Fig. 4.
A Whole-mount MRI slice of the adult mouse penis (P43) in situ and B a mid-sagittal plane MRI slice of the externalized penis. The white box in A shows the location of the penis beneath the EP and extending into the body. The 90° bend in the penis is associated with its attachment to muscles that aid in erection. The vertical white lines (B) indicate the plane of transverse sections shown in C and E. C Still frame images from the transverse plane of the MRI of the externalized penis from distal to proximal (i–iv). D Transverse MRI frames from C with shaded regions of interest, color-coded as indicated in the diagram key. E Corresponding transverse hematoxylin- and eosin-stained stained sections from a P43 externalized mouse penis. For abbreviations, see figures 1 and 2.