Q.34 - Biology

Question

Describe the joints and motions involved in taking a step forward if a person is initially standing still. Assume the person holds his foot at the same angle throughout the motion. 

Step-by-Step Solution

Answer

As the foot comes off the ground in the step, the hip joint is going to move the femur in a protracted motion and the knee will flex the shin toward the thigh. As the foot lands, the knee extends the leg and the hip retracts the femur.

Step 1. Introduction

• The point at which two or more bones meet is called a joint, or articulation. Joints are responsible for movement, such as the movement of limbs, and stability, such as the stability found in the bones of the skull.

Step 2. Explanation

• Taking a step would require bending the knee (modified hinge joint) and moving the leg in the hip (ball and socket joint) since the motion of the foot is excluded. 
• As the foot comes off the ground in the step, the hip joint is going to move the femur in a protracted motion and the knee will flex the shin toward the thigh. 
• As the foot lands, the knee extends the leg and the hip retracts the femur.