Mastoid Process =)
Extensor muscles extend or straighten a body part.
Muscles can contract and shorten
Obviously this Dr is very intelligente and correct, however, if you are using the A&P Lab Manual 10th Ed (Marieb & Mitchell) the answer you are looking for is: Trapezius (found on the top of page 210)Sorry .....In my first answer I repeated myself twice and did not finish one of my answers correctly. The muscles that extend the head on the neck are;Rectus capitis major.Superior oblique.Rectus capitis minor.The muscles that extend the head on the neck are;Rectus capitis posterior major.Super oblique.Rectus capitis posterior major.
The erector spinae
i done no
triceps brachii
Hyper extend
There are four muscles that extend the leg. vastus lateralis, vastus medialis, vastus intermedius and rectus femoris.
The neck extensors are the group of muscles located on the back of the neck that help to extend (tilt backward) the head and neck. These muscles include the splenius capitis, semispinalis capitis, and the upper portion of the trapezius. Strengthening these muscles can help improve posture and reduce neck pain.
Triceps
The heart and the lungs, these are known as involuntary muscles.