Glenohumeral Joint Flashcards
how many axes does this joint have?
it’s mulitaxial, has 3 axes
degrees of movement and types of movement?
3 degrees, adduction, abduction, rotation (L and M), anteversion, retroversion and circumduction
what type of a joint is the GH joint?
it’s a ball and socket joint
what are the articular surfaces?
head of the humerus, and glenoid cavity. both covered with hyaline cartilage. glenoid cavity is too small so it’s widened by the glenoid labrum, which is composed of fibrocartilagous tissue.
what is the size of the glenoid articular surface?
6cm squared
what is the axial recess?
it is a structure the inferior part of the capsule makes once the humerus is in the resting (anatomical) position
is this a stable joint?
No, the glenoidhumeral joint is unstable, because it doesn’t have many strong ligaments. It is a MUSCLE DEPENDENT joint, and the muscles that reinforce it are the deltoid, the biceps brachii, the coracobrachial, the subscapular muscle, bony processes as well as some rotator cuff muscles.
name the most important ligaments of the GH joint, and their origin/attachment sites.
the most important ones are:
- The coracohumeral ligament - from the base of the coracoid process to the greater and lesser tubercle. It radiates INTO the capsule
- Weak glenohumeral ligaments - originate from the glenoid labrum, then attach themselves to the lesser tubercle and the anatomical neck of the humerus. Superior, middle, inferior.
- Coracoacromial ligament - even though it’s not a part of the joint it plays a crucial role in preventing proximal dislocation of the humerus + it restricts abduction
what tendon is really important in securing the GH joint in place?
it is the tendon of m. biceps brachii. it originates from the supraglenoid tubercle, goes over the head of the humerus, and then goes through the intertubercular sulcus.
what are the most important synovial membrane extra strucures?
those are bursae:
1. the subtendinous bursa of m. subscapularis
2. the subacromial/subdeltoid bursa
3. between the acromion and the skin
4.the coracobrachial bursa
5. the synovial sac.
The last one is important because it wraps around the tendon of m. biceps brachii as it exits the capsule-protecting it.
which ligament keeps the tendon of m. biceps brachii in place?
the transverse ligament. goes from the greater to the lesser tubercle, enclosing the intertubercular sulcus where the tendon of m. biceps brachii can be found.
which are the rotator cuff muscles?
m. supraspinatus, m. infraspinatus, m. teres minor, m. subscapularis. they blend with the joint capsule and form a musculotendinous structure which wraps the joint anteriorly, posteriorly, superiorly.
