- Discussion:
- w/ in joint capsule, variable thickenings (superior, middle, &
IGHL), are
primary components of static restraint in glenohumeral joint.
- Scapulohumeral Ligaments: (5 scapulohumeral ligaments):
-
rotator interval capsule:
-
superior glenohumeral ligaments:
- has two sites of origin: supraglenoid tubercle - just anterior to long head of biceps origin on superior labrum and the base of coracoid;
- arthroscopically it may be hidden by the biceps tendon;
- inserts on proximal aspect of
lesser tuberosity;
- at 0 deg abduction, superior & MGHL develops most strain, and together w/ the coracohumeral ligament stabilize the shoulder in adduction;
- it helps to prevent posterior and inferior instability;
-
coacohumeral ligament:
- an extraarticular ligament on the lateral surface of coracoid and inserts into the greater and lesser tuberosities, spanning the bicipital groove;
- sectioning of coracohumeral ligaments produces anteroinferior instability;
- represents folded thickening of glenohumeral capsule in area of rotator interval between subscapularis & supraspinatus;
- w/ body upright & arm in dependent position, coracohumeral & MGHL play important roles in resisting inf translation.
- references:
- The structure and function of the coracohumeral ligament. An anatomic and microscopic study. DE Cooper et al. JSE Surg. Vol 2. 1993. p 70-77.
-
An anatomic and histologic study of the coracohumeral ligament.
-
Arthroscopic release of the rotator interval and coracohumeral ligament: An anatomic study in cadavers.
-
Subscapularis, medial, and lateral head coracohumeral ligament insertion anatomy. Arthroscopic appearance and incidence of "hidden" rotator interval lesions.
- middle glenohumeral ligaments:
- arises from the anatomic neck and inserts into the mid-anterior labrum;
- middle part of the ligament is seen just posterior to subscapularis;
- may be poorly defined in upto 30% of patients;
- when a Buford complex is present (physiologic antero-superior sublabral hole), the middle ligament may appear cord-like and will often be frayed;
- attempts to close down this sub-labral hole w/ a absorable tack anchor may precipitate
frozen shoulder;
- middle glenohumeral ligament limits external rotation at 45 deg of abduction;
- w/ body upright & arm in dependent position, coracohumeral & MGHL play important roles in resisting inf translation;
- references:
The Buford complex - the "cord like" middle glenohumeral ligament and absent anterosuperior labrum complex: a normal anatomic capsulolabral variant.
MM Williams et al. Arthroscopy Vol 10: p 241-247. 1994.
-
midrange stability:
- concavity compression: muscular compression of the humeral head into the glenoid fossa stabilizes the glenohumeral joint against shear forces.
- depends on the depth of the concavity and the magnitude of the compressive force.
- references:
- Dynamic glenohumeral stability provided by rotator cuff muscles in the mid-range and end-range of motion: JBJS Am 2000;82:849-857.
- Mechanics of glenohumeral instability. Clin Sports Med 1991;10:783-788.
- antero-inferior glenohumeral ligament
- Posterior Capsule:
-
antero-inferior glenohumeral ligament
- posteriosuperior quad of capsule is devoid of ligamentous condensations;
- posterior capsule and the
teres minor restrain internal rotation;
- posteroinferior capsule provides primary restraint to post dislocation;
- post-sup capsule & sup GHL provides 2ndry restraint to post dislocation;
Stabilizing mechanism preventing anterior dislocation of GHJ.
J Bone Joint Surg 1981;63A:1208. Turkel SJ, Panio MW, Marshall JL:
Capsular ligaments of the shoulder. Anatomical and functional study of the anterior superior capsule.
Year Book: Anterior Capsulolabral Reconstruction of the Shoulder in Athletes in Overhand Sports.
Capsular restraints to anterior-posterior motion of the abducted shoulder: A biomechanical study.
SJ O'Brien et al. J. Shoulder Elbow Surgery. Vol 4. 1995. p 298-308.
The structure and function of the coracohumeral ligament. An anatomic and microscopic study.
DE Cooper et al. J. Shoulder Elbow Surg. Vol 2. 1993. p 70-77.
The Vascular Anatomy of the Glenohumeral Capsule and Ligaments: An Anatomic Study.
Comparison of Glenohumeral Mechanics Following a Capsular Shift and Anterior Tightening
Combined Posterior Bankart Lesion and Posterior Humeral Avulsion of the Glenohumeral Ligaments Associated With Recurrent Posterior Shoulder Instability.
