The Bony orbit: The eyeball and associated structures are located within the bony orbit. The bony orbit protects the eye, is a container for glandular, vascular, nervous and fat tissues; furthermore provides a firm support for muscle attachment, and connects the deep ocular structures with the brain. It is a cone shaped cavity with its base facing anteriorly (Figure 14-1). The bony orbital rim is open laterally where it is completed by the strong fibrous orbital ligament (Figures 11-34 and 14-2). In brachycephalic dogs, the bony orbit is shallow and the orbital ligament forms a greater part of the orbital rim. These characteristics predispose the globe to prolapse in these animals.On the other hand, the deeper, larger orbit in large breed dogs is responsible for third eyelid protrusion (mild to severe) and mechanical diseases related to eyelid conformation (macropalpebral fissure, entropion). The orbital cavity is limited dorsolaterally by the temporalis muscle. The coronoid process of the mandible is embedded in the temporalis and masseter muscles (Figure 13-12).When the animal opens its mouth, the coronoid process tends to move forward and compress the orbital contents.

The students will have an opportunity to perform mock surgical approaches to the long bones of the limb (radius and humerus), practice suturing of the skin, and complete a mock amputation of the thoracic limb. Once the right thoracic limb is removed, it should be used to revisit the muscles and nerves of the scapular, brachial and antebrachial regions, perform mock surgical approaches to the shoulder joint and elbow joint, and examine the deep muscles of the manus.

•  To gain an understanding of how the various joints of the limbs move, the major muscles responsible for such movement and the nerves and blood vessels that supply them. This information forms the foundation for evaluating various peripheral neuropathies that may result in sensory or motor deficits that must be evaluated in a systematic manner.