Srimad-Bhagavatam: Canto 4 - Chapter 1 - Verse 9

Sanskrit:

अक्षिणी नासिके आस्यमिति पञ्चपुर: कृता: ।दक्षिणा दक्षिण: कर्ण उत्तरा चोत्तर: स्मृत: ।पश्चिमे इत्यधोद्वारौ गुदं शिश्नमिहोच्यते ॥ ९ ॥

ITRANS:

akṣiṇī nāsike āsyamiti pañca puraḥ kṛtāḥdakṣiṇā dakṣiṇaḥ karṇauttarā cottaraḥ smṛtaḥpaścime ity adho dvāraugudaṁ śiśnam ihocyate

Translation:

Two eyes, two nostrils and a mouth — all together five — are situated in the front. The right ear is accepted as the southern gate, and the left ear is the northern gate. The two holes, or gates, situated in the west are known as the rectum and genital organ.

Purport:

Of all sides, the eastern is considered most important, primarily because the sun rises from that direction. The gates on the eastern side — the eyes, nose and mouth — are thus very important gates in the body.