The Shoulder Flashcards
Name the bones of the pectoral girdle
clavicles, scapula, acromion (of scapula) and manubrium of the sternum
What is the role of the clavicles in the pectoral girdle?
Connects the upper limb to the trunk via the sternoclavicular joint, and this is the only connection of the upper limb to the rest of the body
What is the purpose of the pectoral girdle?
To keep the arm away from the thorax to allow maximum freedom of movement.
Describe what would happen if the clavicle was fractured
Weight of arm drags the lateral fragment inferiorly and the action of SCM muscles pulls the medial fragment superiorly leading to fraction. As clavicle also protects the brachial plexus, it’s important to ensure there’s no neurovascular damage incurred.
Name the visible structures present on the scapula
ANTERIOR: subscapular fossa, acromion, coracoid process and glenoid cavity
POSTERIOR: supraspinous fossa, infraspinous fossa, neck of scapula
Describe the location of the scapula
It’s a triangular flat bone on the posterolateral aspect of the thorax and overlies the 2nd to 7th ribs
Describe the function of the scapula
Point of attachment for many shoulder/pectoral girdle muscles
What is the subcutaneous point of the shoulder indicated by?
The acromion, which is the lateral end of the scapula spine.
Describe the sternoclavicular joint
This is a very strong joint, connects clavicle and manubrium (and first costal cartilage). Strength is due to strong ligaments.
Describe the acromioclavicular joint
Joint between acromion and clavicle and there are no muscles crossing this joint; muscles moving the scapula move the AC joint, it also has an articular disc as well as ligaments to restrict movement
What movements are possible at the scapula?
elevation, depression, protraction and retraction, upward and downward rotation
Which muscles control scapula elevation?
descending trapezius
Which muscles control scapula depression?
none, gravity
Which muscles control scapula protraction?
serratus anterior and pectoralis minor
Which muscles control scapula retraction?
middle trapezius
Which muscles control scapula upward rotation?
descending trapezius and serratus anterior
Which muscles control scapula downward rotation?
latissimus dorsi
Describe the glenohumeral joint
also known as the shoulder joint; connects glenoid cavity and the head of the humerus
Describe how the glenoid cavity is deepened
it is deepened by a ring of fibrocartilage known as the glenoid labrum
Which movements are possible at the glenohumeral joint?
All of them
Name the chief flexors of the shoulder joint
pectoralis major and deltoid
Name the chief extensors of the shoulder joint
latissimus dorsi and deltoid
Name the chief abductors of the shoulder joint
first ten degres is supraspinatus, thereafter is deltoid
What is extension at the shoulder joint?
Moving the arm backwards, behind the bum
What is flexion at the shoulder joint?
Bringing the arm forwards and upwards
Name the chief adductors of the shoulder joint
pectoralis major and latissimus dorsi
Name the chief medial rotator of the shoulder joint
Subscapularis
Name the chief lateral rotator of the shoulder joint
Infraspinatus
What is the ‘physiological scapulothoracic joint’?
The head of the humerus uses all of the available articular surface of the glenoid cavity at 90 degrees, so the scapula rotates to allow the remainder of movement using the serratus anterior and trapezius muscles to facilitate this movement . In abduction, 120 degrees occurs at the glenohumeral joint and 60degrees at the scapulothoracic joint
Name the 4 rotator cuff muscles
Supraspinatus, infraspinatus, subscapularis, teres minor
Describe how shoulder dislocation may occur
Tend to occur when shoulder joint fully abducted which tilts the head of the humerus inferiorly onto a weaker part of the joint
