U1: Bones & Joints of Shoulder Region

what is the glenohumeral joint (GH)

a ball & socket joint

• that is formed bw the humeral head / glenoid fossa

• considered highly mobile

movements permitted by the GH joint

1. flexion / extension

2. abduction / adduction

3. medial / lateral rotation

what is the scapulothoracic joint (ST)

a pseudojoint (“false” joint)

• that is formed bw the scapula / thoracic cage (ribs)

• considered highly mobile

movements permitted by the ST joint

1. elevation / depression

2. protraction / retraction

3. superior / inferior rotation

what is the scapula

a flat, triangular bone

• considered free-floating

• found over the posterior rib cage

function of the scapula

1. forms the scapular/pectoral girdle w/ the clavicle + proximal humerus

2. acts as muscle attachment

3. forms the GH joint

features/borders of the scapula

1. glenoid fossa

2. coracoid process

3. acromion process

4. subscapular fossa

5. supraspinous fossa

6. infraspinous fossa

7. spine of scapula

8. lateral border

9. vertebral border

10. inferior angle

11. superior angle

label the features (ANT scapula)

1. A - subscapular fossa

2. B - vertebral border (medial)

3. C - inferior angle

4. D - lateral border

5. E - glenoid fossa

6. F - coracoid process

7. G - acromion process

8. H - superior angle

label the features (POST scapula)

1. A - infraspinous fossa

2. B - spine of scapula

3. C - acromion process

4. D - supraspinous process

label the features (LAT scapula)

1. A - glenoid fossa

2. B - coracoid process

3. C - acromion process

what is the clavicle

the s-shaped long bone

• which holds the upper limb away from trunk

features of the clavicle

1. acromial end

2. sternal end

3. conoid tubercle

4. impression for costoclavicular ligament

label the following (clavicle)

1. A - acromion end

2. B - sternal end

3. C - conoid tubercle

4. D - impression for costoclavicular ligament

label the features (ant/post - proximal humerus)

1. A - deltoid tuberosity

2. B - surgical neck

3. C - anatomical neck

4. D - humeral shaft

5. E - lesser tuberosity

6. F - head of humerus

7. G - greater tuberosity

8. H - intertubecular groove

features of the GH joint

1. inferior capsule

2. glenoid labrum

3. synovium

4. superior capsule

5. bursa

6. biceps brachii tendon

what is the glenoid labrum

a ring of fibrocartilage

• which is attached to the rim of the glenoid fossa

• which deepens the glenoid fossa (stability)

what is the synovium

thin CT membrane

• which lines the inferior capsule

• produces synovial fluid

  • which is for nutrition + preventing friction

what is the inferior/superior capsule

a fibrous capsule

• which surrounds the GH joint

• which stabilizes the GH joint

what is bursa

small synovial fluid-filled sacs

• which reduce friction bw tendons / bones

• or tendons / overlying ligaments

types of bursa (in the GH joint)

1. subacromial bursa

2. subscapular bursa

location of the subacromial bursa

located inferior to the acromion process

location of the subscapular bursa

superficial to the GHJ capsule/ligaments

what is the superior glenohumeral ligament

found bw the glenoid labrum → lesser tuberosity

• which prevents anterior humeral translation

what is the middle glenohumeral ligament

runs to the anatomical neck of humerus

• which prevents anterior humeral translation

• which resists ER

what is the inferior glenohumeral ligament

a weak, loose structure

• which prevents inferior humeral translation

what is the coracohumeral ligament

found bw the coracoid process / greater tuberosity

• which reinforces the GH capsule

• which prevents inferior humeral translation

what is the coracoacromial ligament

found bw the coracoid process / acromion

• which prevents superior humeral translation

what is the transverse humeral ligament

a ligament

• which keeps the biceps brachii tendon tethered to intertubecular groove

• prevents if from popping out

what is the acromioclavicular joint (AC)

a planar joint

• which wants to be stable

movements permitted by the AC joint

1. superior / inferior rotation

2. medial / lateral rotation

3. anterior / posterior tilt of scapula

what is the acromoclavicular ligament

ligament which..

• connects acromion + clavicle

• prevents separation of AC joint

• is intrinsic to the AC joint

what is the coracoclavicular ligament

ligament which..

• has 2 parts:

  • (1) conoid - coracoid process → conoid tubercle of clavicle

  • (2) trapezoid portion

• which prevents superior clavicular translation

what is the coracoclavicular joint (CC)

not an actual joint

• but there’s a ligament holding it together

what is the sternoclavicular joint (SC)

a planar joint

• found bw sternum / clavicle

movements permitted by the SC joint

1. glide anterior / posterior (protraction/retraction)

2. glide superior / inferior (elevation/depression)

3. limited rotation

ligaments which support the SC joint

1. interclavicular ligament

2. costoclavicular ligament

3. anterior / posterior sternoclavicular ligament(s)

what is the interclavicular ligament

found bw the medial ends of both clavicles (across the sternum)

• which is extrinsic

• which prevents inferior gliding of clavicle (depression)

what is the costoclavicular ligament

found bw the 1st rib / clavicle (inferiorly)

• which is extrinsic

• which prevents superior gliding of clavicle (elevation)

what is the anterior/posterior sternoclavicular ligament

found bw the ant/post sternum / clavicle

• which is intrinsic

• which prevents ant/post gliding of clavicle