Cervical rib Classification and external resources ICD-10 Q76.5 ICD-9 756.2 OMIM 117900 DiseasesDB 2317
A cervical rib is a supernumerary (or extra) rib which arises from the seventh cervical vertebra. It is a congenital abnormality located above the normal first rib. A cervical rib is present in only about 1 in 500 (0.2%) of people; in even rarer cases, an individual may have two cervical ribs. Cervical ribs are sometimes known as "neck ribs".
The presence of a cervical rib can cause a form of thoracic outlet syndrome due to compression of the lower trunk of the brachial plexus or subclavian artery. These structures are entrapped between the cervical rib and scalenus muscle.
Compression of the brachial plexus may be identified by weakness of the muscles around the muscles in the hand, near the base of the thumb. Compression of the subclavian artery is often diagnosed by finding a positive Adson's sign on examination, where the radial pulse in the arm is lost during abduction and external rotation of the shoulder.
It is under scientific debate to what degree children born with cervical ribs develop early childhood cancer at a higher rate than the general population . The Hox genes that control the development of cervical vertebrae are believed to play a role in suppressing cancer.
In other vertebrates
Many vertebrates, especially reptiles, have cervical ribs as a normal part of their anatomy rather than a pathological condition. Some sauropods had exceptionally long cervical ribs; those of Mamenchisaurus hochuanensis were nearly 4 meters long.
In birds, the cervical ribs are small and completely fused to the vertebrae.
In mammals the ventral parts of the transverse processes of the cervical vertebrae are the fused-on cervical ribs.
- ^ Galis F (1999). "Why do almost all mammals have seven cervical vertebrae? Developmental constraints, Hox genes, and cancer". J. Exp. Zool. 285 (1): 19–26. doi:10.1002/(SICI)1097-010X(19990415)285:1<19::AID-JEZ3>3.0.CO;2-Z. PMID 10327647. http://www3.interscience.wiley.com/journal/60502054/abstract.
- ^ Selim, Jocelyn. "Useless Body Parts". http://discovermagazine.com/2004/jun/useless-body-parts.
- ^ Myers, PZ. "Debate on Vertebral variation, Hox genes, development, and cancer". http://scienceblogs.com/pharyngula/2006/01/vertebral_variation_hox_genes.php#comment-1157189. Retrieved 2008-04-16.
- ^ a b Myers, PZ. "Vertebral variation, Hox genes, development, and cancer". http://scienceblogs.com/pharyngula/2006/01/vertebral_variation_hox_genes.php. Retrieved 2008-04-16.
Congenital malformations and deformations of musculoskeletal system / musculoskeletal abnormality (Q65–Q76, 754–756.3) Appendicular
limb / dysmeliahand deformity:Lowerhip:knee:foot deformity:Either / bothdactyly / digit:reduction deficits / limb:multiple joints:
AxialCraniofacial dysostosis:other:Thoracic skeletonribs:Cervical · Bifidsternum:
anat(h/c, u, t, l)/phys
noco(arth/defr/back/soft)/cong, sysi/epon, injr
proc, drug(M01C, M4)
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Cervical rib — A supernumerary (extra) rib which arises from the seventh cervical vertebra. It is located above the normal first rib. A cervical rib is present in only about 1 in 200 (0.5%) of people. It may cause nerve and artery problems. There are normally… … Medical dictionary
cervical rib — noun : a supernumerary rib sometimes found in the neck above the usual first rib … Useful english dictionary
cervical rib syndrome — a thoracic outlet syndrome caused by a cervical rib … Medical dictionary
Rib, cervical — A extra rib which arises from the seventh cervical vertebra. It is located above the normal first rib. A cervical rib is present in only about 1 in 200 (0.5%) of people. It may cause nerve and artery problems. There are normally 12 pairs of ribs… … Medical dictionary
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