Case Of the Week (COW) 21 June 2015
Hill Sach lesion
Findings:
X ray true AP view with neutral position does not show the lesion stryker's view shows cortical depression in the posterolateral head of the humerus - Hill sach lesion.
Discussion:
A Hill–Sachs lesion is a cortical depression in the posterolateral head of the humerus. It results from forceful impaction of the humeral head against the anteroinferior glenoid rim when the shoulder is dislocated anteriorly. Stryker notch view /AP radiographs of the shoulder with the arm in internal rotation offer the best yield while axillary views and AP radiographs with external rotation tend to obscure the defect. However, pain and tenderness in the injured joint make appropriate positioning difficult and in a recent study of plain film x-ray for Hill–Sachs lesions, the sensitivity was only about 20%. i.e. the finding was not visible on plain film x-ray about 80% of the time It appears as a sclerotic vertical line running from the top of the humeral head towards the shaft. If large then a wedge defect may be evident. Both MRI and CT are very sensitive to this lesion, which appears as a region of flattening or a wedge-shaped defect (with bone marrow oedema on MRI acutely) seen involving the posterolateral humeral head above the level of the coracoid. This is usually seen in the most superior few slices, were the humeral head should be rounded. It is important to note that below the level of the coracoid the humeral head normally flattens out posterolaterally and this should not be misinterpreted as a Hill-Sachs lesion.
Contributed By:
Prof. S Babu Peter, Dr Arun Prasad
Barnard Institute of Radiology
Hill Sach lesion
Findings:
X ray true AP view with neutral position does not show the lesion stryker's view shows cortical depression in the posterolateral head of the humerus - Hill sach lesion.
Discussion:
A Hill–Sachs lesion is a cortical depression in the posterolateral head of the humerus. It results from forceful impaction of the humeral head against the anteroinferior glenoid rim when the shoulder is dislocated anteriorly. Stryker notch view /AP radiographs of the shoulder with the arm in internal rotation offer the best yield while axillary views and AP radiographs with external rotation tend to obscure the defect. However, pain and tenderness in the injured joint make appropriate positioning difficult and in a recent study of plain film x-ray for Hill–Sachs lesions, the sensitivity was only about 20%. i.e. the finding was not visible on plain film x-ray about 80% of the time It appears as a sclerotic vertical line running from the top of the humeral head towards the shaft. If large then a wedge defect may be evident. Both MRI and CT are very sensitive to this lesion, which appears as a region of flattening or a wedge-shaped defect (with bone marrow oedema on MRI acutely) seen involving the posterolateral humeral head above the level of the coracoid. This is usually seen in the most superior few slices, were the humeral head should be rounded. It is important to note that below the level of the coracoid the humeral head normally flattens out posterolaterally and this should not be misinterpreted as a Hill-Sachs lesion.
Contributed By:
Prof. S Babu Peter, Dr Arun Prasad
Barnard Institute of Radiology