muscle movements, types, and names
extension
is the opposite of flexion, so it is a movement that increases the angle, or the distance, between two bones or parts of the body (straightening the knee or elbow). if extension is greater than 180 degree as when you tip your head or your torso posteriorly so that your chin points toward the ceiling. it is hyperextension
circumduction
is a combination of flexion, extension, abduction, and adduction commonly seen in ball and socket joints such as the shoulder. the proximal end of the limb is stationary, and its distal end moves in a circle. the limb as a whole outlines a cone.
origin
is attached to the immovable or less movable bone
insertion
is attached to the movable bone and when the muscle contracts, the insertion moves toward to the origin.
adduction
is the opposite of abduction so it is the movement of a limb toward the body midline
the most obvious examples of the action of muscles on bones
the movements that occur at the joints of the limbs. the less freely movable bones are also tugged into motion by the muscles such as the vertebrae's movements when the torso is bent to the side.
dorsiflexion and plantar flexion
up and down movements of the foot at the ankle are give special names. lifting the foot so that its superior surface approaches the shine standing on your heels is called dorsiflexion whereas depressing the foot pointing the toes disc called plantar flexion. dorsiflexion of the foot corresponds to extension
body movement occurs when?
when muscles contract across joints.
types of body movements
everyone of our skeletal muscles is attached to bone, connective tissue structures at probably 2 points or less.
some muscles have interchangeable origins and insertions.
examples: rectus femoris muscle of the anterior thigh crosses both the hip and knee joints. it is most common to extend the knee, in which case the proximal pelvic attachment is the origin. when the knee is bent, the rectus femurs can flex the hip, and the distal attachment on the leg is considered the origin.
the type of movement depends on what?
depends on mobility of the joint and on where the muscle is located in relation to the joint.
flexion
movement generally in the sagittal plane, that decreases the angle of the joint and brings two bones closer together joints (bending the knee or elbow), but it is also common at ball and socket joints for example bending forward at the hip
rotation
movement of a bone around its longitudinal axis. it is a common movement of ball and socket joints and describes the movement of the atlas around the dens of the axis as in shaking your head no
abduction
moving a limb away generally on the frontal plane from the midline or median plane of the body. the terminology also applies to the fanning movement of the fingers or toes when they are spread apart