Anatomic study of the superior glenoid labrum

Area of Science:

• Orthopedic Surgery
• Anatomy
• Biomedical Engineering

Background:

• The glenoid labrum is crucial for shoulder joint stability and function.
• Accurate anatomical knowledge is essential for diagnosing labral pathology and performing effective surgical repairs.

Purpose of the Study:

• To delineate the normal anatomy of the glenoid labrum.
• To differentiate normal anatomical variants from pathological lesions.
• To provide anatomical guidance for surgical repair techniques.

Main Methods:

• Examination of 20 dry bone scapulae and 19 cadaveric shoulders.
• Light microscopy of 12 radial slices through the glenoid.
• Detailed measurement of labral and capsular attachments.

Main Results:

• Identified distinct external capsular (7-8 mm from rim) and internal labral (4 mm from rim) circumferential ridges.
• Documented a consistent superior-posterior facet on the glenoid.
• Described variations in superior labrum (concave, loose attachment, common clefts/foramens) versus anterior-inferior labrum (convex, strong attachment).
• Noted common sublabral clefts/recesses/holes in the superior-anterior region, distinguishing them from pathological lesions elsewhere.

Conclusions:

• Normal anatomical landmarks of the glenoid labrum have been described.
• Distinguishing normal variants (e.g., superior-anterior sublabral clefts) from pathology is critical.
• Specific repair guidelines are proposed: biceps anchor to supraglenoid tubercle (6.6 mm from face) for superior labrum tears, and anterior-inferior labrum repair 4 mm onto the glenoid face.