**3.2 Important landmarks**

Recognition of critical landmarks and structures in the ventricles is very important to achieve a successful ETV. **Figure 5** is showing the instruments required for ETV and an endoscopic view showing some important landmarks. In **Table 2**, we discuss few important landmarks with which the surgeons need to be familiar to accomplish the procedure safely.

The supraoptic and paraventricular arcuate nuclei are the structures most prone to injury, which may give rise to endocrine disturbances [20].

To increase the success of the ETV endoscope needs to be progressed and Lilliequest membrane needs fenestration. Basilar artery will be seen during this stage (**Figure 7**).

#### **Figure 5.**

*In the middle, ETV endoscope with side channel with working instrument (forceps for fenestration). In the upper circle, end of the ETV endoscopes. In lower circle, the endoscopic view before entering into the foramen of Monro.*


**Table 2.** *Landmarks for ETV [20].*

**Figure 6.** *Endoscopic view of the floor of the third ventricle before fenestration of the floor of the ventricle.*

**Figure 7.** *Endoscopic view of basilar artery following fenestration of the floor of the third ventricle and Liliequist membrane.*
