Prevalence of agenesis of the palmaris longus muscle in Brazil and its clinics correlation

Introduction: The palmaris longus muscle it is considered one of the most variable muscles in the human body, and its agenesis is the most frequent anatomic variation. The aim of this study was to determine the prevalence of unilateral and bilateral agenesis of palmaris longus muscle for the subjects in the city of Jataí, Goiás. Material and methods: 740 subjects, 279 men and 461 women, in the age of 10-70 years old, were observed through clinical inspection in both forearms to absence of the tendon of palmaris. The data were described in percentage values and the absence of the muscle was analyzed statistically (Chi square test; P < 0.05). Results: The bilateral presence was identified in 73.5%, the absence on the left side in 7.8%, on the right in 6.5% and bilateral absence was observed in 12.2% of subjects. Among women and men the percentage values was 9.3%, 7.3%, 13.1% and 5.4%, 5%, 10.7%, respectively to agenesis in left side, in right side and bilateral agenesis. The unilateral/bilateral agenesis was more frequent in women (29.7%) than in men (21.1%; P < 0.05). Bilateral absence was 12.4% in right handed subjects and 9.1% in left handed subjects (P > 0.05). Left and right handed subjects showed absence of muscle similar in both forearms (P > 0.05). Conclusion: most subjects studied showed bilateral presence of palmaris longus muscle, the agenesis was significantly more common in women and with similar percentage in right and left handed subjects.

Radiological Analysis of Ponticulus Posticus in Koreans

PURPOSE: Since there has been little reporting on the prevalence or morphologic characteristics of ponticulus posticus in Asians, we retrospectively reviewed cervical 3-dimensional CT scan images and plain radiographs which had been ordered by neurosurgeons or orthopaedic surgeons for evaluation of cervical spine problems to investigate the prevalence and morphologic features of the ponticulus posticus in Koreans. PATIENTS AND METHODS: The presence and types of ponticulus posticus were investigated on 200 consecutive cervical 3-D CT scans. RESULTS: Thirty-one patients, 48 ponticulus posticus, complete or partial, bilateral or unilateral, were identified on the 200 cervical 3-D CT scans; therefore, the prevalence was 15.5% in our patient population. In plain radiographs analysis, the prevalence was 6.95%. CONCLUSION: The ponticulus posticus is a relatively common anomaly in Koreans. Therefore, proper identification of this anomaly on preoperative lateral radiographs should alert surgeons to avoid using the ponticulus posticus as a starting point for a lateral mass screw. Because of its size and shape have wide variation, 3-D CT scanning should be considered before lateral mass screw placement into the posterior arch if its presence is suspected or confirmed on radiographs.