What Is the Skeletal System?

Medically Reviewed by Carmelita Swiner, MD on July 07, 2023
Written by WebMD Editorial Contributors
4 min read

The skeletal system is made up of your bones and creates the support structure for the rest of your tissue and organs. Your skeletal system gives your body shape, supports your muscles, provides movement, and makes red blood cells.

Your skeletal system is your body’s frame. While it is most recognized as your bones, your skeletal system also includes connective tissue like cartilage, tendons, and ligaments.‌

Functions of your skeletal system include:

  • Movement. Your skeletal system supports your weight evenly so that you can stand and move with ease. Your connective tissue and muscles work together with the skeletal system to make your body parts mobile.
  • Blood cells. Your bone contains marrow that produces both red and white blood cells for your body.
  • Organs. Your bones are structured in ways that protect your vital organs. Your skull encases your brain, your ribs protect your heart and lungs, and your backbone covers your spine‌.
  • Minerals. Your bones act as storage for some minerals like calcium and vitamin D

The base structure of your skeletal system consists of your 206 bones that form your skeleton. Each bone has three layers:

  • Periosteum. This is the hard outer part of the bone that acts as protection for the inside structures. 
  • Compact bone. The second later acts as the structure and support for your body. It is hard, white, and smooth.
  • Spongy bone. The center of your bone is soft and has pores that store bone marrow. ‌

The parts of your skeletal system that connect and support your bones include:

  • Cartilage. This is smooth and flexible, covering your bones where they meet. It acts as a cover that allows your bones to move against one another without any damage. As you age, your cartilage wears down and movement may become painful. 
  • Immovable joints. The place where two bones meet is called a joint, and there are three types. Immovable joints, like those found in your skull, don’t allow the individual bones to move independently of one another. 
  • Partly movable joints. These joints allow a small range of movement — for example, the bones in your rib cage are partly movable. They expand as you take a deep breath, but don’t have the same range of motion as joints like your knees and wrists. 
  • Movable joints. These joints allow much more movement. They include your shoulders, knees, and elbows, among others. 
  • Ligaments. These strong bands of connective tissue hold your bones in place alongside one another. ‌
  • Tendons. This type of connective tissue connects your muscles and bones together. 

Because your skeletal system is so vast, there are many health conditions that can impact the structure. Some conditions develop naturally over time because of wear and tear from daily movements like walking and lifting. Other conditions develop from an injury or illness that damages your skeletal system.‌

Examples of illness and injury include: 

  • Arthritis. When your joints wear down, it causes pain where your bones meet. Arthritis is a diagnosable condition that may be caused by age, injury, or medical conditions like Lyme disease.
  • Osteosarcoma. This type of cancer forms in your bones and may lead to tumors that fracture your bones.
  • Osteoporosis. While some bone loss is normal with age, this extensive bone loss comes from not getting enough calcium. Your bones become brittle and filled with tiny holes where they should be hard and firm. 
  • Sprains and tears. Your connective tissue is just as susceptible to damage. Over time, the tissues wear down. Trauma or disease may also lead to damage.‌
  • Fracture. Any stress to your bone may cause it to break, also called a fracture. As you get older, your bones weaken and become more susceptible to fractures.‌

Keep in mind that there are varying degrees of bone fracture ranging from minor to complete breaks of your bone. Types of fracture include:

  • Stable. Also called closed, this is what it is called when the place where the two pieces of your broken bone line up.
  • Stress fracture. When you overuse a particular bone, it may crack from the constant pressure.
  • Open. Also called a compound fracture, this is what it is called when your broken bone pierces your skin.

If you suspect you have broken a bone or damaged your skeletal system in any way, talk to your doctor immediately. Your doctor may request an x-ray to examine the bone for fractures. If you did break a bone, you’ll be given a cast, brace, or sling that supports and immobilizes that bone so it can heal properly without further use.

Depending on your age and the severity of the break, it can take months for a broken bone to heal completely. Your doctor may refer you to an orthopedist who specializes in the skeletal system. They may recommend physical therapy, lifestyle changes, weight loss, and pain medication to alleviate symptoms.

Here are some steps you can take to improve your lifestyle and keep your skeletal system strong: 

  • Eat enough foods that contain calcium and vitamin D. This includes dairy products and leafy greens.
  • Prioritize drinking water to hydrate your joints and connective tissue.
  • Exercise regularly to strengthen your bones and joints.
  • If needed, lose weight to take extra pressure off of your bones and limit damage from wear and tear.
  • Protect your bones and joints when you play sports like football or soccer.
  • Be careful in all movements to prevent falls that may lead to skeletal system damage.‌