Shoulder Anatomy Flashcards Preview

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Flashcards in Shoulder Anatomy Deck (48):
1

what is in the shoulder complex?

clavicle
scapula
humerus

2

why is stability sacrificed in the shoulder joint?

so it can have more mobility

3

how many degrees of freedom does the shoulder joint have?

3

4

what is on the end of the long bone?

articular cartilage

5

what kind of CT is the fibrous capsule?

dense irregular

6

what is the purpose of the joint capsule?

adds stability
lowers friction

7

what gives the shoulder the greatest stability?

muscles

8

what is dynamic stability?

when a joint is more dependent on muscles than other structures to give stability

9

what is special about the scapulothoracic joint?

its not a true joint
a/w movement of the sc and ac joints

10

what are the movements of the scapula?

elevation/depression
protration/retraction
upward/downward rotation (look at the inferior angle to identifty this motion)

11

what forces hold the scapula to the thorax?

ATM
link with AC and SC jt
muscles

12

what are functions of the scapula?

orient glenoid fossa to arm
add ROM to the arm
provide a stable base for the controlled rolling and sliding of the articular surface

13

what type of jt is the sternoclavicular jt?

plane (saddle shaped surfaces)
has 3 degress of motion
incongruent

14

what are motions at the sternoclavicular jt?

elevation/depression
protraction/retraction
rotation

15

how is the motion described for the sternoclavicular jt?

in terms of the distal portion of the clavicle

16

protraction/retraction of the sternoclavicular jt is a/w which movement of the scapula?

ab/adduction

17

which direction does sternoclavicular jt rotate?

posteriorly only!

18

what kind of joint disc is in the sternoclavicular jt?

fibrocartilage

19

which ligaments are involved at the SC joint?

anterior and posterior SC ligament
costoclavicular ligament (major constraint on SC motion)
interclavicular ligament

20

what is the function of the SC joint?

protects the brachial plexus and subclavian artery (pass between clavicle and 1st rib)

21

what is the sequence of brachial plexus?

roots
trunks
divisions
cords
nerves

22

what levels are involved in the brachial plexus?

c5-t1

23

which type of joint is the AC joint?

plane

24

what is the primary function of the AC joint?

maintain relationship b/w clavicle and scapula
allow scapula additional ROM on the thorax in latter stages of elevation

25

what are the articulation surfaces in the AC joint?

1. convex facet of lateral end of clavicle
2. concave facet on acromion of the scapula

26

which ligaments are involved in the AC joint?

1. superior and inferior AC ligaments
2. coracoclavicular ligament
3. coracoacromial ligament

27

what are the motions of the AC joint?

1. scapular rotation
2. winging of the scapula
3. tipping of the scapula

28

what motion is altered in pathological winging?

flexion/abduction (scapula does not round around thorax)

29

what motion is altered in pathological tipping?

elevation/depression (scapula does not round around thorax)

30

what are the 2 parts of the coracoclavicular ligament?

1. trapezoid
2. conoid
(separated by fat and a large bursa)

31

which clavicular jt is more likely to get injured?

AC (sprains, subluxations, dislocations)

32

what is the function of the AC joint?

prevent superior dislocation of the clavicle
also provides horizontal stability
also prevent excessive rotation of the scapula
transmits compression forces to the stronger SC joint

33

what is the position of the humeral head?

posterior torsion (retrotorsion)-30 degrees

34

what is the angle of inclination of the humerus?

135 degrees (angle of direction of head compared to rest of the body)

35

what is the glenoid labrum?

dense, fibrous CT that provides excess depth to the socket

36

when does the GH joint tighten?

during motion
(at rest, it is large and loose-2x the size of the humerus)

37

what are the GH ligaments?

superior/middle/inferior GH ligament (not as strong)-forms a Zshape
coracohumeral ligament (inserts on greater tubercle)

38

what is the most important role of the coracohumeral ligament?

passive support against gravity

39

what is the role of the coracoacromial arch?

protect bursa against trauma
prevents superior dislocation of the humeral head

40

what are the joint motions of the shoulder jt?

roll, slide, spin

41

which muscle supports for static stabilization?

supraspinatous muscle
if more force is needed, deltoid also contracts

42

which are the primer movers for abduction?

deltoid
supraspinatous

43

what is the primer movers for GH flexion?

anterior deltoid

44

what is a major role of the rotator cuff?

muscles produce inferiorly directed force which offsets the superior pull of the deltoid
provide stability
reduce forces of the humeral head moving in the glenoid fossa

45

which two muscles are responsible for external rotation?

infraspinatous
teres minor

46

which muscle is responsible for internal rotation?

subscapularis

47

which muscle is responsible for humeral stability against gravity?

suprascapularis then deltoid

48

which muscles cause the scapula to upwardly rotate?

trapezius and serratus anterior

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