Scapula Shoulder Complex

Shoulder complex includes what structures?

scapula, clavicle, sternum, humerus, rib cage

what joints are part of shoulder complex?

sternoclavicular, acromioclavicular, glenohumeral joints

shoulder girdle vs shoulder joint

shoulder girdle: scapula, clavicle and sternum

shoulder joint: scapula and humerus

what are the 2 functions of the scapula

1. orient the glenoid fossa to allow maximum range of motion and use of UE

2. Provide a stable base for ball and socket movements of glenohumeral joint

what are the 4 main joints of the shoulder complex

• sternoclavicular joint

• acromioclavicular joint

• scapulothoracic articulation

• glenohumeral joint

what are the 3 ligaments of the sternoclavicular joint

1. anterior and posterior sternoclavicular joints

2. costoclavicular ligament

3. interclavicular ligament

function of the acromioclavicular ligament

maintain relationship between clavicle and scapula; prevents downward dislocation of the clavicle

function of the coracoclavicular ligament

provides stability

prevents superior dislocation of the clavicle

coracoacromial ligament

provides support to head of the humerus

prevents the upward dislocation of the humeral head

scaption

elevation of the arm in the plane and the scapula

(between flexion and abduction)

glenohumeral joint

articulation of head of humerus and glenoid fossa

labrum fucntions (3)

• deepens the curve of glenoid fossa

• increases articular surface (for stability)

• cushions the humeral head

what is another name for the subacromial bursa

the subdeltoid bursa

what is the main function of the glenohumeral ligaments? how many are there?

function: reinforce capsule

• 3 ligaments (superior, middle and inferior)

what is the function of the coracohumeral ligament

passive support of UE versus gravity

what is another word for protraction

scapular abduction

what is another word for retraction

scapular adduction

what type of force system is upward/downward rotation of the scapula

force couple

where does scapular tilt happen

occurs in the towards the end range of shoulder extension

• anterior capsular ligaments are stretched

• causes forward tilting of the scapula

what is the ratio of scapulohumeral rhythm

2:1 ratio between glenohumeral and scapulothoracic movement

120 degrees of glenohumeral motion

60 degrees of scapulothoracic motion

what are the 3 purposes of scapulohumeral rhythm

1. maintain glenoid fossa in optimal position to receive head of humerus

2. distributes motion between two joints permitting a larger ROM with more stability

3. Permits muscles acting on humerus to maintain a good length-tension relationship

muscles of scapular abduction

• serratus anterior

• pec minor

scapular adduction

• middle trap

• rhomboids

scapular depression

• pectoralis minor

• lower trap

scapular elevation

• upper trap

• levator scap

• rhomboids

scapular downward rotation

• pec minor

• rhomboids

scapular upward rotation

• upper traps

• lower traps

• serratus anterior