Shoulder joint Flashcards
What type of joint is the shoulder joint?
Synovial joint
Ball and socket
What are the articulating surfaces of the shoulder joint?
Head of humerus
Glennoid fossa of scapula
What are the articulating surfaces covered with?
Hyaline cartilage
What else is the glennoid fossa covered with?
What is it called?
Rim of fibrocartilage
Called glennoid labrum
What is the purpose of the glennoid labrum?
To deepen the glennoid cavity
so head of humerus fits into it more
increases stability of joint
What does the joint capsule extend from?
Anatomical neck of humerus
to
Border of glennoid fossa
What is a feature of the joint capsule? Why?
Loose
to allow a greater range of movement - particularly abduction
What is a synovial bursa?
Fluid filled sac
surrounded by synovial membrane
What is the purpose of a synovial bursa?
To reduce friction between tendons and other joint structures
What are the bursae of the shoulder joint?
Subacromial bursa
Subscapular bursa
Where is the subacromial bursa located?
Inferior to acromion, deltoid
Superior to supraspinatus tendon
Where is the subscapular bursa located?
Between scapula
and subscapularis tendon
What are the ligaments of the shoulder joint?
Glenohumeral ligaments
Coracohumeral ligaments
Transverse humeral ligaments
Coracoacromial ligament
What are the different glenohumeral ligaments?
Superior
Middle
Inferior
Where do the glenohumeral ligaments attach?
Anatomical neck of humerus
Border of glennoid fossa
Where does the coracohumeral ligament attach?
Coracoid proces
Greater tubercle of humerus
What is the function of the coracohumeral ligament?
Supports joint capsule superiorly
Where does the transverse humeral ligament attach?
Lesser tubercle
Greater tubercle
What is the function of the transverse humeral ligament?
Hold tendon of long head of biceps in intertubercular groove
Where does the coracoacromial ligament attach?
Coracoid process
Acromion
What is formed by the coracoacromial ligament?
The coracoacromial arch
What is the function of the coracoacromial ligament?
Prevent superior dislocation of humerus
Which ligaments are thickening of the joint capsules? Which isn’t?
Glenohumeral ligaments, coracohumeral ligament, transverse humeral ligament are all thickenings of the joint capsule
Coracoacromial ligament isn’t thickening of joint capsule
What is the blood supply of the shoulder joint?
Anterior and posterior circumflex humeral arteries
What are the movements of the shoulder joint?
Flexion
Extension
Abduction
Adduction
Lateral rotation
Medial rotation
Which muscles flex the shoulder joint?
Coracobrachialis
Biceps brachii
Anterior deltoid
Pectoralis major
Which muscles extend the shoulder joint?
Posterior deltoid
Latissimus dorsi
Which muscles abduct the shoulder joint?
Supraspinatus 0-15 degrees
Lateral deltoid 15-90 degrees
Trapezius and serratus anterior rotate scapula upwards to allow over 90degrees abduction
Which muscles adduct the shoulder joint?
Teres major
Pectoralis major
Latissimus dorsi
Which muscles laterally rotate the shoulder joint?
Infraspinatus
Teres minor
Which muscles medially rotate the shoulder joint?
Subscapularis
Teres major
Latissimus dorsi
Pectoralis major
What factors contribute to stability of the shoulder joint?
Glennoid labrum
Ligaments - reinforce joint capsule
Rotator cuff - resting tone pulls humeral head into glennoid cavity
What factors contribute to mobility of the shoulder joint?
Ball and socket joint
Humeral head is much larger than glennoid fossa
Loose joint capsule
