Question

The following statement or incomplete sentence may have one or more correct answers. Choose the most correct combination of resto Consider the principle: "The position of a muscle relative to a joint determines the plane and direction of movement it can produce at Choose which of the statement(s) below correctly apply that principle. W. The deltoid crosses the shoulder anteriorly, and its contraction in this direction causes an anterior Plexion in the frontal/coronal plane X. The deltoid crosses the shoulder anteriorly, and its contraction in this direction causes an anterior flexion in the sagittal plane Y. The deltoid crosses the shoulder laterally, and its contraction in this direction causes a posterior abduction in the frontal/coronal plane Z. The hamstrings cross the knee posteriorly, and their contraction in this direction causes a posterior flexion in the sagittal plane Select one a. If only W X and Z are correct b. If only X Y and Z are correct If only X - Z are correct d. If only Z is correct e. If they are all correct

Answer 1

The correct option is b. If only X, Y and Z are correct.

Deltoid muscle forms a cap like structure on the top of the shoulder and crosses it from anterior, lateral and posterior sides.

Saggital plane - Forward and backward movements

Frontal plane - Sideways movement.

• The anterior, or front deltoid originates from the lower end of the collar bone. Its main responsibility is to raise the arm upward and to the front (shoulder flexion) and intemal rotation (turning the arm inward). The lateral deltoid originates at the acromion process of the scapula. Its main function is to move the arm upward and to the side abduction). To isolate this portion of the deltoid, be sure to keep movement in the frontal plane. The posterior, or rear deltoid originates from the inner, lower edge of the shoulder blade. It moves the arm back- wards and away from the body (extension). It also aids in external rotation (turning the arm outward).

^{Image adapted from studylib.net}

W. The anterior crossing of the deltoid muscle, and its contraction in this direction causes an anterior flexion in the saggital plane but not in the frontal/coronal plane. So, this statement is wrong.

Also, hamstring muscles cross the knee posteriorly and due to the contraction in this direction, results in posterior flexion in the saggital plane (backward movement).