Human Anatomy, Part 1 - K. A. Dyubenko, A. K. Kolomiyytsev, Yu. B. Chaykovsky 2002

Special Part
Arthrology, artrologia [the study of bone connections] – Classification of joints and their general characteristics
The vertebral column as a whole

THE Vertebral Column, columna vertebralis, consists of 24 true vertebrae, the sacrum, the coccyx, intervertebral discs, as well as articular and ligamentous apparatuses.

The Functional Significance of the vertebral column is immense; it serves as a housing for the Spinal Cord and a support for the trunk, HEAD, shoulder girdle, and upper limbs, and participates in The formation of the thoracic and abdominal walls. In addition, the vertebral column performs a Shock-absorbing function, damping impacts during walking, running, and jumping. Two longitudinal grooves, sulci dorsales, flanked by the spinous and transverse processes, run along the posterior aspect of the spine and house the Deep Muscles of the back. The human vertebral column features curves (see Fig. 25B) that are directed forward in the cervical and lumbar regions (lordosis, lordosis cervicalis et lordosis lumbalis) and backward in the thoracic and sacral regions (Kyphosis, kyphosis thoracica et kyphosis sacralis). The presence of these physiological curves gives the vertebral column spring-like properties and ensures proper posture. Posture is defined as the correct position of the body at rest and during movement. An individual's posture can be influenced by a variety of factors, such as Skeletal Structure, Muscle tone, the state of The Nervous system, and Physical Exercise. Normal posture is characterized by the balanced development of all curves of the vertebral column.

The following variants of physiological spinal curves (according to Ye. T. Sklyarenko, 1993, 1994), which determine human posture, are distinguished:

1. Flat back (flattened) - leads to the Early Development of degenerative-dystrophic lesions of the intervertebral discs due to constant pressure on specific areas of the discs.

2. Round back (stooped) - kyphotic posture leads to The Development of juvenile kyphosis (Scheuermann's disease).

3. Lordotic back - leads to overloading of the lower vertebral column (L IV-L V) and osteolysis of the vertebral arches (spondylolysis), ultimately resulting in spondylolisthesis.

4. Scoliotic posture - causes progression into Scoliosis.

Newborns do not have any spinal curves. They form during the postnatal period. By the third month, an infant begins to lift its head, which leads to the appearance of cervical lordosis. When the child starts sitting, thoracic kyphosis develops. The transition to an upright posture produces lumbar lordosis. The formation of all curves is completed by the age of 18. Lateral curves of the spine in the frontal plane - scoliosis, skoliosis - are pathological curvatures associated with prolonged improper body positioning, as well as Asymmetry in back Muscle Development. In old age, the vertebral column completely loses its physiological curves due to a decrease in the thickness of the intervertebral discs. Loss of elasticity results in a pronounced thoracic curvature known as a dowager's hump (senile hump). Thinning of the spongy bone substance (Osteoporosis) is observed. Occasionally, bony outgrowths (osteophytes) form on the vertebral bodies.

The length of the vertebral column is about 40% of total body height. In men, it is 70-73 cm; in women, 66-69 cm. Relative to body length, the spine of women and children is longer than that of men. In old age, spinal height may decrease by 6-7 cm. Movements around three axes are possible: the frontal axis - flexion and extension; the sagittal axis - lateral flexion to the right and left; and the vertical axis - rotational movements. Together, these movements form circumduction of the vertebral column. The most mobile segments of the vertebral column are the atlanto-occipital joint, the junction between the VII cervical and I thoracic vertebrae, and the I-III lumbar vertebrae.

Blood supply to the vertebral column is provided by Branches of the a. vertebralis in the cervical region; the posterior intercostal Arteries (a. intercostales posterior) in the thoracic region; the lumbar arteries (aa. lumbales) in the lumbar region; and the lateral sacral artery (a. sacralis lateralis) in the sacral region. Venous blood drainage occurs into the internal vertebral venous plexuses (plexus venosi vertebrales) and further into the v. vertebrales in the cervical region; the posterior intercostal Veins (v. intercostales posteriores) in the thoracic region; the lumbar veins (v. lumbales) in the lumbar region; and the internal iliac vein (v. iliaca interna) in the sacral region.

Lymphatic drainage is directed to the occipital, retroauricular, and deep cervical Lymph Nodes (nodi lymphatici occipitales, retroauriculares, cervicales profundi) in the cervical region; the intercostal nodes (nodi intercostales) in the thoracic region; the lumbar nodes (nodi lumbales) in the lumbar region; and the sacral nodes (nodi sacrales) in the sacral region.

Innervation is provided by the posterior branches of the Spinal Nerves.