Fracture of an aberrant os styloideum: a unique case report

Several accessory bones can be found around the wrist, which may pose a diagnostic challenge. Hereby, we report a unique case of a traumatic fracture of an aberrant os styloideum in a 66-year-old male. The patient presented with a swollen dominant right hand and a hematoma on its anterior and posterior aspects, as a result of a fall on an outstretched hand. The diagnosis was based on a CT scan, which showed a fractured accessory bone between the distal portion of the capitate bone and the base of the third metacarpus. Due to its typical location, the ossicle was identified as os styloideum. The patient was treated conservatively and the symptoms subsided on a short forearm cast after 2 weeks. At a 12-month follow-up, no other episodes were declared. Strong anatomical knowledge and sharing of such cases is essential for proper diagnosis and treatment of this very rare condition.

Incidental discovery of a sacral rib: a case report

PURPOSE

The observation of an accessory bone joined to the sacrum (suggestive of a sacral rib) prompted us to describe the structure's morphology and its anatomic relationships and to consider its morphogenesis and clinical implications.

METHOD

A 38-year-old woman underwent computed tomography, to characterize the extension of a thoracic mass. We compared our observations with the literature data.

RESULTS

We observed a voluminous accessory bone located behind and to the right of the sacrum. The bone was articulated with the third sacral vertebra and featured a head and three processes. These characteristics were suggestive of a sacral rib. We also observed involution of the gluteus maximus.

CONCLUSION

This accessory bone probably resulted from overdevelopment of a costal process and an absence of fusion with the primitive vertebral body. Sacral ribs are rare and usually asymptomatic but appear to be more prevalent in young women. The adjacent muscles are often abnormal. Awareness of the potential presence of this bone is essential for surgeons who operate on the lumbosacral junction.

[Os subtibiale: That odd ankle pain]

Os subtibiale is a low prevalence accessory bone of the ankle. This bone is located in the posterior colliculus of the tibial medial malleolus, both in paediatric and adult ages. It can cause pain, redness and/or swelling, which can lead to a mistaken diagnosis of avulsion fracture. Adequate anatomical knowledge is crucial. First, we present the case of a school-aged boy, seen at the outpatient clinic for a 2-month history of pain in both inner ankles after an injury. Second, we present the case of an adult patient with a 3-day history of right medial ankle pain, with no previous injury, evaluated at the Emergency Department. Accurate history-taking and physical examination are essential. The diagnosis is given by conventional radiology of both ankles, in antero-posterior and lateral load views. The initial treatment is conservative (splint or orthesis) to establish and maintain the function of the foot during loading activities. If there is no recovery after 6 months, surgical treatment can be considered.

Symptomatic os infranaviculare

The author observed a new accessory bone of the foot in the distal portion of navicular, which articulated with the medial cuneiform and the intermediate cuneiform, and named it os infranaviculare. A degenerative change was observed between the accessory bone and the navicular; this caused midfoot pain to the patient during weight-bearing. Thus, the patient was treated by excision of the accessory bone. The symptom was relieved at one-year postoperative.