Remember when reporting on shoulder radiographs that these generally include some of the ribs within the area of the radiograph. Do check for any rib injuries such as in image 1, where a fracture of the first rib together with a clavicle fracture is seen. Perhaps these films should be reported by a radiologist, depending on the readers local protocols.

Fractures of the neck of humerus are usually quite straight forward but it should be stated in the report whether the fracture is through the surgical neck of humerus as in image 2, (these are most common), or the anatomical neck of humerus as is indicated in image 3. It is also possible, although not common, to have a lipohaemarthrosis associated with a fracture of the neck of humerus as in image 4 (courtesy of Michael Cotter, Bromley Hospital, Kent). Note also the inferior subluxation of the humerus caused by the pressure of the joint effusion. This can also be seen on images 3 and 5.

Image 5 shows separation of the greater tuberosity. In this case it is pretty obvious but these fractures can be minimally displaced or undisplaced and quite missable.

Image 6 on the left is demonstrating how to check for A.C. joint alignment. Remember that the acromion is a hook shaped bone which projects anteriorly, the reader needs to visualize the inferior surface, which usually appears as a white line because it is projected as end on bone. If a straight line is traced along the inferior surface of the acromion it should run nicely along the inferior surface of the clavicle, as it does in image 7. If it does not, then suspect some A.C.J. disruption as seen in image 8. This technique does not work with the paediatric shoulder as the bones are not fully ossified yet. In this case the reader needs to visualize in their mind what the bones would look like if fully ossified and make an assessment from that.

Scroll down to images 9 and 10 on the left. These will show the typical appearance of the anterior dislocation. With an anterior dislocation, the humeral head always moves anterior and usually medial and inferior to the glenoid. It is not unusual to see a fracture of the greater tuberosity with the anterior dislocation, see image 11. Remember to look at the whole radiograph, not just the area of interest.

Image 12 on the left is a posterior dislocation. However, any normal shoulder radiographed with full internal rotation, will appear the same. The most important thing to remember with posterior dislocations is that it is almost impossible to make the diagnosis from just an A.P. view. You must have a second view to see the humeral head posterior to the glenoid, and the axial is the best, as you can see in image 13, although not always easy to achieve. In which case the lateral scapula or "Y" view is useful. Image 14 is also a posterior dislocation and in this case it is more obvious that there is something wrong. Look at image 15 which is the "Y" view of the same shoulder. It can now be seen that the head of the humerus is posterior to the glenoid which lies at the intersection of the acromion, corocoid and blade of the scapula.

The posterior dislocation is not a very common injury but often follows electrocution or convulsion due to the fact that the internal rotator muscles pull the humerus around violently when they go into spasm.

As in any area of radiography it is important to get appropriate views to make an accurate diagnosis. A lot of radiographers shy away from the axial shoulder view on a traumatized patient as they believe it to be too painful. If done correctly with only a little abduction it will cause little extra pain and will be very useful.

Images 16, 17 and 18 on the left show the importance of the axial view. After seeing the A.P. view the radiographer thought this was a simple anterior dislocation of the shoulder joint as the humeral head was lying medially to the glenoid and therefore must be anterior to it (what about the fragments by the humeral head?). They did not want to cause any more discomfort to the patient and so produced a lateral scapular view. This, as the reader can see, was confusing, as it showed the humeral head partially over the glenoid and therefore not a dislocation as the A.P. suggests. If it were a true appearance it would be a subluxation.

The two radiographs seemed to be in conflict until all was revealed by producing an axial view. It can then be clearly seen that the humeral head has in fact been pushed through the anterior aspect of the glenoid (hence the fragments).

Fractures of the blade of the scapula are not very common but a good lateral view is required to pick them up, any rotation may close the fracture to the point where it is not easy to see. The fracture can usually be seen on the A.P. view but with the ribs and lung fields overlying it can at times be difficult. Look at images 19 and 20 for an example.

Image 23 shows the appearance of a chronic superior subluxation of the gleno-humeral joint. This is probably due to a chronic rotator cuff injury/atrophy. It can be seen that the head of humerus is impinging on the acromion. This is likely to need an orthopaedic referral.

Image 24 (courtesy of Michael Cotter, Bromley Hospital, Kent) shows the appearance of what is often called "the vacuum effect". It appears as a thin curvilinear lucency in the joint space which, although often referred to as a vacuum, some argue that it is in fact gas released into the joint due to atmospheric pressure changes. What ever it's cause, it is transient.