shoulder Flashcards
what type of joint is the shoulder joint? what does it allow?
- ball and socket joint
- allows the most degree of freedom for locomotion
what are the four main bones of the shoulder?
- scapula
- clavicle
- sternum
- humerus
what is the clavicle?
- collarbone
where is the sternum?
- in the middle
what is the scapula?
- irregular shaped bone that has many bony landmarks
what is the humerus? what does it articulate with?
- main bone of the arm
- articulates with glenoid cavity via the head
what is between the acromion and clavicle? what does this do?
- fibrous joint
- made of dense connective tissue
- limits movement
what is the spine of the scapula?
- goes across the middle and forms the acromion
where is the coracoid process? what does it allow?
- sticks out anteriorly
- provides attachment for ligaments & tendons
where is the acromion?
- wraps around coracoid and comes against clavicle
what is the concave hollow surface?
- glenoid fossa
where are the tubercles located?
- greater tubercle is close to humeral head but more later
- lesser tubercle located more anterior and medial
what is the olecranon? what does it provide?
- tuberosity that provides insertion for triceps
what is the purpose of the labrum?
- increases articular surface for movement of the humeral head
what always comes first in ligaments?
- corcaco
what comes last in ligaments?
- clavicular
what are the seven main ligaments?
- acromioclavicular
- sternoclavicular
- coracoacromial
- coracoclavicular
- joint capsule
- coracohumeral
- glenohumeral
what is the acromioclavicular ligament?
- between acromion and clavicle
what is the sternoclavicular ligament?
- between clavicle and sternum
- anterior and posterior to provide stability during movement
what is the coracoacromial ligament?
- between acromion and coracoid
what is the coracoclavicular ligament?
- between coracoid and clavicle
what surrounds the joint? what does it provide?
- joint capsule
- provides stability
what is the coracohumeral ligament?
- between coracoid and humerus
what is the glenohumeral ligament? what are the three types?
- between glenoid cavity and humerus
- superior, middle and inferior
what are the three true joints?
- glenohumeral joint
- sternoclavicular joint
- acromioclavicular joint
what are the other 2 non true joints?
- scapulothoracic articulation
- subacromial articulation
what is the glenohumeral joint?
- ball & socket joint
- formed by head of humerus and glenoid fossa
what is the sternoclavicular joint?
- conformed by articular surface of sternum (manubrium) and lateral end of clavicle will articulate with chromium of scapula
what is the acromioclavicular joint?
- top of the shoulder where the acromion meets the lateral end of the clavicle
- diarthrosis ( 3 axes)
what is the scapulothoracic articulation?
- sliding junction between deep aspect of scapula/ thoracic rib cage
- enables integration of movements of scapula against chest wall
what is the subacromial articulation?
- space directly beneath acromion and directly above shoulder joint
what happens to the humeral head and acromion when the arm is lifted?
- draw nearer to each other
- so space narrows
what is the rotator cuff?
- set of four muscles specialised in structural support
what are the four muscles of the rotator cuff?
- infraspinatus
- teres minor
- supraspinatus
- subscapularis
where is the infraspinatus and what does it cause?
- below the spine of the scapula on posterior side
- pulls on humerus to rotate the shoulder back
where is the teres minor? what does it create?
- below infraspinatus
- synergist with infraspinatus
- creates lateral rotation
where is the supraspinatus? what does it cause?
- above the spine, inserts into humerus
- synergist with deltoid
- lifts humerus up (abduct humerus/ extend shoulder)
where is the subscapularis? what does it cause?
- under scapula on anterior side
- originates on medial side of the scapula and inserts into head of humerus
- pulls on humerus to cause medial & anterior rotation
what does the rotator cuff provide?
- stabilisation
- wraps around the humerus to provide extra support
what is the rotator cuff described as? what would happen without the rotator cuff?
- concavity compression
- without= if deltoid pulled up it would lift the head of the humerus upwards causing less efficient movement
what do the rotator cuff muscles do during movement?
- centralises the head of the humerus
what are the four flexors of the shoulder?
- anterior deltoid
- pectoralis major
- coracobrachialis
- biceps brachii
where does the anterior deltoid originate and insert?
- originates at lateral third of clavicle
- inserts onto deltoid tuberosity of humerus
where does the pectoralis major originate and insert?
- originates at middle half of clavicle, sternum and upper six costal cartilage
- inserts onto lateral lip of bicipital groove of humerus
where does the biceps brachii originate and insert?
short head= tip of coracoid process
long head= supraglenoid tuberosity
- inserts into tuberosity of radius and fascia of forearm via bicipital aponeurosis
what are the three shoulder extensors?
- posterior deltoid
- latissimus dorsi
- triceps brachii
where does the posterior deltoid originate and insert?
- originates at the spine of scapula
- inserts into deltoid tuberosity of humerus
where does the latissimus dorsi originate and insert?
- originates at inferior 6 thoracic vertebrae (T6-T12), lumbar vertebrae (L1-L5), crest of sacrum and iliac crest
- inserts into intertubercle sulcus of humerus
where does the triceps brachii originate and insert?
- originates on infraglenoid tubercle
- inserts into olecranon
what are the two abductors?
- middle deltoid
- supraspinatus
where does the middle deltoid originate and insert?
- originates at lateral third of clavicle, acromion and spine of scapula
- inserts into deltoid tuberosity of humerus
where does the supraspinatus originate and insert?
- originate at supraspinous fossa of scapula
- inserts onto greater tubercle of humerus
what are the four adductors?
- latissimus dorsi
- teres major
- coracobrachialis
- pectoralis major
where does the teres major originate and insert?
- originates at lateral inferior angle and lower 1/2 of lateral border of scapula
- inserts into medial lip of bicipital groove of humerus
what are the five medial rotators?
- latissimus dorsi
- teres major
- subscapularis
- pectoralis major
- anterior deltoid
where does the subscapularis originate and insert?
- originates on subscapular fossa of scapula
- inserts onto lesser tubercle of humerus
what are the three lateral rotators?
- infraspinatus
- teres minor
- posterior deltoid
where does infraspinatus originate and insert?
- originates on infraspinatus fossa of scapula
- inserts into greater tubercle of humerus
where does the teres minor originate and insert?
- originates at lateral border of scapula
- inserts into greater tubercle
where does posterior deltoid originate and insert?
- originates at the spine of the scapula
- inserts into deltoid tuberosity of the humerus
