Sternum cross section (LM, Medium)

Structure List Spongy bone Compact bone Muscle Marrow Low magnification view of sternum

Bone exists in two forms: compact and spongy (or cancellous). The shaft has a cortex composed of compact bone which encloses a central medullary cavity (marrow cavity). The central parts cancellous (spongy) bone consisting of thin fenestrated sheets or trabeculae of bone tissue. Spaces not occupied by bone tissue contain bone marrow. Identify the compact bone forming the cortex of the canine sternebra and the cancellous bone in its center.