Info The Osteotendinous Junction
The osteotendinous junction (OTJ), or enthesis, is the site of connecter betwixt tendon in addition to os in addition to is likewise called the tendon insertion site. The unique cellular in addition to molecular composition of the enthesis provides a gradual transition from tendinous to os tissue. The enthesis is virtually divided into 4 zones: zone one, starting at the tendon side, consists of aligned collagen I fibers in addition to decorin, in addition to exhibits tendon properties only. The minute zone contains collagen types II in addition to III, aggrecan in addition to decorin, resembling fibrocartilage composition. Zone iii is defined equally mineralized fibrocartilage in addition to is comprised of collagen types II in addition to X in addition to aggrecan. Finally, zone 4 is composed of mineralized collagen type I in addition to is considered to hold upwards a os protrusion, providing a dedicated connecter point. The molecular mechanisms responsible for the formation of this slope are to a greater extent than oft than non unknown. However, it was demonstrated inwards the mouse forelimb model that Bmp4, produced in addition to secreted yesteryear maturing tendon cells nether Scleraxis transcriptional regulation, is responsible for initiation of os tuberosity outgrowth at a site of tendon attachment. Other studies disclose the essential contribution of musculus contractions on the formation of os ridge.
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