![]() B, Normal cancellous (trabecular, spongy) bone bathed in normal hematopoietic marrow. ![]() Plump, cytoplasm-rich osteoblasts actively making osteoid, the type I collagen that in the normal sequence of events becomes the fibrous matrix of mineralized bone. 1-3), fatty and hematopoietic marrow elements, and tendon and ligament attachments create a complex system with mechanical, metabolic, and hematopoietic functions.įigure 1-1 A, Osteoblasts. Other associated tissues such as periosteum ( Fig. Osteoclasts are multinucleated macrophage-like cells that perform bone resorption at mineralized bone surfaces ( Fig. The osteocyte is in contact with the osteoblast through the cannular system. As the matrix becomes mineralized bone, these cells become embedded and are transformed into osteocytes. The main function of osteoblasts is to produce osteoid, a collagenized protein that mineralizes at the tidemark zone as hydroxyapatite crystals are incorporated ( Fig. Osteoblasts are cuboid in nature and have abundant cytoplasm. These cells perform key functions in the turnover and remodeling of bone in response to both physical and metabolic stimuli. The matrix is populated by mesenchymal cells, which differentiate into osteocytes, osteoblasts, and osteoclasts. Collagen fibrils, which form a parallel, highly organized arrangement, are known as intrinsic fibers, whereas those that tend to anchor ligaments and tendons at attachment sites and often insert in a perpendicular manner are extrinsic fibers. Collagen is the major extracellular component of bone and is composed of fibrils. The organic matter is composed of collagen, noncollagenized matrix, and proteins. The mineral consists of primarily calcium and phosphorus in a ratio of 2 : 1. Of the dry weight of bone (about 10% of the actual weight in situ), approximately 70% is due to mineral content and 30% is organic matter. 3, 10, 73, 120īone is composed of mineral crystals embedded in an organic matrix. The descriptions that follow are taken in part from standard anatomic texts. Rather than being redundant, we hope that this approach will facilitate the development of a more complete appreciation of the anatomy about the knee. In addition, in many situations, the same structures are presented from different perspectives. To provide a comprehensive description of pertinent anatomic details, text, illustrations, arthroscopic photographs, radiographs, and pictures from cross-sectional imaging studies are used. It is the goal of this chapter to present a thorough review of knee anatomy to help the reader successfully assimilate the material presented in subsequent chapters. However, it is also paramount that the clinician gain the knowledge required to be able to interpret the significance of an identifiable anatomic abnormality within the context of a patient’s complaints. Furthermore, the ability to interpret and correlate information obtained from different sources is highly beneficial. ![]() Any practitioner interested in diagnosing and treating disorders of the knee must have a detailed understanding of both normal and abnormal regional anatomy. The anatomy of the knee can be examined on a number of levels from microscopic to gross and with a variety of techniques, including physical examination, anatomic dissection, radiographic and cross-sectional imaging, and arthroscopic examination.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |