Smallest and Longest Bones in the Human Body: Bone Structure Explained
Medically Reviewed By
Prof. Ashok Rattan
Written By Kirti Saxena
on Apr 3, 2025
Last Edit Made By Kirti Saxena
on Apr 3, 2025
The human body is full of surprises. Every tiny detail, including how it moves and works, is extremely complex.
However, bones are crucial in supporting human structure, helping in movements, and protecting vital organs.
The human skeleton consists of 206 bones, some of which stand out due to their size. The femur is the longest bone in the body, while the stapes is the smallest. Let's understand the longest and shortest bones in detail and their structure, function, and importance.
The longest bone in the human body is the femur
What is the Femur?
The femur bone is the longest and strongest bone in the body. It is important for standing, moving, and maintaining balance.
The femur is your thigh bone. It is the longest and strongest bone in your body.
It connects the hip to the knee, supports body weight, and enables movement. As a weight-bearing bone, it is highly durable and can withstand significant pressure.
It plays an important role in moving and standing. The fetal bone also supports muscles, tendons, ligaments, and other parts of your circulatory system.
The femur bone can be affected by osteoporosis.
What Does the Femur Do?
The femur bone has important functions, including-
- Supports Body Weight- It holds your body weight while standing, walking, or running.
- Facilitates Movement- It is a strong foundation for muscles and joints, enabling mobility.
- It is an Attachment for Muscles, connecting the muscles, tendons, and ligaments in your lips and knees to the rest of the body.
What Does the Femur Look Like?
The femur bone is located in the thigh. It connects your hip to your knee.
The femur has a long, cylindrical shape with two distinct ends:
- Head: A rounded structure that connects to the hip joint.
- Neck: A narrow portion that links the head to the shaft.
- Shaft: The long, thick central part of the femur.
- Distal End: The lower part that connects to the knee joint.
Due to its robust structure, the femur is one of the hardest bones to break.
How Big is the Femur?
The femur is the longest bone, but its size varies among individuals. On average:
- Length: Approximately 48 cm (approx 18 inches) in adults.
- Diameter: Around 2.3 to 2.8 cm (0.9 to 1.1 inches).
- Strength: It can withstand nearly 800 to 1,000 kg of compressive force before breaking. It can support up to 30 times your body weight.
Common conditions and disorders that affect the femur
The most common conditions that may affect the femur are fractures, osteoporosis, and patellofemoral pain syndrome.
Femur fractures
- Femur bones are strong and only broken in serious injuries like car accidents. The symptoms include-
- Pain
- Swelling
- Tenderness
- Inability to move your leg
- Bruising
- A deformity or bump
Consult your healthcare provider and get immediate medical attention if you experience trauma or think you have a fracture.
Osteoporosis
Osteoporosis weakens bones and increases the risk of sudden and unexpected fractures. Females and adults older than 50 are at high risk of developing osteoporosis. Consult your doctor and get your bone density test to catch osteoporosis before it causes a fracture.
Patellofemoral pain syndrome
Patellofemoral pain syndrome (PFPS) is a runner's or jumper's knee. Pain is usually around and under your kneecap (patella). PFPS may cause symptoms like pain while bending the knee, doing squats, or climbing stairs, crackling or popping sounds in your knee, pain after sitting with your knees bent, and more.
What tests are done on femurs?
Several medical tests can be done for femur evaluation. Some key tests include:
Imaging Tests
Laboratory Tests
- Bone Marrow Biopsy
- Blood Tests like CRP and ESR Tests
Specialized Tests
DEXA Scan (Dual-Energy X-ray Absorptiometry)
How do you keep your femur healthy?
To maintain bone health, stick to a healthy lifestyle, exercise plans, and regular health checkups. However, consult your doctor if you are older than 50 or have a family history of osteoporosis.
Follow these tips to reduce the risk of injury:
- Always wear a seatbelt
- Always wear the right protective equipment for all activities and sports.
- Follow a diet plan and exercise plan to maintain good bone health.
Read more: Top 10 Effective Nutrients to Keep Bones Healthy and Stronger.
The shortest bone in the body: Stapes
What are the Stapes?
The stapes is the smallest bone in the middle ear. It is one of the three auditory ossicles that help with hearing. Any damage to this bone may cause partial or complete hearing loss.
What Does the Stapes Bone Do?
The stapes bone transmits the sound vibrations from the middle ear to the inner ear. The work is:
- Amplifying Sound- It helps transfer vibrations from the eardrum to the cochlea.
- Enhancing Hearing Sensitivity- The stapes allow precise sound transmission and improve auditory clarity.
- Maintaining Balance- Hearing indirectly helps balance the body by interacting with the inner ear structures.
What Do the Stapes Look Like?
The stapes has a stirrup-like shape, consisting of three main parts:
- Head: The top part that connects with the incus (another small ear bone).
- Crura (Arches): Two curved structures that provide stability.
- Base (Footplate)- The bottom part that sits against the cochlea's oval window.
Despite their tiny size, the stapes are essential to the hearing process.
How Small are the Stapes?
The stapes are the smallest bone in the human body. Its dimensions are:
- Length: About 3 mm (0.1 inches).
- Width: Approximately 1.4 mm (0.05 inches).
- Weight: Roughly 2 to 4 milligrams.
Stapes are small in size and have delicate structures. The small size makes it highly susceptible to damage, which may cause hearing impairments such as otosclerosis.
What happens if Stape's bone is damaged?
The stape bone is very small and delicate, so damage can cause hearing problems. These bones are the connecting link between healthy hearing, so they can cause hearing loss when they get damaged. But don't worry—surgery can repair or replace the middle ear bones. Hearing loss can cause various complications, such as cognitive decline, hospitalization, isolation, depression, and fatigue.
Also read: Beware: These Foods That Can Weaken Your Bones.
What are the treatment options for Stape's recovery?
Various treatment options are available for hearing problems. For hearing loss caused by otosclerosis, these include hearing aids and surgery (stapedectomy or stapedotomy) to replace the stapes bone with a prosthesis.
- Hearing Aids
- Surgery (Stapedectomy/Stapedotomy)
The Key Takeaways
The human skeletal system contains bones of various sizes, each with its function and purpose. The femur is the longest and strongest bone, supporting mobility and balancing the body's weight while moving, while the stapes is the smallest bone, crucial to hearing.
Understanding their functions and structures highlights the importance of bone health and its impact on overall well-being. Keep your bones healthy and strong via diet and regular exercise.
