the latissimus dorsi and the pectoralis major adduct the humerus
supraspinatus
The muscle you are referring to is the subscapularis muscle. It originates on the subscapular fossa of the scapula and inserts on the lesser tubercle of the humerus. It is responsible for medial rotation of the shoulder joint.
The biceps brachii muscle.
lateral rotation
on the intertubercular groove of the humerus just lateral to pectoralis major
The triceps originates on the scapula and proximal humerus and inserts on the olecranon process. The muscles has three heads (hence its name) so it has multiple origins.
The rotator cuff muscles are referred to occasionally as the SITS muscles. The Supraspinatus, Infraspinatus, Teres minor and the subscapularis. The Supras. originates on the scapula and inserts on the humerus. The Infras. originates on the scapula and inserts on the humerus(greater tubercle. The Teres minor originates on the scapula and inserts on the humerus. The Subscapularis originates on the scapula and inserts on the humerus(lesser tubercle). The function of this muscle group is to stabilize the shoulder joint. Hope this helps.
You have the pectoralis major muscle in the chest wall. It arise from the sternum and the clavicle. It is inserted on the lateral part of the bicipital groove.
Latissimus dorsi
The brachialis muscle originates on the distal anterior humerus and insert at the coronoid process. The function of the brachialis is flexion at the elbow.
Because the latissimus dorsi origin is from the back and it inserts on the humerus. It doesn't cover the abdomen at all.
olecranon fossa