MUSCLES OF RESPIRATION. When the diaphragm contracts in inspiration, initially the lower ribs are fixed and the dome of the diaphragm descends, thus increasing the vertical diameter of thorax.
arrearage. 1  the state or condition of being in arrears. 2  Often, arrearages. arrears; amount or amounts overdue. 3  Archaic. a thing or part kept in reserve.
plural noun. 1. the state of being behind or late, especially in the fulfillment of a duty, promise, obligation, or the like: Many homeowners have fallen into arrears. 2. Sometimes, arrear. something overdue in payment; a debt that remains unpaid: Those countries that have paid their arrears may be granted additional loans. Idioms.