Shoulders receive the lion's share of work in the gym. Nearly all upper body routines involve the shoulder to some extent, if only to be held fixed and motionless for the specific movement. Even during leg work, the shoulders are involved with the stacking and unstacking of plates for all the leg routines. Shoulder pain can greatly hamper any training routine and tends to require long periods of time for complete recuperation.
Severe injuries can prematurely terminate the careers of professional athletes such as baseball pitchers with rotator cuff problems. For the non-professional athlete, even minor shoulder pain can lead to disturbed sleeping patterns from the inability to find a comfortable position at night. Part I of this two part series will examine shoulder anatomy in sufficient detail to highlight the basis for skeletal variations that can predispose certain individuals to persistent shoulder problems. Part II will go on to present routines for strengthening lesser known shoulder muscles and lifting variations to minimize further trauma.
Bear in mind that severe pain, extreme muscle weakness, or inability to perform certain movements may indicate a condition requiring medical attention. Advice presented here should not serve in place of a thorough medical evaluation since certain conditions may require specialized medical intervention or even surgery.
Due to its extremely wide range of mobility, the shoulder is one of the most complex joints in the human body. Because of its unusual bone structure and large number of muscle attachments, shoulder pain can be a daunting challenge to most physicians who typically recommend merely rest and anti-inflammatory medications for weeks to months as therapy which may or may not solve the problem.
In addition, chronic degenerative changes that accumulate from repeated trauma will likely increase the frequency of shoulder problems for most individuals as they age and continue lifting. While any single article can hardly be exhaustive on the subject of shoulder issues (whole books 16,17 have been devoted to the subject), this discussion will focus on one of the more common problems that results from a combination of unlucky anatomy, undesirable lifting technique, and insufficient attention to auxiliary musculature.
The Anatomy Of The Shoulder
The shoulder is the anatomical structure that links the arm with the torso. A wide array of muscles of particular interest to bodybuilders traverse the shoulder including: pecs, lats, delts, and even the biceps. Given that the lats and delts contribute to a wide upper body desirable by bodybuilders, much attention is focused on these muscle groups and considerable stress is applied to the shoulder. Pain and discomfort can dramatically compromise nearly any weightlifting routine.
The shoulder as a joint is classically described as a ball and socket (similar in design to the hip joint)1. The ball portion is derived from the end of the upper arm bone, the humerus, and resembles a ball stuck on the end of a long shaft, and is referred to as the humeral head. The socket side is formed from one corner of a roughly triangular flat bone called the shoulder blade (the scapula), that rests over the rib cage, high on the back and extends over the rib cage to the front of the body. The triangular form of the scapula has one side close to the midline of the back with the lower corner angling up towards the shoulder.
The third side of the triangle runs parallel to the shoulders across the top. The shoulder blade is thicker in its upper portion than the lower portion, so that the very top of the shoulder blade has a surface (rather than just as edge as with the other two sides of the triangle) with two edges (one towards the body and one away). The top edge pointing away from the body is called the spine and the surface of the top of the shoulder blade is slightly depressed and called the supraspinous fossa (fossa is the technical term for a depression). Moving along the spine towards the shoulder, a bony extension, called the acromion, juts out and arches over the top of the scapula just above the humeral head and can be felt as the bony top of the shoulder.
The acromion arches over the top of the scapula from back to front and connects to the collarbone (clavicle) to complete the shoulder girdle. Arising off the top edge opposite the spine, also at the shoulder, across from where the acromion begins and pointing forward over the chest, is a small bony knob called the coracoid process. The short head of the biceps muscles attaches to this piece of bone as well as a small muscle called coracobrachialis and the pectoralis minor muscle (underneath pectoralis major, the main 'pecs'). In addition, a tough ligament connects the coracoid process with the acromion.
The socket portion of the scapula that contacts the humerus is called the 'glenoid fossa,' but rather than looking like a true socket, the glenoid fossa is more open with the appearance of a saucer or rather like a golf tee with the humeral head as the golf ball. The reason for the openness is to permit a large range of motion in the joint. The downside to this large range of motion is the propensity of the shoulder to dislocate. A dislocation occurs when the humeral head moves beyond the confines of the glenoid fossa and slips over the lip of the saucer (your golf ball falls off the tee).
When any muscle acts across a joint, opposing muscles are contracted as well to stabilize the joint. Imbalances in strength between opposing muscles can potentially lead to injuries. With the shoulder, the anatomy is not as simple as a one dimensional joint (such as the elbow). Movement of the shoulder requires many different muscles to create the movement as well as other muscles to stabilize the shoulder joint. In addition, since the shoulder blade is only attached (by other bones) to the upper arm and collar bone at one end, the blade portion must be held fixed by additional muscles.
For example, serratus anterior (best seen in a well muscled, lean individual) is a small group of muscles that arises from the rib cage in front just below the pecs with the muscle bellies extending up and around to the back and disappearing underneath the lats. Serratus anterior attaches to the scapula along the edge closest to the middle of the back. Serratus's job is to prevent the shoulder blade from winging during shoulder movements; in other words, serratus pins the scapula to the back and so serves to stabilize the joint during movements.
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