Cervicothoracic sympathetic system in the dog: new insights by the gross morphological description of each ganglia with their branches in each side.

Much published data exists on the mention of the position of cervicothoracic ganglion, but a little published research has been done on the cervicothoracic system of dog. Herein, we illustrated topographical position, shape of each ganglia of cervicothoracic system to determine the distribution of nerves dispersing from them in two sides; left and right. Our work designed on the usage of ten healthy adult dogs. Left cervicothoracic sympathetic system represented by the presence of two ganglia; caudal and middle ganglion, while the right system represented by the presence of three ganglia; caudal, middle cervical and small accessory ganglia. Left caudal cervical ganglion was elongated triangular, while the right one was elongated spindle in shape. Left caudal cervical ganglion located on lateral surface of longus colli muscle, at first intercostal space, while the right one located at the level of second rib. Left middle cervical ganglion was ovoid in shape and located at first intercostal space, while the right one located at the level of second rib. There are two nerve trunks were forming ansa subclavian trunk in both sides. There are three sympathetic-parasympathetic communicating branches in both sides. Our study recorded the first observation of left pericardial branch in dog, which originated from the caudal angle of middle cervical ganglion. There was a small ganglion located on the lateral surface of trachea at the level of first rib.