Cheiro‐oral topography of sensory disturbances due to lesions of thalamocortical projections

Abstract

Sensory disturbance in the unilateral hand and ipsilateral mouth region, the cheiro-oral syndrome, may be due to cortical, thalamic, or brainstem lesions. We report five patients with this syndrome due to infarction at the border of the posterior limb of the internal capsule and the corona radiata. The sensory fibers from the mouth area and hand probably travel to the cortical sensory areas in close proximity after leaving the posterior ventral thalamic nucleus.

Restricted acral sensory syndrome following minor stroke. Further observation with special reference to differential severity of symptoms among individual digits.

“…25 - 37 Corona radiata strokes causing COS have been reported by previous authors 2325 who believed that sensory fibers from perioral and hand areas may also run in close proximity in this area. Our 2 patients with striatocapsular infarcts and 1 with corona radiata lesion presented with CPS, and 1 patient with corona radiata lesion showed COPS, illustrating that COS is not the only pattern of RASS caused by lesions involving this area.…”

Somatotopic Organization of Thalamocortical Projection Fibers as Assessed with MR Tractography

“…The sensory homunculus at the level of the thalamus lies such that the head part of the homunculus is medial (at the ventroposteromedial nucleus) and the lower extremity part of the homunculus is lateral (within the ventroposterolateral nucleus). The thalamocortical projection starts from this head-medial homunculus, courses through the posterior quarter of the internal capsule (4)(5)(6), and ends at the cortex in a headlateral position.…”

“…The course of the corticospinal tract through the centrum semiovale has been demonstrated; however, to our knowledge, the course of the thalamocortical projection through the centrum semiovale has not been fully documented in an experimental or clinical study (4,(6)(7)(8). In certain textbooks, the trajectory of the thalamocortical projection is shown as being completely parallel to that of the pyramidal tract (2).…”

Assessment of the corona radiata sensory tract using awake surgery and tractography

“…17 Tractography has also been used to characterize the thalamocortical projections of sensory tracts in the living human brain. 4,5 In our study, damage to the sensory tract, located at the corona radiata and detected by tractography, resulted in deficits to deep sensation in patients 1 and 2 with additional superficial sensation deficit in patient 2, both during and after awake surgery.…”