Shoulder Flashcards
What type of joint is the shoulder?
Ball and socket
What bones make up the shoulder?
Humerus
Scapula
What is the ball of the shoulder joint?
Head of the humerus
What is the socket of the shoulder joint?
Glenoid fossa on the scapula
What is the anterior process on the scapula?
Coracoid process
What is the posterior process on the scapula?
Acromion process
What makes the shoulder unstable?
Shallow glenoid fossa
Disproportion of articular surfaces
Multiplanar movements
Lax capsule
How is stability achieved in the shoulder?
Rotator cuff muscles
Ligaments
Capsule
What are the attachments of the shoulder capsule?
Glenoid labrum + margins of glenoid fossa
Anatomical neck of humerus
Bridges the intertubular groove
Where is there a small opening of the capsule?
Anteriorly
Why is there a small opening?
Synovial membrane of shoulder joint communicates with supscapular bursa
What does the synovial membrane line in the shoulder?
Capsule
Intracapsular bone - up to edge of articular cartilage
Tendon of long head of biceps in joint cavity
What are the intracapsular ligaments?
3 gleno-humeral ligaments
- superior
- middle
- inferior
Where do the the gleno-humeral ligaments lie?
From glenoid labrum to the humerous
What is the function of the gleno-humeral ligaments?
Reinforce the capsule anteriorly
What are the extracapsular ligaments?
Coracoacromial ligament
Coracohumeral ligament
Transverse humeral ligament
Where does the coracoacromial ligament run?
Between acromion and coracoid process
Where does the coracohumeral ligament run?
From base of coracoid process to anterior part of greater tubercle
What is the function of the transverse humeral ligament?
Holds the tendon of the long head of biceps in place during shoulder movement
What is the coracoacromial arch?
Strong structure of bone and ligament that overlies the humeral ligament
What makes up the coracoacromial arch?
Coracoacromial ligamen t
Acromion
Coracoid process
What is the function of the coracoacromial arch?
Prevents upper displacement of the humerus
What muscles make up the rotator cuff?
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
Which rotator cuff muscles arise on the dorsal aspect of the scapula?
Supraspinatus
Infraspinatus
Teres minor
Where do the dorsal rotator cuff muscles insert?
Greater tubercle of humerus
Which rotator muscle arises on the ventral aspect of the scapula?
Subscapularis
Where does the ventral rotator cuff muscle insert?
Lesser tubercle of the humerus
Why are they called rotator cuff muscles?
Tendons of the muscles form a cuff - which fuses with the capsule and strengthens it
Which other muscles stabilise the shoulder joint?
Deltoid
Long head of biceps
Long head of triceps
What is a bursa?
Fluid filled sac
What are the main bursae in the shoulder?
Subacromial
Subscapular
What is the function of the subacromial bursa?
Facilitates movement of the supraspinatus tendon under the coracoacromial arch and deltoid
What is the function of the subscapular bursa?
Facilitates movement of the subscapularis tendon over scapula
How much space is there between the acromion and head of humerus?
1-1.5cm
What sits in the space between the acromion and head of humerus?
Subacromial bursa
Supraspinatus tendon
Capsule
Tendon of long head of biceps
What provides blood supply to the shoulder joint?
Anterior circumflex humeral artery
Posterior circumflex humeral artery
Subscapular artery
What is the nerve supply to the shoulder joint?
Axillary nerve
Suprascapular nerve
Lateral pectoral nerves
Which 2 joints supply movement to the shoulder?
Glenohumeral joint
Scapulothoracic joint
Which joint controls first 90 degrees abduction?
Glenohumeral joint
Which joint controls abduction above 90 degrees?
Scapulothoracic joint
Which muscle is responsible for 0-15 degrees abduction?
Supraspinatus
Which muscle is responsible for 15-90 degrees abduction?
Deltoid (central fibres)
Which muscles are responsible for abduction above 90 degrees?
Trapezius
Serratus anterior
Which muscles are responsible for extension of the shoulder?
Deltoid (posterior fibres)
Latissmus dorsi
Teres major
Which muscles are responsible for flexion of the shoulder?
Pec major (clavicular head)
Deltoid (anterior fibres)
Corachobrachialis
Biceps brachii
Which muscles are responsible for adduction of the shoulder?
Pec major
Latissimus dorsi
Teres major
Which muscles are responsible for medial rotation?
Pec major (sternal head)
Subscapularis
Teres major
Latissimus dorsi
Which muscles are responsible for lateral rotation?
Infraspinatus
Teres minor
