Session 7: Functional Anatomy of the Shoulder Flashcards
What does the shoulder girdle consist of?
The clavicle and the scapula.
What is the shoulder joint called?
The glenohumeral joint.
What are the other joints in the shoulder girdle?
Sternoclavicular joint and the acromioclavicular joint.
Articulations of the glenohumeral joint.
The glenoid fossa of the scapula and the head of the humerus.
What is the scapulothoracic joint?
Articulation of the scapula with the thoracic wall however this is not a true joint.
Features of the glenohumeral joint.
The humeral head is larger than the glenoid fossa (golf ball sitting on a tee).
Ball and socket joint + synovial joint.
Large range of movement. Great flexibility and mobility at the expense of lower stability.
What is the anatomical neck of the humerus?
Obliquely directed forming an obtuse angle with the body of the humerus.
It’s between the head of the humerus and the great tubercle/lesser tubercle region.
What attaches on the anatomical neck?
The articular capsule of the shoulder joint. Also marks the region of the epiphyseal growth plate during the growth in length of the humerus in childhood.
What is the surgical neck of the humerus?
A constriction below the tubercles of the greater tubercle and lesser tubercle.
Much more frequently fractured than the anatomical neck of the humerus.
What can a fracture in the area of the surgical neck cause?
Damage to axillary nerve and posterior circumflex humeral artery.
What is the glenoid labrum?
An additional rim of fibrocartilaginous tissue around the edge of the glenoid cavity.
Functions to deepen the socket and reduce the risk of dislocation.
What reinforces the joint capsule of the glenohumeral joint?
The rotator cuff muscles + ligaments.
Where is the glenohumeral joint the weakest?
At its inferior aspect because of no reinforcement.
There are three ligaments of the glenohumeral joint. Which?
Superior GHL
Middle GHL
Inferior GHL
Where can the ligaments of GHJ be found?
On the anterior aspect of the joint which reduces the risk of anterior dislocation which is the most common direction of dislocation of the shoulder.
What are the other ligaments of the shoulder region?
Conoid ligament and trapezoid ligament which form the coracoclavicular ligament linking the coracoid process of the scapula to the clavicle.
Coracohumeral ligament linking the coracoid process of the scapula and the greater tubercle of the humerus.
Transverse humeral ligament.
Coraco-acromial ligament.
Features of the transverse humeral ligament.
Creates a tunnel between the greater and lesser tuberosities of the humerus to allow passage of the long head of the biceps.
Features of the coraco-acromial ligament.
Provides the roof of the subacromial space which is a tunnel above the glenohumeral joint that allows passage of the supraspinatus tendon. This ligament prevents superior dislocation of the humerus when a person falls onto their outstretched hand.
Rotator cuff muscles.
SITS Supraspinatus Infraspinatus Teres minor Subscapularis
Innervation and action of supraspinatus.
Suprascapular nerve C5,C6. First 15 degrees of abduction.
Innervation and action of infraspinatus.
Suprascapular nerve C5, C6 lateral rotation.
Innervation and action of teres minor.
Axillary nerve C5, C6 lateral rotation and adduction.
Innervation and action of subscapularis.
Upper and lower subscapular nerves C5, C6 medial rotation.
C5 is responsible for shoulder abduction and lateral rotation
Bursae of the shoulder girdle.
Subacromial bursa
Subscapular bursa