Shoulder Contusions
Normal Anatomy
The shoulder joint is the second largest and most mobile joint in the human body and can be easily understood if divided into three layers. The first layer is the deepest layer made up of the bones that form the foundation. There are three bones consisting of the arm bone (humerus), the shoulder blade (scapula), and the collar bone (clavicle). There is a rounded head on top of the arm bone called the humeral head and a saucer shaped surface of the shoulder blade called the glenoid which complements the humeral head and together they form the shoulder joint. A layer of cartilage (blue area) covers the articular surfaces of the humeral head and glenoid to provide a cushioned surface which allows for smooth pain free shoulder motion. These three bones unite to form three joints, which are held together by the second layer which keeps the bones from separating during shoulder movement, allowing the bones to function as a unit.
The second layer is comprised of collagen tissue fibers that attach to the bones on both sides of the joint and form the joint capsule. Within the joint capsule, are dense cordlike collagen bundles that unite to form ligaments that in strategic locations further enhance the stability of the joint by resisting the forces created when we perform our routine daily activities.
The rim of the glenoid is encircled by a rubbery fibro-cartilage tissue called the labrum. The labrum is an anchor point for the ligaments of the shoulder capsule and the long head of the biceps tendon which attach to it creating a suction seal mechanism when the humeral head is in contact with the glenoid. This sealing mechanism adds another joint stabilizing effect. The three shoulder bones form there joints called the Glenohumeral (GH) joint, Acromioclavicular (AC) joint, and the sternoclavicular (SC) joint.
The third layer in the shoulder is the muscle layer. Within the muscle layer, there are several potential spaces that carry the arteries which supply the bodies’ nutrition and nerves that deliver the commands sent by the brain and spinal cord for muscle movement. The most important muscle group in the shoulder is called the rotator cuff muscles. They are comprised of four muscles that begin (originate) in the shoulder blades’ flat surfaces and attach to the arm bone in an area called the greater tuberosity footprint as a common tendon unit. The four tendons formed by the four rotator cuff muscles interdigitate with one another forming a protective mechanism that prevents rotator cuff tendon tears from quickly spreading once they occur. The interdigitation also allows the four muscles to work together as a unit, carefully balancing the shoulder joint against the forces of the deltoid muscle to create precise shoulder movement. The deltoid muscle, biceps muscle and other muscles about the shoulder that balance the shoulder blade, called the scapular stabilizers complete the shoulder muscles that make up the third layer and together create a dynamic balanced force which allows for normal function. The major function of the rotator cuff muscles is to provide shoulder joint dynamic stability, shoulder joint motion and strength to the arm.
Pathology
Trauma is the term used to describe injury. Trauma is classified by its severity depending on the amount of force used to cause the injury. Trauma is also distinguished according to whether it is caused by a single major force or minor repetitive, smaller forces which are cumulative (additive) over time. This is referred to as Cumulative Trauma Disorder (CTD). An injury is also classified depending on if the skin was breached, called an open injury or the skin layer stays intact, referred to as a closed injury. When an injury is minor, it is called a contusion and in this instance, it implies that the injury was closed and only involves the soft tissues including the skin, subcutaneous tissue, muscles, tendons, ligaments, arteries and nerves, alone or in combination. In a contusion, the soft tissue is bruised or stretched, but not torn and requires only symptomatic treatment. The same force of trauma sustained by different patients will result in different injury severity because changes that occur in our body’s internal structure with aging. Specific changes occurring with aging is the amount and type of collagen in our body through metabolism is converted from Type I collagen which is the typical collagen most often found in the human body is converted into Type II collagen. Type II collagen is less resilient and is the type of collagen found in healing scar. The protein, elastin, which gives tissue its stretch properties, also decreases in content with aging. Finally, the water content in the cells of the body decrease with aging. Below is a graph that depicts an identical force sustained by individuals at different ages divided into 20-year increments and the time it takes for each group to heal and become symptom-free. The white section is when the patient is symptom-free and the yellow section is when the patient is having symptoms including pain, stiffness, weakness, and poor function. Note the curve does not come back to baseline and shifts to the right with aging.
Treatment
The most common symptomatic treatment used for all types of soft tissue injuries has three approaches: 1. R.I.C.E. treatment, 2. Anti-inflammatory treatment 3. Controlled early motion and therapy.
The acronym RICE stands for Rest, Ice, Compression and Elevation. A Strain is a muscle injury and Sprain is a ligament stretch injury and both conditions are treated with the RICE approach. Rest is usually done for 24-48 hours, and can include the use of slings, splints or other types of immobilizers unless otherwise advised by a physician. Ice is used for no more than 20-30 minutes at a time, three to four times per day. Ice is best applied by using an ice slush which transmits the effects of the cold sensation best and can be made by crushing ice and mixing it with water and then placing it in a zip lock plastic bag. The ice bag should not be placed in direct contact with the skin but instead should have a layer between the skin and ice bag like a towel to prevent the skin from freezing. The ice should be applied for no more than 20-30 minutes to avoid skin freezing as can occur if you fall asleep with an ice pack on your limb. Ice functions by causing the arteries to narrow the size of their lumen which in turn decreases swelling and the pain from the increased pressure caused from swelling.
Compression is the wrapping of a body part to further assist in minimizing swelling and is used in conjunction with elevation. The best way to do a compressive wrapping is by having the compression have multiple layers that provide a cushion effect. The compression should be wrapped without causing the constriction of the blood supply which is recognized by increasing pain to the body part wrapped. Other signs of a tight compressive dressing are the cold sensation of the wrapped limb, blue discoloration of the body part, or change in color from the natural skin color. Elevation of an injured body part is best done by elevating the limb to the level of the heart. If elevation is lower than this, the effects of gravity on the veins, will increase vein pressure and cause the blood in these veins to have difficulty traveling back to the heart and result in limb swelling. Also by elevating, reducing swelling allows the blood supply to travel to the affected area if you are taking antibiotics.
The use of anti-inflammatory medication helps treat the pain, swelling, and inflammation that occur after injury. Examples of anti-inflammatories includes aspirin products, Ibuprofen (Motrin, Advil,) Naprosyn, Mobic, Indocin, Arthrotec,and Celebrex to name a few. All of these medications have side effects and should be taken with this knowledge in mind. Prescriptions should be discussed with your pharmacist and physician.
Controlled early motion and therapy to the involved limb decreases the effects of prolonged immobilization which results in stiffness, muscle atrophy, weakness and also shortens the time to return to the pre-injury state. The type of therapy recommended will depend on the type of tissue injured and the severity of the injury. Consult your surgeon for the best advice.
When treating a shoulder contusion, the use of ice, elevation of the hand, forearm or elbow to heart level and a compressive dressing may be needed. A sling will rest the arm until the doctor is visited for further instructions if the pain persists. Anti-inflammatory medication is helpful during the first 2-4 weeks after injury, depending on the injury severity. The home exercise program given to the elbow is referred to as the six pack shoulder program and is provided below. The program is progressed from exercise one through six and focuses first on obtaining motion in all planes and concludes in strengthening.
Shoulder Muscle injuries are closed injuries from the application of an excessive force in the various motions the shoulder can perform. The rotator cuff muscles for example can sustain a strain if lifting excessive weight one is not accustomed to in overhead or shoulder rotation movements. The exact muscle strain can be diagnosed in a physical exam by demonstrating pain in a muscle that is resisted in the motion in normally makes coupled with tenderness of the muscle. The most common muscle rupture occurring in the shoulder is the pectoralis major muscle. This usually occurs when doing a bench press against excessive weight on the muscle causing it to rupture from its attachment site on the humeral bone. When a pectoralis muscle rupture occurs, there is immediate chest wall pain, lack of chest wall symmetry, bleeding around the chest wall called ecchymoses and muscle spasm. This injury needs to be repaired within a one to two week period because waiting a longer period of time causes the muscle to retract, atrophy and shrink preventing it from being reattached. .
The most common tendon rupture is rupture in the shoulder is the rotator cuff tendons and the long head of the biceps tendon. These shoulder injuries are covered under the tendon section of the shoulder, along with shoulder bursitis and tendonitis.