The Shoulder joint Flashcards
What joints are involved in movement of the shoulder?
- Glenohumeral
- Scapulothoracic
What is the articulating surface of the SJ?
-Between the head of humerus and the glenoid cavity of the scapula
What lines the articulating surface of the GHJ?
-Hyaline articular cartilage
What is the glenoid labrum?
-A fibrocartilaginous rim which deepens the glenoid cavity and increases the area of articulation
What is the cost of the shoulder joint being extremely mobile?
-It is the least stable joint
What makes the shoulder joint unstable?
- Sits shallowly in glenoid cavity
- Disproportionate articular surfaces
- Multiplanar movement
How is stability of the SJ achieved?
- Rotator Cuff muscles
- Ligaments
- Capsule
- Other muscles
What type of joint is the glenohumeral joint?
-Synovial ball and socket joint
What is the anatomical location of the capsule?
- Extends from glenoid labrum and glenoid cavity margins to anatomical neck of humerus
- Bridges the intertubecular groove
- Dips medially to the surgical neck
There is a small anterior gap in the capsule, what does this allow?
-Continuation of synovial membrane into subscapular bursa
What lines the fibrous capsule?
-Synovial membrane
Within the joint cavity, what does the synovial membrane line?
- Capsule
- Bone upto articulating cartilage
- Tubular sleeve around tendon of biceps
What is the function of the capsule of the SJ?
-Provide support as it is tough but lax to allow movement
Describe the intracapsular ligaments
-Fibrous bands which lay within the capsule and extend from the glenoid labrum to the humurus
Name the intracapsular ligaments
-Superior, middle and inferior gleno-humeral ligaments
Where, anatomically, do the intracapsular ligament provide support?
- Anteriorly
- Inferiorly
Name the extracapsular ligaments of the SJ
- Coracoacromial ligament (CAL)
- Coraco-humeral ligament (CHL)
- Coracoclavicular ligament (CCL)
- Transverse humeral ligament (THL)
Where is the coracoacromial ligament?
-Between the acromion and the coracoid process
What is the function of the transverse humeral ligament?
-Holds tendon of long head of biceps in place during movement
Where anatomically do the extracapsular ligaments provide support?
-Superiorly
What is the function of the coracoacromial arch?
-A strong structure which overlies the humeral head and prevents upper displacement of the humerus
Besides the rotator cuff, which other muscle support the SJ?
- Deltoid
- Long head of biceps and triceps
What structures lie inbetween the acromion and the humeral head? Why is this significant?
-Subacromial busa
-Rotator Cuff tendons
-Fibrous capsule
(Synovial membrane)
-Tendon of long head of biceps
-Synovial membrane
Any of these structures are at risk of impingement on aBduction
What are bursae?
-Small sacs filled with synovial fluid and lined with synovial membrane