The Morphology of the Os Penis in the Adult Mouse

Abstract

This study focused on morphology of the os penis in adult mouse (Mus musculus domesticus). The os penis was located within the corpus cavernosum penis and extended up to the half way of the glans penis. With a close resemblance to that of the rat os penis, the shape of the mouse os penis appeared a probe-like structure. Histologically, the body of os penis was consisted of compact bone and a narrow bone marrow. Hyaline cartilage constituted the proximal end, to which the corpus cavernosum penis attached and blended with the perichondrium. A completely ossified proximal end was rarely observed. The organization of hyaline cartilage at the proximal end resembled the growth plate of the long bone. However, chondrocytes did were not well organized into columns as in the growth plate. Like in the physis of the long bone, invasion of hyperthropic chondrocyte by blood vessels originating from the underlying bone was present; however, chondrocytes embedded directly in osteoid matrix were also quite common. While the proximal end of the os penis was covered with hyaline cartilage, the distal bony end was continuous with a type of tissue varied from loose to dense connective tissue and to fibrocartilage-like tissue. At the distal bony end, newly synthesized osteoid matrix was distinguishable. Thus, the os penis in the adult mouse is a dynamic structure exhibiting continuous growth both at the proximal and distal ends.