Applied Study Of The Brachial Plexus And Its Communicating Branches

With development of the society, the quantity of the brachial plexus palsy patients causing by various reasons has an increasing tendency. Modern surgical intervention is growing toward a subtile direction with little injury, which produce a higher and finer request for the anatomy of BP. Data of formation and variation of the BP is helpful for surgeons who need to diagnose the injury of BP, distinguish variation of BP and take correct modus operandi in surgical procedures. Data of communicating branches of the BP is also of interest to the surgeons who perform surgical procedures in the cervical and axillary regions. So, knowledge of the variation of BP and its related communicating branch has been become one of elementary knowledge for these surgeons. Uysal discovered miscellaneous communicating branches of the BPs in human fetuses in 2003. Pandey and Shukla also reported communicating branches between cords of human BPs in 2007. But literature about communicating branches of BPs has not been seen in our country. Though grey and white rami do not belong to variation of BP, few literature about distribution of the grey and white rami in detail has been published so far. Therefore, by investigating 50 fixed human cadavers and another 33 fixed specimens, the purpose of this study was to accumulate more data of the variations of BPs, and provide systemic applied data of the communicating branches of BPs and the grey and white rami between sympathetic trunks and BPs.Part one Anatomical study of the variations of brachial plexuses and its clinical significanceObjective To investigate the variations of brachial plexus(BP) and its clinical significance.Methods 50 fixed human cadavers(32 males, 18 females) were utilized in this study.The plexuses were dissected, the variations of BPs were determined and photographed.Results There were no variations in 84 plexuses, and 16 plexuses were observed to have morphological variations. Prefixed plexuses were observed in 46 BPs, and postfixed plexuses were observed in 18 BPs. Six sides have variations in trunk in, and 13 sides in division or cord(three sides have variations in trunk and division or cord). Other type variations include: C5 nerve penetrated the scalenus anterior in 4 sides; both roots of the median nerve were joined behind the axillary artery to form a median nerve in 1 side. There were no significant statistical differences between the right and left sides or males and females(P> 0.05).Conclusion The anatomical data of variation of BPs is helpful for surgeons who perform surgical procedures in the cervical and axillary regions.Part two Anatomical study of communicating branches of the brachial plexus and its clinical significanceObjective To investigate the occurrence and clinical significance of brachial plexus (BP) .Methods This study was performed with 50 fixed human cadavers(32 males, 18 females) . The plexuses were dissected, the presence of the communicating branches of BPs were determined, measured and photographed. Chi-square test was used to compare the differences between right and left sides or males and females.Results The communicating branches were identified in 27 sides of the upper extremity, 25 sides of which linked the lateral cord with the medial cord of BP. The most common branches communicated the lateral cord with the medial root of median nerve (16 sides). All the communicating branches between lateral cords and medial cords obliquely crossed anterior to the axillary artery and passed below the thoracoacromial artery trunk. The distance of communicating branch with the origin of TAT was (1.60±0.64) cm. The length, transverse diameter and anteroposterior diameter of communicating branch were (1.67±0.62) cm, (1.77±0.63) mm and 0.91±0.34) mm, respectively. There was no significant difference between males and females (P> 0.05), the occurrence of right sides communicating branches of BPs is higher than left sides. Conclusion: There existed extensive communicating branches in BPs, the anatomical data will be helpful for surgeons who perform surgical procedures in the cervical and axillary regions.Part three Anatomical study and its clinical significance of the rami communicans between cervical sympathetic trunk and brachial plexusObjective To explore anatomic features and clinical significance of the rami communicans between cervical sympathetic trunk(CST) and brachial plexus(BP).Methods This study utilized 33 fixed human cadavers: 27 males and 6 females without morphological abnormalities. In the supine position, musculi colli and soft tissue were removed to reveal cervical sympathetic trunk, longus scapitis and longus colli. Then the longus scapitis and longus colli were removed, the transverse foramina of C5,C6 and C7 were opened to observe the anatomic characteristics of communicating branches between CSTs and BPs.Results The rami communicans between CST and BP include white and gray rami communicans. White rami communicans are derived from C8 and/or T1 spinal nerves. Gray rami communicans could be divided two groups: medial group and lateral group . The distribution of the rami communicans of the medial group: 1.Most of the rami communicans between middle cervical ganglion(or interganglionic segments rami) and BP are symmetrical. 42 rami distributed to C5 or C6 spinal nerves run medially first at the level of the transverse process of C5 or C6 spinal nerves, turn backward through the groove between longus scapitis muscle and longus colli muscle, and then joined C5 or C6 spinal nerves. 2.Except 1 case, all the medial rami communicans between the cervicothoracic ganglion (CTG) and C7,C8 spinal nerves are symmetrical. Before joining C8 spinal nerve, in 51 sides rami from the CTG to C8 spinal nerve give off a branch ascending through the C7 transverse foramina and communicating with C7 spinal nerve. Before joining C7 spinal nerve, in 41 sides rami from the CTG to C7 spinal nerve send out a branch ascending posteromedia to the vertebral artery(VA) to the C6 spinal nerve, and fine branches can be seen in 29 sides between the branch and VA or the fibrous capsule of adjacent zygapophyseal and intervertebral joints.Conclusion 1 .The distribution of the rami communicans between CST and BP has typical features. These anatomic data may be useful in studying the inference of sympathetic nerve to upper limb and could avoid injuries of the rami communicans in extensive decompression during anterior cervical approach. 2. The distribution of the branch to the fibrous capsule of adjacent zygapophyseal and intervertebral joints could provide anatomic evidence to clinicians in treating medically intractable neck pain by allowing neural blockade of the vertebral nerve(the rami from CTG to C6,C7 spinal nerves).