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 ...

Flexion – bending a joint. This occurs when the angle ... Ball and socket joints also allow flexion and extension. Flexion of the shoulder joint occurs when the humerus (upper arm) moves ...

The deltoids are the muscles that cover the front, back and side of the shoulder joint ... one dumbbell in each hand. Bend ...