Cervicothoracic sympathetic system in the dog: new insights by the gross morphological description of each ganglion with its branches on each side

BACKGROUND: Much published data exists on the position of cervicothoracic ganglion, but a little published research has been done on the cervicothoracic system of dog. Herein, we illustrated topographical position and shape of each ganglion of cervicothoracic system to determine the distribution of nerves dispersing from them on two sides, left and right. MATERIALS AND METHODS: Our work designed on the usage of 10 healthy adult dogs. Left cervicothoracic sympathetic system is represented by two ganglia: caudal and middle ganglion, while the right system is represented by three ganglia: caudal, middle cervical and small accessory ganglia. RESULTS: Left caudal cervical ganglion was elongated triangular, while the right one was elongated spindle in shape. Left caudal cervical ganglion was located on lateral surface of longus colli muscle, at the first intercostal space, while the right one was located at the level of the second rib. Left middle cervical ganglion was ovoid in shape and located at the first intercostal space, while the right one was located at the level of the second rib. There were two nerve trunks forming ansa subclavian trunk on both sides. There were three sympathetic-parasympathetic communicating branches on both sides. CONCLUSIONS: 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 the first rib.