Natyashastra
आकुञ्चितं समं चैव प्रसारितविवर्तने । उद्वाहितं नतं चैव शयने कर्म कीर्त्यते ॥ २२८॥
A posture that is either contracted or straight, extended or bent, raised or lowered, is to be observed while lying down.
english translation
AkuJcitaM samaM caiva prasAritavivartane । udvAhitaM nataM caiva zayane karma kIrtyate ॥ 228॥
hk transliteration by Sanscript