Shoulder Region I Flashcards
osteology and arthrology
What does the shoulder region consist of?
clavicle, scapula, proximal humerus (also sternum and thoracic cage)
List the movements at the clavicle.
elevation and depression (around an anteroposterior axis), protraction and retraction (around a vertical axis) and posterior and anterior rotation (around a mediolateral axis)
How does the clavicle develop?
the clavicle develops via both intramembranous and endochondral ossification
What type of bone is the clavicle?
Long Bone
List the movements at the scapula.
upward rotation, downward rotation, anterior tilt, posterior tilt, internal rotation, external rotation
What is the scapular plane?
30-45 degrees from the frontal plane
What are the three joints of the shoulder region?
sternoclavicular, acromioclavicular, glenohumeral
What is the structural and functional classification of the sternoclavicular joint?
synovial saddle, biaxial diarthrosis
List the passive structures that stabilise/restrict the SCJ
anterior sternoclavicular ligament, posterior sternoclavicular ligament, intra-articular disc, interclavicular ligament, costoclavicular ligament
What does the anterior sternoclavicular ligament restrict?
retraction of medial end of the clavicle
What does the posterior sternoclavicular ligament restrict?
protraction of medial end of the clavicle
What does the interclavicular ligament restrict?
lateral displacement of medial end of the clavicle
What does the intra-articular disc restrict?
medial displacement of medial end of the clavicle
What does the costoclavicular restrict?
restricts everything apart from inferior displacement
Why are SCJ dislocations uncommon?
bc SCJ is well stabilised, lots of ligaments surround it
What is the structural classification of the acromioclavicular joint?
synovial plane joint
What are the ligaments that are associated with the ACJ?
superior and inferior acromioclavicular ligament, trapezoid ligament, conoid ligament, coracoacromial ligament
What does the superior and inferior acromioclavicular ligament restrict?
restricts all glides of the clavicle on acromion
What does the trapezoid ligament restrict?
restricts scapula moving medial relative to clavicle; helps prevent medial displacement of the acromion process
What does the conoid ligament restrict?
restricts lateral clavicle moving superior
What does the coracoarcomial ligament restrict?
if the GHJ is very unstable it can restrict the superior migration of the HOH
Where does the most common fracture in the clavicle occur?
middle 1/3
What is conjuct rotation?
sequential motion, rotation that only accompanies movement of the arm/shoulder
What is the structural and functional classification of GHJ?
ball and socket multiaxial diarthrosis
Where does the glenoid labrum attach?
fibrocartilage rim attached to the margin of the glenoid fossa
What is the glenoid labrum functions?
increases depth of the glenoid fossa, increases the articular contact area
What are the ligaments which support the GHJ?
coracohumeral ligament, superior glenohumeral ligament, middle glenohumeral ligament, inferior glenohumeral ligament, transverse humeral ligament
Which 2 ligaments provide the main resistance to inferior translation of the humerus when the upper limb is adducted?
coracohumeral and superior glenohumeral ligament
What does the coracoacromial arch consist of?
acromion and coracoid process and coracoacromial ligament
What is the subacromial space?
a space between the acromion of the scapula, where the tendons of long head of biceps brachii and supraspinatus run
What is scapulohumeral rhythm?
kinematic interaction between the scapula and the humerus; interaction is important for optimal function of the shoulder
What is the function of the intra-articular disc?
It increases stability and thus makes an even distribution of forces
Where is the clavicle most commonly fractured and how?
direct fall onto shoulder and the middle 1/3
What is the glenohumeral joint heavily reliant on?
non-bony structures
- labrum
- capsule-ligaments
- muscles
