Conditions of the Shoulder

Question 1

What joint are involved in common injuries of the shoulder?

Answer 1

Glenohumeral joint: the Glenoid of the scapula and the head of the humerus

Scapulothoracic joint: where the scapula adheres to the thorax

Acromialclavicular joint: the articulation of the acromion to the clavicle

Question 2

How much abduction of the humerus does the GH joint do?

Answer 2

The first 90 degrees of abduction (rotator cuff + deltoids). Past that point, the greater tubercle is bumping into the acromion and scapular upward rotation occurs to get the humerus beyond 90 degrees of abduction.

Question 3

Muscles of the GH joint

Answer 3

supraspinatus, infraspinatus, teres minor, subscapularis, delts, pec major, coracobrachialis, lats, ters major, biceps, triceps

Question 4

Muscles of the ST joint

Answer 4

levator scap, rhomboids, serratus anterior, pec minor, traps, subclavius

Question 5

Rotator Cuff Strains

Answer 5

Most common in throwing/striking sports b/c the medial rotators overpower the lateral rotators (more medial than lateral, also bigger).

The medial rotators generate a lot of force during the throwing sequence, but the lateral rotators cannot always handle the eccentric force needed to decelerate the arm

Question 6

AC joint sprain

Answer 6

“separated shoulder”

MOI: forces from lateral to medial causing the AC joint to “become smaller” by separating