Shoulder Impingement itself however is not the most common shoulder injury. The syndrome is not commonly seen on a radiograph at most hospitals and is more prevalent in smaller outpatient based clinics. The case study of impingement took place when a patient presented to the emergency department (ED) with the classical signs and symptoms of shoulder impingement syndrome. On the clinical details, the patient; a middle aged male, found it hard to adduct and abduct his hand after a knock in a weekend soccer a game. The gentleman was a gardener for a living and spent many years trimming hedges and so forth. The final sentence on the referral queried weather the patient may have shoulder impingement and bursitis. In addition to the clinical details it was noted, that the patient presenting to the ED required a translator due to an inability to proficiently speak the English language. The patient was brought into the department with his son and was asked to change into a gown; removing any radiographical artifacts which he may have had on at the time. The room was accordingly set as so the 24 x 30 film was placed portrait in the vertical bucky in readiness of the patient.
The routine projections for an impingement usually have a tendency to vary department to department. Most clinics and hospitals accommodating outpatients will ensure a minimum of four projections are taken. This department was no different as five projections were requested by the radiologist at the time. The hospital protocol required there be an AP shoulder in neutral rotation – with a 15-20 degree tube tilt, internal rotation and external rotation both with a – straight tube, centered approximately 5 cm below the coracoid process and a final, fifth projection which is a superior-inferior shoot down view. This view is particularly important to visualize the humeral head articulating with the glenoid fossa. However since this patient presented to the ED the two standard projection of the shoulder: an AP and a lateral were required. The radiographer upon checking with the radiologist confirmed that even for this patient irregardless of the fact he was not an outpatient would do all three views of the AP shoulder.
The patient was changed and asked the required hospital protocol questions, which ensures appropriate patient identity. Upon this, it was noted by both student and clinical supervisor that the patient was growing exceedingly anxious and distressed in regards to the procedure. The patient refused to face the tube and have his back against the bucky. To solve this misunderstanding, the son was summoned to the room and was asked to wear a lead apron if need be (which eventually wasn’t the case). The student under clinical supervision then proceeded to very slightly oblique the patient towards the affected left shoulder. The student in keeping with what had been taught by both supervisor and lecturer positioned the hand in supination, pronation and neutral rotation for the three views of the AP Shoulder. A left marker was placed on the vertical bucky, in an AP fashion on the lateral aspect of the left shoulder, as to prevent any obscuration of anatomy. Furthermore, it was noted that the field of view was collimated to the 24 x 30 cassette in a landscape orientation for the AP projections. However, In addition to this, for the neutral rotation position the tube was angled 20 degrees caudad to deliberately visualize the sub-acromial space. The same CR was used. The tutor selected an automatic exposure control for the vertical bucky. The exposure factors recorded by the quality assurance officer were in keeping to the usual 70 kV and 6mAs. Henceforth, the exposures for the shoulder were deemed in the acceptable region.
The next to view to query an impingement was the scapula y lateral. For the Y lateral view of the scapula, both student and radiographer found great difficulty in adequately abducting the patients left forearm and humerus due to severe pains. A compromise was reached and the improvised exposure was taken with the arm in partial abduction. For this exposure, the patient was manoeuvred to be partially posteriorly obliqued, hence a ‘PA sided’ left marker and the film was orientated in the correct portrait position, as to accommodate the inferior border of the scapula on the bottom of the cassette. The radiographer selected a manual exposure and increased kV approximately 75 which then meant a subsequent increase in mAs to approximately 13.
The very last projection which would be taken if in fact the patient was an outpatient was the reverse Lawrence method projection. This projection entailed a shoot-through projection centered to the mid anterior margin of the humeral head (‘dip’ in shoulder) to essentially visualise any associated problems to the gleno-humeral joint. The student would’ve used an 18 x 24 cm extremity type cassette and, with great difficulty would have tried to extend the patient’s arm whilst sitting on the chair; out as far as possible. This is the exact reason why this projection was not used, as the patient was in immense pain.
Upon the completion of the final projection, the translator was then politely ushered out and the patient was then re-united with his son. The pictures were then altered by the Medical Imaging Technologist (MIT) for optimal contrast and density whilst the patient was changing. In this while, the room had been reset and the student was then ready to direct the patient back to the waiting room.
Only after the student and MIT reached the processing room, were they clearly able to visualise the patient’s impingement on a sharper resolution PACS monitor.
The syndrome of shoulder impingement classically presents on a radiograph with a narrowing of sub-acromial space due to a possible spur or anything else which may impinge the space (Groud et al 2008). The syndrome of impingement can also be observed through the visualisation of an acromion spur in the sub acromial region. The acromion spur which is a less frequent clinical discovery can also be a major factor in the impingemnt of the shoulder.
As a radiographer images the shoulder for possible impingement, one may ask the question, ‘which projection from an impingement series is most useful in the clinical diagnosis of the condition?’
With the plain film technique, the shoulder as mentioned prior can be imaged in five distinct ways however three of these are all of the variation of one projection, the AP shoulder. The AP shoulder is by far the most beneficial projection in aiding with the diagnosis of shoulder pain and impingement. This is most certainly due to the fact the shoulder girdle is demonstrated in its entirety. The AP position can be achieved in two ways: supine or erect. For the purpose of the case study the patient presenting with impingemnt to the department, was positioned by the student erect; with the shoulders positioned at equidistance from the upright grid holder. Ideally in a true AP shoulder position for all three forms of hand rotation, the scapular body is at 35 to 45 degrees of obliquity, with the lateral scapula situated more anteriorly than the medial scapula and the glenoid fossa articulating surface is visualized. In addition to this, during external rotation the lesser tubercle is visualised most laterally and during internal rotation, most medially.
Furthermore, with the AP projection of the shoulder a radiologist can also visualize and effectively diagnose any major pathology around the sub-acromion and proximal humeral region. The pathology found on an AP shoulder projection is usually spurs, defects such as Hill Sach’s for example and other inflammations. More importantly, Impingemnt itself, may also present clinically with, “subacromial-subdeltoid bursitis and tendinopathy resulting from the compressive forces of the adjacent osseous structures.” (Sanders et al 2005)
The other projection taken by the MIT and student was the scapula y lateral projection. This lateral would be the second most beneficial projection of the impingemnt series. Not only does the Y lateral provide the radiologist with another view at 90 degrees to the AP it also aids in the diagnosis of any shoulder trauma and or impingement. “This projection is useful for delineating fractures of the coracoid process, acromion process, scapula and proximal humeral shaft.” (Sanders et al 2005) In the case study, the MIT positioned the patient as so the scapular body was in the true lateral position. It is vital for the lateral and vertebral borders to be superimposed because this ensures an accurate lateral view of the joint space (Wheless 2009). To properly superimpose the scapula, the patient, needs to be adequately obliqued. This degree of obliquity varies from department to department and is a much debated topic in shoulder radiography. For this study on a patient with impingement it was noted that the MIT didn’t fully bend the affected sides arm due to their being trauma to the shoulder. Henceforth, a modified obliqued lateral position was attained to visualise the all important sub-acromial space. “The scapular Y view is also used to evaluate the contour of the under surface of the acromion process.” (Sanders et al 2005) This evaluation of the acromion may give away clues to the radiologist the possibility of the pain being caused by an impingement.
The final projection from the impingemnt series can be considered as more a supplementary projection than anything else. The reason why this projection was in fact not carried out was because the patient was in alot of pain and it didn’t look as if there would be any reason to carry out this projection, as there were no evident indications of a dislocation to the glenohumeral joint. However, this axial projection is particularly effective in checking for any proximal humeral abnormalities which can be associated with shoulder impingement. This projection was ideally designed to illustrate any dislocations of the gleno-humeral joint and thus is not as beneficial in comparison to the AP shoulder or the Y lateral.
Due to technological advances in the field of medical imaging, shoulder impingement can now be visualised via the medical resonance method. As opposed to the conventional plane film impingement series, a single coronal oblique view will ensure that complete visualisation of any forms of obvious pathology in and around the sub-acromial space. In addition, this form of imaging further enhances the details and subsequent analysis of the patient (Wheless 2009). This will soon become more prevalent in imaging shoulder impingement as the MRI modality becomes more readily available to more clinics and hospitals.
In the case study conducted by both MIT supervisor and student it can be concluded that the AP shoulder projection is by far the most beneficial view using plain film to visualise the pathological condition known as shoulder impingement. The AP projection can be considered the most useful due to the fact it demonstrates all required anatomy and illustrates the relevant pathology which may occur in the shoulder (Wheless 2009). The AP projection is also widely known to be the least painful of the three positions as it does not involve the patient abducting their arm into the painful ‘impingement arc’ (Sanders et al 2005). A radiographer can utilise the AP shoulder and the remaining two projections of the impingement series to aid the radiologist into an accurate diagnosis of this debilitating condition.
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Reference List
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