PROFILPELAJAR.COM

Omega sign

The omega sign, also called the hand knob, is the appearance on axial magnetic resonance imaging of the brain of a knob-shaped part of the precentral gyrus that bulges backward into the central sulcus and resembles the Greek letter omega (Ω).[1] The structure marks the motor area for the hand within the primary motor cortex, and it is used as a landmark to identify the precentral gyrus and the central sulcus on imaging.[1]

On axial images the central sulcus has an S-shaped course with three bends, or genua: superior, middle and inferior. The middle genu is the deepest and is concave toward the front, and the knob of cortex lying in front of it produces the omega shape.[2] The same knob looks like the letter epsilon (ε) in some people and like a hook on sagittal images.[1] It corresponds to the "middle knee" of the central sulcus described by anatomists in the 19th century.[1]

The omega sign is present in both cerebral hemispheres at roughly the same level, and the side opposite a lesion (the contralateral omega) can be used to work out where a lesion sits in relation to the central sulcus.[2][3] The landmark was described by Tarek Yousry and colleagues in 1997 using functional magnetic resonance imaging, which showed that hand movement activated this part of the precentral gyrus.[1]

References

  1. ^ a b c d e Yousry, T. A.; Schmid, U. D.; Alkadhi, H.; Schmidt, D.; Peraud, A.; Buettner, A.; Winkler, P. (1997). "Localization of the motor hand area to a knob on the precentral gyrus. A new landmark". Brain. 120 (1): 141–157. doi:10.1093/brain/120.1.141. PMID 9055804.
  2. ^ a b Kizilca, Ö.; Öztek, A.; Kesimal, U.; Şenol, U. (2017). "Signs in neuroradiology: a pictorial review". Korean Journal of Radiology. 18 (6): 992–1004. doi:10.3348/kjr.2017.18.6.992. PMC 5639165. PMID 29089832.
  3. ^ Campero, A.; Ajler, P.; Martins, C.; Emmerich, J.; de Alencastro, L. F.; Rhoton, A. (2011). "Usefulness of the contralateral omega sign for the topographic location of lesions in and around the central sulcus". Surgical Neurology International. 2: 164. doi:10.4103/2152-7806.89892. PMC 3228394. PMID 22140649.
Stub icon

This neuroscience article is a stub. You can help Wikipedia by adding missing information.

Content Disclaimer

Informasi ini disarikan dari Wikipedia dan disajikan kembali untuk tujuan edukasi. Konten tersedia di bawah lisensi CC BY-SA 3.0. Kami tidak bertanggung jawab atas ketidakakuratan data yang bersumber dari kontribusi publik tersebut.

  1. The information displayed on this website is sourced in part or in whole from Wikipedia and has been adapted for the purpose of restating it. We strive to provide accurate and relevant information, however:
  2. There is no guarantee of absolute accuracy. Wikipedia is an open, collaborative project that can be edited by anyone, so information is subject to change.
  3. It is not intended to constitute professional advice. The content displayed is for informational and educational purposes only. For important decisions (e.g., medical, legal, or financial), please consult a professional.
  4. Content copyright. Wikipedia is licensed under the Creative Commons Attribution-ShareAlike License (CC BY-SA). This means that content may be reused with appropriate attribution and shared under a similar license.
  5. Responsible use. Any risk arising from the use of information from this website is entirely the responsibility of the user.