bhāvasya madhyabhāgo yaḥ sa madhyaṁ parikīrtitaḥ | tatra grahaḥ phalaṁ dadyāt sandhigrahas tu nirphalaḥ ||
The middle portion of a house is called the madhya (cusp); a planet placed in the madhya yields its full fruit, while a planet at the bhava-sandhi (house junction) is fruitless.
Following Sripati's doctrine, the division of houses is declared: measured between the cusps of the ascendant and the seventh (with their midpoints), each house becomes unequal in extent.