In human anatomy Human anatomy , which, with human physiology and biochemistry, is a complementary basic medical science, is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy (also called topographical anatomy, regional anatomy, or anthropotomy) is the study of, the vertebral column (backbone or spine) is a column usually consisting of 24 vertebrae A vertebra is an individual bone in the flexible column that defines vertebrate animals, e.g., humans. The vertebral column encases and protects the spinal cord, which runs from the base of the cranium down the dorsal side of the animal until reaching the pelvis. From there, vertebra continue into the tail,[1] the sacrum In vertebrate anatomy the sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx (tailbone). In children, it consists of usually five unfused, intervertebral discs Intervertebral discs lie between adjacent vertebrae in the spine. Each disc forms a cartilaginous joint to allow slight movement of the vertebrae, and acts as a ligament to hold the vertebrae together, and the coccyx The coccyx , commonly referred to as the tailbone, is the final segment of the ape vertebral column. Comprising three to five separate or fused vertebrae (the coccygeal vertebrae) below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between the sacrum and the situated in the dorsal In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow off that side of an animal. The opposite side of the aspect of the torso Trunk or torso is an anatomical term for the central part of the many animal bodies from which extend the neck and limbs. The trunk includes the thorax and abdomen, separated by spinal discs. It houses the spinal cord The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system. The spinal cord extends down to the space between the first and second lumbar vertebrae; it does not extend the entire length of the vertebral column. It is around 4 in its spinal canal The spinal canal is the space in vertebrae through which the spinal cord passes. It is a process of the dorsal human body cavity. This canal is enclosed within the vertebral foramen of the vertebrae. In the intervertebral spaces, the canal is protected by the ligamentum flavum posteriorly and the posterior longitudinal ligament anteriorly.
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Curves
Viewed laterally the vertebral column presents several curves, which correspond to the different regions of the column, and are called cervical In many vertebrate species, cervical vertebrae are variable in number; however, almost all mammals have seven . The few exceptions include the manatee and the sloths, of which the two-toed sloth has six cervical vertebrae and the three-toed sloth has up to nine cervical vertebrae (Wetzel, 1985), thoracic In human anatomy, twelve thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. They are intermediate in size between those of the cervical and lumbar regions; they increase in size as one proceeds down the spine, the upper vertebrae being much smaller than those in the lower, lumbar The lumbar vertebrae are the largest segments of the movable part of the vertebral column, and are characterized by the absence of the foramen transversarium within the transverse process, and by the absence of facets on the sides of the body. They are designated L1 to L5, starting at the top. This area of the spine is the source of much body, and pelvic.
The cervical curve, convex forward, begins at the apex of the odontoid (tooth-like) process, and ends at the middle of the second thoracic vertebra; it is the least marked of all the curves.
The thoracic curve, concave forward, begins at the middle of the second and ends at the middle of the twelfth thoracic vertebra. Its most prominent point behind corresponds to the spinous process of the seventh thoracic vertebra. This curve is known as a tt curve.
The lumbar curve is more marked in the female Female is the sex of an organism, or a part of an organism, which produces non-mobile ova (egg cells) than in the male Male refers to the sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization. A male cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually; it begins at the middle of the last thoracic vertebra, and ends at the sacrovertebral angle. It is convex anteriorly, the convexity of the lower three vertebrae being much greater than that of the upper two. This curve is described as a lordotic curve.
The pelvic curve begins at the sacrovertebral articulation, and ends at the point of the coccyx The coccyx , commonly referred to as the tailbone, is the final segment of the ape vertebral column. Comprising three to five separate or fused vertebrae (the coccygeal vertebrae) below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between the sacrum and the; its concavity is directed downward and forward. .
The thoracic and pelvic curves are termed primary curves, because they alone are present during fetal A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth life. The cervical and lumbar curves are compensatory or secondary, and are developed after birth Childbirth is the culmination of a human pregnancy or gestation period with the birth of one or more newborn infants from a woman's uterus. The process of normal human childbirth is categorized in three stages of labour: the shortening and dilation of the cervix, descent and birth of the infant, and birth of the placenta. In many cases, with, the former when the child is able to hold up its head (at three or four months) and to sit upright (at nine months), the latter at twelve or eighteen months, when the child begins to walk.
Names of individual vertebrae
Individual vertebrae named according to region and position, from superior to inferior
- Cervical – 7 vertebrae (C1-C7)
- C1 is known as "atlas" and supports the head, C2 is known as "axis"
- Possesses bifid spinous processes, which is absent in C1 and C7
- Small-bodied
- Thoracic – 12 vertebrae (T1-T12)
- Distinguished by the presence of costal facets for the articulation of the heads of ribs
- Body is intermediate in size between the cervical and lumbar vertebrae
- Lumbar – 5 vertebrae (L1-L5)
- Has a large body
- Does not have costal facets nor transverse process foramina
- Sacral – 5 (fused) vertebrae (S1-S5)
- Coccygeal – 4 (3-5) (fused) vertebrae (Tailbone)
Surfaces
Anterior surface
When viewed from in front, the width of the bodies of the vertebrae is seen to increase from the second cervical to the first thoracic; there is then a slight diminution in the next three vertebrae; below this there is again a gradual and progressive increase in width as low as the sacrovertebral angle. From this point there is a rapid diminution, to the apex of the coccyx.
Orientation of the rib cage The human rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic cavity and supports the pectoral (shoulder) girdle, forming a core portion of the human skeleton. A typical human rib cage consists of 24 ribs, the sternum, costal cartilages, and the 12 thoracic vertebrae. It, along with the on the vertebral columnPosterior surface
The posterior surface of the vertebral column presents in the median line the spinous processes. In the cervical region (with the exception of the second and seventh vertebrae) these are short and horizontal, with bifid extremities. In the upper part of the thoracic region they are directed obliquely downward; in the middle they are almost vertical, and in the lower part they are nearly horizontal. In the lumbar region they are nearly horizontal. The spinous processes are separated by considerable intervals in the lumbar region, by narrower intervals in the neck, and are closely approximated in the middle of the thoracic region. Occasionally one of these processes deviates a little from the median line — a fact to be remembered in practice, as irregularities of this sort are attendant also on fractures or displacements of the vertebral column. On either side of the spinous processes is the vertebral groove formed by the laminae in the cervical and lumbar regions, where it is shallow, and by the laminae and transverse processes in the thoracic region, where it is deep and broad; these grooves lodge the deep muscles of the back. Lateral to the vertebral grooves are the articular processes, and still more laterally the transverse processes. In the thoracic region, the transverse processes stand backward, on a plane considerably behind that of the same processes in the cervical and lumbar regions. In the cervical region, the transverse processes are placed in front of the articular processes, lateral to the pedicles and between the intervertebral foramina. In the thoracic region they are posterior to the pedicles, intervertebral foramina, and articular processes. In the lumbar region they are in front of the articular processes, but behind the intervertebral foramina.
Lateral surfaces
The lateral surfaces are separated from the posterior surface by the articular processes in the cervical and lumbar regions, and by the transverse processes in the thoracic region. They present, in front, the sides of the bodies of the vertebrae, marked in the thoracic region by the facets for articulation with the heads of the ribs. More posteriorly are the intervertebral foramina, formed by the juxtaposition of the vertebral notches, oval in shape, smallest in the cervical and upper part of the thoracic regions, and gradually increasing in size to the last lumbar. They transmit the spinal nerves and are situated between the transverse processes in the cervical region, and in front of them in the thoracic and lumbar regions.
Orientation of vertebral column on surface.T3 is at level of medial part of spine of scapula The spine of the scapula is a prominent plate of bone, which crosses obliquely the medial four-fifths of the scapula at its upper part, and separates the supra- from the infraspinatous fossa. T7 is at inferior angle of the scapula The inferior angle of the scapula, thick and rough, is formed by the union of the vertebral and axillary borders; its dorsal surface affords attachment to the Teres major and frequently to a few fibers of the Latissimus dorsi. L3 is at highest point of iliac crest The crest of the ilium is the superior border of the wing of ilium and the superolateral margin of the greater pelvis. S2 is at the level of posterior superior iliac spine The posterior border of the ala, shorter than the anterior, also presents two projections separated by a notch, the posterior superior iliac spine and the posterior inferior iliac spine. The posterior superior iliac spine serves for the attachment of the oblique portion of the posterior sacroiliac ligaments and the Multifidus. T12 can be found by identifying the lowest pair of ribs and tracing them to their thoracic attachment.[2] Furthermore, C7 is easily localized as a prominence at the lower part of the neck. [3]
Vertebral canal
The vertebral canal follows the different curves of the column; it is large and triangular in those parts of the column which enjoy the greatest freedom of movement, such as the cervical and lumbar regions; and is small and rounded in the thoracic region, where motion is more limited.
Abnormalities
Occasionally the coalescence of the laminae is not completed, and consequently a cleft is left in the arches of the vertebrae, through which a protrusion of the spinal membranes (dura mater The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for keeping in the cerebrospinal fluid. The name "dura mater" is derived from and arachnoid The arachnoid mater is one of the three meninges, the membranes that cover the brain and spinal cord. It is interposed between the two other meninges, the more superficial dura mater and the deeper pia mater, and is separated from the pia mater by the subarachnoid space), and generally of the spinal cord The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system. The spinal cord extends down to the space between the first and second lumbar vertebrae; it does not extend the entire length of the vertebral column. It is around 4 (medulla spinalis) itself, takes place, constituting the malformation known as spina bifida Spina bifida is a developmental birth defect caused by the incomplete closure of the embryonic neural tube. Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open. If the opening is large enough, this allows a portion of the spinal cord to protrude through the opening in the bones. There may or may not be a fluid-. This condition is most common in the lumbosacral region, but it may occur in the thoracic or cervical region, or the arches throughout the whole length of the canal may remain incomplete.
The following abnormal curvatures may occur in some people:
- Kyphosis Kyphosis , also called hunchback, is a common condition of a curvature of the upper spine. It can be either the result of degenerative diseases (such as arthritis), developmental problems, osteoporosis with compression fractures of the vertebrae, and/or trauma is an exaggerated kyphotic (posterior) curvature in the thoracic region. This produces the so-called "humpback" or "dowager's hump", a condition commonly observed in osteoporosis.
- Lordosis Lordosis is a medical term used to describe an inward curvature of a portion of the vertebral column. Two segments of the vertebral column, namely cervical and lumbar, are normally lordotic, that is, they are set in a curve that has its convexity anteriorly and concavity posteriorly (behind), in the context of human anatomy. When referring to the is an exaggerated lordotic (anterior) curvature of the lumbar region, "swayback". Temporary lordosis is common among pregnant Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the womb of a female. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets. Human pregnancy is the most studied of all mammalian pregnancies. Childbirth usually occurs about 38 weeks after conception; i.e., approximately 40 weeks women A woman is a female human. The term woman is usually reserved for an adult, with the term girl being the usual term for a female child or adolescent. However, the term woman is also sometimes used to identify a female human, regardless of age, as in phrases such as "Women's rights".
- Retrolisthesis is a posterior displacement of one vertebral body with respect to the adjacent vertebral segment to a degree less than a luxation (dislocation).
- Scoliosis Scoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an x-ray, viewed from the rear, the spine of an individual with a typical scoliosis may look more like an "S" or a "C" than a straight line. It is typically classified as either, lateral curvature, is the most common abnormal curvature, occurring in 0.5% of the population. It is more common among females Female is the sex of an organism, or a part of an organism, which produces non-mobile ova (egg cells) and may result from unequal growth of the two sides of one or more vertebrae. It can also be caused by pulmonary atelectasis (partial or complete deflation of one or more lobes of the lungs) as observed in asthma or pneumothorax.
Additional images
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Relation of the vertebral column to the surrounding muscles. |
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See also
- Coccyx (tailbone) The coccyx , commonly referred to as the tailbone, is the final segment of the ape vertebral column. Comprising three to five separate or fused vertebrae (the coccygeal vertebrae) below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between the sacrum and the
- Low back pain Low back pain is a common musculoskeletal disorder affecting 80% of people at some point in their lives. It accounts for more sick leave and disability than any other medical condition. It can be either acute, subacute or chronic in duration. Most often, the symptoms of low back pain show significant improvement within a few weeks from onset with
- Vertebral subluxation Vertebral subluxation is a chiropractic term that is used to describe numerous signs and symptoms thought to occur as a result of a misaligned or dysfunctional spinal joint segment. Chiropractors believe that a vertebral subluxation complex is a dysfunctional biomechanical spinal segment that can alter neurological function, which in turn, is
- Retrolisthesis
- Spinal disc herniation A spinal disc herniation , informally and misleadingly called a "slipped disc", is a medical condition affecting the spine, in which a tear in the outer, fibrous ring (annulus fibrosus) of an intervertebral disc (discus intervertebralis) allows the soft, central portion (nucleus pulposus) to bulge out. Tears are almost always posterior-
- Scoliosis Scoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an x-ray, viewed from the rear, the spine of an individual with a typical scoliosis may look more like an "S" or a "C" than a straight line. It is typically classified as either
- Spinal stenosis Spinal stenosis is a medical condition in which the spinal canal narrows and compresses the spinal cord and nerves. This is usually due to the common occurrence of spinal degeneration that occurs with aging. It can also sometimes be caused by spinal disc herniation, osteoporosis or a tumor. In the cervical and lumbar (low back) region it can be a
References
| This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be and removed. (June 2008) |
- ^ vertebral column at Dorland's Medical Dictionary Dorland's is the brand name of a family of medical reference works in various media (including printed books, CD-ROMs, and online content). The flagship products are Dorland's Illustrated Medical Dictionary (currently in its 31st edition) and Dorland's Pocket Medical Dictionary (currently in its 27th edition). The principal dictionary was first
- ^ Swash, M, Glynn, M.(eds). 2007. Hutchison's Clinical Methods. Edinburgh. Saunders Elsevier.
- ^ Anatomy Compendium (Godfried Roomans and Anca Dragomir)
External links
- North American Spine Society is a multidisciplinary medical organization that advances quality spine care through education, research and advocacy.
- Spinal Cord Injuries Australia (formerly Australian Quadriplegic Association AQA, established 1967) provides information about the disability and services for affected people, advocacy, accommodation, employment, peer support.
- Spinal Cord Injury Peer SupportPeer support for those living with spinal injuries.
- Vertebral column basics
- Spinal Term Glossary
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Categories: Skeletal system | Retrolisthesis
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