ABSTRACT
Objective To establish the biomechanical model of skeletal muscle during hand grasping for reverse dynamics simulation, so as to obtain the maximum muscle force of each muscle involved in the process of hand grasping under different forces. Methods CT scanning was performed on a volunteer’s hand, and CT data of his hand were imported into Mimics software for 3D reconstruction, so as to obtain the bone models of each segment. After adjusting the model coordinates by Geomagic Studio, the model was imported in AnyBody software for establishing the kinematics model of the hand skeleton. The related muscles involved in the flexion of each finger were added, to establish the skeletal muscle model of the hand. The model was then used to simulate the reverse dynamics of hand grasping. ResultsThe maximum muscle force of each muscle in the whole process of finger movement was obtained after the 5-30 N external force was applied to each distal phalanx. With the increase of force, the maximum muscle force of each muscle showed a linear trend. For example, the maximum muscle force of flexor pollicis longus increased from 18.49 N to 110.93 N; when the external force was 5 N, the maximum muscle force of flexor pollicis brevis, flexor pollicis longus, adductor pollicis and flexor digiti minimi brevis during hand grasping was 7.70, 18.49, 9.49, 8.39 N, respectively. The muscle force of superficial and deep flexors was greater than that of other muscles in the process of finger movement, which played a major role in grasping the hand. Conclusions The maximum muscle force of the muscles involved in hand grasping under different resistance, and the relationship between muscle force of main muscles and joint angles, can provide guidance and references for the evaluation of hand rehabilitation effect of stroke patients, as well as certain theoretical basis for the manufacture of rehabilitation equipment.
ABSTRACT
Neurofibromatosis 1 (NF1) is an autosomal dominant genetic disease first manifesting in childhood, which affects multiple organs, childhood development and neurocognitive status. These patients have a high predisposition to develop both benign and malignant tumors. On September 30, 2018, a rare case of NF1 with B-lineage acute lymphocytic leukemia (ALL) was treated in the Department of Pediatrics, Third Xiangya Hospital, Central South University. The child presented with café au lait macules (CALM) since the date of birth. And the diagnosis of B-lineage ALL was made by bone marrow cytomorphologic examination and immunological phenotype detection. ETV6/RUNX1 fusion gene was positive. Also, a de novo mutation of c. 2773delT (p. Leu925Ter) was found in the exon of NF1 gene by gene sequencing, which was a nonsense mutation and led to the premature termination of peptide synthesis. Molecular genetic testing is recommended to confirm NF1, particularly in children with only pigmentary features of the diagnostic criteria. NF1-affected individuals should be referred to a specialist of NF1 clinical network for long-term follow-up and surveillance.