Glenoid labrum
Glenoid
labrum. Schematic drawing of the transverse section. Morphologic variants of the glenoid labrum with relative distribution in percentage for the anterior labrum. a: 50%. Triangular with line of increased signal intensity along the hyalin articular cartilage. b: 20%. Rounded. c: 7%. Comma-shaped flattened. d: 3%. Absent. e: 15%. Cleaved. f: 8%. Notched. g: Central increase in signal intensity. h: Linear increase in signal intensity. The posterior labrum generally exhibits a triangular or rounded form. After "MRI of the musculoskeletal system; Martin Vahlensieck; ISBN 0865778752, 9780865778757"
The glenoid labrum is a fibrocartilaginous structure that attaches as a rim to the articular cartilage of the glenoid fossa and serves to deepen and increase the surface area. In this capacity, it acts as a static stabilizer of the glenohumeral joint, preventing dislocation and subluxation at the extremes of the range of motion.
Gross anatomy
The glenoid labrum is approximately 4 mm thick and is round or triangular in cross-section.
Attachments
The capsule of the glenohumeral joint attaches to the glenoid labrum. The glenoid labrum is continuous with:
- superiorly: tendon of the long head of biceps brachii
- anteriorly:
- anterior band of the inferior glenohumeral ligament
- middle glenohumeral ligament (variably)
Blood supply and innervation
The outer glenoid is vascular and the inner glenoid is avascular . See glenohumeral joint for further details of named vessels and nerves.
Radiographic features
The glenoid labrum can be described in two ways :
- clock face
- 12 o'clock: superior
- 3 o'clock: anterior
- 6 o'clock: inferior
- 9 o'clock: posterior
- segments
- superior
- anterosuperior
- anteroinferior
- inferior
- posteroinferior
- posterosuperior
Variant anatomy
Related pathology
Siehe auch:
