Significant Asymmetry of the Bilateral Upper Extremities of a Skeleton Excavated from the Mashiki-Azamabaru Site, Okinawa Island, Japan

The human skeleton of a young adult male with marked asymmetry of the bilateral upper extremities was excavated from the Mashiki-Azamabaru site (3000–2000 BCE) on the main island of Okinawa in the southwestern archipelago of Japan. The skeleton was buried alone in a corner of the cemetery. In this study, morphological and radiographic observations were made on this skeleton, and the pathogenesis of the bone growth disorder observed in the left upper limb was discussed. The maximum diameter of the midshaft of the humerus was 13.8 mm on the left and 21.2 mm on the right. The long bones comprising the left upper extremity lost the structure of the muscle attachments except for the deltoid tubercle of the humerus. The bone morphology of the right upper extremity and the bilateral lower extremities was maintained and was close to the mean value of females from the Ohtomo site in northwestern Kyushu, Japan, during the Yayoi period. It is assumed that the anomalous bone morphology confined to the left upper extremity was secondary to the prolonged loss of function of the muscles attached to left extremity bones. In this case, birth palsy, brachial plexus injury in childhood, and acute grey matter myelitis were diagnosed. It was suggested that this person had survived into young adulthood with severe paralysis of the left upper extremity due to injury or disease at an early age.

Reliability of Towel Test for Elbow Flexion Assessment in Brachial Plexus Birth Palsy

Background and Objectives The towel test is a reliable and straightforward technique to find elbow flexion in brachial plexus birth palsy. This study evaluates the role and reliability of towel test in children at 6 and 9 months of age. Materials and Methods We conducted the towel test in 30 consecutive children at 6 and 9 months of their ages between 2015 and 2020. We recorded the results along with the side involved in these children and the mother’s handedness. Based on the results of towel tests, we did a statistical correlation. Results Sixteen of the 30 children were boys. Twelve of the 30 children had left-side involvement. Four mothers were left handed. Four (13%) infants (male = 3; female = 1) had false-negative towel test at 6 and 9 months. There is a significant correlation between the left-hand mother’s and infant who had false-negative towel test (p < 0.01) Conclusion The towel test is reliable and straightforward to assess the elbow flexion at 6 and 9 months. It can be falsely negative in 13% of children because of handedness. Mother’s handedness is crucial and should be recorded during the children assessment. Alternate tests will further evaluate the elbow flexion in such false-negative towel-tested brachial plexus birth palsy children.

Structures contributing to the shoulder contracture in brachial plexus birth palsy. An intraoperative biomechanical study

Internal rotation contracture of the shoulder is a common sequel of the brachial plexus birth palsy. The purpose of this study is to describe the surgical method used in our centre and to measure the effect of sequentially releasing several anatomical structures that have been ascribed as the cause of the contracture. Twenty-four consecutive patients were operated on with an open release. We documented the increase in passive external rotation after each surgical step. We found small gains in passive external rotation when performing coracoidectomy and division of the upper part of the subscapularis tendon; 4° (95% confidence interval [CI] 2°–6° p < 0.01) and 6° (95% CI 4°–8° p < 0.01), respectively. A substantial gain in external rotation occurred when dividing the entire subscapularis tendon, 43° (95% CI 38°–48°, p < 0.01). Our findings indicate that a clinically relevant surgical release of the contracture requires lengthening of the entire subscapularis musculo-tendinous unit. Level of evidence: IV