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55-581: Sacro may refer to : Sacro - a Scottish voluntary organisation, 'Safeguarding Communities, Reducing Offending', formerly known as the Scottish Association for the Care and Resettlement of Offenders In combination with other words, the sacrum (e.g. sacroiliac) The Sacro Convento , a Franciscan friary in Assisi, Umbria, Italy Monte Sacro ,

110-526: A hill in Rome on the banks of the river Aniene Sacromonte , a neighbourhood of Granada, Spain Sacro Vergente , an Apostolic Letter of Pope Pius XII to all people of Russia Cuore Sacro , a 2005 Italian-language film directed by Ferzan Ozpetek Sacro Culto , the second album by Opera IX Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

165-413: A network of interconnecting nerves. Nerves emerging from a plexus contain fibers from various spinal nerves, which are now carried together to some target location. The spinal plexuses are the cervical plexus , brachial plexus , lumbar plexus , the sacral plexus and the much smaller coccygeal plexus . The cervical nerves are the spinal nerves from the cervical vertebrae in the cervical segment of

220-460: A translation of Greek ἱερόν ὀστέον, the term found in the writings of Galen . Prior to the adoption of sacrum , the bone was also called holy bone in English, paralleling German heiliges Bein or Heiligenbein (alongside Kreuzbein ) and Dutch heiligbeen . The origin of Galen's term is unclear. Supposedly the sacrum was the part of an animal offered in sacrifice (since the sacrum

275-399: Is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1–S5) between ages 18 and 30. The sacrum situates at the upper, back part of the pelvic cavity , between the two wings of the pelvis . It forms joints with four other bones. The two projections at the sides of the sacrum are called the alae (wings), and articulate with the ilium at

330-457: Is that of caudal regression syndrome also known as sacral agenesis . This is characterised by an abnormal underdevelopment in the embryo (occurring by the seventh week) of the lower spine. Sometimes part of the coccyx is absent, or the lower vertebrae can be absent, or on occasion a small part of the spine is missing with no outward sign. Sacral fractures are relatively uncommon; however, they are often associated with neurological deficits. In

385-452: Is the sacral plexus , and next to the lower sacrum and coccyx is the very small coccygeal plexus . The muscles that one particular spinal root supplies are that nerve's myotome , and the dermatomes are the areas of sensory innervation on the skin for each spinal nerve. Lesions of one or more nerve roots result in typical patterns of neurologic defects ( muscle weakness , abnormal sensation, changes in reflexes) that allow localization of

440-426: Is the large triangular orifice of the sacral canal, which is completed by the lamina and spinous process of the first sacral vertebra. The superior articular processes project from it on either side; they are oval, concave, directed backward and medialward, like the superior articular processes of a lumbar vertebra. They are attached to the body of the first sacral vertebra and to each ala, by short thick pedicles; on

495-603: Is the seat of the organs of procreation ). Others attribute the adjective ἱερόν to the ancient belief that this specific bone would be indestructible. As the Greek adjective ἱερός may also mean "strong", it has also been suggested that os sacrum is a mistranslation of a term intended to mean "the strong bone". This is supported by the alternative Greek name μέγας σπόνδυλος by the Greeks, translating to "large vertebra", translated into Latin as vertebra magna . In Classical Greek

550-418: Is tilted forward as the sacral promontory internally. The central part is curved outward toward the posterior , allowing greater room for the pelvic cavity . In all other quadrupedal vertebrates , the pelvic vertebrae undergo a similar developmental process to form a sacrum in the adult, even while the bony tail (caudal) vertebrae remain unfused. The number of sacral vertebrae varies slightly. For instance,

605-470: The central nervous system (CNS) and motor impulses from the CNS to the pelvis that control the movements of these pelvic organs. The bilateral coccygeal nerves, Co, are the 31st pair of spinal nerves. It arises from the conus medullaris, and its ventral ramus helps form the coccygeal plexus . It does not divide into a medial and lateral branch. Its fibers are distributed to the skin superficial and posterior to

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660-424: The cervical plexus (C1–C4) and brachial plexus (C5–T1). The cervical nerves innervate the sternohyoid , sternothyroid and omohyoid muscles . A loop of nerves called ansa cervicalis is part of the cervical plexus. The thoracic nerves are the twelve spinal nerves emerging from the thoracic vertebrae. Each thoracic nerve T1–T12 originates from below each corresponding thoracic vertebra . Branches also exit

715-407: The coccyx bone via the anococcygeal nerve of the coccygeal nerve plexus. A spinal plexus is a weblike nerve plexus formed by the anterior nerve roots that branch and merge repeatedly. The only region that does not have a plexus is the thoracic region. The small cervical plexus is in the neck, the brachial plexus is in the shoulder, the lumbar plexus is in the lower back, beneath this

770-442: The lumbar plexus with the sacral plexus . In the articulated pelvis, the alae are continuous with the iliac fossa . Each ala is slightly concave from side to side, and convex from the back and gives attachment to a few of the fibers of the iliacus muscle . The posterior quarter of the ala represents the transverse process, and its anterior three-quarters the costal process of the first sacral segment. Each ala also serves as part of

825-435: The lumbar plexus . The smaller part of the fourth joins with the fifth to form the lumbosacral trunk , which assists in the formation of the sacral plexus . The fourth nerve is named the furcal nerve , from the fact that it is subdivided between the two plexuses. The sacral nerves are the five pairs of spinal nerves which exit the sacrum at the lower end of the vertebral column . The roots of these nerves begin inside

880-411: The multifidus muscle . The floor of the groove is formed by the united laminae of the corresponding vertebrae. The laminae of the fifth sacral vertebra, and sometimes those of the fourth, do not meet at the back, resulting in a fissure known as the sacral hiatus in the posterior wall of the sacral canal . The sacral canal is a continuation of the spinal canal and runs throughout the greater part of

935-419: The public domain from page 106 of the 20th edition of Gray's Anatomy (1918) Spinal nerve Each spinal nerve is a mixed nerve , formed from the combination of nerve root fibers from its dorsal and ventral roots . The dorsal root is the afferent sensory root and carries sensory information to the brain. The ventral root is the efferent motor root and carries motor information from

990-476: The sensory perception and the movements of the lower extremities of the human body. From the S2, S3 and S4 arise the pudendal nerve and parasympathetic fibers whose electrical potential supply the descending colon and rectum , urinary bladder and genital organs . These pathways have both afferent and efferent fibers and, this way, they are responsible for conduction of sensory information from these pelvic organs to

1045-461: The L-shaped sacroiliac joints . The upper part of the sacrum connects with the last lumbar vertebra (L5), and its lower part with the coccyx (tailbone) via the sacral and coccygeal cornua. The sacrum has three different surfaces which are shaped to accommodate surrounding pelvic structures. Overall, it is concave (curved upon itself). The base of the sacrum , the broadest and uppermost part,

1100-536: The S1–S5 vertebrae of a horse will fuse, the S1–S3 of a dog will fuse, and four pelvic vertebrae of a rat will fuse between the lumbar and the caudal vertebrae of its tail. The Stegosaurus dinosaur had a greatly enlarged neural canal in the sacrum, characterized as a " posterior brain case ". The sacrum is a complex structure providing support for the spine and accommodation for the spinal nerves . It also articulates with

1155-432: The back and middle, and articulate with the facets on the inferior processes of the fifth lumbar vertebra. The tubercles of the inferior articular processes of the fifth sacral vertebra, known as the sacral cornua, are projected downward and are connected to the cornua of the coccyx. At the side of the articular processes are the four posterior sacral foramina ; they are smaller in size and less regular in form than those at

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1210-402: The bodies of the next bones get progressively smaller, are flattened from the back, and curved to shape themselves to the sacrum, being concave in front and convex behind. At each end of the transverse ridges, are the four anterior sacral foramina , diminishing in size in line with the smaller vertebral bodies. The foramina give exit to the anterior divisions of the sacral nerves and entrance to

1265-487: The bone was known as κλόνις (Latinized clonis ); this term is cognate to Latin clunis "buttock", Sanskrit śróṇis "haunch" and Lithuanian šlaunis "hip, thigh". The Latin word is found in the alternative Latin name of the sacrum, ossa clunium , as it were "bones of the buttocks". Due to the fact that the os sacrum is broad and thick at its upper end, the sacrum is alternatively called os latum , "broad bone". [REDACTED] This article incorporates text in

1320-424: The border of the pelvic brim . The alae also form the base of the lumbosacral triangle. The iliolumbar ligament and lumbosacral ligaments are attached to the ala. In the middle of the base is a large oval articular surface, the upper surface of the body of the first sacral vertebra, which is connected with the under surface of the body of the last lumbar vertebra by an intervertebral fibrocartilage . Behind this

1375-494: The brain. The spinal nerve emerges from the spinal column through an opening ( intervertebral foramen ) between adjacent vertebrae. This is true for all spinal nerves except for the first spinal nerve pair (C1), which emerges between the occipital bone and the atlas (the first vertebra). Thus the cervical nerves are numbered by the vertebra below, except spinal nerve C8, which exists below vertebra C7 and above vertebra T1. The thoracic, lumbar, and sacral nerves are then numbered by

1430-418: The branches from different nerves join with one another, some of them also joining with lumbar or coccygeal nerve branches. These anastomoses of nerves form the sacral plexus and the lumbosacral plexus . The branches of these plexus give rise to nerves that supply much of the hip , thigh , leg and foot . The sacral nerves have both afferent and efferent fibers , thus they are responsible for part of

1485-422: The coccyx, and this transmits the anterior division of the fifth sacral nerve. The thin lower half of the lateral surface gives attachment to the sacrotuberous and sacrospinous ligaments , to some fibers of the gluteus maximus at the back and to the coccygeus in the front. The sacrum articulates with four bones: Rotation of the sacrum superiorly and anteriorly whilst the coccyx moves posteriorly relative to

1540-405: The fresh state, are filled by the intervertebral discs . The dorsal surface of the sacrum is convex and narrower than the pelvic surface. In the middle line is the median sacral crest , surmounted by three or four tubercles —the rudimentary spinous processes of the upper three or four sacral vertebrae. On either side of the median sacral crest is a shallow sacral groove, which gives origin to

1595-404: The front, and transmit the posterior divisions of the sacral nerves. On the side of the posterior sacral foramina is a series of tubercles, the transverse processes of the sacral vertebrae, and these form the lateral sacral crest . The transverse tubercles of the first sacral vertebra are large and very distinct; they, together with the transverse tubercles of the second vertebra, give attachment to

1650-421: The hip bones. The sacrum has a base, an apex, and three surfaces – a pelvic, dorsal and a lateral surface. The base of the sacrum , which is broad and expanded, is directed upward and forward. On either side of the base is a large projection known as an ala of sacrum and these alae (wings) articulate with the sacroiliac joints . The alae support the psoas major muscles and the lumbosacral trunk which connects

1705-428: The horizontal parts of the posterior sacroiliac ligaments; those of the third vertebra give attachment to the oblique fasciculi of the posterior sacroiliac ligaments; and those of the fourth and fifth to the sacrotuberous ligaments. The lateral surface of the sacrum is broad above, but narrows into a thin edge below. The upper half presents in front an ear-shaped surface, the auricular surface, covered with cartilage in

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1760-405: The horizontal plane that provides a useful marker for a sling implant procedure. The pelvic surface of the sacrum is concave from the top, and curved slightly from side to side. Its middle part is crossed by four transverse ridges, which correspond to the original planes of separation between the five sacral vertebrae. The body of the first segment is large and has the form of a lumbar vertebra;

1815-460: The ilium is sometimes called "nutation" (from the Latin term nutatio which means "nodding") and the reverse, postero-inferior motion of the sacrum relative to the ilium whilst the coccyx moves anteriorly, "counter-nutation". In upright vertebrates, the sacrum is capable of slight independent movement along the sagittal plane . On bending backward the top (base) of the sacrum moves forward relative to

1870-421: The ilium; on bending forward the top moves back. The sacrum refers to all of the parts combined. Its parts are called sacral vertebrae when referred individually. In some cases, the sacrum will consist of six pieces or be reduced in number to four. The bodies of the first and second vertebrae may fail to unite. The somites that give rise to the vertebral column begin to develop from head to tail along

1925-411: The immature state, for articulation with the ilium. Behind it is a rough surface, the sacral tuberosity , on which are three deep and uneven impressions, for the attachment of the posterior sacroiliac ligament. The lower half is thin, and ends in a projection called the inferior lateral angle. Medial to this angle is a notch, which is converted into a foramen by the transverse process of the first piece of

1980-439: The lateral sacral arteries. Each part at the sides of the foramina is traversed by four broad, shallow grooves, which lodge the anterior divisions of the sacral nerves. They are separated by prominent ridges of bone which give origin to the piriformis muscle . If a sagittal section be made through the center of the sacrum, the bodies are seen to be united at their circumferences by bone, wide intervals being left centrally, which, in

2035-435: The length of the notochord. At day 20 of embryogenesis , the first four pairs of somites appear in the future occipital bone region. Developing at the rate of three or four a day, the next eight pairs form in the cervical region to develop into the cervical vertebrae; the next twelve pairs will form the thoracic vertebrae; the next five pairs the lumbar vertebrae and by about day 29, the sacral somites will appear to develop into

2090-468: The lumbar and some caudal and thoracic vertebrae to form a single structure called the synsacrum . In the frog , the ilium is elongated and forms a mobile joint with the sacrum that acts as an additional limb to give more power to its leaps. English sacrum was introduced as a technical term in anatomy in the mid-18th century, as a shortening of the Late Latin name os sacrum "sacred bone", itself

2145-530: The lumbar nerves (rami anteriores) increase in size from above downward. They are joined, near their origins, by gray rami communicantes from the lumbar ganglia of the sympathetic trunk . These rami consist of long, slender branches which accompany the lumbar arteries around the sides of the vertebral bodies, beneath the psoas major . Their arrangement is somewhat irregular: one ganglion may give rami to two lumbar nerves, or one lumbar nerve may receive rami from two ganglia . The first and second, and sometimes

2200-424: The multifidus and longissimus dorsi , occasionally they give off filaments to the skin near the middle line. This sensitive branch is called the posterior cutaneous ramus. The lumbar nerves are the five spinal nerves emerging from the lumbar vertebrae. They are divided into posterior and anterior divisions. The medial branches of the posterior divisions of the lumbar nerves run close to the articular processes of

2255-422: The presence of neurological signs, they are mostly treated with surgical fixation . The sacrum is one of the main sites for the development of the sarcomas known as chordomas that are derived from the remnants of the embryonic notochord . In dogs , the sacrum is formed by three fused vertebrae. The sacrum in the horse is made up of five fused vertebrae. In birds , the sacral vertebrae are fused with

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2310-433: The sacral vertebrae; finally on day 30, the last three pairs will form the coccyx. The congenital disorder , spina bifida , occurs as a result of a defective embryonic neural tube , characterised by the incomplete closure of vertebral arch or of the incomplete closure of the surface of the vertebral canal. The most common sites for spina bifida malformations are the lumbar and sacral areas. Another congenital disorder

2365-465: The sacrum. Above the sacral hiatus, it is triangular in form. The canal lodges the sacral nerves , via the anterior and posterior sacral foramina. On the lateral aspect of the sacral groove is a linear series of tubercles produced by the fusion of the articular processes which together form the indistinct medial sacral crest . The articular processes of the first sacral vertebra are large and oval-shaped. Their facets are concave from side to side, face to

2420-428: The skin and muscles of the back ( epaxial muscles ). The ventral ramus contains nerves that serve the remaining anterior parts of the trunk and the upper and lower limbs ( hypaxial muscles ) carrying visceral motor, somatic motor, and sensory information to and from the ventrolateral body surface, structures in the body wall, and the limbs. The meningeal branches (recurrent meningeal or sinuvertebral nerves) branch from

2475-514: The spinal cord. Although there are seven cervical vertebrae (C1–C7), there are eight cervical nerves C1 – C8 . C1–C7 emerge above their corresponding vertebrae, while C8 emerges below the C7 vertebra. Everywhere else in the spine, the nerve emerges below the vertebra with the same name. The posterior distribution includes the suboccipital nerve (C1), the greater occipital nerve (C2) and the third occipital nerve (C3). The anterior distribution includes

2530-412: The spinal nerve and re-enter the intervertebral foramen to serve the ligaments, dura, blood vessels, intervertebral discs, facet joints, and periosteum of the vertebrae. The rami communicantes contain autonomic nerves that serve visceral functions carrying visceral motor and sensory information to and from the visceral organs. Some anterior rami merge with adjacent anterior rami to form a nerve plexus ,

2585-405: The spine and go directly to the paravertebral ganglia of the autonomic nervous system where they are involved in the functions of organs and glands in the head, neck, thorax and abdomen. The intercostal nerves come from thoracic nerves T1–T11, and run between the ribs. At T2 and T3, further branches form the intercostobrachial nerve . The subcostal nerve comes from nerve T12, and runs below

2640-403: The third and fourth lumbar nerves are each connected with the lumbar part of the sympathetic trunk by a white ramus communicans . The nerves pass obliquely outward behind the psoas major, or between its fasciculi , distributing filaments to it and the quadratus lumborum . The first three and the greater part of the fourth are connected together in this situation by anastomotic loops, and form

2695-502: The title Sacro . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Sacro&oldid=1141159907 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Sacrum The sacrum ( pl. : sacra or sacrums ), in human anatomy ,

2750-429: The twelfth rib. The medial branches (ramus medialis) of the posterior branches of the upper six thoracic nerves run between the semispinalis dorsi and multifidus , which they supply; they then pierce the rhomboid and trapezius muscles , and reach the skin by the sides of the spinous processes. This sensitive branch is called the medial cutaneous ramus. The medial branches of the lower six are distributed chiefly to

2805-403: The two pieces of sacrum. Normally, it is greater than 60 degrees. A sacral angle of lesser degree suggests funneling of the pelvis. The sacral promontory marks part of the border of the pelvic inlet , and comprises the iliopectineal line and the linea terminalis . The sacral promontory articulates with the last lumbar vertebra to form the sacrovertebral angle , an angle of 30 degrees from

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2860-418: The upper surface of each pedicle is a vertebral notch, which forms the lower part of the foramen between the last lumbar and first sacral vertebrae. The apex is directed downward and presents an oval facet for articulation with the coccyx . The sacral canal as a continuation of the vertebral canal runs throughout the greater part of the sacrum. The sacral angle is the angle formed by the true conjugate with

2915-413: The vertebra above. In the case of a lumbarized S1 vertebra (also known as L6) or a sacralized L5 vertebra, the nerves are typically still counted to L5 and the next nerve is S1. Outside the vertebral column, the nerve divides into branches. The dorsal ramus contains nerves that serve the posterior portions of the trunk carrying visceral motor, somatic motor, and somatic sensory information to and from

2970-447: The vertebrae and end in the multifidus muscle . The laterals supply the erector spinae muscles . The upper three give off cutaneous nerves which pierce the aponeurosis of the latissimus dorsi at the lateral border of the erector spinae muscles, and descend across the posterior part of the iliac crest to the skin of the buttock , some of their twigs running as far as the level of the greater trochanter . The anterior divisions of

3025-497: The vertebral column at the level of the L1 vertebra , where the cauda equina begins, and then descend into the sacrum. There are five paired sacral nerves, half of them arising through the sacrum on the left side and the other half on the right side. Each nerve emerges in two divisions: one division through the anterior sacral foramina and the other division through the posterior sacral foramina . The nerves divide into branches and

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