The external obliques are responsible for rotating the trunk and pulling the chest downward to compress the abdominal cavity. They also provide support for the rotation of the spine. These muscles are some of the largest parts of the human trunk. They have a "V" shape that follows the pattern of putting one's hands into a pocket, according to About.com.
The obliques are the outermost of the abdominals. These large, flat muscles cover the sides of the trunk. A subcutaneous fat layer covers the obliques in most humans, especially females, which means they often are not visible. The obliques connect to the seven lower ribs. They contract to aid in breathing, causing the lungs to expel air. Certain motions require the external obliques to work with other muscles. These motions include flexing the spine and rotating the trunk in a direction opposite to that of the pelvis.
The subcostal and intercostal nerves connect these muscles to the brain. They play a vital role in the minor adjustments to the abdomen to maintain balance. As a result, injury to one of these muscles is often debilitating. Their blood supply comes from the intercostal arteries, the deep circumflex iliac artery and the iliolumbar artery.Learn More
The gluteus maximus muscle is responsible for the movement of the hips and thighs. Rising from a seated position, climbing stairs and standing are all aided by this muscle.Full Answer >
Humans have two internal oblique muscles, which are located on either side of the rectus abdominis (the "six-pack" muscles). One quick way to locate them is to place a hand below the armpit and follow the side of the torso below the ribs.Full Answer >
Deltoid muscles, situated in the shoulders, are responsible for the majority of arm movements, including arm abduction, arm flexion and medial rotation, and arm extension and lateral rotation. These movements involve the deltoids working with the rotator cuff muscles, supraspinatus, pectoralis major, infraspinatus, terres minor and terres major.Full Answer >
According to Inner Body, the trapezius muscle is responsible for shoulder shrugging and head extension. The trapezius is a wide, superficial muscle that covers most of the upper back and the posterior side of the neck. There is a trapezius muscle on the left and right side of the body.Full Answer >