Artery, Posterior Communicating

The posterior communicating artery, AKA PCOM artery, connects the internal carotid artery with the posterior cerebral artery (PCA). It is called fetal PCOM artery if it is bigger than the first segment (P1) of the PCA (Case 1). There are perforators originating from the PCOM artery (Case 1) that should be carefully preserved during PCOM artery aneurysm clipping.

Cases

1

This patient has a left fetal PCOM artery (yellow arrow) supplying the left PCA (blue arrow) and shows an absence of the left P1. On the right VA injection, the right PCOM (green arrow) can be discerned with a perforator (black arrow) heading toward the right thalamus. Additionally, there is a duplicate left SCA (red arrow). By the way, did you notice the hidden aneurysm? :)