Vegetation acts as an interface between the atmosphere and the soil. It increases the permeability of the soil to rainwater, thus decreasing runoff. It shelters the soil from winds, which results in decreased wind erosion, as well as advantageous changes in microclimate.
The shoulder is a ball-and-socket type of joint and is anatomically referred to as the gleno-humeral joint, describing the two bony structures involved. The socket is the glenoid cavity, a cup-shaped piece of bone that juts out from a corner of the shoulder blade (scapula).
Hence, the socket of the glenoid cavity articulates with the ball of the humerus. Therefore, the main portion of the shoulder joint is called a ball and socket joint. The smooth semi-circular humeral head, the ball, fits into the concave structure of the glenoid cavity, the socket.