THE INDIVIDUAL ARTERIES AND B nANCHES. —Lenticulo-striate Artery (One of the Preperf orating from First Part of Sylvian).—Partial softening in shape of a wedge with its tip in the in terior part of the lenticular nucleus, while its base is directed forward and takes in the anterior two-thirds of the striate body. The wedge is formed of the anterior part of caudate, the internal capsule, and the third segment of the lenticular nucleus. Motor paralysis of the opposite side.
Lentieulo-o ptie Artery (also front S yl v ian). — Softening of post-external part of lenticular nucleus, of part of internal capsule, of anterior part of thalamus, and of tail of caudate.
Perforating Arteries from Choroid Plexus.—Partial softening of thalamus, size of a pea to a filbert.
Post-external Optic Artery.— Walnut sized softening in the subposterior part of thalamus and in the peduncle.
Precerebral plus Sylvian Artery. Block at bifurcation of internal carotid, extending in the precerebral beyond the precommunicans. Softening of frontal, parietal, and sphenoidal lobes, the stri ate body, etc.: i.e., of the whole territory supplied by both the precerebral and medicerebral arteries. Here we may have opposite hemiplegia; and, if on the side of the speech-centres, "total aphasia, together with an altogether unusual amount of mental degradation, in addi tion to blindness and loss of smell on the side of the lesion. The extramental degradation would be due to the fact of the cutting off of the blood-supply from the callosum, seeing that this is mainly supplied from the precerebral." Precerebral Artery Alone.—Softening of the frontal convolutions and of the inner surface of the hemisphere as far as the calloso-marginal fissure.
[In Freitcl aad Baumgartner's ease Archiv, 'SS) obstruction at the beginning of the precercbral, by cuti lug off fine branches to the region of the chiasm, produced partial femoral fiemianopsia on that side and palsies of ere-muscles. WILLIAM BROWNING.]
Branches of the Precerebral.-1. Sub frontal Branches. — Softening of orbital convolutions. No distinguishing symp toms.
2. Interior Prefrontal Branches.—Soft ening of first and of much of second frontal convolutions. Likewise part of so-called "silent" regions of brain.
3. Posterior Branches — Softening of remaining median surface of hemisphere supplier] by precerebral artery. Crural monoplegia.
(A) Medicereb•al Artery (in its first two centimetres, from which part are given off the preperforatings above men tioned). — Softening of whole territory of Sylvian artery (same parts as in B), also motor segment of internal capsule, corpus striatum (thus including lenticu lar and caudate nuclei), and anterior third of thalamus. The symptomatology is also practically same as in B, except— if possible—more pronounced and with deeper mental impairment.
(B) Sylvian Artery, Beyond the Perfo ratings, or all its Branches.—Total soft ening of cortical territory of Sylvian (v. infra: branches). Blocking here causes complete hemiplegia of opposite side (with exception of the trunk and other bilaterally acting muscles) and "total aphasia" if on the side of the speech centres; "that is, in addition to aphasia proper there would also be agraphia, as well as complete word-deafness and word-blindness, carrying with them that amount of mental degradation which is inseparable from a blotting out of all the word-centres in the leading hemisphere." Cortical Branches of Sylvian Artery.— The clinical results here vary some ac cording to the slight variation in differ ent individuals in the extent of cortex supplied by this vessel, but even more upon the differences in the freedom of the anastomoses existing between its branches (cortical) and those of the pre cerebral and post-cerebral.
1. Subfrontal Branch. — Softening of part of insula and of the subfrontal (Broca's) convolution. Aphasia if on the left side, without other paralytic compli cations.