The affix kap does not come after the words nāḍī and tantrī final in a bahuvrīhi samāsa when they mean organs of the body.,
Thus बह्व्योः नाड्योऽस्य = बहुनाडिः कायः, बहुतन्त्रीर्ग्रीवा ॥ The word तन्त्री means 'artery'. Why do we say meaning \parts of body\? Observe, बहुनाडीकः स्तम्भः, बहुतन्त्रीका वीणा ॥ The word नाडी is a feminine word formed by ङीप् that comes after jati; तन्त्री is formed by the unadi affix ई (un III. 158). In बहुनाडिः the long ई is shortened as being an upasarjana 1.2.48; but the ई of तन्त्री is not shortened, as ई here is not a feminine affx, but a krit affix (कृत् स्त्रियाः प्रतिषेधः; See 1.2.48 also).,