2.**Cavity of the third ventricle in this space, we must identify:**



**Table 2.**

*Anatomical lesions and their clinical correlation.*

c. Infundibular recess.

This space presents many anomalies or variants, as can be seen in the following figure, where a band was found that traversed the premammillary membrane transversely. The ostomy of the floor of the third ventricle is recommended to be performed at an intermediate point between the mammillary bodies and the infundibular recess, where in this case it is marked by this transverse band (**Figures 4**–**6**).

**Figure 4.** *Cavity and floor of the 3rd ventricle.*

**Figure 5.** *3rd ventricle floor.*
