disease, Alzheimer's disease, and other metabolic and vascular diseases.
A corset is a support garment worn to hold and train the torso into the desired shape and posture. They are traditionally constructed out of fabric with boning made of whalebone or steel, a stiff panel in the front called a busk which holds the torso rigidly upright, and some form of lacing which allows the garment to be tightened. Corsets were an essential undergarment in European women's fashion from the 17th century to the early 20th century. In the 17th and 18th centuries they were commonly known as "stays" and had a more conical shape. This later evolved into the curvaceous 19th century form which is commonly associated with the corset today. By the beginning of the 20th century, shifting gender roles and the onsets of World War I and II led the corset to be largely discarded by mainstream fashion.
Wasp waist is a women's fashion silhouette, produced by a style of corset and girdle, that has experienced various periods of popularity in the 19th and 20th centuries. Its primary feature is the abrupt transition from a natural-width rib cage to an exceedingly small waist, with the hips curving out below. It takes its name from its similarity to a wasp's segmented body. The sharply cinched waistline also exaggerates the hips and bust.
The joint European standard for size labelling of clothes, formally known as the EN 13402 Size designation of clothes, is a European standard for labelling clothes sizes. The standard is based on body dimensions measured in centimetres, and as such, and its aim is to make it easier for people to find clothes in sizes that fit them.
The waistline is the line of demarcation between the upper and lower portions of a garment, which notionally corresponds to the natural waist but may vary with fashion from just below the bust to below the hips. The waistline of a garment is often used to accentuate different features. The waistline is also important as a boundary at which shaping darts can be ended.
The waist–hip ratio or waist-to-hip ratio (WHR) is the dimensionless ratio of the circumference of the waist to that of the hips. This is calculated as waist measurement divided by hip measurement. For example, a person with a 75 cm waist and 95 cm hips has WHR of about 0.79.
An hourglass corset is a garment that produces a silhouette resembling an hourglass shape characterized by wide hips, narrow waist, and wide bust.
The hourglass figure is one of four traditional female body shapes described by the fashion industry. The other shapes are the rectangular, inverted triangle, and spoon/pear. The hourglass shape is defined by a woman's body measurements- the circumference of the bust, waist and hips. Hourglass body shapes have a wide bust, a narrow waist, and wide hips with a similar measurement to that of the bust. This body shape is named for its resemblance to that of an hourglass where the upper and lower half are wide and roughly equal while the middle is narrow in circumference, making the overall shape wide-narrow-wide. Women who exhibit the hourglass figure have been shown to be more admired, which can put pressure on women whose body shapes are noticeably different to strive to achieve the hourglass figure. This can lead to body dissatisfaction which can cause eating disorders in young women from all over the globe.
Clothing sizes are the sizes with which garments sold off-the-shelf are labeled. Sizing systems vary based on the country and the type of garment, such as dresses, tops, skirts, and trousers. There are three approaches:
Sagittal abdominal diameter (SAD) is a measure of visceral obesity, the amount of fat in the gut region. SAD is the distance from the small of the back to the upper abdomen. SAD may be measured when standing or supine. SAD may be measured at any point from the narrowest point between the last rib and the iliac crests to the midpoint of the iliac crests.
A bustline is an arbitrary line encircling the fullest part of the bust or body circumference at the bust. It is a body measurement which measures the circumference of a woman's torso at the level of the breasts. It is measured by keeping a measuring tape horizontal and wrapping it around the body so that it goes over the nipples and under the arms.
Human body shape is a complex phenomenon with sophisticated detail and function. The general shape or figure of a person is defined mainly by the molding of skeletal structures, as well as the distribution of muscles and fat. Skeletal structure grows and changes only up to the point at which a human reaches adulthood and remains essentially the same for the rest of their life. Growth is usually completed between the ages of 13 and 18, at which time the epiphyseal plates of long bones close, allowing no further growth.
Female body shape or female figure is the cumulative product of a woman's bone structure along with the distribution of muscle and fat on the body.
Obesity classification is a ranking of obesity, the medical condition in which excess body fat has accumulated to the extent that it has an adverse effect on health. The World Health Organization (WHO) classifies obesity by body mass index (BMI). BMI is further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors. In children, a healthy weight varies with sex and age, and obesity determination is in relation to a historical normal group.
Android fat distribution describes the distribution of human adipose tissue mainly around the trunk and upper body, in areas such as the abdomen, chest, shoulder and nape of the neck. This pattern may lead to an "apple"-shaped body or central obesity, and is more common in males than in females. Thus, the android fat distribution of men is about 48.6%, which is 10.3% higher than that of premenopausal women. In other cases, an ovoid shape forms, which does not differentiate between men and women. Generally, during early adulthood, females tend to have a more peripheral fat distribution such that their fat is evenly distributed over their body. However, it has been found that as females age, bear children and approach menopause, this distribution shifts towards the android pattern of fat distribution, resulting in a 42.1% increase in android body fat distribution in postmenopausal women. This could potentially provide evolutionary advantages such as lowering a woman's center of gravity making her more stable when carrying offspring.
The body adiposity index (BAI) is a method of estimating the amount of body fat in humans. The BAI is calculated without using body weight, unlike the body mass index (BMI). Instead, it uses the size of the hips compared to the person's height.
A person's waist-to-height ratio – occasionally written WHtR – or called waist-to-stature ratio (WSR), is defined as their waist circumference divided by their height, both measured in the same units. It is used as a predictor of obesity-related cardiovascular disease. The WHtR is a measure of the distribution of body fat. Higher values of WHtR indicate higher risk of obesity-related cardiovascular diseases; it is correlated with abdominal obesity.
A Body Shape Index (ABSI) or simply body shape index (BSI) is a metric for assessing the health implications of a given human body height, mass and waist circumference (WC). The inclusion of WC is believed to make the BSI a better indicator of risk of mortality from excess weight than the standard body mass index. ABSI correlates only slightly with height, weight and BMI, indicating that it is independent of other anthropometric variables in predicting mortality.
Body roundness index (BRI) is a calculated geometric index used to quantify a person's individual body shape. Based on the principle of body eccentricity, it provides a rapid visual and anthropometric tool for health evaluation.