distal force couple

Question 1

what muscles make up the distal force couple

Answer 1

deltoid + rotator cuff
- supraspinatus
- infraspinatus
- subscapularis
- teres minor

Question 2

origin and insertion of deltoids

Answer 2

origin
anterior - lateral 1/3 of clavicle
middle - acromion
posterior - scapula spine
insertion - deltoid tuberosity

Question 3

origin and insertion teres minor

Answer 3

origin - lateral border of scapula
insertion - lower facet greater tubercle

Question 4

origin and insertion infraspinatus

Answer 4

origin - infraspinatus fossa
insertion - middle facet of greater tubercle

Question 5

origin and insertion of supraspinatus

Answer 5

origin - supraspinatus fossa
insertion - superior facet of greater tubercle

Question 6

origin and insertion of subscapularis

Answer 6

origin - subscapular fossa
insertion - lesser tubercle

Question 7

what does the distal force couple do?

Answer 7

• rotator cuff contract to centralise the humeral head in the glenoid fossa
• prevents deltoid from pulling humeral heaf upwards which would otherwise narrow the subachromial space

Question 8

What is a force couple

Answer 8

• Two or more forces producing a rotational displacement (movement)
• The object that rotates must be free to rotate about a fixed axis
• Linear forces need to be applied on opposite sides of this axis and in an opposite direction