(Source:plate23A&Bhttp://www.google.co.in/search?hl=en&q=Pin+joints&bav=on.2,or.r_gc.r_p
w.r_qf.&biw=1341&bih=581&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=MGY8U
N3-CMXprAfcyoDoDg ; Aug. 28, 2012)
23Chttp://www.google.co.in/search?hl=en&q=Elbow+Joints&bav=on.2,or.r_gc.r_pw.r_qf.&biw=
1341&bih=581&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=9tI8UKftBcPZrQflv
4CABg ; Aug. 28, 2012)

Elbow joints bend only around a single axis, therefore it can move in one single plane. The interesting part of elbow joint, it is not joined by pin. It is held by ligaments (plate 23C) where the concave and convex surfaces match with each other and held them together with help of the ligaments.

The human skeleton consists of more than 200 bones. The different parts of the body demonstrate various coordinated movements because of the individual bone’s attachment to another bone. The movements are possible due to ‘skeletal muscles’, where the bones act as levers, cartilage which reduces friction. Ligaments hold the joining bones together which prevent dislocation and the presence of movable joints. Thus, the bending of bones is synonymous to movement. The joints can be classified according to the degree and type of movement they allow which are freely movable joints. The bones are covered with cartilages that hold the bones together.

Ball and Socket

Plate 24A Ball & Socket	24B Bone Joint	24C Camera Stand	24D Pen Stand	24E Lamp