The Mukhya Upaniṣads

Māṇḍūkya · Om and the Four Quarters of the Self

Mantra 3

जागरितस्थानो बहिःप्रज्ञः सप्ताङ्ग एकोनविंशतिमुखः स्थूलभुग्वैश्वानरः प्रथमः पादः ॥ ३ ॥

In plain words

The first quarter is Vaiśvānara: its field is waking, its awareness is outward, it has seven limbs and nineteen mouths, and it experiences gross objects.