Shoulder Joint Flashcards
Name and classify
Ball and socket synovial joint
Bones
Head of humerus - 1/3 of a sphere
Glenoid fossa of scapula - shallow socket
Cartilage
Hyaline cartilage - friction free movement and shock absorbing
Additional features
Labrum - fibrocartilaginous, deepens the socket of glenoid fossa, stabilises joint
Subscapula and subacromial bursa - reduces friction
Capsule
Attached to articular margins
Loose inferiorly - allows mobility, allows movement of head of humerus when lifting the arm
Encloses tendon of long head of biceps
Strengthened by ligaments and the rotator cuff muscles
Synovial membrane
Lines capsule
Synovial fluid - nourishes cartilage, removes waste and reduces friction
Ligaments
Coracohumeral ligament - helps the integrity of the joint
Glenohumeral ligament - joint capsule support
Transverse humeral ligament - helps locate long head of biceps brachii in the intertubercular sulcus
Degrees of freedom
Three
Movements
Flexion
Extension
Abduction
Adduction
Circumduction
Medial (internal) rotation
Lateral (external) rotation
Blood supply
Branched of subclavian and axillary arteries
Nerve supply
Branches of suprascapular , axillary, subscapular, lateral pectoral and musculocutaneous nerves
Muscles - flexors
Deltoid (anterior fibres)
Pectoralis major
Biceps brachii
Coracobrachialis
Muscles - extensors
Deltoid (posterior fibres)
Latissimus dorsi
Teres major
Triceps (long head)
Muscles - abductors
Deltoid (middle fibres)
Supraspinatus
muscles - adductors
Pectoris major
Latissimus dorsi
Teres major
Coracobrachialis
Subscapularis
Muscles - medial rotators
Subscapularis
Deltoid (anterior fibres)
Pectoris major
Muscles - lateral rotators
Deltoid (posterior fibres)
Teres minor
Infraspinatus
