Joints Of The Shoulder Flashcards
Name the 3 joints of the shoulder complex.
- Sternoclavicular
- Acromioclavicular
- Glenohumeral
Where does the sternoclavicular joint occur?
Between proximal end (sternal facet) of clavicle and clavicular notch of sternum.
Which movement(s) does the sternoclavicular joint allow?
Movement of clavicle:
- predominantly in antero-posterior and vertical planes
- some rotation also occurs
Where does the acromioclavicular joint occur?
Between acromial end of clavicle and medial surface of acromium.
Which movement(s) does the acromioclavicular joint allow?
Movement in anteroposterior and vertical planes with some axial rotation.
What is the acromioclavicular joint reinforced by?
- Small acromioclavicular ligament
- superior to joint, running horizontally from acromion to lateral clavicle.
- Much larger coracoclavicular ligament
- provides much of the weight-bearing support for upper limb on clavicle
- maintains position of clavicle on acromion
- spans distance between coracoid process and inferior surface of acromial clavicle end
- comprises an anterior trapezoid ligament (inserts on trapezoid line of clavicle) and a posterior conoid ligament (inserts on conoid tubercle of clavicle)
Where does the glenohumeral joint occur? What type of joint is it?
Between head of humerus and glenoid cavity of scapula.
Ball and socket joint.
Which movements does the glenohumeral joint allow?
Flexion, extension, abduction, adduction, redial rotation, lateral rotation and circumduction.
What are the static stabilisers of the glenohumeral joint?
- Articular congruency/anatomy
- Glenoid labrum
- fibrocartilaginous collar that deepens and peripherally expands the glenoid cavity
- Fibrous membrane of joint capsule
- Superior, middle and inferior glenohumeral ligaments
- Extracapsular ligaments:
- coracoacromial ligament
- coracoclavicular ligaments
- coracohumeral ligament (less important)
- transverse humeral ligament
- Negative intra-articular pressure
Name the dynamic stabilisers of the glenohumeral joint.
- Rotator cuff muscles
- Biceps brachii
- Muscles crossing shoulder
Name the rotator cuff muscles (and their innervation).
- Supraspinatus (suprascapular nerve)
- Infraspinatus (suprascapular nerve)
- Teres minor (axillary nerve)
- Subscapularis (upper and lower subscapular nerves)
What are the actions of the rotator cuff?
- Supraspinatous: abduction of the shoulder
- Infraspinatous and teres minor: external rotation of the shoulder
- Subscapularis: internal rotation of the shoulder
Which muscles (and nerves) cause shoulder abduction?
1st 90 degrees come from GH joint:
- 0-15 degrees = supraspinatus (suprascapular n.)
- 15-90 degrees = deltoid (axillary n.)
> 90 degrees comes from scapulo-thoracic joint through scapula rotation:
- upper trapezius and serratus anterior
Which muscles (and nerves) cause shoulder adduction?
(Muscles joining humerus to trunk)
- Pectoralis major (medial and lateral pectoral n.)
- Latissimus dorsi (thoracodorsal n.)
- Teres major (thoracodorsal n.)
Which muscles (and nerves) cause shoulder flexion?
- Anterior deltoid fibres (axillary n.)
- Pectoralis major (medial and lateral pectoral n.)
- Coracobrachialis (musculocutaneous n.)
- Biceps brachii (musculocutaneous n.)
