Human skeleton - wikipedia Human skeleton This is the latest accepted revision, reviewed on 5 April 2018. `` Bone structure '' and `` skeletal system '' redirect here. For skeletal systems of other animals, see Skeleton. For for the scientific study of bones, see Osteology. Human Skeleton Diagram of the human skeleton Details Identifiers Greek σκελετός TA A02. 0.00. 000 FMA 23881 Anatomical terminology ( edit on Wikidata ) The human skeleton is the internal framework of the body. It is composed of around 270 bones at birth -- this total decreases to around 206 bones by adulthood after some bones get fused together. The bone mass in the skeleton reaches maximum density around age 21. The human skeleton can be divided into the axial skeleton and the appendicular skeleton. The axial skeleton is formed by the vertebral column, the rib cage, the skull and other associated bones. The appendicular skeleton, which is attached to the axial skeleton, is formed by the shoulder girdle, the pelvic girdle and the bones of the upper and lower limbs. The human skeleton performs six major functions ; support, movement, protection, production of blood cells, storage of minerals, and endocrine regulation. The human skeleton is not as sexually dimorphic as that of many other primate species, but subtle differences between sexes in the morphology of the skull, dentition, long bones, and pelvis exist. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within a given population. The human female pelvis is also different from that of males in order to facilitate childbirth. Unlike most primates, human males do not have penile bones. Contents 1 Skeletal divisions 1.1 Axial skeleton 1.2 Appendicular skeleton 2 Functions 2.1 Support 2.2 Movement 2.3 Protection 2.4 Blood cell production 2.5 Storage 2.6 Endocrine regulation 3 Gender differences 3.1 Skull 3.2 Dentition 3.3 Long bones 3.4 Pelvis 4 Clinical significance 4.1 Arthritis 4.2 Osteoporosis 5 History 5.1 The Renaissance 6 See also 7 References Skeletal divisions Axial skeleton Main article : Axial skeleton 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 ). The upright posture of humans is maintained by the axial skeleton, which transmits the weight from the head, the trunk, and the upper extremities down to the lower extremities at the hip joints. The bones of the spine are supported by many ligaments. The erector spinae muscles are also supporting and are useful for balance. Appendicular skeleton Main article : Appendicular skeleton The appendicular skeleton ( 126 bones ) is formed by the pectoral girdles, the upper limbs, the pelvic girdle or pelvis, and the lower limbs. Their functions are to make locomotion possible and to protect the major organs of digestion, excretion and reproduction. Functions A human skeleton on exhibit at the Museum of Osteology, Oklahoma City, Oklahoma The skeleton serves six major functions : support, movement, protection, production of blood cells, storage of minerals and endocrine regulation. Support The skeleton provides the framework which supports the body and maintains its shape. The pelvis, associated ligaments and muscles provide a floor for the pelvic structures. Without the rib cages, costal cartilages, and intercostal muscles, the lungs would collapse. Movement The joints between bones allow movement, some allowing a wider range of movement than others, e.g. the ball and socket joint allows a greater range of movement than the pivot joint at the neck. Movement is powered by skeletal muscles, which are attached to the skeleton at various sites on bones. Muscles, bones, and joints provide the principal mechanics for movement, all coordinated by the nervous system. It is believed that the reduction of human bone density in prehistoric times reduced the agility and dexterity of human movement. Shifting from hunting to agriculture has caused human bone density to reduce significantly. Protection The skeleton helps to protect our many vital internal organs from being damaged. The skull protects the brain The vertebrae protect the spinal cord. The rib cage, spine, and sternum protect the lungs, heart and major blood vessels. Blood cell. production The skeleton is the site of haematopoiesis, the development of blood cells that takes place in the bone marrow. In children, haematopoiesis occurs primarily in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum. Storage The bone matrix can store calcium and is involved in calcium metabolism, and bone marrow can store iron in ferritin and is involved in iron metabolism. However, bones are not entirely made of calcium, but a mixture of chondroitin sulfate and hydroxyapatite, the latter making up 70 % of a bone. Hydroxyapatite is in turn composed of 39.8 % of calcium, 41.4 % of oxygen, 18.5 % of phosphorus, and 0.2 % of hydrogen by mass. Chondroitin sulfate is a sugar made up primarily of oxygen and carbon. Endocrine regulation Bone cells release a hormone called osteocalcin, which contributes to the regulation of blood sugar ( glucose ) and fat deposition. Osteocalcin increases both the insulin secretion and sensitivity, in addition to boosting the number of insulin - producing cells and reducing stores of fat. Gender differences During construction of the York to Scarborough Railway Bridge in 1901, workmen discovered a large stone coffin, close to the River Ouse. Inside was a skeleton, accompanied by an array of unusual and expensive objects. This chance find represents one of the most significant discoveries ever made from Roman York. Study of the skeleton has revealed that it belonged to a woman. Anatomical differences between human males and females are highly pronounced in some soft tissue areas, but tend to be limited in the skeleton. The human skeleton is not as sexually dimorphic as that of many other primate species, but subtle differences between sexes in the morphology of the skull, dentition, long bones, and pelvis are exhibited across human populations. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within a given population. It is not known whether or to what extent those differences are genetic or environmental. Skull A variety of gross morphological traits of the human skull demonstrate sexual dimorphism, such as the median nuchal line, mastoid processes, supraorbital margin, supraorbital ridge, and the chin. Dentition Human inter-sex dental dimorphism centers on the canine teeth, but it is not nearly as pronounced as in the other great apes. Long bones Long bones are generally larger in males than in females within a given population. Muscle attachment sites on long bones are often more robust in males than in females, reflecting a difference in overall muscle mass and development between sexes. Sexual dimorphism in the long bones is commonly characterized by morphometric or gross morphological analyses. Pelvis The human pelvis exhibits greater sexual dimorphism than other bones, specifically in the size and shape of the pelvic cavity, ilia, greater sciatic notches, and the sub-pubic angle. The Phenice method is commonly used to determine the sex of an unidentified human skeleton by anthropologists with 96 % to 100 % accuracy in some populations. Women 's pelvises are wider in the pelvic inlet and are wider throughout the pelvis to allow for child birth. The sacrum in the women 's pelvis is curved inwards to allow the child to have a `` funnel '' to assist in the child 's pathway from the uterus to the birth canal. Clinical significance See also : Bone disease There are many classified skeletal disorders. One of the most common is osteoporosis. Also common is scoliosis, a side - to - side curve in the back or spine, often creating a pronounced `` C '' or `` S '' shape when viewed on an x-ray of the spine. This condition is most apparent during adolescence, and is most common with females. Arthritis Main article : Arthritis Arthritis is a disorder of the joints. It involves inflammation of one or more joints. When affected by arthritis, the joint or joints affected may be painful to move, may move in unusual directions or may be immobile completely. The symptoms of arthritis will vary differently between types of arthritis. The most common form of arthritis : Osteoarthritis can affect both the larger and smaller joints of the human skeleton. The cartilage in the affected joints will degrade, soften and wear away. This decreases the mobility of the joints and decreases the space between bones where cartilage should be. Osteoporosis Main article : Osteoporosis Osteoporosis is a disease of bone where there is reduced bone mineral density, increasing the likelihood of fractures. Osteoporosis is defined by the World Health Organization in women as a bone mineral density 2.5 standard deviations below peak bone mass, relative to the age and sex - matched average, as measured by Dual energy X-ray absorptiometry, with the term `` established osteoporosis '' including the presence of a fragility fracture. Osteoporosis is most common in women after menopause, when it is called `` postmenopausal osteoporosis '', but may develop in men and premenopausal women in the presence of particular hormonal disorders and other chronic diseases or as a result of smoking and medications, specifically glucocorticoids. Osteoporosis usually has no symptoms until a fracture occurs. For this reason, DEXA scans are often done in people with one or more risk factors, who have developed osteoporosis and be at risk of fracture. Osteoporosis treatment includes advice to stop smoking, decrease alcohol consumption, exercise regularly, and have a healthy diet. Calcium supplements may also be advised, as may Vitamin D. When medication is used, it may include bisphosphonates, Strontium ranelate, and osteoporosis may be one factor considered when commencing Hormone replacement therapy. History This section needs expansion. You can help by adding to it. ( November 2014 ) See also : Paleoanthropology The study of human bones probably started in ancient Greece under Ptolemaic kings due to their link to Egypt. Herophilos, through his work by studying dissected human corpses in Alexandria is credited to be the pioneer of the field. His works are lost but are often cited by notable persons in the field such as Galen and Rufus of Ephesus. Galen himself did little dissection though and relied on the work of others like Marinus of Alexandria, as well as his own observations of gladiator cadavers and animals. According to Katherine Park, in medieval Europe dissection continued to be practiced, contrary to the popular understanding that such practices are taboo and thus completely banned. The practice of holy autopsy, such as in the case of Clare of Montefalco further supports the claim. Alexandria continued as a center of anatomy under Islamic rule, with Ibn Zuhr a notable figure. Chinese understandings are divergent, as the closest corresponding concept in the medicinal system seem to be the meridians, although given that Hua Tuo regularly performs surgery, there must be some distance between medical theory and actual understanding. The Renaissance Leonardo Da Vinci, among his many talents also contributed to the study of the skeleton, albeit unpublished in his time. Many artists, Antonio Pollaiuolo being the first, performed dissections for better understanding of the body, although they concentrated mostly on the muscles. Vesalius, regarded as the founder of modern anatomy authored the book De humani corporis fabrica, which contained many illustrations of the skeleton and other body parts, correcting some theories dating from Galen, such as the lower jaw being a single bone instead of two. Various other figures like Alessandro Achillini also contributed to the further understanding of the skeleton. See also List of bones of the human skeleton Distraction osteogenesis References Library resources about Skeletal system Resources in your library Jump up ^ Mammal anatomy : an illustrated guide. New York : Marshall Cavendish. 2010. p. 129. ISBN 9780761478829. Jump up ^ Thieme Atlas of Anatomy, ( 2006 ), p 113 Jump up ^ Patterns of Sexual Behavior Clellan S. Ford and Frank A. Beach, published by Harper & Row, New York in 1951. ISBN 0 - 313 - 22355 - 6 Jump up ^ `` Switching Farming Made Human Bone Skeleton Joint Lighter ''. Smithsonian Magazine. 23 December 2014. Jump up ^ `` Light human skeleton may have come after agriculture ''. Retrieved 4 March 2017. Jump up ^ `` With the Advent of Agriculture, Human Bones Dramatically Weakened ''. 22 December 2014. Retrieved 4 March 2017. Jump up ^ Fernández, KS ; de Alarcón, PA ( Dec 2013 ). `` Development of the hematopoietic system and disorders of hematopoiesis that present during infancy and early childhood ''. Pediatric clinics of North America. 60 ( 6 ) : 1273 -- 89. doi : 10.1016 / j. pcl. 2013.08. 002. PMID 24237971. Jump up ^ Lee, Na Kyung ; Sowa, Hideaki ; Hinoi, Eiichi ; Ferron, Mathieu ; Ahn, Jong Deok ; Confavreux, Cyrille ; Dacquin, Romain ; Mee, Patrick J. ; McKee, Marc D. ; Jung, Dae Young ; Zhang, Zhiyou ; Kim, Jason K. ; Mauvais - Jarvis, Franck ; Ducy, Patricia ; Karsenty, Gerard ( 2007 ). `` Endocrine Regulation of Energy Metabolism by the Skeleton ''. Cell. 130 ( 3 ) : 456 -- 69. doi : 10.1016 / j. cell. 2007.05. 047. PMC 2013746. PMID 17693256. Jump up ^ Buikstra, J.E. ; D.H. Ubelaker ( 1994 ). Standards for data collection from human skeletal remains. Arkansas Archaeological Survey. p. 208. Jump up ^ Phenice, T.W. ( 1969 ). `` A newly developed visual method of sexing the os pubis ''. American Journal of Physical Anthropology. 30 ( 2 ) : 297 -- 301. doi : 10.1002 / ajpa. 1330300214. PMID 5772048. ^ Jump up to : Britton, the editors Nicki R. Colledge, Brian R. Walker, Stuart H. Ralston ; illustrated by Robert ( 2010 ). Davidson 's principles and practice of medicine ( 21st ed. ). Edinburgh : Churchill Livingstone / Elsevier. pp. 1116 -- 1121. ISBN 978 - 0 - 7020 - 3085 - 7. Jump up ^ WHO ( 1994 ). `` Assessment of fracture risk and its application to screening for postmenopausal osteoporosis. Report of a WHO Study Group ''. World Health Organization technical report series. 843 : 1 -- 129. PMID 7941614. Jump up ^ Rocca, Julius ( 9 August 2010 ). `` A Note on Marinus of Alexandria ''. Journal of the History of the Neurosciences. 11 ( 3 ) : 282 -- 285. doi : 10.1076 / jhin. 11.3. 282.10386. Jump up ^ Charlier, Philippe ; Huynh - Charlier, Isabelle ; Poupon, Joël ; Lancelot, Eloïse ; Campos, Paula F. ; Favier, Dominique ; Jeannel, Gaël - François ; Bonati, Maurizio Rippa ; Grandmaison, Geoffroy Lorin de la ; Herve, Christian ( 2014 ). `` Special report : Anatomical pathology A glimpse into the early origins of medieval anatomy through the oldest conserved human dissection ( Western Europe, 13th c. A.D. ) ''. Archives of Medical Science. 2 : 366 -- 373. doi : 10.5114 / aoms. 2013.33331. Jump up ^ `` Debunking a myth ''. Harvard Gazette. Retrieved 12 November 2016. Jump up ^ Hairston, Julia L. ; Stephens, Walter ( 2010 ). The body in early modern Italy. Baltimore : Johns Hopkins University Press. ISBN 9780801894145. Jump up ^ Sooke, Alastair. `` Leonardo da Vinci : Anatomy of an artist ''. Telegraph.co.uk. Retrieved 9 December 2016. Jump up ^ Bambach, Carmen. `` Anatomy in the Renaissance ''. The Met 's Heilbrunn Timeline of Art History. Jump up ^ `` Vesalius 's Renaissance anatomy lessons ''. www.bl.uk. Retrieved 18 December 2016. Bones in the human skeleton Axial skeleton Skull Neurocranium occipital parietal frontal temporal sphenoid ethmoid Face nasal maxilla lacrimal zygomatic palatine inferior nasal conchae vomer mandible hyoid Ear ossicles malleus incus stapes Thorax sternum rib cage rib Vertebral column vertebrae cervical thoracic lumbar sacrum coccyx Appendicular Shoulder clavicle scapula Arm humerus ulna radius Hand carpals ( scaphoid, lunate bone, triquetral, pisiform, trapezium, trapezoid, capitate, hamate ) metacarpals phalanges ( prox, int, dist ) Pelvis ilium ischium pubis Leg femur patella fibula tibia Foot tarsals heelbone anklebone navicular cuneiform cuboid metatarsals phalanges proximal intermediate distal accessory accessory navicular Human systems and organs Musculoskeletal Skeletal system Bone Carpus Collar bone ( clavicle ) Thigh bone ( femur ) Fibula Humerus Mandible Metacarpus Metatarsus Ossicles Patella Phalanges Radius Skull Tarsus Tibia Ulna Rib Vertebra Pelvis Sternum Cartilage Joints Fibrous joint Cartilaginous joint Synovial joint Muscular system Muscle Tendon Diaphragm Circulatory system Cardiovascular system peripheral Artery Vein Lymphatic vessel Heart Lymphatic system primary Bone marrow Thymus secondary Spleen Lymph node CNS equivalent Glymphatic system Nervous system Brain Spinal cord Nerve Sensory system Ear Eye Integumentary system Skin Subcutaneous tissue Breast Mammary gland Immune system Myeloid Myeloid immune system Lymphoid Lymphoid immune system Respiratory system Upper Nose Nasopharynx Larynx Lower Trachea Bronchus Lung Digestive system Mouth Salivary gland Tongue upper GI Oropharynx Laryngopharynx Esophagus Stomach lower GI Small intestine Appendix Colon Rectum Anus accessory Liver Biliary tract Pancreas Urinary system Genitourinary system Kidney Ureter Bladder Urethra Reproductive system Female Uterus Vagina Vulva Ovary Placenta Male Scrotum Penis Prostate Testicle Seminal vesicle Endocrine system Pituitary Pineal Thyroid Parathyroid Adrenal Islets of Langerhans Retrieved from `` https://en.wikipedia.org/w/index.php?title=Human_skeleton&oldid=834439276 '' Categories : Endocrine system Human anatomy Skeletal system Hidden categories : Pages with unresolved properties Wikipedia indefinitely semi-protected pages Articles to be expanded from November 2014 All articles to be expanded Articles using small message boxes Talk View source Contents About Wikipedia Afrikaans አማርኛ অসমীয়া Asturianu Azərbaycanca Bân - lâm - gú Български Bosanski Català Čeština Cymraeg ދިވެހިބަސް Ελληνικά Español Esperanto فارسی Français Gaeilge 한국어 Հայերեն हिन्दी Hrvatski Ido Bahasa Indonesia Interlingua Íslenska Italiano ಕನ್ನಡ Қазақша Кыргызча Latviešu Lingála Bahasa Melayu မြန်မာဘာသာ Nederlands नेपाल भाषा 日本 語 ភាសា ខ្មែរ Polski Português Română Runa Simi Русский Scots Shqip Sicilianu සිංහල Simple English Slovenčina Slovenščina Soomaaliga کوردی Srpskohrvatski / српскохрватски Suomi Svenska Tagalog தமிழ் ไทย Türkçe Українська اردو Vepsän kel ' Tiếng Việt Võro 中文 57 more Edit links This page was last edited on 5 April 2018, at 18 : 58. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: how many bones are in an infants body
Answer: 270