Shoulder Arthrology Flashcards
What is the shoulder complex comprised of?
Glenohumeral joint
Acromioclavicar joint
Sternoclavicular joint
Scapulothoracic articulation
What are the articulating surfaces in the glenohumeral joint?
The glenoid fossa of the scapula and head of the humerus.
Both covered in hyaline cartilage (typical for all synovial joints
What type of joint is the glenohumeral joint?
Ball and socket (diarthrodial)
What is the glenoid labrum and why does it exist?
The humeral head is larger that the glenoid fossa which gives the joint inherent instability.
The glenoid fossa is deepened by the glenoid labrum to try and reduce this effect
What ligaments exist at this shoulder region to provide stability?
Glenohumeral (3 bands)
Coracohumeral
Coracoacromial
Transverse humeral
What is considered the 5th rotator cuff (muscle coaptation)
Long head of biceps
Explain the negative intra-articular pressure that is maintained within the joint capsule?
The shoulder gets 10% of its stability from this.
It essentially sucks the humeral head, during injury/dislocation this pressure is lost
What type of joint is the acromioclavicular joint and what are its articulating surfaces?
A plane type synovial joint
Articulation between lateral end of clavicular and acromion of scapula
What are the ligaments at the AC joint?
AC ligament Coracoclavicular ligament (consists of Conoid/trapezoid ligament)
What are the articulating surfaces and type of joint for the sternoclavicular joint?
Saddle type synovial joint
Articulation between the sternal end of clavicle and manubriam of sternum
Ligaments at sternoclavicular joint?
SC ligament
Inter clavicular ligament
Costoclavicular ligament (key in biomechanics, acts as both fulcrum and axis of rotation)
What are bursa?
They act as a cushion between tendons
Example include supra-acromial,subscapularis,coracoclavicular
What is external shoulder impingement?
Mechanical encroachment of the soft tissue in the sub acromial place between humeral head and acromial arch
What is internal shoulder impingement?
Encroachment of the rotator cuff tendons between the humeral head and glenoid rim
