Brain of a Dog
Brain of dog, viewed from above and in profile. F, frontal fissure sometimes termed crucial sulcus, corresponding to the fissure of Rolando in man. S, fissure of Sylvius, around which the four longitudinal convolutions are concentrically arranged; 1, flexion of head on the neck, in the median line; 2, flexion of head on the anterior limb; 5, 6, flexion and extension of posterior limb; 7, 8, 9, contraction of orbicularis oculi, and the facial muscles in general. The unshaded part in that exposed by the opening of the skull.