Irregular bone
From Wikipedia, the free encyclopedia
| Irregular bone | |
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| Latin | os irregulare |
| Gray's | subject #17 80 |
The irregular bones are such as, from their peculiar form, cannot be grouped as long bone, short bone, flat bone or sesamoid bone. Irregular bones serve some unique purpose in the body of combining: (1) protection of nervous tissue (such as the vertebrae protect the spinal cord), (2) 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.
The irregular bones are: the vertebræ, sacrum, coccyx, temporal, sphenoid, ethmoid, zygomatic, maxilla, mandible, palatine, inferior nasal concha, and hyoid.
There are five general classifications of bones: (1) Long bones, (2) Short bones, (3) Flat bones, (4) Irregular bones, and (5) Sesamoid bones.
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
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| Cartilage | perichondrium, fibrocartilage callus, metaphysis
cells (chondroblast, chondrocyte) types (hyaline, elastic, fibrous) |
| Bone | ossification (intramembranous, endochondral, epiphyseal plate)
cycle (osteoblast, osteoid, osteocyte, osteoclast) types (cancellous, cortical) regions (epiphysis, metaphysis, diaphysis) structure (osteon/Haversian system, Haversian canals, endosteum, periosteum, Sharpey's fibres, enthesis, lacunae, canaliculi, trabeculae, medullary cavity, bone marrow) shapes (long, short, flat, irregular, sesamoid) |