FUNCTIONS OF THE INTERNAL CAPSULE 569 



the larynx, thorax and abdomen, those associated with symmetrical move- 

 nents escape paralysis for the reason that in all such movements each side of 

 the brain controls the muscles of both sides of the body. If the extravasation 

 of blood also destroys the fibers of the posterior, one-third of the internal 

 capsule hi the region between the optic thalamus and the lenticular nucleus, 

 there will be a destruction of the afferent or sensor fibers and a separation of 

 the cutaneous areas from the cortical sensor areas and, therefore, a loss of 

 sensation on the opposite side of the body. If the extravasation is confined 

 to the external limits of the posterior one-third of the capsule, there would be 

 a loss of sensation without impairment of motion, a rare condition however. 

 In these hemorrhages the optic and auditory tracts are seldom involved. 

 Coincident with the rupture of these vessels there is a loss of consciousness 

 as a rule, and the patient falls as if struck and hence this condition received 

 the name of apoplexy. With the recovery of consciousness the paralysis of 

 motion becomes apparent and is usually permanent. Not infrequently, how- 

 ever, partial recovery of motion and sensation takes place after the blood 

 coagulates and the serum is absorbed, thus relieving pressure on adjoining 

 nerve-tracts which were not otherwise injured. 



