SCM
The two pectoral muscles found in the thoracic wall are the pectoralis major and the pectoralis minor. The other two muscles found there are the serratus anterior and the subclavius.
Antagonist muscles are muscles that counteract the action of agonist muscles.Some examples of antagonist muscles are:Triceps work opposite of biceps.Hamstrings works opposite of quadriceps.The sternocleidomastoid works opposite of the deltoids.
If I'm not mistaken I believe that for this movement to happen there are two muscles that need to be used- because muscles work in pairs. For this particular movement I am sure that the Agonist muscle (prime mover), the muscle that relaxes, is the Bicep. And the Antagonist, the muscle that contracts, is the Tricep.
This is not possible. The spinal cord is wired so that when an extensor muscle contracts, a flexor muscle must relax. It is not possible to contract antagonizing muscle groups at the same time.
Cremaster muscle & Dartos muscle
The iris of the eye has two main types of muscles - the radial muscle and the sphincter muscle. The radial muscle lies on the outside of the iris, and the sphincter muscle surrounds the pupil, allowing it to dilate and contract.
Of the three types of muscle, the two that are involuntary are cardiac muscle and smooth muscle.
The two main types of muscles are voluntary muscles and involuntary muscles. An voluntary muscle is a muscle that you use and work at your own will power such as your biceps or quads. In involuntary muscle is a muscle that is always being uses and you can not direct it otherwise, such as the heart.
Cardiac muscle is found in the heart. The other two types of muscle are smooth and striated (skeletal) muscle.Cardiac muscle, the third kind of muscle (the other two being skeletal and smooth muscle.
The digastric muscle, which is a small muscle located under the jaw.
Two muscles: The masster(jaw) The tongue
The name of the muscle is sternocleidomastoid. As the name suggests, the muscle arise from the sternum and clavicle to reach the mastoid process. You have two muscles, one muscle on each side.