The Lateral Ventricles

The lateral ventricles sometimes become distended by serous or purulent effusions or, as in apoplexy, by blood. In order to tap them Keen ("Reference Handbook of the Medical Sciences," vol. viii., p. 229) has given three points, as follows: (1) One-half to three-fourths of an inch (1.25 to 2 cm.) on either side of the median line and one-third of the distance from the glabella to the upper end of the central (Rolandic) fissure. This is high enough to avoid the frontal air-sinuses and is in advance of the motor area. A grooved director is to be thrust in the direction of the inion. The ventricle is reached at a depth of 5 to 6.5 cm. (2 to 2 1/2. in.) through the first frontal convolution. (2) Midway between the inion and upper end of the central (Rolandic) fissure 1.25 to 2 cm. (1/2 to 3/4 in.) from the median line. The director is to be thrust toward the inner end of the supra-orbital ridge of the same side. The ventricle will be reached at a depth of 5.5 to 7 cm. (2% to 2 3/4 in.) from the surface. (3) Three centimetres (1 1/4 in.) behind the external auditory meatus and the same above Reid's base line (from the lower border of the orbit through the centre of the external auditory meatus). The director is to be thrust toward a point 6.25 to 7.5 cm. (2 /2 to 3 in.) directly above the opposite external meatus. The ventricle will be reached 5 to 5.75 cm. (2 to 2% in.) from the surface. The director passes through the second temporal convolution; this is the preferred method.

Fig. 53.   Tapping the lateral ventricles and trephining for cerebral abscess. Semidiagrammatic view of head, showing relation of Rolandic and Sylvian fissures and lines.

Fig. 53. - Tapping the lateral ventricles and trephining for cerebral abscess. Semidiagrammatic view of head, showing relation of Rolandic and Sylvian fissures and lines.

Spitzka (New York Med. Jour., Feb. 2, 1901, p. 177) has pointed out how these ventricles vary in shape, and has given the surface relations in two brains. T. T. Wilson {Jour. Anat. and Phys., vol. xxviii, 1894, pp. 228-235) has described and figured them in three drawings. Spitzka states that the ventricles will hold about 60 c.c. of liquid.

Cerebral Abscess

About one-half of the abscesses of the brain occur from disease of the middle ear, and they are located in the temporosphenoidal lobe, in the cerebellum, or between the dura and petrous portion of the temporal bone. The remainder are caused either by blows or infection carried to the part in infectious diseases. They may, therefore, occur anywhere in the brain.

When the motor areas around the fissure of Rolando are involved, the location of the trouble will be shown by spasm or paralysis of the corresponding muscles. If the occipital lobe is affected there may be disturbance of sight, as hemiopia. Involvement of the frontal lobes produces mental dulness, and if of the third left frontal gyrus, or Broca's convolution there may be impairment of speech. Disease of the middle lobe of the cerebellum may be accompanied by a staggering gait. In many cases localization symptoms are rare, particularly when the abscess is small and located in the temporosphenoidal, parietal, or frontal lobes (see chapter on cerebral localization).