The 'rotator cuff' is a term that many people have heard of but probably don't really understand. You will hear talk of it down at the gym, or perhaps know someone who says they injured it, but what does it mean?
The shoulder is a very mobile joint - it has to be in order to give us the free range of movement that we often take for granted. If you compare it to your hip for instance, you will quickly realise that the shoulder allows much more movement and in a multitude of directions. But nothing comes for free as they say, and at the shoulder at least, all that movement comes at the cost of stability. Unlike the hip, the socket of the shoulder is shallow to allow free range, and the ligaments that bind it in place are relatively weak and flimsy. Because of this, the shoulder relies greatly on muscular control for reinforcement; correct function relies on having comprehensive, controlled, and well stabilised movement, and it is exactly this that the rotator cuff provides.
Comprised of four small muscles, the 'rotator cuff' collectively wraps around the humeral head and stabilises it in the socket while at the same time generating and dynamically controlling movement. Each muscle plays an individual part in shoulder movement, but the cuff is considered collectively because they all work together (or 'synergistically'). It is an amazing adaptation, but certainly carries a risk of injury, particularly as we age.
Injuries to the cuff most commonly start to occur through mid-life and as we age. Supraspinatus is by far the most observed tendon tear, subscapularis and infraspinatus tears being less common. In the elderly, degenerative tearing of the rotator cuff is almost a given; it is something that we expect to see almost 100% of the time in those over 80 years of age for instance, yet it may remain asymptomatic and not pose the patient any real issues.
So, to a degree, rotator cuff degeneration seems to be unavoidable and a part of the normal aging process. However, in younger and more active individuals, pain arising from tendon inflammation, strains and tears can impact dramatically on shoulder function and quality of life.