tailieunhanh - Atlas of Neuromuscular Diseases - part 5

Các sợi đi qua thân cây phía trên và trung bình và dây sau, và tiếp tục với các dây thần kinh subscapular thấp hơn. Đôi khi dây thần kinh này là một chi nhánh của dây thần kinh nách và xuyên tâm. | 189 Thoracodorsal nerve Genetic testing NCV EMG Laboratory Imaging Biopsy Fig. 29. Thoracodorsal nerve anatomy. 1 Thoracodorsal nerve. 2 Latissimus dorsi muscle 190 Anatomy Fibers stem from C5-C7 roots. Only 50 of cases have fibers from C7. The fibers pass through the upper and middle trunks and the posterior cord and continues with the lower subscapular nerve. Occasionally this nerve is a branch of the axillary and radial nerves. A motor branch goes to the latissimus dorsi muscle and may also innervate the teres major muscle. Both muscles are adductors and inward rotators of the scapulohumeral joint and help to bring down the elevated arm see Fig. 29 . Symptoms Few clinical symptoms weakness compensated in part by pectoralis major and teres major muscles. Signs Atrophy and slight winging of the inferior margin of the scapula Motor Latissimus dorsi weakness in adduction and medial rotation of shoulder and arm. Causes Isolated lesion is very uncommon. Neuralgic amyotrophy rarely Plexus lesions injury in association with posterior cord or more proximal brachial plexus lesions. Diagnosis EMG Differential diagnosis Plexus posterior cord lesions upper middle trunk lesions Radicular C5-C7 lesion Therapy Conservative. Surgical interventions are not necessary because of the minor dysfunction. Due to this fact this muscle can be used for grafting to the biceps brachii and outward rotators of humeroscapular joint. Prognosis Good 191 Pectoral nerve Patients note painless atrophy. Weakness and atrophy of the pectoral muscle. Compensatory hypertrophy of other chest muscles. Lateral pectoral nerve Receives fibers from C5-7 lateral cord of plexus and supplies upper part of pectoral muscle. Medial pectoral nerve Receives fibers from C8 T1 and supplies lower part of pectoral muscle. Aplasia Entrapment in hypertrophies of minor pectoral muscle Neck dissection Weight lifting Bird SJ 1996 Acute focal neuropathy in male weight lifters. Muscle Nerve 19 897-899 Symptoms Signs Anatomy .