The spine, also known as the vertebral column or spinal column, is a column of 26 bones in an adult body — 24 separate vertebrae interspaced with cartilage, and then additionally the sacrum and coccyx. What is primary curve? In the womb and for a period of time following birth, a baby's spine is shaped like the letter C. This curve is termed a primary curve, which is Kyphotic. During the time the baby is learning to lift his head and eventually walk, muscles develop.
What is a Zygapophyseal joint? The facet joints, or zygapophysial joints, zygapophyseal, apophyseal, or Z-joints are a set of synovial, plane joints between the articular processes of two adjacent vertebrae.
There are two facet joints in each spinal motion segment and each facet joint is innervated by the recurrent meningeal nerves. How do secondary curvatures develop? The cervical curve of the neck region develops as the infant begins to hold their head upright when sitting. What are the 5 parts of the spine? As mentioned above, our vertebrae are numbered and divided into five regions: cervical, thoracic, lumbar, sacrum, and coccyx.
Welcome to my site. Browse through the articles to learn how Alexander Technique can enrich your life. Instead, the posture should be viewed as a dynamic interplay between body parts, ever changing from one instant to the next. In order to better understand this interplay between different body parts, I will introduce the concept of primary and secondary curves, and demonstrate how viewing the movement through this lens can improve not only posture, but also give dancing power, fluidity, and control.
It is important to keep in mind that it is not the comprehensive and only system of training, but it opens doors for further exploration and improvement. The concept of primary and secondary curves is an integral part of Dart Procedures, a movement sequence based on developmental and evolutionary patterns. In neutral position, an adult spine maintains two primary curves: thoracic and sacral.
Secondary curve is achieved by hyper extension of the spine. In neutral position, the adult spine has two secondary curves: cervical and lumbar. As the child grows, lifts the head, and begins to assume an upright position, the secondary curves cervical and lumbar develop. The cervical curve forms when the infant is able to hold up his or her head at three or four months and sit upright at nine months. The lumbar curve forms between twelve to eighteen months when the child begins to walk.
Learning Objectives Describe the vertebral column, the protective structure of the spinal cord. Key Points The human spine consists of 24 articulating vertebrae grouped into cervical, thoracic, and lumbar regions.
Nine more vertebrae make up the sacrum and coccyx. Typical vertebrae consist of the anterior vertebral body and the posterior section, which contains the vertebral foramen through which the spinal cord passes. There are four main curves of the spine: cervical, thoracic, lumbar, and pelvic. Facets of the vertebrae restrict range of movement to prevent shearing of the spinal cord.
Blood vessels and nerves exit the spinal column at intervertebral foramina. The vertebral column originally develops as a series of 33 vertebrae, but this number is eventually reduced to 24 vertebrae, plus the sacrum and coccyx.
The vertebral column is subdivided into five regions, with the vertebrae in each area named for that region and numbered in descending order. Superiorly, the C1 vertebra articulates forms a joint with the occipital condyles of the skull. Inferiorly, C1 articulates with the C2 vertebra, and so on. Below these are the 12 thoracic vertebrae, designated T1—T The lower back contains the L1—L5 lumbar vertebrae.
The single sacrum, which is also part of the pelvis, is formed by the fusion of five sacral vertebrae. Similarly, the coccyx, or tailbone, results from the fusion of four small coccygeal vertebrae. However, the sacral and coccygeal fusions do not start until age 20 and are not completed until middle age. An interesting anatomical fact is that almost all mammals have seven cervical vertebrae, regardless of body size.
This means that there are large variations in the size of cervical vertebrae, ranging from the very small cervical vertebrae of a shrew to the greatly elongated vertebrae in the neck of a giraffe. In a full-grown giraffe, each cervical vertebra is 11 inches tall. The adult vertebral column does not form a straight line, but instead has four curvatures along its length see Figure 7. When the load on the spine is increased, by carrying a heavy backpack for example, the curvatures increase in depth become more curved to accommodate the extra weight.
They then spring back when the weight is removed. The four adult curvatures are classified as either primary or secondary curvatures.
Primary curves are retained from the original fetal curvature, while secondary curvatures develop after birth. During fetal development, the body is flexed anteriorly into the fetal position, giving the entire vertebral column a single curvature that is concave anteriorly.
In the adult, this fetal curvature is retained in two regions of the vertebral column as the thoracic curve , which involves the thoracic vertebrae, and the sacrococcygeal curve , formed by the sacrum and coccyx.
Each of these is thus called a primary curve because they are retained from the original fetal curvature of the vertebral column. A secondary curve develops gradually after birth as the child learns to sit upright, stand, and walk. Secondary curves are concave posteriorly, opposite in direction to the original fetal curvature. The cervical curve of the neck region develops as the infant begins to hold their head upright when sitting. Later, as the child begins to stand and then to walk, the lumbar curve of the lower back develops.
In adults, the lumbar curve is generally deeper in females. Disorders associated with the curvature of the spine include kyphosis an excessive posterior curvature of the thoracic region , lordosis an excessive anterior curvature of the lumbar region , and scoliosis an abnormal, lateral curvature, accompanied by twisting of the vertebral column. Developmental anomalies, pathological changes, or obesity can enhance the normal vertebral column curves, resulting in the development of abnormal or excessive curvatures Figure 7.
Kyphosis, also referred to as humpback or hunchback, is an excessive posterior curvature of the thoracic region. This can develop when osteoporosis causes weakening and erosion of the anterior portions of the upper thoracic vertebrae, resulting in their gradual collapse Figure 7. Lordosis, or swayback, is an excessive anterior curvature of the lumbar region and is most commonly associated with obesity or late pregnancy. The accumulation of body weight in the abdominal region results an anterior shift in the line of gravity that carries the weight of the body.
This causes in an anterior tilt of the pelvis and a pronounced enhancement of the lumbar curve. Scoliosis is an abnormal, lateral curvature, accompanied by twisting of the vertebral column.
Compensatory curves may also develop in other areas of the vertebral column to help maintain the head positioned over the feet. Scoliosis is the most common vertebral abnormality among girls. The cause is usually unknown, but it may result from weakness of the back muscles, defects such as differential growth rates in the right and left sides of the vertebral column, or differences in the length of the lower limbs.
When present, scoliosis tends to get worse during adolescent growth spurts. Although most individuals do not require treatment, a back brace may be recommended for growing children. In extreme cases, surgery may be required. Excessive vertebral curves can be identified while an individual stands in the anatomical position.
Observe the vertebral profile from the side and then from behind to check for kyphosis or lordosis. Then have the person bend forward. If scoliosis is present, an individual will have difficulty in bending directly forward, and the right and left sides of the back will not be level with each other in the bent position.
Osteoporosis is a common age-related bone disease in which bone density and strength is decreased. Watch this video to get a better understanding of how thoracic vertebrae may become weakened and may fracture due to this disease.
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