Irregular bone

Irregular bone
Sphenoid bone, one of the most complex bones of the human body, is classified as irregular bone.
Irregular bones in human skeleton. (shown in red).
Details
Identifiers
Latin	os irregulare
Dorlands /Elsevier	o_07/12598430
TA	A02.0.00.014
FMA	7477
Anatomical terms of bone [edit on Wikidata]

The irregular bones are bones which, from their peculiar form, cannot be grouped as long bone, short bone, flat bone or sesamoid bone. Irregular bones serve various purposes in the body, such as protection of nervous tissue (such as the vertebrae protect the spinal cord), affording multiple anchor points for skeletal muscle attachment (as with the sacrum), and maintaining pharynx and trachea support, and tongue attachment (such as the hyoid bone). They consist of cancellous tissue enclosed within a thin layer of compact bone. Irregular bones can also be used for joining all parts of the spinal column together. The spine is the place in the human body where the most irregular bones can be found. There are, in all, 33 irregular bones found here.

The irregular bones are: the vertebræ, sacrum, coccyx, temporal, sphenoid, ethmoid, zygomatic, maxilla, mandible, palatine, inferior nasal concha, and hyoid.

Additional images

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  Irregular bones in human skeleton. (shown in red).

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  Irregular bones in human skull. (shown in red)

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  Classification of bones by shape.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

• Stedman's Online Medical Dictionary, 27th Edition