ball & socket
flexion, extension, adduction, abduction, horizontal flexion, horizontal extension, medial & lateral rotation
Flexion: agonist is the anterior deltoid
Extension: agonist is the posterior deltoid
Adduction: agonist is the latissimus dorsi
Abduction: agonist is the middle deltoid
Horizontal Flexion: agonist is the pectoralis major
Horizontal Extension: agonist is the posterior deltoid
Medial: agonist is the teres major
Lateral: agonist is the teres minor