Bone growth 2 directions length and width Interstitial

Bone growth 2 directions – length and width Interstitial growth- lengthwise growth –chondrocytes in the epiphyseal. plate produce new cartilage, replaced in the diaph. by bone --will continue until growth stops (hormones, genes, etc. tell it to stop). Epiph. and Diaph. will fuse, epiph. line forms in the bone where epiph. plate used to be Appositional growth- inc. in width. --Osteoblasts in periosteum deposit new bone tissue at the same time osteoclasts destroy bone tissue in the medullary cavity.

Joints/Articulations • Junction between 2 or more bones • • 3 Categories of Joints Immovable Semi-movable Freely movable

Immovable/Synarthroses • Dense conn tissue holding them together • Bones that closely contact each other • EX: skull sutures • epiph plate

Semi-immovable/Amphiarthroses • Slight movement • Cartilage between • EX: pubic bone Vertebral discs

Freely Movable/Synovial/Diarthroses • Synovial fluidlubricates, nourishes and prevents friction • Articular capsule covers joint and contains fluid • Art. discs between cartilage-shock absorbers

Ball and Socket • round head of one bone moves in cuplike cavity of another EX: hip [femur/acetabulum] shoulder [humerus/glenoid fossa]

Condyloid/ Ellipsoid • Variation on a ball and socket except the shape is more OVAL; not a complete rotation • EX: metacarpal and phalanx

Gliding • Sliding, back and forth and twisting movement • Flat , curved surfaces • EX: wrist [carpals] ankle [tarsals]

Hinge • Convex surface of one bone fits in concave surface of another • EX: elbow [humerus/ulna], phalanges

Pivot • Cylindrical surface of one bone rotates in the ring formed in another bone • EX: skull on top of Cervical vertebrae [atlas and dens]

Saddle • Bones that contain both concave and convex regions that fit complementary • EX: Thumb [1 st metacarpal and carpal]