An "os bone," is not a general term for bone. Instead, it refers to a specific type of bone called a sesamoid bone, which are small, round or oval bones embedded within a tendon. These bones are named using the Latin word "os" meaning bone, followed by a specific descriptive term, and are most often found in areas where tendons pass over joints.
Understanding Sesamoid Bones
To better understand what an "os bone" is, it’s helpful to look at an example:
Os Peroneum
One example is the os peroneum.
| Feature | Description |
|---|---|
| Shape | Round or oval |
| Type | Sesamoid Bone |
| Location | Embedded within the peroneus longus tendon, located at the lateral plantar aspect of the cuboid. |
| Prevalence | 4.7% to 30% in the population. |
- Key Characteristics:
- Embedded in Tendon: The os peroneum is unique because it's embedded within the peroneus longus tendon.
- Protection: Sesamoid bones like the os peroneum protect the tendon and can change the angle of the tendon to improve force production.
- Variable Prevalence: As the reference explains, it has a range of prevalence among individuals.
Why "Os Bone"?
The term "os bone" can be confusing because "os" itself means "bone" in Latin. However, in medical terminology, “os” is used to specify a particular bone, commonly a sesamoid bone, when referring to it by name (e.g., os peroneum, os trigonum).
- Examples of Other "Os Bones":
- Os trigonum (located posterior to the talus in the ankle)
- Os fabella (located behind the knee joint)
In Summary:
An "os bone" is a sesamoid bone, a small bone embedded within a tendon. The os peroneum, as an example, is a sesamoid bone located in the foot embedded within the peroneus longus tendon. These bones help with tendon function and joint movement.
