The functional morphology of the avian flight muscle M. coracobrachialis posterior

The extensive range of movement of the avian glenohumeral joint makes funct ional interpretation of any muscle that crosses the joint difficult. Multip le functional roles for the M. coracobrachialis posterior (CBP), an archite cturally complex muscle that lies deep to the M. pectoralis, have been assi gned on the basis of its anatomical position. The mechanical properties, ne uromotor pattern during flight and the biochemical properties of the CBP in pigeons (Columba livia) were studied by in situ length/active tension and length/passive tension measurements, in vivo electromyography ana muscle hi stochemistry. The action of the muscle was studied directly through in situ stimulation and measurement of humeral excursion in non-reduced preparatio ns.