The back and shoulder regions Flashcards
what does the gelnohumeral joint do
The glenohumeral joint provides the articulation between the scapula and the humerus
what is the glenohumeral joint designed for
it is designed for movement rather than stability
how is the joint held tighter
The joint is held together by the action of shoulder region muscles
where do the scapula and clavicle articular with the thorax and with each other
The scapula and clavicle articulate with the thorax at the sternoclavicular joint and with each other at the acromioclavicular join
what does the clavicle do
The clavicle acts to transmit impacts from the upper limb to the axial skeleton
what are fractures to the clavicle caused by
Fractures of the clavicle tend to be caused therefore by falls on an outstretched hand where the force is transmitted back up the arm to the clavicle
what is the main joint of the shoulder
glenohymeral joint
what to the tendons of the rotator cuff muscles do
The tendons of the rotator cuff muscles strengthen the joint as well as three thickenings of the glenohumeral ligaments
describe the glenohumeral joint
- the glenoid cavity is shallow compared to the head of the humerus (4:1 disproportion),
- the joint capsule is baggy to allow the free movement of the joint.
- The glenoid labrum, a fibrocartilage ring around the glenoid cavity, helps slightly to deepen the glenoid cavity.
what are the main muscles of the back
- trapeizus
- latissimus dorsi
what do the trapezius and latissimus dorsi do
Muscles pull the scapula forward and backwards (protraction and retraction) and rotate the scapula which moves the glenoid fossa to allow more movement by the humerus.
what are the muscles around the shoulder
the deltoid and the four rotator cuff muscles (supraspinatus, infraspinatus, teres minor and subscapularis)
what do the rotator cuff muscles tendons do
Not only do the rotator cuff muscles move the shoulder joint, but their tendons merge together to form a protective sheath holding the head of the humerus in the glenoid cavity.
what is the main flexor of the shoulder
biceps
