Anatomy of the shoulder region Flashcards
Skeletal components
Clavicle
Scapula
Humerus
Joints
- glenohumeral joint
- acromioclavicular joint
Pectoral girdle
Clavicle
Scapula
Ligaments of the shoulder region
Stabilise/ support the shoulder region
- coracoclavicular
- acromioclavicular
- coracoacromial
- glenohumeral
Coracolavicular
Two parts
Major stabilising ligament
Coracoacromial
Forms arch
Provides support for head of humerus
Prevents superior dislocation
Glenohumeral joint
Highly mobile ball and socket joint
- abduction/ adduction
- flexion/ extension
- lateral/ medial rotation
- circrumduction
Abduction of the arm
Performed by deltoid
Supplied by axillary nerve
Deltoid
Origin: spine of scapula and acromion and clavicle
Insert: deltoid tuberosity
Deltoid muscle fibres
Posterior fibres: extension and lateral rotation
Anterior fibres: flexion and medial rotation
Adduction of the arm
Performed by latissimus dorsi, pectoralis major
Abduction/ adduction of the arm
Glenohumeral joint accommodates parts of movement
Rotation of scapula increases range of movement
Flexion of the arm
Short head of biceps
Long head of biceps
Coracobrachialis
Anterior fibres of deltoid
Extension of the arm
Long head of triceps
Posterior fibres of deltoid
Latissimus dorsi
Glenohumeral joint stability
Large humeral head
Shallow glenoid fossa
Unstable structure
Most frequently dislocated joint
Factors increasing stability
Coracoacromial arch
Glenohumeral ligaments
Deepening of glenoid fossa by glenoid labrum
Long heads of biceps (above) and triceps (below)
Tendons of rotator cuff muscles
Coracoacromial arch
Prevents superior dislocation
Glenohumeral ligaments
Supports anterior of joint
Glenoid labrum
Deepends glenoid fossa
Long head of niceps and triceps
Split joint
Long head biceps passes through capsule
Tendons of the rotator cuff
Four muscles
Insert on humerus close to joint
Fuse with the joint capsule
Forms cuff around joint
Rotator cuff muscles
Supraspinatus
Infraspinatus
Teres minor
Subscpularis
Surround joint on all sides except inferiorly
Rotator cuff muscles insertion
Supraspinatus, infraspinatus and teres minor insert into the greater tubercle
Rotator cuff function
Together: stabilise humeral head on glenoid fossa
Supraspinatus: initiate abduction
Infraspinatus: lateral rotation
Teres minor: lateral rotation
Subscapularis: medial rotation
Teres major
Should also be considered with the rotator cuff muscles
Performs medial rotation
Stabilises the humerus during abduction
Supraspinatus impingement
Supraspinatus most commonly injured
Limited space for tendon under coracoacromial arch
Blood supply
Rich blood supply
Scapula anastomosis
Allows continuous supply of blood to shoulder region during movement
From subclavian and axillary arteries
Nerve supply to the shoulder
From the brachial plexus
Posterior cord
Suprascapular nerve
Cords of the brachial plexus
Within axilla
Below pectoralis minor
Posterior cord
Upper/ lower subscapular nerves- subscapularis, teres major
Thoracodorsal nerve- latissimus dorsi
Quadrangular space
Between teres minor, humerus, teres major, long head of triceps
Clinical- fractiure of surgical neck can damage nerve and vessel
Lateral cord
Lateral pectoral nerve- pectoralis major
Medial cord
Medial pectoral nerve- pectoralis major/ minor
Medial cutaneous nerves to arm and forearm
