Corticospinal tract

Eloquence

• The internal capsule and brainstem, through which the tract passes, are classed as eloquent by Spetzler-Martin and Sawaya. (Spetzler and Martin 1986; Sawaya et al. 1998)

What it does

• Descends from motor and premotor cortex through the corona radiata, the posterior limb of the internal capsule, the cerebral peduncle and the pons to the medullary pyramids. (Catani and Thiebautdeschotten 2008; Schmahmann and Pandya 2006)

Arterial supply

• Along its course it is supplied by medullary and lenticulostriate branches of the middle cerebral artery in the corona radiata, by lenticulostriate and anterior choroidal branches in the posterior limb of the internal capsule, and by paramedian basilar branches in the brainstem. (Tatu et al. 1998; Tatu et al. 1996)

Deficits if injured

• Injury anywhere along the tract above the pyramidal decussation causes contralateral weakness. (Schmahmann and Pandya 2006; Catani and Thiebautdeschotten 2008)

Surgical relevance

• Tractography estimates of its course near tumours have been compared with subcortical stimulation mapping, which remains the intraoperative reference. (Berman et al. 2004; Keles et al. 2004)

On the template

HCP-1065 tracts. Values describe the fsaverage template, not an individual or a population norm.

Area: pial surface of the fsaverage average, which is smoother than individual cortex. Volume: voxel count of the fsaverage aseg segmentation at 1 mm isotropic.

References

1. Spetzler RF, Martin NA. A proposed grading system for arteriovenous malformations. Journal of Neurosurgery 1986;65(4):476-483. doi:10.3171/jns.1986.65.4.0476
2. Sawaya R, Hammoud M, Schoppa D, Hess KR, Wu SZ, Shi WM, et al.. Neurosurgical Outcomes in a Modern Series of 400 Craniotomies for Treatment of Parenchymal Tumors. Neurosurgery 1998;42(5):1044-1055. doi:10.1097/00006123-199805000-00054
3. Catani M, Thiebautdeschotten M. A diffusion tensor imaging tractography atlas for virtual in vivo dissections. Cortex 2008;44(8):1105-1132. doi:10.1016/j.cortex.2008.05.004
4. Schmahmann JD, Pandya DN. Fiber Pathways of the Brain. Oxford University Press 2006. doi:10.1093/acprof:oso/9780195104233.001.0001
5. Tatu L, Moulin T, Bogousslavsky J, Duvernoy H. Arterial territories of the human brain. Neurology 1998;50(6):1699-1708. doi:10.1212/WNL.50.6.1699
6. Tatu L, Moulin T, Bogousslavsky J, Duvernoy H. Arterial territories of human brain. Neurology 1996;47(5):1125-1135. doi:10.1212/WNL.47.5.1125
7. Berman JI, Berger MS, Mukherjee P, Henry RG. Diffusion-tensor imaging-guided tracking of fibers of the pyramidal tract combined with intraoperative cortical stimulation mapping in patients with gliomas. Journal of Neurosurgery 2004;101(1):66-72. doi:10.3171/jns.2004.101.1.0066
8. Keles GE, Lundin DA, Lamborn KR, Chang EF, Ojemann G, Berger MS. Intraoperative subcortical stimulation mapping for hemispheric perirolandic gliomas located within or adjacent to the descending motor pathways: evaluation of morbidity and assessment of functional outcome in 294 patients. Journal of Neurosurgery 2004;100(3):369-375. doi:10.3171/jns.2004.100.3.0369