diagnosing other pathologies of the shoulder joint. the logical use of diagnostic tests is an important component of effective clinical practice. clinical judgement, rather than over-reliance on mri or any other modality, is strongly advised in determining the cause of shoulder pain, or planning its treatment, since rotator cuff tears are also found in some without pain or symptoms. the role of x-ray, mri, and ultrasound is adjunctive to clinical assessment and serves to confirm a diagnosis provisionally made by a thorough history and physical examination. over-reliance on imaging may lead to overtreatment or distract from the true dysfunction causing symptoms. symptoms symptoms may occur immediately after trauma (acute) or develop over time (chronic). acute injury is less frequent than chronic disease, but may follow bouts of forcefully raising the arm against resistance, as occurs in weightlifting, for example. in addition, falling forcefully on the shoulder can cause acute symptoms. these traumatic tears predominantly affect the supraspinatus tendon or the rotator interval and symptoms include severe pain that radiates through the arm, and limited range of motion, specifically during abduction of the shoulder. chronic tears occur among individuals who constantly participate in overhead activities, such as pitching or swimming, but can also develop from shoulder tendinitis or rotator cuff disease. symptoms arising from chronic tears include sporadic worsening of pain, debilitation, and atrophy of the muscles; noticeable pain during rest; crackling sensations (crepitus) when moving the shoulder; and inability to move or lift the arm sufficiently, especially during abduction and flexion motions. pain in the anterolateral aspect of the shoulder is not specific to the shoulder, and may arise from, and be referred from, the neck, heart, or gut. symptoms will often include pain or ache over the front and outer aspect of the shoulder, pain aggravated by leaning on the elbow and pushing upward on the shoulder (such as leaning on the armrest of a reclining chair), intolerance of overhead activity, pain at night when lying directly on the affected shoulder, and pain when reaching forward (e.g., unable to lift a gallon of milk from the refrigerator). weakness may be reported, but is often masked by pain and is usually found only through examination. with longer-standing pain, the shoulder is favored and gradually loss of motion and weakness may develop, which, due to pain and guarding, are often unrecognized and only brought to attention during the physical exam. primary shoulder problems may cause pain over the deltoid muscle intensified by abduction against resistance – the impingement sign. this signifies pain arising from the rotator cuff, but cannot distinguish among inflammation, strain, or tear. individuals may report that they are unable to reach upward to brush their hair or to lift a can of food from an overhead shelf. signs no single physical examination test distinguishes reliably between bursitis, partial-thickness, and full-thickness tears. the most useful single test for infraspinatous tendon tears is the drop sign (the examiner lifts the arm straight out from the body with the palm up, the person then needs to hold it there for 10 seconds) and the external rotation lag sign (with the arm by the side and the elbow bent to 90 degrees the person tries to rotate outwards against resistance). a combination of tests seems to provide the most accurate diagnosis. for impingement, these tests include the hawkins-kennedy impingement sign, in which an examiner medially rotates the injured individual's flexed arm, forcing the supraspinatus tendon against the coracoacromial ligament and so producing pain if the test is positive, a positive painful arc sign, and weakness in external rotation with the arm at the side. another common impingement test is the neer test. the neer test is performed by the examiner maximally forward flexing the patient's arm with the scapula in a depressed position. localized pain on the anterior shoulder suggests subacromial impingement, whereas posterior shoulder pain suggests internal impingement. for the diagnosis of full-thickness rotator cuff tear, the best combination appears to include once more the painful arc and weakness in external rotation, and in addition, the drop arm sign. this test is also known as codman's test. the arm is raised to the side to 90° by the examiner. the injured individual then attempts to lower the arm back to neutral with palm down. if the arm drops suddenly or pain is experienced, the test is considered positive. mri mri of normal shoulder intratendinous signal mri of rotator cuff full-thickness tear magnetic resonance imaging (mri) and ultrasound are comparable in efficacy and helpful in diagnosis, although both have a false positive rate of 15–20%. mri can reliably detect most full-thickness tears, although very small pinpoint tears may be missed. in such situations, an mri combined with an injection of contrast material, an mr-arthrogram, may help to confirm the diagnosis. it should be realized that a normal mri cannot fully rule out a small tear (a false negative) while partial-thickness tears are not as reliably detected. while mri is sensitive in identifying tendon degeneration (tendinopathy), it may not reliably distinguish between a degenerative tendon and a partially torn tendon. again, magnetic resonance arthrography can improve the differentiation. an overall sensitivity of 91% (9% false negative rate) has been reported, indicating that magnetic resonance arthrography is reliable in the detection of partial-thickness rotator cuff tears. however, its routine use is not advised, since it involves entering the joint with a needle, with the potential risk of infection. consequently, the test is reserved for cases in which the diagnosis remains unclear. ultrasound musculoskeletal ultrasound has been advocated by experienced practitioners, avoiding the radiation of x-ray and the expense of mri while demonstrating comparable accuracy to mri for identifying and measuring the size of full-thickness and partial-thickness rotator cuff tears. this modality can also reveal the presence of other conditions that may mimic rotator cuff tear at clinical examination, including tendinosis, calcific tendinitis, subacromial subdeltoid bursitis, greater tuberosity fracture, and adhesive capsulitis. however, mri provides more information about adjacent structures in the shoulder, such as the capsule, glenoid labrum muscles, and bone, and these factors should be considered in each case when selecting the appropriate study. xray projectional radiograph of normal glenohumeral position. high-riding humeral head in a rotator cuff tear. x-ray projectional radiography cannot directly reveal tears of the rotator cuff, a 'soft tissue', and consequently, normal x-rays cannot exclude a damaged cuff. however, indirect evidence of pathology may be seen in instances where one or more of the tendons has undergone degenerative calcification (calcific tendinitis). the humeral head may migrate upward (high-riding humeral head) secondary to tears of the infraspinatus, or combined tears of the supraspinatus and infraspinatus. the migration can be measured by the distance between: a line crossing the center of a line between the superior and inferior rims of the glenoid articular surface (blue in image). the center of a "best-fit" circle positioned over the humeral articular surface (green in image) normally, the former is positioned inferiorly to the latter, and a reversal therefore indicates a rotator cuff tear. prolonged contact between a high-riding humeral head and the acromion above it may lead to x-ray findings of wear on the humeral head and acromion; secondary degenerative arthritis of the glenohumeral joint (the ball and socket joint of the shoulder), called cuff arthropathy, may follow. incidental x-ray findings of bone spurs at the adjacent acromioclavicular joint may show a bone spur growing from the outer edge of the clavicle downward toward the rotator cuff. spurs may also be seen on the underside of the acromion, once thought to cause direct fraying of the rotator cuff from contact friction, a concept currently regarded as controversial. in-office testing as part of clinical decision-making, a simple, minimally invasive, in-office procedure, the rotator cuff impingement test, may be performed. a small amount of a local anesthetic and an injectable corticosteroid are injected into the subacromial space to block pain and provide anti-inflammatory relief. if pain disappears and shoulder function remains good, no further testing is pursued. the test helps to confirm that the pain arises primarily from the shoulder, rather than being referred from the neck, heart, or gut. if pain is relieved, the test is considered positive for rotator-cuff impingement, of which tendinitis and bursitis are major causes. however, partial rotator-cuff tears may also demonstrate good pain relief, so a positive response cannot rule out a partial rotator-cuff tear. however, with demonstration of good, pain-free function, the treatment will not change, so the test is useful in helping to avoid overtesting or performing unnecessary surgery. classification tears of the rotator cuff tendon are described as partial or full thickness, and full thickness with complete detachment of the tendons from bone. partial-thickness tears often appear as fraying of an intact tendon. full-thickness tears are "through-and-through". these tears can be small pinpoint or larger buttonhole, or involve the majority of the tendon where it still remains substantially attached to the humeral head and thus maintains function. full-thickness tears may also involve complete detachment of the tendon(s) from the humeral head and may result in significantly impaired shoulder motion and function. shoulder pain is variable and may not be proportional to the size of the tear. tears are also sometimes classified based on the trauma that caused the injury: acute, as a result of a sudden, powerful movement which might include falling onto an outstretched hand at speed, making a sudden thrust with a paddle in kayaking, or following a powerful pitch/throw subacute, arising in similar situations but occurring in one of the five layers of the shoulder anatomy chronic, developing over time, and usually occurring at or near the tendon (as a result of the tendon rubbing against the overlying bone), and usually associated with an impingement syndrome. prevention long-term overuse/abuse of the shoulder joint is generally thought to limit range of motion and productivity due to daily wear and tear of the muscles, and many public web sites offer preventive advice. (see external links) the recommendations usually include: regular shoulder exercises to maintain strength and flexibility using proper form when lifting or moving heavy weights resting the shoulder when experiencing pain application of cold packs and heat pads to a painful, inflamed shoulder strengthening program to include the back and shoulder girdle muscles as well as the chest, shoulder and upper arm adequate rest periods in occupations that require repetitive lifting and reaching size according to a study which measured tendon length against the size of the injured rotator cuff, researchers learned that as rotator cuff tendons decrease in length, the average rotator cuff tear severity is proportionally decreased, as well. this shows that larger individuals are more likely to develop a severe rotator cuff tear if they do not "tighten the shoulder muscles around the joint". position another study observed 12 different positions of movements and their relative correlation with injuries occurred during those movements. the evidence shows that putting the arm in a neutral position relieves tension on all ligaments and tendons. stretching one article observed the influence of stretching techniques on preventive methods of shoulder injuries. increased velocity of exercise increases injury, but beginning a fast-movement exercise with a slow stretch may cause muscle/tendon attachment to become more resistant to tearing. muscle groups when exercising, exercising the shoulder as a whole and not one or two muscle groups is also found to be imperative. when the shoulder muscle is exercised in all directions, such as external rotation, flexion, and extension, or vertical abduction, it is less likely to develop a tear of the tendon. treatment a rotator cuff tear can be treated operatively or non-operatively. no benefit is seen from early rather than delayed surgery, and many with partial tears and some with complete tears will respond to nonoperative management. consequently, an individual may begin with nonsurgical management. however, early surgical treatment may be considered in significant (>1 cm – 1.5 cm) acute tears, in young individuals with full-thickness tears who have a significant risk for the development of irreparable rotator cuff damage, or the patient is very active and/or uses their arms for overhead work or sports. rotator-cuff surgery appears to result in similar benefits as nonoperative management. as a conservative approach has less complications and is less expensive it is recommended as initial treatment. non-operative treatment those with