How Much Force Does It Take To Break A Bone?

Summary

This DNews episode explores the complexity of bone fractures, highlighting the differences in force required to break various bones due to their size and structure. Dr. Cindy Bir explains that the femur can withstand around 4,000 newtons of force compared to the rib's 3,300 newtons, influenced by muscle support and bone tissue composition. Factors such as diet, exercise, and age also affect bone strength, with a decline in bone density post-age 30 potentially leading to osteoporosis.

Takeaways

• 🦴 Humans have 206 bones, varying in shape and size, which affects their susceptibility to breaking.
• 💪 The femur, being the largest bone, is harder to break compared to the more slender clavicle, which is commonly broken.
• 🏋️ Muscle support around a bone plays a role in absorbing impact and protecting it from fractures.
• 🔢 An estimated force of 3,300 newtons has a 25% chance of breaking a rib, while the femur requires around 4,000 newtons.
• 👊 The angle of impact is crucial; a perpendicular blow is more damaging than a parallel one due to bone structure.
• 🦴 Bones consist of two types of tissue: cancellous (spongy inner material) and cortical (dense outer layer).
• 🧬 Cortical bone, which makes up 80% of the skeleton's mass, is composed of collagen and calcium phosphate for strength and flexibility.
• 🤸‍♂️ Bones are dynamic, undergoing a constant process of resorption and rebuilding, influenced by diet, exercise, and age.
• 🥦 A diet low in calcium can lead to brittle bones, while exercise can strengthen them by stressing the bone structure.
• 👵 Bones reach peak density around age 30 and decline thereafter, increasing the risk of osteoporosis with age.
• 🧑‍🦳 In the US, 55% of people over 50 are estimated to have osteoporosis, which weakens bones and makes them prone to fractures.
• 🎥 The video also mentions a new Seeker VR channel for an immersive video experience using VR devices.

Q & A

What incident during the filming of a Star Wars movie prompted the discussion on bone strength?

A hydraulic door broke Harrison Ford's leg, which led to the discussion on how much force it takes to break a bone.

How many bones do adults typically have in their body?

Adults have 206 bones in their body, which come in various shapes and sizes.

Which is the largest bone in the human body and why is it harder to break?

The femur, or thigh bone, is the largest bone in the human body. It is harder to break due to the muscle mass surrounding it that helps absorb impact.

What is the role of muscle around a bone in terms of bone strength?

Muscles around a bone support the bone and absorb some of the impact from a hit, providing additional protection against fractures.

What is the estimated force required to have a 1 in 4 chance of cracking an average person's rib according to Dr. Cindy Bir?

Dr. Cindy Bir estimates that a force of 3,300 newtons has a 1 in 4 chance of cracking an average person's rib.

How does the angle of force application affect the likelihood of breaking a bone?

A blow perpendicular to the bone does more damage than the same force applied almost parallel because of the bone's structure.

What are the two types of bone tissue that make up human bones?

The two types of bone tissue are cancellous bone, which is the spongy inner material, and cortical bone, which is the dense, hard, and stiff outer layer.

Why are bones good at handling compressive forces but not shear forces?

Bones are good at handling compressive forces due to their columnar structure, but they are not as effective at dealing with shear forces because of the way the collagen and calcium phosphate are arranged.

How does diet, particularly calcium intake, affect the strength of bones?

A diet low in calcium can lead to more brittle bones because calcium is a major component of bones, and its deficiency can compromise bone strength.

What is the impact of exercise on bone strength and why is it important for astronauts?

Exercise puts stress on bones, which can make them stronger. Astronauts experience reduced bone density in space because the lack of gravity means their bones aren't getting the stress they would on Earth.

Why do bones become weaker with age and what condition can this lead to?

Bones reach peak density around age 30 and then begin to decline as the resorption of bone happens faster than formation, which can eventually lead to osteoporosis, a condition where bones are weaker and more prone to fractures.

What percentage of people over 50 in the US are estimated to have osteoporosis?

In the US, an estimated 55% of people over 50 have osteoporosis.