Lülisammas

Lülisammas, known scientifically as the vertebral column or spine, is a fundamental part of vertebrate anatomy that provides structural support, protection for the spinal cord, and enables flexible movement. It is composed of a series of individual bones called vertebrae, which are linked together by intervertebral discs, ligaments, and muscles.

In humans, the vertebral column typically consists of 33 vertebrae, divided into five regions: cervical (neck), thoracic (upper back), lumbar (lower back), sacral, and coccygeal (tailbone). The cervical region contains seven vertebrae, the thoracic region twelve, and the lumbar five, while the sacrum and coccyx are fused bones forming the posterior pelvic structure.

The primary functions of the lülisammas include supporting the head and upper body, maintaining posture, allowing for a range of movements such as bending and twisting, and serving as a protective conduit for the spinal cord. The spinal cord runs through a central canal within the vertebrae, transmitting nerve signals between the brain and the rest of the body.

The structure of vertebrae varies across different regions, with cervical vertebrae being smaller and featuring openings for blood vessels and nerves, and lumbar vertebrae being larger to bear more weight. The intervertebral discs act as cushions, absorbing shocks and allowing flexibility.

The lülisammas is present in all vertebrates, including fish, amphibians, reptiles, birds, and mammals, with variations adapted to their specific locomotion and lifestyle needs. Its design exemplifies efficient structural support, protection of vital nervous tissue, and flexibility essential for diverse environments and activities.