SC Joint

Question 1

what joints make up the shoulder complex?

Answer 1

• SC joint
• AC joint
• GH joint
• Scapulothoracic “joint” (physiologic joint; scapula and ribcage with muscle in between)

Question 2

the shoulder complex can be said to have ____ with dynamic ____

Answer 2

mobility with dynamic stability

Question 3

why is the shoulder complex susceptible to dysfunction and instability?

Answer 3

due to competing mobility and stability demands

Question 4

SC joint = ____ moving on ____

Answer 4

clavicle moving on sternum

Question 5

what articulation forms the SC joint?

Answer 5

medial clavicle with notch formed by manubrium and 1st costal cartilage

Question 6

what type of joint is the SC joint?

Answer 6

saddle joint

Question 7

when the clavicle is moving medial to lateral on the sternum, what is the convex/concave relationship?

Answer 7

concave on convex

Question 8

when the clavicle is moving anterior to posterior on the sternum, what is the convex/concave relationship?

Answer 8

convex on concave

Question 9

what increases congruency between the articulating surfaces of the SC joint?

Answer 9

SC disc (fibrocartilage disc/meniscus)

Question 10

how does the SC disc promote stability in the SC joint?

Answer 10

• increases joint congruence
• absorbs forces
• helps limit medial movement of clavicle

Question 11

what are the resting characteristics of the SC joint?

Answer 11

• wedge-shaped

- open superiorly

Question 12

OK of the SC joint

Answer 12

• elevation/depression
• protraction/retraction
• ant/post rotation (spin)

Question 13

AK of the SC joint

Answer 13

• sup/inf
• ant/post
• spin

Question 14

what is our reference point when describing OK of the SC joint?

Answer 14

distal (or lateral) clavicle

Question 15

what is the convex/concave relationship during elevation/depression of the SC joint?

Answer 15

convex on concave

Question 16

describe elevation of SC joint

Answer 16

• lateral clavicle rotates upward

- superior roll, inferior glide

Question 17

describe depression of SC joint

Answer 17

• lateral clavicle rotates downward

- inferior roll, superior glide

Question 18

what does the SC disc do during elevation/depression?

Answer 18

remains stationary

Question 19

what does the SC disc do during protraction/retraction?

Answer 19

moves with the clavicle

Question 20

what is the convex/concave relationship during protraction/retraction of the SC joint?

Answer 20

concave on convex

Question 21

describe protraction of SC joint

Answer 21

• lateral clavicle moves anteriorly

- anterior roll and glide

Question 22

describe retraction of SC joint

Answer 22

• lateral clavicle moves posteriorly

- posterior roll and glide

Question 23

anterior/posterior rotation occurs around the clavicle’s _____ axis

Answer 23

longitudinal

Question 24

ant/post rotation occurs as a ____ between the saddle-shaped surfaces

Answer 24

spin

Question 25

describe post rotation of SC joint

Answer 25

• occurs when you elevate your arm/shoulder
• inferior surface turns anteriorly
• also described as backward rotation

Question 26

describe ant rotation of SC joint

Answer 26

• can only occur after post rotation, when you’re coming back to your resting position
• inferior surface returns to inferior position
• minimal motion from neutral

Question 27

what is the closed packed position of the SC joint?

Answer 27

full posterior rotation