Srimad-Bhagavatam: Canto 4 - Chapter 1 - Verse 46

Sanskrit:

पञ्च द्वारस्तु पौरस्त्या दक्षिणैका तथोत्तरा ।पश्चिमे द्वे अमूषां ते नामानि नृप वर्णये ॥ ४६ ॥

ITRANS:

pañca dvāras tu paurastyādakṣiṇaikā tathottarāpaścime dve amūṣāṁ tenāmāni nṛpa varṇaye

Translation:

My dear King, of the nine doors, five led toward the eastern side, one led toward the northern side, one led toward the southern side, and two led toward the western side. I shall try to give the names of these different doors.

Purport:

Of the seven doors on the surface — namely the two eyes, two ears, two nostrils and one mouth — five look forward, and these are described as the doors facing the eastern side. Since looking forward means seeing the sun, these are described as the eastern gates, for the sun rises in the east. The gate on the northern side and the gate on the southern side represent the two ears, and the two gates facing the western side represent the rectum and the genitals. All the doors and gates are described below.