Editing Long bone

{{short description|Bone that is longer than it is wide}}
{{Infobox bone
| Name        = Long bone
| Latin       = os longum
| Image       = 603 Anatomy of Long Bone.jpg
| Caption     = Structure of a long bone (femur)
| Image2      = Long bones - anterior view - with legend.png
| Caption2    = Long bones in [[human skeleton]] (shown in red)
}}
The '''long bones''' are those that are longer than they are wide. They are one of five types of [[bone]]s: long, [[Short bone|short]], [[Flat bone|flat]], [[Irregular bone|irregular]] and [[Sesamoid bone|sesamoid]]. Long bones, especially the [[femur]] and [[tibia]], are subjected to most of the load during daily activities and they are crucial for skeletal mobility. They grow primarily by elongation of the [[diaphysis]], with an [[epiphysis]] at each end of the growing bone. The ends of epiphyses are covered with [[hyaline cartilage]] ("articular cartilage").  The longitudinal growth of long bones is a result of [[endochondral ossification]] at the [[epiphyseal plate]]. Bone growth in length is stimulated by the production of [[growth hormone]] (GH), a secretion of the [[Anterior pituitary|anterior lobe of the pituitary gland]].

The long bone category includes the femora, tibiae, and [[fibula]]e of the legs; the [[humerus|humeri]], [[Radius (bone)|radii]], and [[ulna]]e of the arms; [[metacarpals]] and [[metatarsals]] of the hands and feet, the [[Phalanx bones|phalanges]] of the fingers and toes, and the [[clavicle]]s or collar bones. The long bones of the human leg comprise nearly half of adult height. The other primary skeletal component of height are the [[vertebrae]] and [[human skull|skull]].

The outside of the bone consists of a layer of connective tissue called the [[periosteum]].  Additionally, the outer shell of the long bone is [[compact bone]], then a deeper layer of [[cancellous bone]] (spongy bone) which contains in the [[medullary cavity]]  the [[bone marrow]].

==Structure==
The outer shell of the long bone is made of [[cortical bone]] also known as compact bone.<ref name="Nelms">{{Cite book|last1=Nelms|first1=Marcia|last2=Sucher|first2=Kathryn P.|title=Nutrition Therapy and Pathophysiology|date=2019|publisher=Cengage Learning|isbn=9780357390597|page=731|url=https://books.google.com/books?id=uhEYEAAAQBAJ&pg=PT764}}</ref> This is covered by a membrane of [[connective tissue]] called the [[periosteum]]. Beneath the cortical bone layer is a layer of spongy [[cancellous bone]]. Inside this is the [[medullary cavity]] which has an inner core of bone marrow, it contains nutrients and help in formation of cells, made up of yellow marrow in the adult and red marrow in the child.

<gallery>
File:Long bones - animation.gif|Long bones in human skeleton (shown in red)
File:Structure of a Long Bone.png|Parts of a long bone (Femur)
File:Blausen 0229 ClassificationofBones.png|Classification of bones by shape
File:Blausen 0401 Femur DistributionofForces.png|Distribution of forces on a long bone (Femur)
File:Os longum 1.png|Part of a long bone of a large [[ungulate]]
</gallery>

==Clinical significance==
There are two [[congenital disorder]]s of the long bones. In a disorder known as ''rachitis fetalis anularis'' the ends of the long bones (epiphyses) are enlarged.<ref name="Dorland's">{{cite book|last1=al.]|first1=consultants Daniel Albert ... [et|title=Dorland's illustrated medical dictionary.|date=2012|publisher=Saunders/Elsevier|location=Philadelphia, PA|isbn=978-1-4160-6257-8|page=1570|edition=32nd}}</ref> Another disorder, ''rachitis fetalis micromelica'', is a deficiency in the growth (as a shortness) of the bones.<ref name="Dorland's"/>

There is a surgical procedure called [[distraction osteogenesis]] which is used to lengthen long bones.<ref name="Mucci">{{Cite book|last1=Mucci|first1=Grace A.|last2=Torno|first2=Lilibeth R.|title=Handbook of Long Term Care of The Childhood Cancer Survivor|date=2015|publisher=Springer|isbn=9781489975843|page=163|url=https://books.google.com/books?id=SLA0CgAAQBAJ&pg=PA163}}</ref>

==References==
{{Reflist}}

==External links==
{{Commons category|Long bones}}{{Bone and cartilage}}
{{Authority control}}

[[Category:Long bones| ]]