Presentation
Shoulder pain for two years, no trauma history given.
Patient Data
Thickening, mild signal inhomogeneity and loss of fibrillar appearance in the place of overlap between supraspinatus and infraspinatus muscle tendons - signs of moderate tendinosis.
Absent labrum in anterosuperior quadrant of the glenoid.
Thickened, cordlike appearance of the middle glenohumeral ligament (MGHL).
Atypical glenoid origin of the anterior band of inferior glenohumeral ligament (IGHL), which originates together with the middle glenohumeral ligament anteriorly to the origin of the long head biceps tendon (LHBT). It then courses medially to the MGHL and inserts typically, at the surgical neck of the humerus.
Extravasation of the contrast agent inferiorly to the axillary pouch - given the normal appearance of both IGHL bands (anterior and posterior) - it is most likely iatrogenic in nature. Similar extravasation is also visible below the subscapular recess of the shoulder joint capsule.
Case Discussion
This case provides two interesting anatomical variants: the Buford complex and an atypical glenoid insertion of the anterior band of inferior glenohumeral ligament.
Buford complex is a pretty rare glenoid labrum variant (incidence of about 3%). It consists of absent glenoid labrum in the anterosuperior quadrant (from 12 to 3 o'clock) and a thickened medial glenohumeral ligament. The resulting altered mechanics of the shoulder joint probably makes it more prone to SLAP lesions 5, but that is not the case in this study.
The usual origin of the IGHL is the anterior labrum between 2 and 4 o'clock 2,3. There is, however, some variance of the origin point - the so-called high origin (above the glenoid's equator) was in one study described in 4 out of 10 cadavers 4.
The cause of pain in this patient was (in absence of labral pathology) probably the aforementioned focal rotator cuff tendinopathy.