I am trying to visualize crista junctions in mitochondria in the liver (mammalian). These might be visible here, in a KO mouse which has increased oxidative stress (previous posts). It looks to me like there is a small consistent area at the place around cristae approaching the outer mitochondrial membrane that looks “different”? Find the 100nm markers (vertical at the edge of a crista and horizontal by the red dot over on the right hand side) are an approximate marker for the size of a cytoplasmic ribosome (27nm) and calculation for 100nm from that.
Cristae in this particular mitochondrion and many others show an increase in the amount of matrix space and a more vesicular type of cristae, and some times have cristae inclusions.