The affix ṇamul comes after a verb when a word in the Accusative -2nd case is in composition, signifying the limbs of one's own body, when the limb is such that its loss will not destroy life.,
Thus ध्रुविक्षेपं कथयति 'he narrates, throwing his eye-brows (glances) about in all directions'. अक्षिनिकाणम् जल्पति 'he prattles, having closed the eyes'.
The स्वाङ्ग word is \a word denoting a thing which not being liquid or gaseous, and being capable of being perceived by the senses, and not being one produced by a change from the natural state, exists in a living being, or though found elsewhere actually or at any particular time, had previously been known as existing in only a living being, or is found to have actually, (not figuratively) the same relation to the being it is in, as a similar thing has to a living being.\
The word अध्रुव means 'non-vital organ', or a limb which even being cut off, does not necessarily destroy life. Therefore, we cannot use the affix णमुल् in the following, as head is not an अध्रुव limb:- उत्क्षिप्य शिरः कथयति 'he narrates, having thrown the head on one side'. Compare 6.2.177.,