The coccyx (pronounced kok-siks) (Latin: os coccygis), commonly referred to as the tailbone, is the final segment of the human vertebral column. In Human anatomy, the vertebral column ( backbone or spine) is a column of 34 Vertebrae the Sacrum, Intervertebral Comprised of three to five separate or fused vertebrae (the coccygeal vertebrae), below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, which permits limited movement between the sacrum and the coccyx. A vertebra (plural vertebrae) is an individual Irregular bone in the spinal or Vertebral column ( aka ischis a flexuous and flexible column 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 A joint is the location at which two or more Bones make contact The term coccyx comes originally from the Greek language and means "cuckoo," referring to the shape of a cuckoo's beak^[1]. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly The cuckoos are a family Cuculidae, of Near passerine Birds The order Cuculiformes, in addition to the cuckoos also includes the

Contents 1 Function 2 Structure 2.1 Surfaces 2.2 Borders 2.3 Apex 2.4 Sacrococcygeal and intercoccygeal joints 3 Pathology 4 Additional images 5 See also 6 References 7 External links

Function

The coccyx provides an attachment for nine muscles, such as the gluteus maximus, and those necessary for defecation. Muscle (from Latin musculus, diminutive of mus "mouse" is contractile tissue of the body and is derived from the The gluteus maximus' (or glutæus maximus) is the largest and most Superficial of the three Gluteal muscles. Defecation is the final act of Digestion by which organisms eliminate solid semisolid or liquid Waste material ( Faeces) from the Digestive tract It also acts as something of a shock absorber when a person sits down, although forceful impact can cause damage and subsequent bodily pains. A shock absorber in common parlance (or damper in technical use is a mechanical device designed to smooth out or dampen shock impulse and dissipate The remnant of a vestigial tail in humans, in many other species the coccygeal vertebrae support a full tail and accommodate its nerves. In the context of Human evolution, human vestigiality involves those characters (such as organs or behaviors occurring in the Human A vertebra (plural vertebrae) is an individual Irregular bone in the spinal or Vertebral column ( aka ischis a flexuous and flexible column ^[2]

Structure

The coccyx is usually formed of four rudimentary vertebrae; the number may be as high as five or as low as three. A vertebra (plural vertebrae) is an individual Irregular bone in the spinal or Vertebral column ( aka ischis a flexuous and flexible column It articulates superiorly with the sacrum. 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 In each of the first three segments may be traced a rudimentary body and articular and transverse processes; the last piece (sometimes the third) is a mere nodule of bone. All the segments are destitute of pedicles, laminae, and spinous processes. The pedicles (from Latin pediculus, "small foot" are two short thick processes which project backward one on either side from the upper part of the body at the The laminæ are two broad plates directed backward and medially from the pedicles. The first is the largest; it resembles the lowest sacral vertebra, and often exists as a separate piece; the last three diminish in size from above downward. 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 Most anatomy books wrongly state that the coccyx is normally fused in adults. In fact it has been shown^[3][4] that the coccyx may consist of up to five separate bony segments, the most common configuration being two or three segments. Only about 5% of the population have a coccyx in one piece, separate from the sacrum, as described in anatomy books. This error in anatomy teaching can lead doctors to diagnose a 'fractured coccyx' when they see a coccyx in several segments on x-ray.

Surfaces

The anterior surface is slightly concave, and marked with three transverse grooves which indicate the junctions of the different segments. In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species It gives attachment to the anterior sacrococcygeal ligament and the Levatores ani, and supports part of the rectum. The Anterior Sacrococcygeal Ligament consists of a few irregular fibers which descend from the anterior surface of the Sacrum to the front of the Coccyx, blending The Levator ani is a broad thin Muscle, situated on the side of the Pelvis. The rectum (from the Latin rectum intestinum, meaning straight intestine) is the final straight portion of the Large intestine in some Mammals

The posterior surface is convex, marked by transverse grooves similar to those on the anterior surface, and presents on either side a linear row of tubercles, the rudimentary articular processes of the coccygeal vertebrae. In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species Of these, the superior pair are large, and are called the coccygeal cornua; they project upward, and articulate with the cornua of the sacrum, and on either side complete the foramen for the transmission of the posterior division of the fifth sacral nerve. 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

Borders

The lateral borders are thin, and exhibit a series of small eminences, which represent the transverse processes of the coccygeal vertebrae. Of these, the first is the largest; it is flattened from before backward, and often ascends to join the lower part of the thin lateral edge of the sacrum, thus completing the foramen for the transmission of the anterior division of the fifth sacral nerve; the others diminish in size from above downward, and are often wanting. The borders of the coccyx are narrow, and give attachment on either side to the sacrotuberous and sacrospinous ligaments, to the Coccygeus in front of the ligaments, and to the gluteus maximus behind them. The sacrotuberous ligament ( great or posterior sacrosciatic ligament) is situated at the lower and back part of the Pelvis. The Coccygeus is situated behind the Levator ani. It is a triangular plane of muscular and tendinous fibers arising by its apex from the spine of the Ischium The gluteus maximus' (or glutæus maximus) is the largest and most Superficial of the three Gluteal muscles.

Apex

The apex is rounded, and has attached to it the tendon of the Sphincter ani externus. The Sphincter ani externus ( external anal sphincter) is a flat plane of muscular fibers elliptical in shape and intimately adherent to the integument surrounding the margin It may be bifid. Spina bifida ( Latin: "split spine" is a developmental Birth defect involving the Neural tube: incomplete closure of the Embryonic neural

Sacrococcygeal and intercoccygeal joints

The joints are variable and may be: (1) synovial joints; (2) thin discs of fibrocartilage; (3) intermediate between these two; (4) ossified. Synovial joints (or diarthroses, or diarthroidal joints) are the most common and most moveable type of Joints in the human body White fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions to the former of these constituents it owes its flexibility and toughness ^{[5] [6]}

Pathology

Injuring the coccyx can give rise to a condition called coccydynia. Coccydynia is a medical term meaning pain in the Coccyx or tailbone area usually brought on by sitting ^{[7] [8]}

Additional images

Vertebral column.	Vertebral column.	Left Levator ani from within.	Median sagittal section of male pelvis.
Median sagittal section of female pelvis.

See also

• Coccydynia (coccyx pain, tailbone pain)
• Bone terminology
• Terms for anatomical location
• Ganglion impar
• Human vestigial

References

1. ^ Coccyx, Dorland's Illustrated Medical Dictionary
2. ^ The Human Tail, and Other Tales of Evolution. Coccydynia is a medical term meaning pain in the Coccyx or tailbone area usually brought on by sitting 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 The pelvic portion of each Sympathetic trunk is situated in front of the Sacrum, medial to the Anterior sacral foramina. In the context of Human evolution, human vestigiality involves those characters (such as organs or behaviors occurring in the Human
3. ^ Idiopathic coccygodynia. Analysis of fifty-one operative cases and a radiographic study of the normal coccyx. The Journal of bone and joint surgery. American volume. 1983 Oct; 65(8): 1116-1124. Postacchini F, Massobrio M
4. ^ Clinical and radiological differences between traumatic and idiopathic coccygodynia. Yonsei Medical Journal, 1999 Jun, 40:3, 215-20. Kim NH; Suk KS
5. ^ Maigne JY, Molinie V, Fautrel B. (1992). "Anatomie des disques coccygiens. ". Revue de Médecine Orthopedique 28: 34-35.  
6. ^ Saluja PG. (1988). "The incidence of ossification of the sacrococcygeal joint. ". Journal of Anatomy 156: 11-15.  
7. ^ Causes and Mechanisms of Common Coccydynia. Spine, 2000, volume 25, number 23, 3072-3079. Maigne, J-Y, Doursounian, L, Chatellier, G.
8. ^ Foye P, Buttaci C, Stitik T, Yonclas P (2006). "Successful injection for coccyx pain. ". Am J Phys Med Rehabil 85 (9): 783-4. doi:10.1097/01.phm.0000233174.86070.63. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 16924191.  

External links

• Gray's s24
• SUNY Labs 41:os-0107 - "The Female Perineum: Osteology"
• Cross section at UV pelvis/pelvis-e12-15
• Coccyx pain: diagnosis, coping and treatment at coccyx.org
• coccyx-fracture(Tailbone Fracture) at al-hikmah.org
• Coccydynia (coccyx pain, tailbone pain) at eMedicine (Peer-reviewed medical chapter, available free online)

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 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 Medical University of Vienna (German Medizinische Universität Wien short MUW, formerly the faculty of Medicine of the University of Vienna, became an

© 2009 citizendia.org; parts available under the terms of GNU Free Documentation License, from http://en.wikipedia.org
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic