title: Neuroanatomical localization of the 'precentral knob' with computed tomography imaging.
abstract: OBJECTIVE
  The 'precentral knob', a cortical representation of the motor hand function, can be identified and localized consistently using magnetic resonance imaging (MRI) and functional MRI. We present a method of indirectly identifying and localizing the Omega-shaped precentral knob using the anatomical landmarks on computed tomography (CT).
  
  
  METHODS
  CT and MRI obtained within 24 h from 10 patients undergoing a headache workup and found to be negative for any anatomical abnormalities were studied. First, the precentral knob was identified in the CT images. Then, the 'coronal suture line' and 'midline' were identified and used to measure the distance to the precentral knob on both hemispheres. MRI was used to confirm the location of the precentral knob in the CT images based on anatomical landmarks (i.e. sulcal configurations).
  
  
  RESULTS
  The precentral knob is located 45.1 +/- 5.2 mm posterior with respect to the coronal suture line and 33.9 +/- 3.4 mm lateral to the midline on the right hemisphere, and 44.6 +/- 5.7 mm posterior and 33.2 +/- 2.5 mm lateral on the left hemisphere.
  
  
  CONCLUSIONS
  We present a method of consistently identifying and localizing the Omega-shaped precentral knob, a cortical representation of the motor hand function, using CT.
authors.affiliation: Department of Clinical Neurosciences Program in Neurosurgery, Brown Medical School, Rhode Island Hospital, Providence, RI 02903, USA. michael_park@brown.edu
authors.forename: Michael C
authors.initials: MC
authors.lastname: Park
authors.forename: Marc A
authors.initials: MA
authors.lastname: Goldman
authors.forename: Min J
authors.initials: MJ
authors.lastname: Park
authors.forename: Gerhard M
authors.initials: GM
authors.lastname: Friehs
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006225:Hand / Q000294:innervation / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000502:physiology; D009445:Neuroanatomy / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D014057:Tomography, X-Ray Computed