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20 Fun Facts About the Skeletal System

Beneath our skin lies a structure as strong as the foundation of a building – our skeletal system. Like the wood and bricks that hold a structure together, our bones provide the framework that supports and protects our body.

Without it, we would be nothing more than a puddle of organs and tissues. But the skeletal system is more than just a framework. It plays a vital role in the functioning of other systems, such as the muscular system.

So, to this end, let us learn more about the skeletal system through some fun facts!

1. There are 206 Bones in the Entire System

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The adult human body has 206 bones, but interestingly, the number of bones can vary from person to person. Some individuals may have an extra rib bone or a fused vertebra, while others may be born with a missing or undeveloped bone.

Despite these variations, the human body is incredibly adaptable. The skeletal system can adjust to accommodate changes in our environment, diet, and lifestyle.

Fun fact, Babies are born with around 270 bones. As we grow older, babies some of these tiny bones fuse together to form the larger bones of the skeletal system.

2. The Smallest Bone Is About 2.8 Millimeters in Length

The human skeletal system includes bones of all shapes and sizes. The femur, or thigh bone, holds the title of the longest bone, with an average length of around 19 inches in adult males.

On the other hand, the smallest bone in the body is the stapes bone in the middle ear, which is only about 2.8 millimeters in length.

3. There Are 2 Types of Bones in The Skeletal System

The human skeletal system is composed of two main types of bones – compact (or cortical) bone and cancellous (or spongy) bone. Compact, also called cortical bone, is the denser and harder of the two types.

It forms the outer layer of most bones and is primarily regarded as the ‘structure’ bone. It’s made up of tightly packed layers of bone tissue, giving it strength and durability.

On the other hand, cancellous bone (also called trabecular bone) has a more porous and honeycomb-like structure, which makes it lighter and more flexible (spongier if you will). It’s typically found in the interior of bones and plays a crucial role in bone metabolism and remodeling.

4. More Than Half of Your Bones Are in The Hands and Feet

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It may come as a surprise but more than half of the bones in the human body are located in our hands and feet. That’s right, these two extremities contain a whopping 106 out of the 206 bones in the body!

Each hand contains 27 bones, including the eight bones of the wrist, the five bones of the palm, and the 14 bones of the fingers. Meanwhile, each foot contains 26 bones, including the seven bones of the ankle, the five bones of the midfoot, and the 14 bones of the toes.

Why this many? Well, The reason for this is that our hands and feet require a complex and intricate arrangement of bones to perform their many functions, such as grasping objects, walking, and running.

5. Only One Isolated Bone (Not Connected to Any Other)

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The hyoid bone is a very unique bone in the human body because it is not connected to any other bone. Instead, it is suspended in the neck by a network of muscles and ligaments. This is because it allows for greater flexibility of the tongue and larynx, which are attached to the hyoid bone.

The hyoid bone also plays a crucial role in speech and swallowing, as it helps to control the movement and position of the tongue and other muscles in the throat. According to some researchers, the evolution of the hyoid bone was a key factor in the development of human language and communication.

6. The Femur is The Longest Bone in The Human Body

The Femur, also known as the thighbone, is the longest and strongest bone in the human body. It is about a quarter of a person’s height.

The thighbone is also magnificent as it can support up to 30 times a person’s body weight. In terms of appearance, it has a ball-shaped head that fits into the hip socket, and a long, straight shaft that connects the hip to the knee.

It is the most commonly fractured bone in adults and also the only bone in the body with self-repairing capabilities. The Femur is also the site of attachment for many muscles, including the quadriceps femoris, hamstrings, and gluteus maximus.

7. Bones Are Filled With Spongy Tissue (Bone Marrow)

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Not all bones in our bodies are completely solid. Some, mostly large bones like the hip, pelvis, and femur among others, have a spongy substance known as bone marrow.

The bone marrow houses stem cells which are responsible for producing many of your body’s most important cells, including blood, brain, heart, and bone cells.

There are 2 types of bone marrow, red bone marrow, and yellow bone marrow. The red bone marrow is where red blood cells, white blood cells, and platelets are made.

The yellow bone marrow, on the other hand, is where fat is stored. Yellow bone marrow is more common in adults than red bone marrow.

8. Only Red Bone Marrow Is Transplantable

There are about 2.6 pounds (about 1.2 kg) of bone marrow in the human body. It is a very crucial part of the immune system and is constantly being recycled.

However, while there are two types, Red bone marrow is the only type that is transplantable. This is because it contains stem cells which produce blood cells.

Bone marrow transplants treat a variety of blood diseases, including leukemia, lymphoma, and sickle cell anemia.

Here’s a list of 10 famous people living with sickle cell anemia!

9. Most People Have 12 Ribs but Some Have 13

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There’s a theory based on a passage in the bible that suggests men have one fewer rib than women. In the book of Genesis, it says that God created Eve from Adam’s rib.

However, this is not true at all. Most people, regardless of gender, have 12 ribs. However, there are rare cases (not specific to any gender) of people having 13 ribs.

The extra rib is known as a supernumerary rib. It is a rare condition that affects about 1 in 500 people. The extra rib is usually located on the lower right side of the rib cage.

While it can sometimes cause pain and discomfort, it is usually not a serious problem. In most cases, the extra rib does not need to be removed although it can be if need be.

10. Bones Are Constantly Being Remodeled

Remodeling is the process of breaking down an old bone and producing a new one. This is a crucial procedure since it keeps the bones strong and healthy while also allowing for bone development and healing.

Remodeling involves two types of cells: osteoclasts and osteoblasts. Osteoclasts degrade existing bone while osteoblasts build new bone.

11. The Knee Is the Biggest Joint

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There are about 360 joints in the human body. The knee is by far the biggest of them all. Well, this is understandable as it connects, to large bones, the thighbone (femur) to the shinbone (tibia).

The knee’s size is necessary since it has to support the weight of the entire body. The knee joint is also very complex, with many different parts that work together to allow us to move our legs.

It is also the largest sesamoid bone and one of the most commonly injured joints in the body.

12. The Human Skeleton Is Not Symmetrical

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In a rather astonishing fashion, the human skeleton is not symmetrical. The left and right sides of the skeleton are not identical and this can be explained by various factors.

The first is functional differences. The left and right sides of the body are not used in exactly the same way, so the bones on each side need to be slightly different to support the different movements. For example, the humerus (upper arm bone) is slightly longer on the dominant side since it is used more.

The second is developmental factors. The bones in the human skeleton develop from a template that is not perfectly symmetrical. Factors such as genetic variations and environmental factors can affect the development of any bone.

13. Bones Produce Hormones

Just like the thyroid gland and the pancreas, the skeletal system is also considered an endocrine organ since it produces hormones.

Some of the hormones that bones produce include Calcitonin, which helps to regulate calcium levels in the blood, Osteocalcin which helps to build and maintain strong bones, and Parathyroid hormone (PTH) which helps to break down bone and release calcium into the blood.

14. Bones Are Not the Hardest Substance in The Human Body

Despite the popular notion that bones are the hardest substance in the human body, they are actually not. The hardest substance in the human body is enamel, which is the outer layer of the teeth.

Tooth enamel is composed of mostly calcium and phosphorus, and it is about 96% mineral by weight. This makes it much harder than bone, which is only about 70% mineral by weight.

15. The Spine Has 33 Bones

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As mentioned above, the entire human skeleton has 206 bones. However, the spine is made up of 33 individual bones called vertebrae.

The bones in the vertebrae are stacked on top of each other, forming the spinal column, which supports the head and trunk and also allows for movement.

It is divided into five regions namely, cervical (neck), thoracic (chest), lumbar (lower back), sacral (lower back), and coccyx (tailbone).

Each region has a different number of vertebrae. There are 7 in the cervical, 12 in the thoracic, 5 in the lumbar, 5 in the sacral, and 4 in the coccygeal.

16. Some Joints Do Not Move At All

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There are roughly 360 joints in the human body. While there are some that are very movable like the knee, some are completely immovable.

For example, the joints found in the skull. These joints are held together by bands of fibrous tissue called sutures.

Sutures allow the bones of the skull to grow as the brain and body grow, while not allowing the bones to move. This is necessary since the bones of the skull need to be held together tightly to protect the brain.

17. The Skeletal System Has 2 Main Parts

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The human skeletal system, while a complex structure, is divided into two main parts: the axial skeleton and the appendicular skeleton.

The axial skeleton forms the central or vertical axis of the body. It includes the skull, spine, ribs, and sternum. The Axial skeleton serves to protect the brain, spinal cord, heart, and lungs.

The appendicular skeleton forms the limbs and includes the bones of the arms, legs, hands, and feet. It is responsible for movement.

18. Bones Heal Themselves Naturally

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One of the many fascinating facts about the skeletal system is its ability to heal itself. When a bone fractures, for example, a process called fracture healing begins.

The first step in fracture healing is inflammation. Where the body fights infection and chemicals to stimulate the production of new bone and scar tissue are released.

The next step is called callus formation. This is when the body forms a soft, temporary bridge of bone and scar tissue between the broken ends of the bone. The final step is called bone remodeling (discussed above).

This is when the body replaces the soft callus with new, strong bone. The remodeling process can take several months or even years to complete, dependent on the fracture.

19. The Upper and Lower Parts of the Skeletal System Have Different Functions

The skeletal system can be simply separated into two sections. That is the upper and lower parts which have different functions.

The upper skeletal system is responsible for supporting the head and providing a base for the arms. It also allows us to make a variety of movements with our arms, such as reaching, grasping, and lifting.

The lower part, on the other hand, is responsible for supporting the weight of the body and providing a base for the legs. It also allows you (us), to walk, run, and jump.

20. The ‘Funny Bone’ Is Not a Bone

The so-called ‘funny bone’ is not a bone. It is the ulnar nerve, which runs from the neck down the arm to the pinky and ring fingers.

When the ulnar nerve is hit or compressed, it can cause a tingling or numb sensation in the pinky and ring fingers. This is because the ulnar nerve is very close to the surface of the skin at the elbow.

Hitting the nerve sometimes triggers a surprisingly tingling, prickly pain. However, the pain usually fades away relatively quickly as the nerve heals itself.

While the most critical function of the skeletal system is movement and support of the body, this article shows it serves as so much more than that to the functioning of the body.

It is therefore critical to comprehend the importance of the human skeleton in relation to the other systems of the human body.

Here are some 20 weird facts about the human body!