Biomechanics of shoulder

Question 1

Glenohumeral Joint type

Answer 1

Ball and socket

Head of humerus joins with glenoid fossa

Question 2

glenohumeral ligaments

Answer 2

radiate laterally from the supraglenoid tubercle in three bands

Superior, middle and inferior

Function to strengthen the anterior capsule of the joint

Question 3

rotator cuff interval

Answer 3

defined by
base- the coracoid process
superiorly- border of anterior margin of supraspinatus tendon
inferiorly- superior margin of subscaplaris tendon

Question 4

sternoclavicular joint type

Answer 4

saddle joint

clavicle is convex superior/inferior and concave anterior/posterior

sternum is concave superior/inferior and convex anterior/posterior

articular disc connecting medial end of clavicle to the first costal cartilage and sternum

Question 5

Costoclavicular ligament

Answer 5

First rib and it’s costal Cartilage to the anterior margin of the medial end of the clavicle

Question 6

blood supply of sternoclavicular joint

Answer 6

Internal thoracic and suprascapular arteries

Question 7

nerve supply of sternoclavicular joint

Answer 7

Branches of subscapular nerve and nerve to subclavius

Question 8

Acromioclavicular joint

Answer 8

plane joint

Junction of lateral end of clavicle to the acromion process of the scapula

Capsule strengthen superiorly by the acromioclavicular ligament

Question 9

Coricoclavicular ligament

Answer 9

strengthens lateral end of the clavicle by attaching to the coracoid process

Two parts- trapezoid, and conoid

Question 10

blood supply of AC joint

Answer 10

Suprascapular and thoracoacromial arteries

Question 11

nerve supply of AC joint

Answer 11

Lateral pectoral and axillary nerves

Question 12

What muscles attached to the coracoid process

Answer 12

pec minor
short head of biceps brachii
coracobrachialis

Question 13

Resting position of shoulder

Answer 13

55° of abduction
30° of horizontal adduction

Question 14

Close packed position of shoulder

Answer 14

Full abduction and full lateral rotation

Question 15

The order of movement lost in capsular pattern

Answer 15

lateral rot
Abduction
Medial rotation

Question 16

Glenohumeral joint ROM norms

Answer 16

Flexion- 100 to 115°
Extension - 20 to 25°
Abduction - 90 to 125°
Lateral rotation - 80 to 90°
Medial rotation - 50 to 60°

Question 17

Shoulder complex range of motion norms

Answer 17

flexion- 165 to 180°
Extension - 50 to 60°
Abduction - 170 to 180°
Lateral rotation- 90 to 100°
Medial rotation - 70 to 90°

Question 18

Resting position of scapula

Answer 18

Vertebral border- 5 cm lateral to the spinal processes and between ribs 2-7

Superior angle - T2
Spine of scapula - T4
Inferior angle - T7-T9

Upper rotation 10 to 20°
Internally rotated 30 to 45°
Anteriorly tipped 10 to 20°

Question 19

Kinematic Principle 1 - ratio

Answer 19

based on generalized 2:1 scapulohumeral rhythm,
active shoulder abduction of about 180° occurs as a result of simultaneous 120° of GH joint abduction and 60° of scapula thoracic upward rotation

Question 20

principle 2 - upward rotation of scapula is due to

Answer 20

The 60° of upward rotation of the scapula during full shoulder abduction is the result of a simultaneous elevation at the SC joint, combined with upward rotation at the AC joint

Question 21

principle 3- clavicle…

Answer 21

The clavicle retracts at the SC joint during shoulder abduction

Question 22

principle 4- upwardly rotating scapula…

Answer 22

The upwardly rotating scapula posteriorly tilts and less consistently externally rotates slightly during full shoulder abduction

Question 23

principle 5- clavicle rotates…

Answer 23

Clavicle posteriorly rotates around its own axis during shoulder abduction

Question 24

principle 6- GH rotates…

Answer 24

the GH externally rotates during shoulder abduction

Question 25

upper trapezius

Answer 25

Spinal accessory nerve Scapular elevation Some contribution to scapular upward rotation

Question 26

levator scapulae

Answer 26

dorsal scapular nerve Scapular elevation scapular adduction Some scapular downward rotation

Question 27

serratus anterior

Answer 27

Long thoracic nerve Scapular protraction Abduction/ upward rotation

Question 28

pec minor

Answer 28

medial pectoral nerve Scapular protraction abduction

Question 29

Lower trapezius

Answer 29

Spinal accessory nerve Scapular upward rotation, and depression

Question 30

Middle trapezius

Answer 30

spinal accessory nerve Scapular retraction adduction

Question 31

Rhomboids, major and minor

Answer 31

dorsal Scapular nerve scapular retraction, and downward rotation

Question 32

Deltoid anterior fibers

Answer 32

axillary nerve Shoulder flexion Internal rot Horizontal adduction

Question 33

coracobrachialis

Answer 33

musculocutaneous nerve shoulder flexion Horizontal adduction

Question 34

pec major- clavicular portion

Answer 34

Lateral pectoral nerve shoulder horizontal adduction Internal rotation Flexion

Question 35

pec major sternocostal portion

Answer 35

medial pectoral nerve Shoulder horizontal adduction Extension

Question 36

Deltoid middle fibers

Answer 36

Axillary nerve Shoulder abduction

Question 37

Long head of biceps

Answer 37

Musculocutaneous nerve shoulder abduction (Only if shoulder is externally rot)

Question 38

supraspinatus

Answer 38

suprascapular n Maintains humeral head in glenoid fossa Some external rotation

Question 39

Which muscles depressed head of humerus to assist with abduction

Answer 39

Infraspinatus Teres minor Subscapularis

Question 40

Deltoid posterior fibers

Answer 40

axillary nerve Shoulder extension External rotation Horizontal abduction

Question 41

latt Dorsi

Answer 41

Thoracodorsal nerve Shoulder extension Adduction Internal rotation

Question 42

Teres major

Answer 42

lower subscapular nerve Shoulder extension from flexed position internal rotation Adduction and extension

Question 43

Infraspinatus

Answer 43

Shoulder external rotation Stabilizes glenohumeral joint by depressing humeral head within the glenoid fossa

Question 44

Teres Minor

Answer 44

Shoulder external rotation Stabilizes GH joint by maintaining humeral within the glenoid fossa

Question 45

Subscapularis

Answer 45

Subscapular nerve, upper and lower Shoulder internal rotation Abduction Maintains humeral head in fossa

Question 46

Internal rotation

Answer 46

Subscapularis Teres major Pectoralis major latissimus dorsi

Question 47

external rotation

Answer 47

infraspinatus Teres minor

Question 48

extension and horizontal abduction

Answer 48

Deltoid posterior fibers lat dorsi Teres major

Question 49

abduction

Answer 49

Deltoid middle fibers Long head of biceps Supraspinatus Infraspinatus, teres minor and subscapularis depress head

Question 50

horizontal adduction

Answer 50

Pec major- clavicular and sternocostal portions

Question 51

flexion

Answer 51

Deltoid anterior fibers Coracobrachialis Pectoralis major clavicular portion

Question 52

primary retractors ( adductors)

Answer 52

Middle trapezius Rhomboids major and minor

Question 53

primary protractors and upward rotators

Answer 53

Serratus anterior Pec minor Lower trapezius

Question 54

Primary elevators

Answer 54

upper trapezius levator scapulae

Question 55

Non-ligamentous mechanisms

Answer 55

balance Concavity compression Adhesion cohesion

Question 56

ligamentous mechanisms

Answer 56

capsuloligamentous constraint

Question 57

Capsular tightness in posterior inferior: limited motions

Answer 57

Elevation in anterior planes Internal rotation of elevated arm Cross body adduction

Question 58

capsular tightness in posterior superior: limited motion

Answer 58

Reach up behind the back

Question 59

capsular tightness in anterior superior: limited motion

Answer 59

External rotation with arm at the side

Question 60

capsular tightness in anterior inferior: limited motion

Answer 60

External rotation with arm elevated

Question 61

capsular tightness inferior: limited motion

Answer 61

Elevation in scaption/abduction