Shoulder Joint. Rotator Cuff Muscles and Shoulder Joint Muscles Flashcards
What type of joint is the shoulder joint?
Synovial ball and socket
What are the articular surfaces in the shoulder joint?
Head of the humerus
Glenoid cavity of scapula
What surrounds the socket of the shoulder joint?
Glenoid/acetabular labrum
Rim of cartilage
What is the function of the glenoid labrum?
Increase depth of shoulder joint
Add stability to shoulder joint
Identify the structures labelled 1-5
SHOULDER LIGAMENTS
1- Coracohumeral ligament
2- Joint capsule
3- Coraco-acromial ligament
4- Glenohumeral ligaments
5- Transverse humeral ligament
What is the function of the glenohumeral ligaments?
Strengthen the anterior aspect of the joint capsule
What is the function of the coracohumeral ligament?
Strengthens the superior aspect of the joint capsule
What structures make up the coraco-acromial arch?
Acromion
Coracoid process of scapula
Coraco-acromial ligamenyt
What is the weakest part of the shoulder joint capsule and why?
The inferior part of the capsule
It is not protected by muscles or ligaments
What is the main function of bursae?
Provide cushioning around joints via their fluid filled interior
Which bursa communicates with the shoulder joint cavity?
The subscapular bursa
Identify the structures labelled 1-3
1- Subacromial bursa
2- Glenoid/acetbular labrum
3- Inferior pouch of glenohumeral joint capsule
What is the role of the subacromial bursa?
Allows movement of the supraspinatous tendon and deltoid
What common sporting injury damages the subacromial bursa?
Shoulder dislocation
Identify the structures labelled 1-4
ROTATOR CUFF MUSCLES
1- Subscapularis
2- Supraspinatus
3- Infraspinatus
4- Teres minor
What are the actions of the rotator cuff muscles on the glenohumeral joint?
Abduction
Adduction
Medial rotation
What is the most important function of the rotator cuff muscles?
To hold the humeral head in the glenoid cavity
What are the attachments of the deltoid muslce?
Lateral spine of scapula
Lateral third of clavicle
What are the actions of the anterior fibres of the deltoid?
Medially rotates and flexes at the shoulder joint
What are the actions of the middle fibres of the deltoid?
Abducts at the shoulder joint
What are the actions of the posterior fibres of the deltoid?
Extends and laterally rotates at the shoulder joint
What is the nerve supply to the deltoid?
Axillary nerve
C5 + C6
In what common injury is the axillary nerve often trapped and damaged?
Shoulder dislocation
In which dermatomes would you check for damage of the axillary nerve?
C5 and C6
What are the attachments of pectoralis major?
Medial third of the clavicle
Sternum
Ribs
What action does pectoralis major have on the shoulder joint?
Adduct and medially rotate the humerus
Where is the deltopectoral triangle?
Triangular space below the clavicle and between the deltoid and pectoralis major
What vein is found in the deltopectoral triangle?
Cephalic vein
What are the actions of serratus anterior?
Stabilise scapula during limb movements and keep it pulled against thoracic cage (MAIN FUNCTIONS)
Protraction of scapulae
What is the nerve supply of serratus anterior?
Long thoracic nerve
C5-7
What clinical sign is seen when the long thoracic nerve is injured?
Scapular winging
What is the function of the superior, middle and inferior fibres of the trapezius?
Supeior fibres- elevates the scapula
Middle fibres- retracts the scapula
Inferior fibres- depresses the scapula
What is the innervation of the trapeius?
Spinal accessory nerve CNXI
What actions do teres major have on the shoulder joint?
Adducts and medially rotates the shoulder
What are the actions of latissimus dorsi on the shoulder joint?
Extends, adducts and medially rotates the shoulder
What shoulder joint muscles cause flexion of the shoulder joint?
Anterior part of deltoid
What shoulder joint muscles cause extension of the shoulder joint?
Latissimus dorsi
Posterior part of deltoid
Which shoulder joint muscles cause adduction of the shoulder joint?
Latissimus dorsi
Teres major
Subscapularis
What shoulder joint muscles cause abduction of the shoulder joint?
Middle part of deltoid
Supraspinatus
What shoulder joint muscles casue medial/internal rotation of the shoulder joint?
Subscapularis
Latissimus dorsi
Pectoralis major
Teres major
Anterior part of deltoid
What shoulder joint muscles cause lateral/external rotation of the shoulder joint?
Teres minor
Infraspinatus
Posterior part of deltoid
