The term anga is defined and used by grammarian Panini in his system of grammatical morphology. In the second century B.C., Patanjali commented on Panini's rules in his Mahabhasya, and the arguments and conclusions presented in the text constitute the basis of much of medieval grammatical literature. Benson here provides an examination of Patanjali's remarks, offering a useful introduction to Panini's system. Passages from the Mahabhasya and later grammatical treatises are provided in translation.