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).
The bones entering into its formation are the hemispherical head of the humerus and the shallow glenoid cavity of the scapula, an arrangement which permits of very considerable movement, while the joint itself is protected against displacement by the tendons which surround it.