![]() C, Coronal T1-weighted magnetic resonance image of the orbit of the same cat. ![]() Lysis of the cribriform plate and cortical bone of the right frontal sinus are present dorsally, ventrally, and laterally. A large soft tissue mass with central areas of mineral opacity is present. B, Transverse computed tomographic scan of the orbit of the same cat. Fluid density is present in the right tympanic bulla (arrowhead). Lysis of cortical bone of the right frontal sinus is present (open arrow). Orbital disease processes may thus be located in one of the following three planes:įigure 17-19 A, Rostrocaudal radiographic view of the skull of a cat with a frontal sinus/orbital mass. In animals with an incomplete bony orbit, the masticatory muscles play a critical role in providing posterior support for the orbital contents. Intraorbital fat lies between the muscles and fascial layers ( Figure 17-15). The orbital fat pad lies between the periorbita and the extraocular muscles. The periorbita is continuous with the periosteum of the facial bones at the orbital rim, with the orbital septum anteriorly, and with the dura mater of the optic nerve. The periorbita is reflected over the extraocular muscles and forward over the globe to become Tenon’s capsule, lying beneath the conjunctiva (Figure 17-14). The orbital contents are completely enclosed in a sheet of connective tissue-the periorbita-that lies next to the bone in the bony parts of the orbital wall and that is thicker laterally where the wall is incomplete (in carnivores). (Modified from Evans HE : Miller’s Anatomy of the Dog, 3rd ed. Note multiple ducts of the zygomatic gland entering the oral cavity. The vessels and nerves that pass through these foramina and fissures in the dog are shown in Figures 1-16, 1-17, and 1-19 to 1-22 in Chapter 1 and Figure 17-6.įigure 17-13 Lateral aspect of canine orbital contents and the zygomatic salivary gland. In cattle, the orbital foramen and the foramen rotundum fuse to form the foramen orbitorotundum. The basic foramina and fissures of the orbit are the orbital, rostral and caudal alar, oval, supraorbital, ethmoidal, lacrimal, maxillary, sphenopalatine, round, and palatine. In the dog and cat the dorsolateral portion of the orbit is spanned by the dense collagenous orbital ligament, which passes from the zygomatic process of the frontal bone to the frontal process of the zygomatic bone. ![]() The walls of the equine orbit are formed by the frontal, lacrimal, zygomatic, temporal, presphenoid, palatine, and maxillary bones, which are similar in other species. The orbit separates the eye from the cranial cavity, and the foramina and fissures in its walls determine the path of blood vessels and nerves from the brain to the eye. (Modified from Getty R : Sisson and Grossman’s the Anatomy of the Domestic Animals, 5th ed. Figure 17-5 Dorsal view of the equine skull.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |