Most originate on the Scapula (the Shoulder Girdle), not all though. The Pectoralis Major & Minor and the Latissimus Dorsi do not.
d. Latissimus dorsi and pectoralis major
there are two muscles with pectoralis in their name, Pectoralis Major and Pectoralis Minor. Pectoralis Major is the main muscle of the chest and pectoralis minor is deep to it (so you can't feel it because pectoralis major completely covers it)
Pectoralis minor.
The heart is deep to the pectoralis major. The pectoralis major is superficial to the heart.
Enneanectes pectoralis was created in 1941.
Ophiclinus pectoralis was created in 1980.
Dactyloscopus pectoralis was created in 1861.
pectoralis minor and subclavius muscle.
The Pectoralis Major (large superficial) and Pectoralis Minor
the Pectoralis Profundus is found in the "chest" of quadrapeds, in their Thoracic. It is part of the Quadruped Sling, and works with the Serratus Ventralis muscle to allow forward and backwards movement for quadrupeds of the forelimbs.
No. They are synergists to each other.