Editing Bone (section)

==Types==
[[File:603 Anatomy of Long Bone.jpg|thumb|left|220px|Structure of a long bone]]
[[File:Blausen 0229 ClassificationofBones.png|300px|right|One way to classify bones is by their shape or appearance.]]

Five types of bones are found in the human body: long, short, flat, irregular, and sesamoid.<ref>{{cite web|title=Types of bone|url=http://www.mananatomy.com/basic-anatomy/types-bone|access-date=6 February 2016|publisher=mananatomy.com}}</ref>
* [[File:Skeletal system.svg|thumb|Skeletal System of Human Body]][[Long bone]]s are characterized by a shaft, the [[diaphysis]], that is much longer than its width; and by an [[epiphysis]], a rounded head at each end of the shaft. They are made up mostly of [[Cortical bone|compact bone]], with lesser amounts of [[Bone marrow|marrow]], located within the [[medullary cavity]], and areas of spongy, cancellous bone at the ends of the bones.<ref name="TLP">{{cite web|title=DoITPoMS – TLP Library Structure of bone and implant materials – Structure and composition of bone|url=https://www.doitpoms.ac.uk/tlplib/bones/structure.php| work = Dissemination of IT for the Promotion of Materials Science (DoITPoMS) | publisher = University of Cambridge | location = Cambridge, UK }}</ref> Most bones of the [[Limb (anatomy)|limbs]], including those of the [[metacarpus|fingers]] and [[metatarsus|toes]], are long bones. The exceptions are the eight [[carpal bones]] of the [[wrist]], the seven articulating [[tarsal bone]]s of the [[tarsus (skeleton)|ankle]] and the sesamoid bone of the [[kneecap]]. Long bones such as the clavicle, that have a differently shaped shaft or ends are also called ''modified long bones''.
* [[Short bone]]s are roughly [[cube]]-shaped, and have only a thin layer of compact bone surrounding a spongy interior. Short bones provide stability and support as well as some limited motion.<ref name="Openstax Anatomy & Physiology attribution">{{CC-notice|cc=by4|url=https://openstax.org/books/anatomy-and-physiology/pages/6-2-bone-classification}} {{cite book| vauthors = Betts JG, Desaix P, Johnson E, Johnson JE, Korol O, Kruse D, Poe B, Wise J, Womble MD, Young KA |title=Anatomy & Physiology|location=Houston|publisher=OpenStax CNX|isbn=978-1-947172-04-3|date=June 8, 2023|at=6.2 Bone classification}}</ref> The bones of the wrist and ankle are short bones.
* [[Flat bone]]s are thin and generally curved, with two parallel layers of compact bone sandwiching a layer of spongy bone. Most of the bones of the [[skull]] are flat bones, as is the [[sternum]].<ref>{{Citation |title=Normal Bone Anatomy and Physiology | vauthors = Clarke B | journal=Clinical Journal of the American Society of Nephrology | year=2008 | volume=3 | issue=Suppl 3 | pages=S131–S139 | doi=10.2215/CJN.04151206 | pmid=18988698 | pmc=3152283 }}</ref>
* [[Sesamoid bone]]s are bones embedded in tendons. Since they act to hold the tendon further away from the joint, the angle of the tendon is increased and thus the leverage of the muscle is increased. Examples of sesamoid bones are the [[patella]] and the [[pisiform]].<ref>{{Citation |title=Occurrence and distribution of sesamoid bones in squamates: a comparative approach | vauthors = Jerez A, Mangione S, Abdala V | journal=Acta Zoologica | year=2010 | volume=91 | issue=3 | pages=295–305 | doi=10.1111/j.1463-6395.2009.00408.x | hdl=11336/74304 | hdl-access=free }}</ref>
* [[Irregular bone]]s do not fit into the above categories. They consist of thin layers of compact bone surrounding a spongy interior. As implied by the name, their shapes are irregular and complicated. Often this irregular shape is due to their many centers of ossification or because they contain bony sinuses. The bones of the [[Vertebral column|spine]], [[pelvis]], and some bones of the skull are irregular bones. Examples include the [[ethmoid]] and [[sphenoid bone|sphenoid]] bones.<ref>{{cite web| vauthors = Pratt R |title=Bone as an Organ |url= https://www.zoylo.com/diagnostics/organs/bones|archive-url=https://web.archive.org/web/20191030122832/https://www.zoylo.com/diagnostics/organs/bones|archive-date=2019-10-30|work=AnatomyOne|publisher=Amirsys, Inc.|access-date=2012-09-28}}</ref>