From the forefront of the chest up to the neck of the universal form of the Lord are situated the planetary systems named Janaloka and Tapoloka, whereas Satyaloka, the topmost planetary system, is situated on the head of the form. The spiritual planets, however, are eternal.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
ग्रीवायां जनलोकश्च तपोलोकः स्तनद्वयात् । मूर्धभिः सत्यलोकस्तु ब्रह्मलोकः सनातनः
grīvāyāṃ janalokaśca tapolokaḥ stanadvayāt | mūrdhabhiḥ satyalokastu brahmalokaḥ sanātanaḥ
SB 2.5.39