Physiologic Relationships Between Intrathoracic, Intraspinal and Arterial Pressures

Characterization of the oscillometric method for measuring indirect blood pressure

“…It also overestimates direct systolic pressure in the animal. It should be pointed out that auscultatory systolic pressure is slightly below true systolic pressure (7,12); therefore in man S o may not overestimate arterial systolic pressure by the amount reported herein.…”

Tapering of the Cervical Spinal Canal in Patients with Distended or Nondistended Syringes Secondary to Chiari Type I Malformation

“…Based on established hydrodynamics principles, the intrathoracic pressures are transmitted toward the spinal and cranial compartments and further to the subarachnoid space. 25,26 Hence, one can hypothesize that in patients with CMI, the physiologic pressure transmission that normally exists between the intrathoracic and CSF compartments is exaggerated as a consequence of the steeper tapering of spinal canal, which, in turn, exacerbates the pressure differentials between the cranial and spinal compartments as well as their possibility of equalization, both of which are already altered by the herniated cerebellar tonsils. Intuitively, the elevated pressure differential may precipitate hyperkinetic CSF flow, and once a critical threshold is surpassed, a syrinx could be created.…”

Cardiovascular Adjustments to Gravitational Stress

“…Extravascular pressure changes with varying body position have been measured in the cerebrospinal fluid compartment (139,216,217) and th e abdominal cavity (284). The extravascular pressure in these systems also changes with gravitational force and modifies the effective vascular pressure, i.e., the transmural pressure.…”