Shoulder And Arm Flashcards
Bones of the shoulder
Clavicle
Scapula
Humerus
List the shoulder joints
Stenoclavicular
Acromioclavicular
Glenohumeral
(Scapulothoracic)
What type of joint is the glenohumeral joint?
Ball + socket
Difference between the shoulder and hip joint
Glenohumeral joint is shallower - more mobile
What type of bone is the scapula?
Irregular bnoe
What is the articulation of the scapula?
Glenohumeral joint
Acromioclavicular joint
What does the glenohumeral joint articulate?
Scapula - glenoid fossa
Humerus - head
What does the Acromioclavicular joint articulate?
Clavicle - acromial facet
Scapula - acromion
Bony landmarks on lateral surface of scapula
Glenoid fossa
Supraglenoid tubercle
Infraglenoid tubercle
Bony landmarks on the posterior surface of the scapula
Spine
Acromion
Infraspinatus fossa
Supraspinous fossa
What type of bone is the clavicle?
Long bone
Location of the clavicle
Extends between manubrium of sternum + acromion of scapula
Functions of the clavicle
- Attaches upper limbs to trunk
- Protects underlying neurovascular structures
- Transmits force from the upper limb to axial skeleton
Articulation of the clavicle
Sternoclavicular joint
Acromioclavicular joint
What does the sternoclavicular joint articulate?
Manubrium of sternum
Clavicle - sternal facet
Function of the shaft of the clavicle
Acts as a lint of origin + insertion for:
- deltoid
- trapezius
- subclaviculus
- pectoral major
- stenocleidomastoid
- sternohyoid
What type of joint is the acromioclavicular joint?
Plane type synovial joint
Function of the acromioclavicular joint
Small degree of axial rotation
Anteroposterior movemnent
Initiated by movement elsewhere due to no muscles directly on joint - passive
What attaches to the acromial end of the clavicle and where?
Coracoclavicular ligament
Conoid ligament to consider tubercle
Trapezoid ligament to trapezoid line
What are the atypical features of the acromioclavicular joint?
Articulate surfaces lined with fibrocartilage
Joint cavity partially divided by articular disc
What normally lines the articular surfaces of joints?
Hyaline cartilage
What is the articular disc in the joint cavity of he acromioclavicular joint?
A wedge of fibrocartilage
Suspended form upper part of capsule
What are the stabilising ligaments of the acromioclavicular joint?
Acromioclavicular ligament
Coracoclavicular ligament - conoid + trapezoid
Where is the acromioclavicular ligament between?
Acromion to lateral clavicle
Horizontally
Where is the conoid ligament between?
Coracoid process of scapula to conoid tubercle of clavicle
Vertically
Where is the trapezoid ligament between?
Coracoid process of scapula to trapezoid line of clavicle
Vertically
What does the joint capsule of the acromioclavicular joint consist of?
- Loose fibrous layer
- Synovial membrane lining > secretes synovial fluid
Function of the loose fibrous layer of the joint capsule of the acromioclavicular joint
Encloses two articular surfaces
Gives rise to articular disc
What type of joint is the sternoclavicluar joint?
Saddle type synovial joint
What does the sternocalvicular joint consist of?
Sternal end of clavicle
Manubrium of sternum
Upper medial part of 1st costal cartilage
Atypical features of sternoclavicular joint
Articular surfaces lined with fibrocartilage
What does the articular disc of the sternoclavicular joint do?
What is its function?
- Separates joint into two compartments
- Allows clavicle + manubrium to slide over each other more freely
Mobility of sternoclavicular joint
Very mobile
Strength of sternoclavicular joint
Very strong
Movements of the sternoclavicular joint
Elevation/shrugging of shoulders
Depression/drooping of shoulders
Rotation
Protraction
Retraction
What is protraction?
Moving shoulder girdle anteriorly
What is retraction?
Moving shoulder girdle posteriorly
What does the proximal humerus articulate with?
Glenoid fossa
Glenohumeral joint
What does the distal humerus articulate with?
Head of the radius
Trochlear notch of ulna
Function of the intertubercular sulcus/groove
- Separates the two tubercles
- Tendon of long head of bicep brachii runs through
What are the edges of the intertubercluar sulcus called?
Lips
What does ‘a lady between two majors’ refer to?
Insertions of the intertubercular sulcus + lips
Lateral lip - pectoralis major
Intertubercular sulcus - latissimus doris
Medial lip- teres major
Insertion of lateral lip of intertubercular sulcus
Pectoralis major
Insertion of medial lip of intertubercular sulcus
Teres major
Insertion of intertubercular sulcus
Latissimus dorsi
What cartilage lines the glenohumeral joint?
Hyaline cartilage
What type of joint is the glenohumeral joint?
Ball + socket synovial joint
Is the glenoidhumeral joint more stable or mobile?
Highly mobile + flexible at the expense of stability
Why is the glenohumeral joint not very stable?
Shallow glenoid fossa
What is the glenoid labrum?
Rim of fibrocartilaginous tissue around edge of glenois fossa
Function of the glenoid fossa
Increases stability by deepening socket
Decreased risk of dislocation
What makes the glenohumeral joint more stable?
Glenoid fossa
Rotator cuff muscles
Ligaments - superior, middle + inferior
What part of the glenohumeral joint is the weakest and why?
Inferior aspect
No rotator cuffs to reinforce
List the glenohumeral ligaments
Superior GHL
Middle GHL
Inferior GHL
Where are the glenoidhumeral ligaments located?
Anterior aspect of the glenohumeral joint
Function of the glenohumeral joint
Reinforce the joint capsule
Increase stability
Decrease risk of anterior dislocation
List the ligaments of the shoulder
Superior GHL
Middle GHL
Inferior GHL
Coracoclavicular ligament - conoid + trapezoid
Transverse humeral ligament
Coraco-acromial ligament
Where is the transverse humeral ligament?
Between the greater + lesser tubercles of humerus
Function of the transverse humeral ligament
Provides tunnel for long head of biceps
Where is the coraco-acromial ligament
Between the Coracoid process + acromion
Function of the coraco-acromial ligament
Provides tunnel for supraspinatus tendon
Prevents superior dislocation
Mechanism of superior dislocation of shoulder
Falling on outstretched hand
List the superficial extrinsic shoulder muscles
Trapezoid
Latissimus dorsi
List the deep extrinsic shoulder muscles
Levator scapulae
Rhomboid minor
Rhomboid major
List the intrinsic shoulder muscles
Deltoid
Teres major
Rotator muscles - supraspinatus
- infraspinatus
- teres minor
- subscapualris
Origin of the trapezius muscle
External occipital protuberance
Nuchae ligament
Spinous processes C7-T12
Insertion of the trapezius
Clavicle
Acromion
Spine of scapula
Innervation of the trapezius
Spinal accessory nerve
Proprioceptor fibres from C3-4
Action of the trapezius
Upper fibres - ABduction >90°
Middle fibres - retract scapula
Lower fibres - pull scapular inferiorly
Clinical test for the power of the trapezius muscle
Ask patient to shrug their shoulders whilst you attach to push them back down
