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The number of vertebrae in a region can vary but overall the number remains the same. In a human spinal column, there are normally 33 vertebrae. [3] The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs, and the lower nine are fused in adults, five in the sacrum and four in the coccyx, or tailbone.
A typical vertebra has a body (vertebral body), also known as the centrum, which consists of a large anterior middle portion, and a posterior vertebral arch, [2] also called a neural arch. [3] The body is composed of cancellous bone , which is the spongy type of osseous tissue , whose microanatomy has been specifically studied within the ...
In human anatomy, the five vertebrae are between the rib cage and the pelvis.They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse process (since it is only found in the cervical region) and by the absence of facets on the sides of the body (as found only in the thoracic region).
The atlas is the topmost vertebra and the axis (the vertebra below it) forms the joint connecting the skull and spine. The atlas and axis are specialized to allow a greater range of motion than normal vertebrae. They are responsible for the nodding and rotation movements of the head.
Feeding on land is a completely different task than feeding in water. Water is much more dense and viscous compared to air, causing hunting techniques adapted in water to be less successful when applied on land. [11] The main technique used in water is suction feeding and is used by most aquatic vertebrates.
The axial skeleton (80 bones) is formed by the vertebral column (32–34 bones; the number of the vertebrae differs from human to human as the lower 2 parts, sacral and coccygeal bone may vary in length), a part of the rib cage (12 pairs of ribs and the sternum), and the skull (22 bones and 7 associated bones).
Internal skeletal structures showing the vertebral column running from the head to the tail Marine vertebrates are vertebrates that live in marine environments , which include saltwater fish (including pelagic , coral and deep sea fish ) and marine tetrapods (primarily marine mammals and marine reptiles , as well as semiaquatic clades such as ...
Sectional organization of spinal cord. The spinal cord is the main pathway for information connecting the brain and peripheral nervous system. [3] [4] Much shorter than its protecting spinal column, the human spinal cord originates in the brainstem, passes through the foramen magnum, and continues through to the conus medullaris near the second lumbar vertebra before terminating in a fibrous ...