The thymus is an important part of your child’s lymphatic system. It is an organ comprised of two lobes, which are encased in a capsule that sits behind the sternum and above the heart. A missing or malfunctioning thymus can make your child vulnerable to infections or developmental disorders.

Bone marrow is a soft spongy material that is located inside of the bones. Bone marrow is necessary for the transition that stem cells make to become one of the types of blood cells (red blood cells, platelets or white blood cells).

Gout is a condition characterized by the deposit of uric acid in the joints. People with gout may experience a sudden onset of arthritis-like symptoms, including swelling, redness and warmth in one or more joints.

The fifth lumbar vertebra, also known as the L5 vertebra, can be a source of tremendous pain and discomfort.

The thoracic spine is the mid-portion of your back and extends from the base of the neck to the bottom of the rib cage. It is made up of 12 thoracic vertebrae, which are separated by soft spongy discs that aid in shock absorption.

The flank is the area on the sides of the body between the lower rib and hip bone, including the front and back aspects of the torso. It is commonly referred to as the side. Pain can radiate to the back or flank because of a problem in any of the nearby organs, or it may arise due to a neuromuscular condition.

The spine is composed of small bones called vertebrae that surround the spinal cord. Between each vertebra is a cushion called a disc. With time or trauma, the jelly-like center of the disc may shift and leak out through a crack in the tougher, outer covering. This is called a disc herniation or "slipped disc."

Bone spurs are caused by extra bone growth and can exist for years without ever causing any symptoms. In these cases, no treatment is required. However, they can also rub on nearby tissues, nerves and muscles and cause pain and swelling.

Exercising is rough when you have tired, aching legs. Walking on hard, flat surfaces can cause your legs to rotate inward in such a way that injures your calf muscles. Your feet flatten and twist to accommodate unnatural flooring or poorly-fitting shoes, which then puts pressure on the musculature of your legs.

Muscle cramps can be excruciating and debilitating, often strike without warning. If you find your back tensing up and cramping after you stretch, it may be related to any number of underlying causes from dehydration to an insufficient supply of blood leading to muscle tissues.

Five types of bones make up the human skeleton: flat bones, long bones, short bones, irregular bones and sesamoid bones. Flat bones, true to their name, are flat, thin, curved bones.

The teres minor muscle is one of four rotator cuff muscles that surround the shoulder. According to the Sports Injury Clinic, the teres muscle helps to externally rotate the shoulder. Injuries to the teres minor can be treated with stretches that help to restore flexibility and reduce pain.