Superior labrum and labral-bicipital complex: MR imaging with pathologic-anatomic and histologic correlation

Area of Science:

• Orthopedic Surgery
• Radiology
• Anatomy

Background:

• The superior labrum anterior-posterior (SLAP) lesion is a common shoulder injury.
• Accurate diagnosis of SLAP lesions is crucial for effective treatment.
• Understanding the anatomy of the superior labrum and its relationship with the biceps tendon is key.

Purpose of the Study:

• To analyze the anatomic relationship between the superior labrum, superior glenoid rim, superior glenohumeral ligament, and the long head of the biceps tendon.
• To evaluate the effectiveness of different Magnetic Resonance (MR) imaging techniques in visualizing these structures.
• To correlate imaging findings with histologic analysis.

Main Methods:

• Seventeen cadaveric shoulder specimens were imaged using 1.5-T MR scanners.
• Both unenhanced and gadolinium-enhanced MR arthrography (T1-weighted fat-suppressed) were performed.
• Specimens were histologically analyzed after gross anatomic correlation.

Main Results:

• A sublabral recess was identified in 71% of specimens.
• MR arthrography was superior to unenhanced MR imaging in visualizing the sublabral recess.
• Histologic analysis revealed altered intralabral patterns in 63% of sections, with some suggesting trauma.
• A close association between the superior labrum and biceps tendon was confirmed both grossly and histologically.

Conclusions:

• The attachment of the superior glenoid labrum to the glenoid rim exhibits significant variability.
• MR imaging may show overlap between physiologic recesses and type 2 SLAP lesions.
• T1-weighted fat-suppressed MR arthrography offers the optimal visualization of the superior labrum and the labral-bicipital complex.