Topic 3 - The Upper Limb Flashcards
What are the 3 bones of the shoulder complex?
- Clavicle
- Scapula
- Humerus
What are the 4 joints of the shoulder complex?
- Glenohumeral
- Scapulothoracic
- Acromioclavicular
- Sternoclavicular
Function & Fracture of clavicle
- Connection b/w axial and appendicular skeleton
- increases ROM of scapula, thus upper limb
- Lateral 1/3rd goes inward to articulate with scapula. this bend is a weaker spot and is thus more susceptible to fractures.
- medial aspect tends to jut out of skin while lateral aspect is pulled down due to weight of UL
SCAPULA ANATOMY
CALVICLE ANATOMY
PROX. HUMERUS ANATOMY
Sternoclavicular joint properties
Only joing connecting UL to axial skeleton
- synovial saddle (biaxial) joint between sternal end of clavicle and clavicular notch of manubrium
- contains a fibrocartilaginous disc separating the joing into 2 distinct synovial cavities.
- disc increases ROM and allows the clavicle to move independantly of the manubrium. also plays a role in shock absorption
Ligaments of Sternoclavicular joint
- interclavicular ligament: stops elevation
- costoclavicular ligament: stops moving up
- sternoclavicular ligament (anterior and posterior) thickens capsule and prevents forwards and backwards movement
Movements of sternoclavicular joint
- elevation and depression
- protraction and retraction
- axial rotation: allowing for a greater ROM of scapula and GH joint (e.g. abduction)
Acromioclavicular joint properties
- articulation between medial acromion and lateral clavicle
- synovial plane (uniaxial) joint
- contains an incomplete/ partial disc
- reinforced by 3 ligaments grouped into 2 categories
Ligaments of acromioclavicular joint
- acromioclavicular ligament: wraps around the articulation
- coracoclavicular ligament: can be further divided into 2 parts. is v important for weight bearing and vertical stability
1. anterior trapezoid ligament (more lateral, limits scapular rotation)
2. posterior conoid ligament (more medial, prevents upward dislocation)
Sublaxation of acromioclavicular joint
- partial disclocation, is common
- occurs if coracoclavicular ligaments are torn
- complete ligament tear will result in an elevated clavicle and a drop in the shoulder and UL
Properties of the glenohumeral joint
- Ball and socket thus provides multiaxial movement
- shallow fossa in scapula and large humeral head. Allows for greater motility however less stability
Movements permitted at glenohumeral joint
- flexion/extension
- rotation
- adduction/ abduction
- medial and lateral rotation
- circumduction
- horizontal abduction/ adduction
When and where is the joint cpasule and synovial membrane of the glenohumeral joint loose? Why?
the joint capsule and synovial membrane is loose inferiorly during adduction of the shoulder to allow for stretch and permit movement for abduction.
What creates passive stability of the glenohumeral joint?
Bony projections: coracoid and acromion, prevents superior dislocation
ligaments
glenoid labrum
What is the Glenoid Labrum and what is its function?
the glenoid labrum is a fibrocartillaginous ring located outside of the glenoid fossa which deepens the socket
Name and describe the bony connections of the four ligaments of the glenohumeral joint as well as their function.
- glenohumeral ligaments: superior, middle and inferior bands reinforcing the capsule anteriorly
- coracohumeral ligament: runs from the coracoid process of the scapula to the greater tubercle of the humerus. limits external rotation, inferior translation and excessive upwards movement
- transverse humeral ligament: located over intertibecular sulcus, holds tendon of long head of biceps into place
- coracoacromial ligament: runs from the coracoid process to the acromion. prevents superior dislocation
What provides active stability to the glenohumeral joint?
Muscles - specifically the rotator cuff muscles
How many rotator cuff muscles are there? Name each of them.
What are bursae? What are they made of? Where are they likely to be found in the GH joint?
small, fluid filled sacs. are located in areas requiring extra cushioning eg.
- between tendons and the joint capsule
- between bony protrusions and the joint capsule
- can be subcutaneous (between acromion and skin)
What movements are likely to cause dislocation of the GH joint?
- abduction, external rotation and extended position, causing the joint to become dislocated anteriorly and inferiorly, placing the neurovasculature at risk.
Why is the scapulothoracic joint not considered a true joint
Although it is bone on bone, it does not fit synovial or fibrocartilaginous categories.
Location and function of the scapulothoracic joint
Between anterior part of scapula (front) and the thoracic cage. It does not have any supporting ligaments.
It increases the range of movement at the shoulder which is aided by lateral and medial rotation of clavicular joints
