Macro-Anatomical Investigations of the Cervicothoracic Sympathetic System in the Horse (Equus Ferrus Caballus)

Twelve healthy adult horses (Equus ferrus caballus) were dissected to provide the anatomical description of bilaterally cervicothoracic sympathetic system macroscopically. On the left side, cervicothoracic sympathetic system was represented only by the caudal cervical ganglion, which located on the lateral surface of the esophagus cranial to the first rib. On the right side, cervicothoracic sympathetic system was represented by the caudal and middle cervical ganglion. The caudal cervical ganglion consisted of the fusion of the eighth cervical and the first three thoracic nerve ganglia. The caudal directed continuated branch of left ansa subclavia gave off; a pericardial branch and then give branch for ligamentum arteriosum. There was a special sympathetic–parasympathetic communicating branches; on the left side, there was only one branch that located on the lateral surface of the esophagus, while on the right side, there were four branches; two from the caudal cervical ganglion and two from the middle cervical ganglion. The most suitable site of ganglion block from both sides; the needle was placed medioventrally between the articulation of the first and second rib.