FIG 5. Schematic drawings show comparison of the rete mirabilia and the supply arteries in the pig and sheep.

A, In the pig, the rete mirabile receives most of its blood supply from the ascending pharyngeal artery, whereas only a small amount of flow is derived from branches of the IMA.

B, In the sheep, the fetal ascending pharyngeal artery undergoes atrophy, becoming a residual thread after birth. Branches of the IMA, the ramus anastomoticus, and the arteria anastomotica form the major arterial contributions to the rete mirabile.