In: Anatomy and Physiology
The steps are as below.
1. Oxygen poor blood returning in Right Atrium/ventricle cannot exit fast enough to Lungs
2. As a result too much blood remains in right pump.
3. Thus, Venae Cavae have difficulty bringing blood within the heart chambers
4. Blood stagnates or pools within body organs
5. Consequently, this widespread pooling of fluid impair the ability of body cells to obtain adequate nutrients and oxygen and to rid themselves of wastes.
6. Pooled blood leads to fluid leaking in the tissue spaces.
7. Peripheral Edema occurs.
8. This swelling or congestion will be most noticeable in the extremities like feet, ankles, and fingers.
The edema is caused due to the accumulation of fluid in the tissue spaces and in the lymph. This is due to the lack of blood pumping. Here it's due to the right sides heart failure. Due to it more blood will remain in the right side heart making the blood from the organs to be pooled there itself. There are the reason for the swelling in the ankles and fingers.