The hand has two constant sesamoid bones at the thumb MCP joint, one in the flexor pollicis brevis (radial sesamoid) and one in the adductor pollicis (ulnar sesamoid), and variable sesamoids at other MCP joints and the thumb IP joint. The thumb MCP sesamoids distribute the enormous pinch forces at the thumb MCP level and protect the FPL tendon beneath them. The radial sesamoid (in the FPB tendon) is the more commonly fractured of the two.
| Articulations |
|
|---|---|
| Landmarks |
|
| Ossification | The thumb MCP sesamoids begin to ossify between ages 12 and 14 during puberty. |
Thumb MCP sesamoid fractures from hyperextension injuries produce palmar MCP joint pain with point tenderness over the affected sesamoid. They are distinguished from the normal sesamoids on radiograph by their acuity of margin and surrounding oedema on MRI. Management is conservative with splinting and modification of thumb pinch activities.
Hyperextension of the thumb MCP joint or a direct blow can fracture a sesamoid, causing pain on the palmar side of the joint.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
