2)Osteology & Arthrology Glenohumeral Joint

Question 1

What does the triad-arrangement of the sternoclavicular, acromioclalivular and glenohumeral joint ensure

Answer 1

> Ensures that clavicular movements at the sternoclavicular and acromioclavicular joints are always associated with movements of the scapula

> And movements of the scapula are often accompanied by movements of the humerus at the glenohumeral joint.

Question 2

What gives the upper limb its freedom of movement

Answer 2

Summation of the movements of these three individual yet mutually interdependent joints which gives the upper limb its freedom of movement.

Question 3

Describe the articular surface

Answer 3

See file

Question 4

Describe the fibrous capsule

Answer 4

See file

Question 5

Synovial membrane

Bursa also included but on a separate card

Answer 5

Lines capsule extends downwards as a pouch when arm is hanging by the side

Attaches articular margin of both bones = reflected upwards on medial side of humeral shaft

Medial part of epiphyseal line Intercaspular but is extrasynovial

Limited posteriorly surface due to subscapularus tendon= may be sufficiently large to extend and lie below subcoracoid bursa

Double layer tubular sheath of synovial membrane continues with glenoid attachment encloses the intercaspular part of the long head of biceps

Question 6

Caspular ligaments

Answer 6

Superior glenohumeral ligament
Middle glenohumeral ligament
Inferior glenohumeral ligament
Transverse humeral

Question 7

Superior glenohumeral ligament

Answer 7

Slender

Lat, parallel bicep tendon to upper lesser tubercle

Glenoid margin + adjacent labrum ➖anterior attachment bicep

Question 8

Middle glenohumeral ligament

Answer 8

Below superior glenohumeral ligament ➖ lesser tubercle below insertion of subscapularis

Question 9

Inferior glenohumeral ligament

Answer 9

• most well developed occasionally absent

Obliquely

Glenoid margin below notch anterior boarder glenoid labrum➖ anteroinferior part neck of humerus

As it passes from scapula to humerus the upper part of the inferior ligament merges with lower part of middle glenohumeral ligament

Question 10

Glenohumeral ligaments have no real stabilising function what movement increases and decreases tension in all 3 ligaments

Answer 10

Lateral rotation of humerus put all 3 ligaments under tension

Medial rotation relaxes all 3

Abduction – only the middle and inferior ligaments are taught superior is relaxed

Question 11

Transverse humeral ligament

Answer 11

Upper end of inter-trabecular groove bridges gap between greater and lesser tubercles

Formed by some transverse capsular fibres

Holds biceps tendon in the intertrabecular grooves as it leaves joint

Question 12

Bursas

Answer 12

1. Subscapularis bursa- Synoival membrane Extends through interior opening of capsule
2. Subcoracoid bursa- extension of subscapularis
3. Infraspinatus bursa- posterior extension of the membrane through the joint capsule
4. Subacromial bursa- important but non-communicating bursa associated with shoulder joint lies between and separates the coracoacromial arch and deltoid = form superolateral part of shoulder joint. Subdeltoid bursa- extends laterally under deltoid

Question 13

Clinical significance of bursa

Answer 13

Adhesions made for preventing free gliding movement of shoulder

True for the biciptal sheath and subdeltoid bursa

Subdeltoid bursa= inflamed= bursitis then affects tendon of supraspinatis= rupture

Question 14

Intra-articular structures

Answer 14

Glenoid labrum

Long head of biceps

Question 15

Glenoid labrum

Answer 15

Triangular fibrocartilageinous rim

Thin free edge 4mm deep

Deepens glenoid fossa

Question 16

Glenoid labrum attachments

Answer 16

Base of labrum attaches to margin of glenoid fossa

Outer surface gives attachment to joint capsule posteriorly and superiorly -gives attachment to long head of biceps superiorly

Inner joint surface is in contact with head of humerus and is lined by Cartilage continuous with that of glenoid fossa

Upper part of labrum not completely fixed to bone its inner edge may project into joint like a meniscus

Question 17

Function of glenoid labrum

Answer 17

Deepens shoulder socket

1. Reduces chance of dislocation by anchoring humeral head to scapula increasing contact 2mm AP and 4.5mm SI
2. Provides insertion for stabilizing structures (Capsule and Glenohumeral Ligaments), as a fibrous “crossroad”
3. Contributes to the “Viscoelastic Piston” effect

Question 18

Long head of biceps

Answer 18

Runs intercaspularly from Supraglenoid tubercle and adjacent superior margin of glenoid leave room until emerges from the joint deep to the transverse humeral ligament

Intercourse purely and 2 cm beyond tendon is ensheathed into synovial sheath

Question 19

Accessory ligaments

Answer 19

Coracohumeral ligament

Coracoacromial ligament

Question 20

Coracohumeral ligament

Answer 20

Fairly strong broad

Laterally

Lateral boarder of coracoid process ➖becomes flattened with margins diverging above the intertubercular groove attaches to upper part of the anatomical neck - region of greater and lesser tubercles and intervening transverse ligament

Anterior boarder of medial ligament is free as it passes laterally fuses with tendon of subscapularus

Posterior part blends with the tendon of supraspinatus as it attaches to the superior facet on the greater tubercle of humerus

Question 21

Coracoacromial - fibro-osseous arch above joint

Answer 21

Not directly associated with joint forms together with coracoid process and acromion of fibro-osseous arch above head of humerus

Strong triangular ligament

Posterior borders thicker than intermediate part

Attached by broadbase to the lateral border of horizontal part of coracoid process blunt apex attaching to the apex of acromion in front of acromioclavicular joint

In fairly separated from tendon of supraspinatus and shoulder joint by subacromial bursa

Question 22

Arch of coracoacromial ligament

Answer 22

Arch formed by ligament and Boney processes increases the surface which the head of humerus is supported when forces are transmitted upwards along humerus

Roof of subacromial space - subacromial bursa sit in here= shoulder problems, long head of biceps and supraspinatus

Question 23

Movements of Glenohumeral joint

Answer 23

Flexion
Extension
Abduction 
Adduction 
Medial rotation 
Lateral rotation

Question 24

NOM and limiting factors flexion

Answer 24

0-180°

Extent of articular surfaces
Tension in capsular structures
Tension extensors

Question 25

NOM and limiting factors Extension

Answer 25

0-50°

Extent of articular surfaces.
Tension in capsular structures +surrounding
Tension in flexors

Question 26

NOM and limiting factors Abduction

Answer 26

0-150°

Glenohumeral ligs (middle and inferior bands) 
 Inferior part of the fibrous capsule

Question 27

NOM and limiting factors Adduction

Answer 27

0-40°

Extent of articular surface

Question 28

NOM and limiting factors Medial rotation

Answer 28

0-80°

Posterior part of fibrous capsule
Posterior Laurel rotators (infraspinatus and teres minor)

Question 29

NOM and limiting factors lateral rotation

Answer 29

0-90°

Anterior part of fibrous capsule
All three bands of the glenohumeral ligament.
Anterior video repeaters (subscapularis)

Question 30

Nerve supply Glenohumeral joint

Answer 30

Super scapular
Axillary
Subscapular
Lateral pectorial
Musculocutaneous

C5,6,7

Question 31

Stability

Answer 31

Incongruity and laxness= x stable

Glenoid labrum= deepens socket improves congruity = stabilises

Rotator cuff= fuses lateral part joint capsule holds humeral head in glenoid fossa

Coracoacromial arch= x displacement humerus

Question 32

Combination movements of shoulder complex

Answer 32

Glenohumeral joint movement is responsible for bringing the arm to the horizontal position whilst the scapular movements of the pectoral girdle facilitate bringing the arm into a vertical position, eg. reaching above the head.

Question 33

Glenohumeral joint range of movement

Shoulder complex

Answer 33

Relatively large due to incongruity of articular surfaces

Increased by movements of the pectoral girdle occurring simultaneously with that of the humeral head against the glenoid fossa.

Question 34

Describe Shoulder flexion

Answer 34

Initial phase nearly all glenohumeral joint movement

However pectoral girdle movement occurs in order to laterally rotate and protract scapula to allow for 180 ̊ of flexion into elevation.

Question 35

Describe Shoulder extension

Answer 35

Contribution of scapular movements during shoulder extension increases the range to
70 ̊- 90 ̊

Question 36

Describe Shoulder abduction

Answer 36

Initial 25 ̊–30 ̊ of abduction is nearly all glenohumeral movement with no pectoral girdle involvement. Initiated by supraspinatus

After this point, movements of the shoulder complex occur with clavicular and scapular movements occurring simultaneously at the Sternoclavicular and Acromiocalavicular joints (Pectoral Girdle) with the Glenohumeral joint

Deltoid continues movement after initial 20° of abduction

Initially there is elevation of the Pectoral Girdle but by approximately 90˚ of abduction, the articular surfaces of these joints are exhausted and posterior axial rotation of the clavicle occurs allows further lateral rotation of the scapula.

Between 30 ̊ and 180 ̊, for every 15 ̊ of abduction, the shoulder is thought to contribute 10 ̊ whilst the scapula contributes 5 ̊.
This normal ratio of 2:1 of humeral-scapular movement permits full range of movement of the shoulder.
Referred to as the normal humeral-scapular rhythm

Final range of movement, lateral rotation of the humerus occurs this provides further articular surface on the humeral head for the glenoid fossa. Lateral rotation of the scapula causes the glenoid fossa to face superiorly which facilitates an increased ROM at the Glenohumeral joint.

Anything that prevents lateral rotation of the scapula will impair the range of movement of shoulder

Hypothesised to be necessary in order to prevent the greater tubercle impinging upon the coraco-acromial arch.

Question 37

Shoulder adduction

Answer 37

Involves eccentric muscle activity of:

serratus anterior
trapezius
deltoid
supraspinatus

> in order to control medial rotation of the scapula as the arm returns to the side of

Question 38

Classification glenohumeral joint

Answer 38

Ball and socket, simple, synovial, multiaxail

Question 39

What is the Glenohumeral rhythm

Answer 39

Between 30˚ and 180˚, for every 15˚ of abduction, the shoulder is thought to contribute 10˚ whilst the scapula contributes 5˚. This normal ratio of 2:1 of humeral-scapular movement is essential to permit full range of movement of the shoulder