Reciprocal tension membrane

The mobility of the intracranial and intraspi-nal membranes and the function of the reciprocal tension membrane... 

The Mobility of the Intracranial and Intraspinal Membranes and the Function of the Reciprocal Tension Membrane... 

The reciprocal tension membrane (RTM) refers to the function ofthe mobility of intracranial and intraspinal membranes, the pia, arachnoid, and dura. Understanding the development and the anatomy of the membranes helps illustrate their function (see Section X, Chapter 102). The intracranial membranes are intimately related to the fascia throughout the rest of the body. 

THE INTRACRANIAL AND INTRASPINAL MEMBRANES AND THE RECIPROCAL TENSION MEMBRANE... 

FIG. 104-1 PRM, flexion phase. (A) Relationship of sphenoid to occiput. (B) Effects on reciprocal tension membrane system. (C) Direction offeree in flexion. 

Unrestricted movement of dural membranes The dural membranes must be unrestricted in their areas of reciprocal tension to allow such movement to occur within normal limits. 

The CO diffusing capacity, DPco, of sheep was measured at various 02 tensions in a hyperbaric chamber using a method similar to that outlined above (12). DPco varied as a function of the oxygen tension. In Figure 2 the reciprocal of DPco is plotted as a function of the reciprocal of the diffusing capacity of the maternal and fetal red blood cells. From the plot the slope is the reciprocal of the value of V, the maternal and fetal capillary blood volume while the intercept is the reciprocal of Dmco- From these studies we calculated that the resistance of maternal and fetal red blood cells was approximately one-third of the total resistance while the resistance of the placental membrane per se was about two-thirds of the total resistance to 02 diffusion (12). This is in contrast to previous studies which assumed that the placental membrane per se constituted the total resistance to diffusion. 

---