Unit 3- shoulder

Question 1

trapezoid ligament

Answer 1

extends superolaterally from superior surface of coracoid process to the trapezoid line on the clavicle (lateral)

Question 2

conoid ligament

Answer 2

extends vertically from the base of coracoid process to conoid tubercle of the clavicle

Question 3

motions at the AC joint

Answer 3

how scapula moves on distal clavicle

• upward and downward rotation
• internal and external rotation
• anterior tilt and posterior tilt

Question 4

motions at the ST joint

Answer 4

cooperation between AC and SC motions

• elevation and depression
• protraction and retraction
• upward and downward rotation

Question 5

motions at the SC joint

Answer 5

• elevation and depression
• protraction and retraction
• forward and backward rotation

Question 6

elevation at the ST joint

Answer 6

combination of elevation of SC and downward rotation at AC

Question 7

depression at the ST joint

Answer 7

combination of depression of SC and upward rotation at AC

Question 8

protraction at ST joint

Answer 8

protraction at SC and IR at AC

Question 9

retraction at ST joint

Answer 9

retraction at SC and ER at AC

Question 10

upward rotation of ST

Answer 10

elevation of SC and upward rotation of AC

Question 11

SC joint articulations

Answer 11

medial end of clavicle, clavicular facet on sternum, superior border of cartilage of first rib

Question 12

AC joint articulations

Answer 12

acromion and lateral end of clavicle

Question 13

GH joint

Answer 13

large convex head of humerus and shallow concavity of the glenoid fossa

Question 14

superior GH ligament

Answer 14

from supraglenoid tubercle to above the lesser tubercle

-becomes taut in adduction, restrains inferior and AP translation

Question 15

shoulder elevation: contribution from clavicle

Answer 15

• posterior rotation
• retraction
• elevation

Question 16

shoulder elevation: contribution from scapula

Answer 16

• upward rotation
• internal rotation
• posterior tilt

Question 17

shoulder elevation: contribution from humerus

Answer 17

• elevation (abd or flexion)

- external rotation

Question 18

ratio for humerus to scapula movement

Answer 18

2:1 GH to ST movement

Question 19

passive stabilization of the shoulder

Answer 19

1. structures of the superior capsule, supraspinatus tendon and rotator interval capsule
2. vacuum pressure of capsule (negative intraarticular pressure)
3. glenoid inclination/gravity (slight upward tilt of fossa)

Question 20

rotator interval

Answer 20

provides stability against anterior translation
space between supraspinatus and subscap tendon on the head of the humerus
-contains coracohumeral ligament and superior GH ligament

Question 21

GH ligament

Answer 21

inferior (a/p bands, axillary pouch)
middle
superior

Question 22

angle of torsion

Answer 22

axis through humeral head in relation to axis through condyles (approx 30 degrees)

Question 23

angle of inclination

Answer 23

axis through head and neck relative to shaft (130-150 degrees)

Question 24

glenoid labrum

Answer 24

attachment site for GH ligaments and long head of biceps tendon

Question 25

superior GH ligament

Answer 25

resists anterior and inferior translation when arm is at side

Question 26

middle GH ligament

Answer 26

resists anterior translation when arm is abducted at the side and up to 60 degrees

Question 27

inferior GH ligament

Answer 27

major restrain is with arm abd beyond 45 degrees resisting inferior translation
anterior band: resists anterior translation when arm is ER and abd
posterior band: resists posterior translation when arm is IR and abd

Question 28

dynamic stabilization of GH

Answer 28

function of:

1. force of prime movers
2. force of gravity
3. force of muscle stabilizers
4. articular surface geometry
5. passive capsuloligamentous structures
6. friction
7. force of joint reaction forces

Question 29

supraspinatus as a prime GH joint mover

Answer 29

• action line runs superior, parallel to rotator interval
• large ability to abduct arm and compress joint (drives humeral head into glenoid to stabilize so deltoid can take over) due to greatest MA of RTC muscles
• with gravity, contributes to inferior glide of humeral head during abduction (offsets vertical torque of deltoid)

Question 30

dynamic stabilization of the GH due to RTC

Answer 30

during movement of the arm, the axis of rotation of the humeral head only moves a few millimeters within the glenoid

Question 31

dynamic stabilization of the GH during ER

Answer 31

infraspinatus and teres minor cause ER

humerus goes posteriorly, glides forward and is stabilized by tension in subscap

Question 32

role of long head of biceps in GH stabilization

Answer 32

attaches to superior labrum and capsule, pulls humeral head down when it contracts and stabilized the humeral head as the shoulder flexes

Question 33

role of gravity in GH stabilization

Answer 33

facilitates inferior glide, can approzimate and acts as a stabilizer depending on position of arm

Question 34

ST elevators

Answer 34

upper traps, levator scap, a little rhomboids

Question 35

ST depressors

Answer 35

lower traps, lats, pec minor, subclavius

Question 36

protractors at ST joint

Answer 36

serratus anterior

Question 37

retractors at ST joint

Answer 37

middle traps

also lower traps and rhomboids

Question 38

abductors at GH joint

Answer 38

anterior and middle deltoid, supraspinatus

Question 39

flexors at GH joint

Answer 39

coracobrachialis, anterior delt, long head of biceps

Question 40

upward rotators at ST joint

Answer 40

serratus anterior and traps **force couple

middle traps does retraction while upper and lower do upward rotation with serratus