Fig. 3. A diagram of the model of the giraffe cranial circulation used. P1, P2, P3, P4, P5, P6 were sites of pressure measurement. R1, R2, R3 and R4 were sites where external pressure could be applied using a sphygmomanometer. A submerged pump and/or jugular limb extension tube was used to generate flow through the system. The jugular tube terminated outside the bath to allow for siphon operation, and bath water level was maintained with a valve-controlled constant inflow.