What are the Sesamoid Bones: An Essential Guide to Understanding These Small but Mighty Bones

Have you ever heard of sesamoid bones? No, I’m not talking about the latest trend in health-conscious eating. Sesamoid bones are small, circular bones that are found in several key joints in the body. These bones are unique in that they are not connected to any other bones in the body. Instead, they are embedded in tendons or muscles, where they act as pulleys to help move the joint.

The most well-known sesamoid bone is the kneecap, or patella, but there are actually sesamoid bones in a number of other joints as well. In the foot, for example, there are two sesamoid bones at the base of the big toe that help support the foot and distribute weight evenly when we walk. Sesamoid bones also play an important role in the thumb, where they help move the joint more efficiently.

Despite their small size, sesamoid bones are essential for proper joint movement and function. Unfortunately, they can also be vulnerable to injury, particularly in athletes and dancers who put significant stress on their joints. In the following article, we’ll explore the role of sesamoid bones in the body and look at some common injuries and treatments. So settle in, grab a cup of tea, and let’s dive in!

Definition of Sesamoid Bones

Sesamoid bones are unique bones found in the human body that are shaped like a sesame seed, hence the name. These bones are typically small, round, and located in tendons, where they serve to protect the tendon or alter its direction of pull. Sesamoid bones can be found throughout the body, but are most commonly found in the hands and feet.

Sesamoid bones are not part of the axial or appendicular skeleton, but are classified as small bones or short bones. Unlike long bones, sesamoid bones do not have a shaft, end, or marrow cavity. They are formed during the process of intramembranous ossification, where bone tissue forms within a layer of mesenchymal tissue.

Location of sesamoid bones in the body

Sesamoid bones are small bones located within tendons that connect muscles to bones. These bones are unique because they are not anchored to any other bone in the body, but are instead held in place by the tendons themselves. Sesamoid bones can be found in various locations throughout the body, serving a range of functions.

  • Foot: The foot contains the largest concentration of sesamoid bones, with two located under the first metatarsal bone (the bone connecting to the big toe) and one located under the second metatarsal bone. These sesamoid bones assist in weight-bearing and reduce friction within the tendons of the foot.
  • Hand: The hand contains two small sesamoid bones in the thumb, one located at the knuckle and one at the base of the thumb. These bones assist with gripping and provide additional stability for the thumb.
  • Knee: The knee contains the patella, the largest sesamoid bone in the body. The patella assists with extension of the knee and protects the knee joint from excessive pressure.

Other less common locations for sesamoid bones include the wrist, elbow, and hip. These bones can vary in size and shape, with some being as small as a grain of rice and others as large as the patella. Despite their small size, sesamoid bones play an important role in the proper functioning of the musculoskeletal system.

To get a closer look at the location and size of specific sesamoid bones within the body, refer to the table below:

Body Part Sesamoid Bone(s)
Foot First metatarsal – 2 sesamoid bones
Second metatarsal – 1 sesamoid bone
Hand Thumb – 2 sesamoid bones
Knee Patella – 1 sesamoid bone
Wrist Radial sesamoid – 1 sesamoid bone (not present in all individuals)
Elbow Ulnar sesamoid – 1 sesamoid bone (not present in all individuals)
Hip Iliopsoas tendon – 1 sesamoid bone (not present in all individuals)

Understanding the location and function of sesamoid bones can provide insight into the important role they play in the overall health and mobility of the body. If you are experiencing pain or discomfort in any area containing sesamoid bones, it is important to seek professional medical advice to properly diagnose and treat the issue.

Types of Sesamoid Bones

There are two types of sesamoid bones: those that are present in everyone and those that are only present in some individuals. The former includes the patella, located in the knee joint, while the latter varies from person to person.

  • The most common sesamoid bones found in some individuals are the two small bones located on the underside of the first metatarsal bone of the foot. Known as the medial and lateral sesamoids, their purpose is to protect the tendon that runs to the big toe and to increase its leverage when it flexes.
  • The fabella is another sesamoid bone that is only present in about 1 in 4 people. It is located behind the knee and serves to increase the area over which the tendon that runs from the thigh muscle to the calf muscle can act.
  • The pisiform bone in the wrist is another example of a rare sesamoid bone, present in about 10% of people. Like other sesamoid bones, it serves to protect the nearby tendon and increase its leverage.

Developmental Sesamoid Bones

Other sesamoid bones, known as developmental sesamoids, may develop in response to trauma or mechanical stress. These bones are not present in everyone and may vary in size and number from person to person.

In the foot, the sesamoids that develop in response to stress or injury are usually located near the ball of the foot, where the foot absorbs the most shock. These bones can cause pain and inflammation, particularly in athletes or those who spend long periods standing or walking.

Some common examples of developmental sesamoid bones include:

Bone Location Purpose
Accessory navicular Foot, near the ankle Provides an attachment point for a tendon that controls the arch of the foot
Fibular sesamoid Foot, near the big toe Stabilizes the joint of the big toe
Hallux sesamoids Foot, under the big toe joint Aid in weight-bearing and shock absorption

While sesamoid bones may seem like small and insignificant structures, they play a vital role in the proper functioning of our skeletal system.

Function of Sesamoid Bones

Sesamoid bones are small, oval-shaped bones that are embedded within tendons, joint capsules, and other connective tissues of the body. These bones have a variety of functions, including:

  • Redistributing forces: Sesamoid bones act as pulleys, changing the direction of forces and reducing the load on nearby tissues. This helps to protect the joints and other structures from excessive wear and tear.
  • Increasing leverage: By increasing the distance between a muscle’s attachment and the joint’s pivot point, sesamoid bones increase the muscle’s mechanical advantage. This helps the muscle exert more force on the joint.
  • Absorbing shock: Sesamoid bones can absorb some of the shock that occurs during weight-bearing activities like running and jumping. This helps to protect the bones, joints, and other tissues from the damaging effects of repetitive impact.

The most well-known sesamoid bones are found in the feet, where they help to support the body’s weight and facilitate movement. The two largest sesamoid bones in the body are the patellae, or kneecaps. These bones play a critical role in the movement of the lower leg and help to protect the knee joint from injury.

Sesamoid Bones in the Foot

In the foot, sesamoid bones are located beneath the first metatarsal bone, near the big toe joint. These bones are part of the ball of the foot and help to bear weight and distribute forces during standing, walking, and running.

The sesamoid bones in the foot have several important functions, including:

  • Providing a smooth surface for joint movement: By reducing friction, sesamoid bones allow the tendons and other soft tissues to move freely over the joint surfaces.
  • Stabilizing the big toe joint: The sesamoid bones help to maintain the position of the big toe and prevent it from drifting out of alignment.
  • Supporting the arch of the foot: By increasing the height of the medial arch, the sesamoid bones help to distribute weight more evenly across the foot and reduce the risk of injury.

Common Injuries and Conditions

Like any bone in the body, sesamoid bones can be susceptible to injury and disease. Some of the most common sesamoid bone injuries and conditions include:

  • Sesamoiditis: This is an overuse injury that results from repetitive stress to the sesamoid bones. It can cause pain, swelling, and difficulty moving the affected joint.
  • Sesamoid fractures: These can occur as a result of trauma or overuse and can cause severe pain, swelling, and difficulty bearing weight on the affected foot.
  • Hallux limitus/rigidus: This is a condition in which the big toe joint becomes stiff and painful, making it difficult to move the toe. It can be caused by damage to the sesamoid bones or other underlying conditions.

The Bottom Line

Sesamoid bones play an important role in the movement and function of the human body. By redistributing forces, increasing leverage, and absorbing shock, these small bones help to protect the joints and other structures from damage. If you experience pain or other symptoms related to your sesamoid bones, it’s important to seek medical attention promptly to prevent further injury and ensure a speedy recovery.

Common problems associated with sesamoid bones

Sesamoid bones are small, round bones embedded in tendons, and they are unique since they are not connected to other bones. These bones are present in various parts of the body, such as the hands, feet, and knees. However, the most common type of sesamoid bone injury occurs in the foot, behind the big toe, and is known as the “great toe” or “hallux” sesamoid.

The following are common problems and conditions associated with sesamoid bones:

  • Sesamoiditis: This is a condition characterized by inflammation of the sesamoid bones, usually the hallux sesamoid. It occurs due to repetitive activities, such as running or ballet dancing, that exert excessive pressure on the foot’s ball. Symptoms include pain, swelling, and difficulty bearing weight on the affected foot.
  • Sesamoid Fracture: A fracture occurs when there is a break in the bone’s continuity, and it can occur due to a direct impact or a sudden change in direction while playing sports such as football or soccer. Symptoms include severe pain, swelling, and bruising of the foot’s bottom.
  • Turf Toe: This condition is characterized by damage to the ligaments and tendons that support the big toe joint. The condition’s name comes from playing sports on artificial turf, where the toe gets caught and twisted. Symptoms include pain, swelling, and difficulty bending the toe.

The Treatment of sesamoid bone injuries

The treatment of sesamoid bone injuries varies from conservative measures such as RICE (rest, ice, compression, and elevation) and the use of cushioned pads, orthotics, or shoe inserts to surgical intervention. Stress fractures of sesamoid bones require immobilization, while sesamoiditis responds well to nonsteroidal anti-inflammatory drugs, steroid injections, and physical therapy. If conservative methods fail, surgery can be an option to remove the injured bone or the surrounding tissue and restore joint function.

Prevention of sesamoid bone injuries

Sesamoid injuries can be preventable by following the below measures:

  • Wear shoes that provide enough cushion and support to your foot
  • Avoid wearing high-heeled footwear
  • Gradually increase physical activity level rather than engaging in abrupt intensity changes
  • Choose appropriate footwear for specific sports and activities
  • Stretch before and after any physical activity to warm up and cool down the muscles


Sesamoid bone injuries can be painful and significantly limit your mobility. However, with proper diagnosis and treatment, most individuals can recover and return to their normal activities. Prevention plays a vital role in avoiding these injuries, so it is essential to prioritize good footwear choices and take precautions while participating in physical activities.

Condition Symptoms Treatment Options
Sesamoiditis Pain, swelling, difficulty bearing weight Rest, ice, compression, elevation, NSAIDs, steroid injections, physical therapy, immobilization, surgery
Sesamoid Fracture Severe pain, swelling, bruising Rest, ice, compression, elevation, immobilization, surgery
Turf Toe Pain, swelling, difficulty bending Rest, ice, compression, elevation, NSAIDs, steroid injections, physical therapy, surgery

*NSAIDs: Nonsteroidal anti-inflammatory drugs

Diagnosis of Sesamoid Bone Injuries

Diagnosing sesamoid bone injuries can be a challenge as the symptoms are often similar to those of other foot injuries. Health care professionals often rely on a combination of physical examination, medical history, and imaging studies to make a diagnosis.

The following are some of the methods used to diagnose sesamoid bone injuries:

  • Physical examination: A doctor will examine the affected foot and ask about the onset, duration, and location of the pain. They may also check for swelling, tenderness, and range of motion of the joint.
  • X-ray: This imaging study can show any fractures or dislocation in the sesamoid bones.
  • MRI: An MRI can provide a more detailed image of the bones and the surrounding soft tissues, such as ligaments and tendons.

In some cases, a doctor may recommend a bone scan or a CT scan to confirm the diagnosis or rule out other conditions.

It is essential to seek medical attention if you experience persistent pain or swelling in your foot. Delaying the treatment can lead to more severe complications, such as osteonecrosis, a condition that damages the bone due to a lack of blood supply.

Symptoms of Sesamoid Bone Injuries Possible Causes
Pain under the big toe joint Fracture, dislocation, or pressure from overuse
Swelling and bruising Trauma, repetitive activities or stress on the foot
Limited range of motion Damaged tendons or arthritis

Knowing the symptoms and possible causes can help you communicate better with your doctor and receive a prompt diagnosis and treatment.

Treatment options for sesamoid bone injuries

Sesamoid bones are small, round bones that are embedded within tendons. They are commonly found in the feet, where they help to reduce friction and assist with weight-bearing. However, sesamoid bone injuries can occur due to repetitive stress, trauma, or inflammation. These injuries can be incredibly painful and may require specialized treatment options.

  • Rest: The first step in treating a sesamoid bone injury is to rest the affected foot. This means avoiding physical activities that may further exacerbate the injury, such as running or jumping. Instead, try to stay off your feet as much as possible. You may need to use crutches or a walking boot to keep weight off the injured foot.
  • Pain medication: Over-the-counter pain relievers, such as acetaminophen or ibuprofen, may be used to help manage pain and reduce inflammation. However, it is important to avoid taking these medications for an extended period of time, as they can have negative side effects.
  • Ice: Applying ice to the affected area can help to reduce swelling and numb the pain. Wrap a cold pack or bag of ice in a towel and apply it to the affected area for 15 to 20 minutes at a time, several times a day.

In addition to the above treatment options, there are a few other interventions that may be necessary, depending on the severity of the injury:

Physical therapy: A physical therapy program may be recommended to help improve mobility and reduce pain in the affected foot. Physical therapists can provide exercises and stretches that can help strengthen the surrounding muscles and relieve pressure on the sesamoid bone.

Sesamoid pads: If the pain is persistent, your doctor may recommend the use of sesamoid pads. These are small pads that are placed over the affected area to help cushion the sesamoid bone and reduce discomfort. They can be purchased over-the-counter or through a doctor’s prescription.

Treatment Pros Cons
Injection therapy – Provides immediate pain relief
– Can be administered in a doctor’s office
– May need multiple injections over time
– Can cause tissue damage if not administered correctly
Surgery – Can result in complete pain relief and improved function
– Only necessary for severe cases of sesamoid injury
– Recovery time can be lengthy
– Surgery may not be successful in all cases

Injection therapy: If other treatments prove ineffective, a doctor may recommend injection therapy. This involves injecting medication, such as a corticosteroid, into the affected area to provide immediate pain relief. However, this treatment may need to be repeated over time.

Surgery: In severe cases of sesamoid bone injury, surgery may be necessary. This may involve removing the affected sesamoid bone, or using screws or wires to stabilize the bone and promote healing. However, surgery has its own risks and can have a lengthy recovery time.

It is important to consult with a medical professional if you are experiencing sesamoid bone pain or discomfort. Proper diagnosis and treatment can help prevent long-term damage and improve your quality of life.

What are Sesamoid Bones?

1. What exactly are sesamoid bones?

Sesamoid bones are small, floating bone-like structures that are embedded in the tendons of certain muscles found within the body. These bones are typically short and oval-shaped.

2. Where are Sesamoid Bones found in the body?

Sesamoid bones are found in the knees, hands, and feet. The most commonly known sesamoid bone is the patella or kneecap. In the foot, they are located at the base of the big toe.

3. What is the function of Sesamoid Bones?

The primary role of Sesamoid Bones is to provide protection to the tendons and muscles within the joint. They also assist in reducing friction and are important for weight-bearing.

4. Can Sesamoid Bones become injured?

Yes, Sesamoid Bones are susceptible to a variety of injuries such as fractures, inflammation, and tendinitis. Overuse or repetitive actions can lead to Sesamoid Bone injuries.

5. How can Sesamoid Bone injuries be treated?

Treatment options depend on the type and severity of the Sesamoid Bone injury. Rest, ice, compression, and elevation, as well as pain management, are commonly used treatment measures. In some cases, surgery may be required.

6. Are there exercises that can help strengthen Sesamoid Bones?

Yes, exercises such as toe curls with a towel or a tennis ball and calf stretches can help strengthen Sesamoid Bones and prevent injuries.

7. Can Sesamoid Bone injuries be prevented?

Yes, Sesamoid Bone injuries can be prevented by ensuring appropriate footwear is worn during physical activity and taking breaks to rest and stretch the affected area to avoid overuse.

Closing Thoughts

Thank you for learning about Sesamoid Bones with us today. We hope this information has been helpful for you. If you have any more questions feel free to come back and visit us again. Take care!