ṛjudravyasya kuṭilatvaheturākuñcanam, yathoktam ṛjuno bāhvādidravyasya ye 'grāvayavā aṅgulyādayas teṣāṃ svasaṃyogibhir ākāśādair vibhāge sati mūlapradeśaiścāṃśādibhiḥ saṃyoge sati yena karmaṇāvayavī bāhvādilakṣaṇaḥ kuṭilaḥ samutpadyate tadākuñcanam iti /
Contraction is the cause of curvature in a straight object, as has been described thus: When the front parts like fingers of a straight object like an arm become disjoined from their associated spaces while remaining in conjunction with their base parts, that action by which the whole object characterized as the arm becomes curved is called contraction.