Shoulder Biomechanics

Question 1

How is restraint to gravity

provided?

Answer 1

By the superior joint capsule and tension in the coracohumeral ligament

Question 2

What happens as a load increases?

Answer 2

To supraspinatus begins to assist and deltoid assists when load is very heavy

Question 3

What is the carrying angle of the humeral head?

Answer 3

125-150 degrees which allows our arm to be carried away from our body

Question 4

What are the mobilizing muscles in glenohumeral joint abduction? (90-110 degrees RoM)

Answer 4

The supraspinatus initiates movement for first 30 degrees then deltoid for 30 degree to end of range

Question 5

What are the stabilizing

Muscles in glenohumeral joint abduction?

Answer 5

Rotator cuff, long head biceps and scapula

Question 6

What is the limiting factor in glenohumeral abduction?

Answer 6

The greater tuberosity hitting the superior margin of the glenoid

Question 7

What does the clavicle do?

Answer 7

Connects the upper limb to the skeleton
Acts as a strut to maintain the scapula distance from the trunk
Transmits forces from the upper limb to the axial skeleton
No muscles attaching to clavicle produce clavicular movement