Farnum and Wilsman (1989) and Farnum et al. At maturity the physeal cartilage ceases to grow, and the epiphysis fuses with the shaft as both share in the bony replacement of the physeal cartilage. The rapidly growing, flared end of the bone between the shaft and the epiphysis is called the metaphysis. The epiphysial cartilage ( cartilago epiphysialis) is the cartilage on the articular surface of the epiphysis. During development each end is separated from the shaft by a plate of growing cartilage, the physeal cartilage. Typically a long bone, during its growth, possesses a shaft, or diaphysis, and two ends, the epiphyses (Haines 1942). The bones of the thigh and arm, that is, the femur and humerus, are good examples. Long bones ( ossa longa) are characteristic of the limbs. Some sesamoid elements never ossify but remain as cartilages throughout life, such as those of the distal interphalangeal joints. Sesamoid bones vary from tiny spheres to the slightly bent, ovoid patella that is 2 cm or longer in a large dog. The terms are readily understandable, except possibly sesamoid, which is derived from the Greek word for a seed that is small, flat, and ovate. Long, short, and sesamoid bones are found in the limbs, whereas the flat and irregular bones are characteristic of the skull and vertebral column. For descriptive purposes five general divisions on this basis are recognized: long bones, short bones, sesamoid bones, flat bones, and irregular bones. Anatomists have long grouped bones according to shape, although borderline forms exist. (1976), and Wayne (1984, 1985, 1986), studied comparative skeletal morphology in canids and Huja and Beck (2007), described bone remodeling of the maxilla, mandible, and femur in young dogs.Ĭlassification of Bones According to Shapeīones may be classified in various ways. Various aspects of skeletal morphology in the dog have been considered by multiple authors: Lumer (1940) has studied evolutionary allometry Stockard (1941), genetic and endocrine effects Haag (1948), osteometric analysis of aboriginal dogs Hildebrand (1954), Clutton-Brock et al. For more recent reviews of bone and cartilage biology see Buckwalter et al. For a helpful atlas of radiographic anatomy, see Schebitz and Wilkins (1986).įor a discussion of the structure and function of bone in health and disease, reference may be made to The Biochemistry and Physiology of Bone by Bourne (1972, 1976), The Biology of Bone by Hancox (1972), Biological Mineralization by Zipkin (1973), The Physiological and Cellular Basis of Metabolic Bone Disease by Rasmussen and Bordier (1974), and Bone: A Treatise by Hall (1989-1992). Specific information and references on the skeleton of the dog and other domestic animals can be found in current veterinary anatomy texts and the classic out-of-print Handbuch der Vergleichenden Anatomie der Haustiere by Ellenberger and Baum (1943). Much useful information on the skeleton can be found in such older works as Owen (1866), on all vertebrates, and Flower (1870), on mammals. Inherent in these responses are changes in the physiognomy, construction, and mechanical function of the body.įor a review of the history of the vertebrate skeleton and the bones that constitute it, reference may be made to comparative anatomy texts, such as The Vertebrate Body by Romer and Parsons (1986) or Hyman’s Comparative Vertebrate Anatomy by Wake (1979). Bone responds in a variety of ways to vitamin, mineral, and hormone deficiencies or excesses. The process of bone repair and the incorporation of heavy metals and rare earths (including radioisotopes) in the adult skeleton attest to its dynamic nature. For a consideration of various aspects of development, maintenance, and repair of the skeleton, reference can be made to Kimmel and Jee (1982), Kincaid and Van Sickle (1983), Jurvelin et al. In the living body the skeleton is composed of a changing, actively metabolizing tissue that may be altered in shape, size, and position by mechanical or biochemical demands. It functions as a storehouse for minerals and as a site for fat storage and blood cell formation. The skeleton serves for support and protection while providing levers for muscular action.
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