Os Intermetatarseum is a relatively uncommon anatomical anomaly that affects the bones of the foot. This condition occurs when an extra bone, known as an os intermetatarseum, forms within the foot’s midfoot region. While not a well-known condition, it can lead to discomfort, pain, and mobility issues for those affected. This article will delve into the causes, symptoms, diagnosis, and various treatment options for Os Intermetatarseum.

Deformed Foot  - Bunion stock photo

Anatomy Of The Foot

Before we delve into Os Intermetatarseum, it’s important to understand the basic anatomy of the foot. The human foot consists of numerous bones, muscles, ligaments, and tendons, all working together to support the body’s weight, facilitate movement, and absorb shock during walking and running. There are 26 bones in the human foot, which are typically divided into three main regions: the hindfoot (ankle and heel), the midfoot, and the forefoot (toes).

The midfoot, where the Os Intermetatarseum is located, includes a cluster of small bones known as the metatarsal bones. These five long bones extend from the midfoot to the base of the toes and play a crucial role in supporting body weight and maintaining balance.

What Is Os Intermetatarseum?

Os Intermetatarseum, also known as the os intermetatarsal or the accessory metatarsal bone, is an additional bone that can develop within the midfoot region. It typically forms between the first and second metatarsal bones, although it can occasionally occur between the second and third metatarsals or in other locations within the foot. This extra bone is usually small and round or oval, resembling a sesame seed.

Causes of Os Intermetatarseum

The precise cause of Os Intermetatarseum is not well understood, but it is generally believed to be a congenital anomaly, meaning it is present at birth. Some theories suggest that it may result from genetic factors or abnormal bone development during fetal development. It can also be associated with other foot deformities or conditions, such as flat feet or bunions.

Symptoms Of Os Intermetatarseum

Os Intermetatarseum may not cause any symptoms in some individuals and can go unnoticed for years. However, when symptoms do occur, they can range from mild discomfort to severe pain. Common symptoms associated with Os Intermetatarseum include:

  • Pain: Many individuals with Os Intermetatarseum experience pain in the midfoot region. The pain can be intermittent or persistent and may worsen with physical activity, such as walking or running.
  • Swelling: Swelling and inflammation may occur around the area where the extra bone is located.
  • Tenderness: The affected area may become tender to the touch.
  • Limited Range of Motion: Some individuals may experience a reduced range of motion in the affected foot, making it difficult to flex or extend the toes.
  • Numbness and Tingling: In rare cases, the presence of Os Intermetatarseum can put pressure on nearby nerves, leading to numbness and tingling sensations in the toes or surrounding areas.

Diagnosis Of Os Intermetatarseum

Diagnosing Os Intermetatarseum typically involves a combination of medical history, physical examination, and imaging studies. Here’s how the diagnosis process generally unfolds:

  • Medical History: The healthcare provider will ask about the patient’s symptoms, including the location and duration of pain or discomfort.
  • Physical Examination: A thorough physical examination of the affected foot is conducted to assess for tenderness, swelling, and abnormalities in the midfoot region.
  • Imaging Studies: X-rays are the most common imaging tool used to confirm the presence of Os Intermetatarseum. X-rays provide detailed images of the bones, allowing the healthcare provider to identify any extra bone formation.

Treatment Options For Os Intermetatarseum

The treatment approach for Os Intermetatarseum depends on the severity of symptoms and their impact on the patient’s daily life. In many cases, conservative treatments are effective in managing the condition. However, in severe or persistent cases, surgical intervention may be considered.

Conservative Treatment

  • Rest and Activity Modification: Patients with mild symptoms may find relief by resting the affected foot and avoiding activities that exacerbate pain.
  • Footwear Modification: Wearing shoes with good arch support and cushioning can help alleviate discomfort and reduce pressure on the Os Intermetatarseum.
  • Orthotic Devices: Custom-made orthotic inserts can be designed to provide additional support to the midfoot and distribute weight more evenly.
  • Physical Therapy: Physical therapists can recommend exercises and stretches to strengthen the foot muscles, improve flexibility, and enhance overall foot function.
  • Medications: Over-the-counter pain relievers, such as nonsteroidal anti-inflammatory drugs (NSAIDs), can help manage pain and inflammation.

Surgical Treatment

  • Excision of Os Intermetatarseum: In cases where conservative treatments do not provide relief or if the condition is causing severe pain and mobility issues, surgical removal of the extra bone may be necessary. This procedure is known as excision.
  • Realignment Surgery: In some instances, the Os Intermetatarseum may be associated with other foot deformities, such as bunions. In such cases, surgery to realign the bones and correct the deformity may be recommended.
  • Rehabilitation: After surgery, patients will typically undergo a period of rehabilitation, including physical therapy, to regain strength and mobility in the affected foot.

It’s essential to note that surgical intervention is usually considered a last resort when conservative treatments fail to provide relief, as surgery carries its own risks and recovery period.

It’s important to note that the choice between conservative and surgical treatment options depends on factors such as the severity of symptoms, the impact on daily activities, and the individual’s overall health. Additionally, surgical intervention is typically considered a last resort when conservative treatments fail to provide relief.

Patients considering surgical treatment should discuss the risks, benefits, and expected outcomes with their healthcare provider. They should also follow post-operative instructions carefully to optimize the healing process.

The treatment of Os Intermetatarseum is tailored to each individual’s specific circumstances. With appropriate care and intervention, individuals with this condition can experience significant relief from pain and improved foot function, allowing them to lead active and fulfilling lives.

Recovery And Prognosis

The recovery period for Os Intermetatarseum depends on the chosen treatment approach. In cases where conservative treatments are successful, patients may experience relief from their symptoms within a few weeks to a few months. Physical therapy and continued use of orthotic devices can help maintain foot health.

For those who require surgical intervention, the recovery period may be longer, typically ranging from several weeks to a few months. Patients must follow their healthcare provider’s post-operative instructions, including keeping the foot elevated and avoiding weight-bearing activities during the initial stages of recovery.

The overall prognosis for Os Intermetatarseum is generally positive, especially with appropriate treatment. Most individuals can expect a significant reduction in pain and an improvement in foot function following treatment. However, it’s essential to maintain good foot care practices and follow up with healthcare providers as needed to prevent recurrence or the development of other foot-related issues.


Os Intermetatarseum is a relatively rare but potentially painful condition that affects the midfoot region of the foot. While the exact cause remains unclear, it is often present from birth and may lead to symptoms such as pain, swelling, and limited mobility. Fortunately, a variety of treatment options, including conservative approaches and, in some cases, surgery, can effectively manage Os Intermetatarseum and improve the quality of life for those affected.

Early diagnosis and appropriate treatment can help individuals regain comfort and functionality in their feet, allowing them to lead active and fulfilling lives.

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