Vijñāna Bhairava Tantra 1.30

1.30

मध्यनाडी मध्यसंस्था बिससूत्राभरूपया । ध्यातान्तर्व्योमया देव्या तया देवः प्रकाशते ॥३०॥

madhyanāḍī madhyasaṃsthā bisasūtrābharūpayā | dhyātāntarvyomayā devyā tayā devaḥ prakāśate

anuṣṭubh

— the central channel (suṣumnā) ; — abiding in the middle ; — of a form like a lotus-fiber thread ; — (being) meditated upon ; — with the inner void ; — by the Goddess ; — by her ; — the God (Śiva) ; — shines forth

The central channel — established in the middle — meditated upon as the Goddess with the form of a lotus-fiber, having inner space as her body: through her, the God shines forth.