Quain's elements of anatomy . in the cartilaginous head of the bone (Ranvier). This groove is filled withthe same tissue as that which underlies the rest of the periosteum, namely avascular tissue with branched cells and osteoblasts and osteogenic fibres. Thelatter are prolonged from the periosteal bone, and have for the most part alongitudinal direction (fig. 110). Blood-vessels extend from the newly-formed osseous tissue beyond it into theCartilage. The vessels are lodged in excavations or branching canals in thecartilage (fig. 105) which also contain granular corpuscles (? osteoblasts). Oth
Quain's elements of anatomy . in the cartilaginous head of the bone (Ranvier). This groove is filled withthe same tissue as that which underlies the rest of the periosteum, namely avascular tissue with branched cells and osteoblasts and osteogenic fibres. Thelatter are prolonged from the periosteal bone, and have for the most part alongitudinal direction (fig. 110). Blood-vessels extend from the newly-formed osseous tissue beyond it into theCartilage. The vessels are lodged in excavations or branching canals in thecartilage (fig. 105) which also contain granular corpuscles (? osteoblasts). Othervascular canals enter the cartilage from its outer surface, and conduct vessels intoit directly from the perichondrium. The fonnation of osseous tissue, having thus proceeded for some time in theshaft, at length begins in the extremities of the bone from one or more inde-pendent centres, and extends through the cartilage, leaving, however, a thick VOL. II. 1. 114 BONE OR OSSEOUS TISSUE. superficial layer of it unossified, wliich permanently covers the articular ends ofthe bone. The epiphyses thus formed are separated, as long as growthcontmues, from the shaft or diaphysis by an intervening portion of cartilage,which is at last ossified, and the bone is then consolidated. A remarkable exception to the ordiiinry mode of ossification of the cartilage-bonesoccurs in the terminal phalanges of the digits. In these the calcification of thecartilage beghis at the distal extremity or tip, and the sub-periosteal depositappears simultaneously at the same point, and forms a cap-like expansion overthe end of the lohalanx. The irruption of the osteoblastic tissue also first occm-sat this place. The expanded portion of the phalanx which bears the nail isformed independently of cartilage. Growth and Absorption of Bone.—Tlie time of final junction of theepiphyses is different in different bones ; in many it does not arrive until thebody has reached its f
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Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
