The descending respiratory pathway in man

The descending respiratory pathway may be con-sidered to be the most important tract of the spinal cord; yet its position in man is unknown. It is important to work out the location of these descend-ing fibres not only to complete anatomical knowledge but also to provide those practising surgery on the cervical cord with essential information. The absence of this knowledge contributed to the death of some of our patients after cordotomy and this has also been a cause of death in patients from other series of cordotomies. Following Stookeys (1943) report of his experience of high cervical cordotomies, Penfield (1943) said: I have had a patient in whom I sectioned the pain tract at the second cervical segment under local anaesthesia. Suddenly, as the wound was being sutured, while he was talking and in the midst of a sentence, he died... Autopsy showed no explanation of it. Stookey replied that he had never had such an experience following unilateral cordotomy but he had with the bilateral operation. He added: In bilateral cordotomy, I think that sectioning of the anterior lateral columns probably interferes with the higher respiratory pathway coming down from the medulla to the diaphragm... The difficulties I have had have been with bilateral cordotomies and I felt they were respiratory deaths, due to interruption of an upper respiratory path-way. Undoubtedly many neurosurgeons have had the same experience: patients having had unilateral and more commonly bilateral cordotomies in the cervical region may die suddenly, often in their sleep, and at necropsy no explanation has been forthcoming. It will be shown in this paper that an adequate high cervical cordotomy will damage most of the descending fibres controlling respiratory movements. In 1830, Sir Charles Bell made the suggestion that the tract for controlling respiratory movements lies in the lateral part of the cord, somewhere between the anterior and posterior roots. Although since then there has been work on animals that confirms Sir Charles Bells conjecture, there has been, as far as I can ascertain, no evidence produced for man. In 1895, Porter looked for the location of the pathway running from the bulb to the phrenic