Musculoskeletal System

The musculoskeletal system consists of the muscles, bones, ligaments, and tendons. In marine mammals, one of the first noticeable differences during a necropsy is the dark red color of the muscles compared with terrestrial animals.

This color is a result of a high concentration of myoglobin (the oxygen carrying protein in muscle). The high myoglobin load acts as a SCUBA tank for these diving animals by storing oxygen in the muscles. There are special features of the skeletal system of marine mammals as well. For example, you will notice when dissecting the ribs that there is a joint in most of the ribs which allows the rib cage to collapse as the animal dives and is exposed to increasing amounts of pressure. NECROPSY TRICK: When dissecting the ribs, locate the joint with your finger and cut through the rib at this point – it will be easier on YOUR musculoskeletal system!

Detailed annotated images of the musculoskeletal system in a California Sea Lion are shown below.  CLICK on an image to see an enlarged view.