Ball and socket joints also allow flexion and extension. Flexion of the shoulder joint occurs when the humerus (upper arm) moves forwards from the rest of the body, which happens at the end of an ...

A hinge joint is a type of synovial joint that works like the hinge on a door, allowing bending and straightening only. The shoulder and hip joints are both ball and socket joints. A ball and ...

Here’s one more thing you can (not) look forward to in middle age ... a painful condition where inflammation immobilizes the ...