[Anatomy of the glenoid labrum]

Most instabilities or pain syndromes are associated with injuries or morphologic changes in the glenoid labrum complex or long head of the biceps tendon origin. The first anatomic descriptions go back to Fick in 1910 and since then many authors have described the anatomy of these structures. It was Snyder who introduced the term SLAP lesions, classifying superior, anterior, posterior labrum changes into four grades. It is still unclear whether all of the described and arthroscopically observed changes are due to a post-traumatic, acquired lesion or whether anatomic variations can be present as well. In order to elucidate this problem, 36 cadaver shoulder joints were inspected macroscopically and sectioned for microscopic evaluation. Here the glenoid could be divided into an superior and an anterior- superior area demonstrating a wide variety of morphologic labral glenoid changes, while the dorsal and inferior sectors of the glenoid showed a relatively uniform anatomy of a firm labrum-glenoid bond. Four types of biceps tendon attachments could be identified similar to the description given by Vangsness. In addition, a variety of anterior-superior changes could be found. The sublabral hole as described by Esch in the clinical setting was found to be a physiologic variant. Precise knowledge of the anatomic morphology of the normal glenoid in its variations seems to be necessary to understand variants and allow for distinguishing between physiologic anatomic variants and pathoanatomic changes in imaging and the clinical setting.