A Practical Approach, Second Edition=Ronald D. Ho.pdf

POSTNATAL DEVELOPMENTAL MILESTONES 973InterstitiallamellaeInnercircumferentiallamellaeTrabeculaeof cancellousboneOuter circumferentialIamellaeHaversian systems(osteons)PeriosteumBlood vesselsSharpey'sfibersEndosteumHaversiancanalsFigure 3 (3) Diagram of a sector of the shaft of a long bone, showing the disposition of the lamellae in theosteons, the interstitial lamellae, and the outer and inner circumferential lamellae.connective tissue and is thinner than the periosteum. All of the cavities of bone, including themedullary cavities and haversian canals are lined with endosteum.The long bones include the clavicle, humerus, radius, ulna, femur, tibia, fibula, metacarpals,metatarsals, and phalanges (7).2.2 Short BonesUnlike long bones, short bones do not consist of a diaphysis, metaphysis, and epiphysis. Shortbones are made up of a core of cancellous bone that is surrounded by a thin layer of compact bonethat is covered with periosteum.The short bones include the carpus, tarsus and sometimes the patellae (7).2.3 Flat BonesMany of the flat bones are found in the skull, these include the occipital, parietal, frontal, nasal,lacrimal, and vomer (7). The flat bones of the skull are made up of two layers of compact bonecalled inner and outer plates or tables. A layer of cancellous bone called the diploe separates theseinner and outer plates from one another (8, 3). These flat bones are lined by connective tissue thatis similar to the periosteum and endosteum of long bones. The outer surfaces of the flat bones ofthe skull are covered with a layer of vascular and osteogenic connective tissue called the pericranium,whereas the inner surface of the skull flat bones are lined with a vascular connective tissuecalled the dura mater (3).Other flat bones include the scapula, os coxae, sternum, and ribs (7). These bones are also madeup of two thin layers of compact bone separated by cancellous bone and are covered with periosteum.2.4 Irregular BonesVolkmann'scanalsThe irregular bones of the skeleton are those that due to their shape cannot be grouped with thelong, short, or flat bones. These bones are made up of cancellous tissue that is enclosed in a thinlayer of compact bone covered by the periosteum. Irregular bones include the vertebrae, sacrum,© 2006 by Taylor & Francis Group, LLC