| Bone: Sacrum | |
|---|---|
 |
|
| Sacrum, pelvic surface | |
 |
|
| Image of pelvis. The pelvis (pl pelvises or pelves) or pelvic girdle is the irregular bony structure located at the base of the spine (properly known Sacrum is in center. | |
| Latin | os sacrum |
| Gray's | subject #24 106 |
| MeSH | Sacrum |
| Dorlands / Elsevier |
o_07/12598664 |
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. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Introduction ( classes Long bones body or Diaphysis Medullary canal Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Elsevier, the world's largest Publisher of Medical and Scientific literature, forms part of the Reed Elsevier group In Human anatomy, the vertebral column ( backbone or spine) is a column of 34 Vertebrae the Sacrum, Intervertebral The pelvic cavity is a Body cavity that is bounded by the bones of the Pelvis and which primarily contains Reproductive organs, the Urinary bladder The hip bone, innominate bone or coxal bone is a large flattened irregularly shaped bone constricted in the center and expanded above and below Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx (tailbone). 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 coccyx (pronounced kok -siks (Latin os coccygis) commonly referred to as the tailbone, is the final segment of the human vertebral column
It is curved upon itself and placed obliquely (that is, tilted forward). It is kyphotic — that is, concave facing forwards. The base projects forward as the sacral promontory internally, and articulates with the last lumbar vertebra to form the prominent sacrovertebral angle. The sacral promontory is the anatomical term for the superiormost portion of the Sacrum. The Sacrum is curved upon itself and placed very obliquely its base projecting forward and forming the prominent sacrovertebral angle when articulated with the last Lumbar The central part is curved outward towards the posterior, allowing greater room for the pelvic cavity. In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species The pelvic cavity is a Body cavity that is bounded by the bones of the Pelvis and which primarily contains Reproductive organs, the Urinary bladder
Contents |
Etymology
The name is derived from the Latin sacer, "sacred", a translation of the Greek hieron (osteon), meaning sacred or strong bone. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. SACRED was a Cubesat built by the Student Satellite Program of the University of Arizona. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly [1] This is supposedly because the sacrum was the part of an animal offered in sacrifice. Sacrifice (from a Middle English verb meaning "to make sacred" from Old French, from Latin sacrificium: sacr, "sacred" In Slavic languages and in German this bone is called the "cross bone". The Slavic languages (also called Slavonic languages) a group of closely related Languages of the Slavic peoples and a subgroup of Indo-European languages The German language (de ''Deutsch'') is a West Germanic language and one of the world's major languages. [2]
Parts
- The pelvic surface of the sacrum is concave from above downward, and slightly so from side to side. The pelvic surface of sacrum is concave from above downward and slightly so from side to side
- The dorsal surface of the sacrum is convex and narrower than the pelvic. The dorsal surface of sacrum is convex and narrower than the pelvic
- The lateral surface of the sacrum is broad above, but narrowed into a thin edge below. The lateral surface of sacrum is broad above but narrowed into a thin edge below
- The base of the sacrum, which is broad and expanded, is directed upward and forward. The base of the sacrum, which is broad and expanded is directed upward and forward
- The apex (apex oss. sacri) is directed downward, and presents an oval facet for articulation with the coccyx.
- The vertebral canal (canalis sacralis; sacral canal) runs throughout the greater part of the bone; above, it is triangular in form; below, its posterior wall is incomplete, from the non-development of the laminae and spinous processes. The spinal canal (or vertebral canal or spinal cavity) is the space in Vertebrae through which the Spinal cord passes It lodges the sacral nerves, and its walls are perforated by the anterior and posterior sacral foramina through which these nerves pass out. The five sacral nerves emerge from the Sacrum. Although the vertebral components of the sacrum are fused into a single bone the sacral vertebrae are still used to number the
Articulations
The sacrum articulates with four bones:
- the last lumbar vertebra above
- the coccyx (tailbone) below
- the hip bone on either side
Rotatation of the sacrum forward a few degrees vis-à-vis the ilia is sometimes called "nutation", and the reverse motion "counter-nutation. 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 coccyx (pronounced kok -siks (Latin os coccygis) commonly referred to as the tailbone, is the final segment of the human vertebral column The hip bone, innominate bone or coxal bone is a large flattened irregularly shaped bone constricted in the center and expanded above and below The ilium of the Pelvis is divisible into two parts the body and the ala the separation is indicated on the top surface by a curved line the arcuate line and on the Nutation is a slight irregular motion (etymologically a "nodding" in the Axis of rotation of a largely axially symmetric object such as a Gyroscope "[3]
It is called the sacrum when referred to all of the parts combined, but sacral vertebrae when referred individually.
Sexual dimorphism
The sacrum is noticeably sexually dimorphic (differently-shaped in males and females). Sexual dimorphism is the systematic difference in form between individuals of different Sex in the same Species.
In the female the sacrum is shorter and wider than in the male; the lower half forms a greater angle with the upper; the upper half is nearly straight, the lower half presenting the greatest amount of curvature. The bone is also directed more obliquely backward; this increases the size of the pelvic cavity and renders the sacrovertebral angle more prominent.
In the male the curvature is more evenly distributed over the whole length of the bone, and is altogether greater than in the female.
Variations
The sacrum, in some cases, consists of six pieces [1]; occasionally the number is reduced to four [2]. The bodies of the first and second vertebrae may fail to unite.
Sometimes the uppermost transverse tubercles are not joined to the rest of the ala on one or both sides, or the sacral canal may be open throughout a considerable part of its length, in consequence of the imperfect development of the laminae and spinous processes.
The sacrum also varies considerably with respect to its degree of curvature.
Additional images
 Vertebral column. |
 |
 Pelvis |
 Sacrum, dorsal surface. |
 Lateral surfaces of sacrum and coccyx. |
 Base of sacrum. |
 Median sagittal section of the sacrum. |
 Vertebral column. |
 Left Levator ani from within. |
 The posterior divisions of the sacral nerves. |
 Median sagittal section of male pelvis. |
 Median sagittal section of female pelvis. |
See also
External links
- SUNY Labs 43:os-0401 - "The Female Pelvis: Articulated bones of pelvis"
- SUNY Labs 43:st-0401 - "The Female Pelvis: Bones"
- sacrum at eMedicine Dictionary
References
- ^ Online Etymology Dictionary
- ^ LEO E-G Results for "sacrum"
- ^ The AS Ilium Fixation, Nutation, and Respect | Joseph D. Kurnik, DC
This article was originally based on an entry from a public domain edition of Gray's Anatomy. Bones are rigid organs that form part of the Endoskeleton of Vertebrates They function to move support and protect the various organs of the body produce In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species Pelvimetry is the assessment of the female Pelvis in relation to the Birth of a baby The State University of New York Health Science Center at Brooklyn, better known as SUNY Downstate Medical Center, is an academic medical center and is the only one of its kind The State University of New York Health Science Center at Brooklyn, better known as SUNY Downstate Medical Center, is an academic medical center and is the only one of its kind eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely two medical doctors The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone Henry Gray's Anatomy of the Human Body (or Gray's Anatomy as it has commonly been shortened is an English-language Human anatomy Textbook As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic