Posterior Division Of Upper Trunk Research Articles

Erb’s Palsy in a Newborn Child and Clinicoanatomical Approach

Erb’s palsy is found in upper trunk of brachial plexus. C5, C6 roots join to from upper trunk. Each trunk again divides into anterior and posterior divisions. All trunks and divisions are found above the clavicle in the posterior triangle of neck. Branches from the upper trunk are suprascapular nerve and nerve to subclavius. Suprascapular nerve supplies supraspinatus and infraspinatus muscle along with it a articular trig to capsule of shoulder joint. Supraspinatus helps in initial 15 ºabduction at shoulder joint. Infraspinatus acts as lateral rotator of shoulder joint and assists subscapularis and teres minor muscles to abduct at this joint when there is contraction of middle fibers of deltoid and supraspinatus. Some fibers of C5 also give contribution to accessory phrenic nerve. Lateral cord of brachial plexus giving– musculocutaneous nerve, lateral pectoral nerve, lateral root of median nerve. Musculocutaneous nerve supplies all flexor muscles of arm like biceps brachii, brachialis, coracobrachialis. Brachialis muscle flexes the elbow joint, coracobrachialis is a weak flexor of shoulder joint and biceps brachii is a strong supinator of forearm, flexor of elbow joint only when forearm is supinated. Injury occurs in the Erb’s point found in the upper trunk of brachial plexus where there are emergence of six branches- C5 & C6 nerve roots, suprascapular nerve, nerve to subclavius, anterior and posterior division of upper trunk of the plexus. In this palsy, the arm remains medially rotated and adducted at the shoulder joint, the elbow is extended or semiflexed, forearm is pronated, and the wrist semiflexed. In this case a newborn child was found unable to flex his elbow, and abducted the arm on the right side. The limb is medially rotated, adducted in shoulder joint, semiflexion at the elbow joint and forearm pronated and wrist semiflexed. The child was kept on artificial respiratory ventilation. Plain Chest X-ray done to see if any musculoskeletal abnormality is there but no positive findings found so far. Both the clavicles and all ribs were found intact. Both domes of diaphragm were moving normally. On the other hand left sided upper limb found fully flexed at the elbow joint, supinated at forearm, abducted externally rotated at the shoulder joint and wrist extended. Moros reflex on the right side was absent but on left side it was clearly present. So, there is asymmetrical Moros reflex.

Long-Term Outcome of Phrenic Nerve Transfer in Brachial Plexus Avulsion Injuries.

In brachial plexus injuries, useful recovery of arm function has been documented in most patients after phrenic nerve transfer after variable follow-up durations, but there is not much information about long-term functional outcomes. In addition, there is still some concern that respiratory complications might become manifest with aging. The aim of this study was to report the outcome of phrenic nerve transfer after a minimum follow-up of 5 years. Twenty-six patients were reviewed and evaluated clinically. Age at surgery averaged 25.2 years and follow-up averaged 9.15 years. Shoulder abduction and external rotation achieved by transfer of phrenic to axillary nerve (or posterior division of upper trunk), combined with spinal accessory to suprascapular nerve transfer, were better than that achieved by transfer of phrenic to suprascapular nerve, combined with grafting the posterior division of upper trunk from C5, 52.3 and 45.5 degrees versus 47.5 and 39.4 degrees, respectively. There was no difference in abduction when the phrenic nerve was transferred directly to the posterior division of upper trunk or to the axillary nerve using nerve graft. Elbow flexion (≥M3 MRC) was achieved in 5 (83.3%) of 6 cases. Elbow extension M4 MRC or greater was achieved in 4 (66.6%) of 6 cases. All patients, including those who exceeded the age of 45 years and those who had concomitant intercostal nerve transfer, continued to have no respiratory symptoms. The long-term follow-up confirms the safety and effectiveness and of phrenic nerve transfer for functional restoration of shoulder and elbow functions in brachial plexus avulsion injuries.

The outcome of primary brachial plexus reconstruction in extended Erb\u2019s obstetric palsy when two roots are available for intraplexus neurotization

BackgroundThe outcome of primary brachial plexus reconstruction in extended Erb’s obstetric palsy with single root avulsion has not been specifically documented in the literature.MethodsA series of 46 consecutive cases of extended Erb’s obstetric palsy with single root avulsion was retrospectively reviewed. The upper and middle trunks were reconstructed with nerve grafts from the available two roots. No nerve transfers were used. The percentage of a satisfactory motor recovery was documented.ResultsThe postoperative motor recovery was excellent (over 97%) satisfactory outcome for elbow flexion, elbow extension, and digital extension. A satisfactory wrist extension was noted in 84.8% of children. The lowest rates of satisfactory outcomes were for shoulder external rotation (65.2%) and shoulder abduction (56.5%).ConclusionsIn extended Erb’s obstetric palsy with single root avulsion, two ruptured roots are available for intraplexus neurotization of the upper and middle trunks. The surgeon gives a priority to elbow flexion and this is translated in an excellent outcome for elbow flexion. The triceps and digital extensors get a major contribution form the unaffected C8 root, and this is also translated in an excellent outcome for these two functions. Fewer cable grafts are available for reconstruction of the posterior division of upper trunk and the middle trunk, resulting in a lower rate of satisfactory outcomes at the shoulder for wrist extension.Level of Evidence: Level IV, therapeutic study.

Variations in brachial plexus and the relationship of median nerve with the axillary artery: a case report

BackgroundBrachial Plexus innervates the upper limb. As it is the point of formation of many nerves, variations are common. Knowledge of these is important to anatomists, radiologists, anesthesiologists and surgeons. The presence of anatomical variations of the peripheral nervous system is often used to explain unexpected clinical signs and symptoms.Case PresentationOn routine dissection of an embalmed 57 year old male cadaver, variations were found in the formation of divisions and cords of the Brachial Plexus of the right side. Some previously unreported findings observed were; direct branches to the muscles Pectoralis Minor and Latissimus dorsi from C6, innervation of deltoid by C6 and C7 roots and the origin of lateral pectoral nerve from the posterior division of upper trunk. The median nerve was present lateral to axillary artery. The left side brachial plexus was also inspected and found to have normal anatomy.ConclusionThe probable cause for such variations and their embryological basis is discussed in the paper. It is also concluded that although these variations may not have affected the functioning of upper limb in this individual, knowledge of such variations is essential in evaluation of unexplained sensory and motor loss after trauma and surgical interventions to the upper limb.

An Uncommon Variation In The Formation Of Trunks Of The Brachial Plexus A Case Report.

Brachial plexus is the nerve plexus which gives innervation to the upper limb. Variation in the formation of brachial plexus is often reported. But variation in the trunk stage of brachial plexus is very rare. In this case report, we report an unusual variation in the formation of trunks of brachial plexus found in an elderly male cadaver during routine dissection. The upper trunk of brachial plexus was normal. The middle and lower trunks fused to form a common trunk. This was observed bilaterally. The upper trunk divided into anterior and posterior divisions. The common trunk divided into three divisions, anteromedial, anterolateral and posterior. The anterolateral division of common trunk joined with the anterior division of upper trunk and formed the lateral cord. The posterior division of common trunk joined with the posterior division of upper trunk and formed the posterior cord and the anteromedial division of common trunk continued as medial cord. The branches arising from the cords were normal.

Posterior cord of brachial plexus and its branches: anatomical variations and clinical implication.

Background. Knowledge of anatomical variations of posterior cord and its branches is important not only for the administration of anaesthetic blocks but also for surgical approaches to the neck, axilla, and upper arm. The present study aimed to record the prevalence of such variations with embryological explanation and clinical implication. Material and Method. 37 formalin-preserved cadavers, that is, 74 upper extremities from the Indian population, constituted the material for the study. Cadavers were dissected during routine anatomy classes for medical undergraduate. Dissection includes surgical incision in the axilla, followed by retraction of various muscles, to observe and record the formation and branching pattern of posterior cord of brachial plexus. Results. Posterior cord was formed by union of posterior division of C5 and C6 roots with posterior division of middle and lower trunk (there was no upper trunk) in 16.2% of upper extremities. Posterior cord of brachial plexus was present lateral to the second part of axillary artery in 18.9% of upper extremities. Axillary nerve was taking origin from posterior division of upper trunk in 10.8% upper extremities and thoracodorsal nerve arising from axillary nerve in 22.9% upper extremities. Conclusion. It is important to be aware of such variations while planning a surgery in the region of axilla as these nerves are more liable to be injured during surgical procedures.

Incomplete formation of posterior cord of brachial plexus: A case report

Brachial plexus is a network of nerves formed at the root of the neck to provide motor and sensory branches to the upper limb. The major contribution for this plexus is by the anterior primary rami of C5,6,7,8 and T1. The roots join to form the trunks which in tum divide into anterior and posterior divisions to form the cords. The knowledge of brachial plexus is important for the anaesthetists while administering brachial blocks. During routine dissection in a female cadaver aged 65years, the posterior division of upper trunk fails to fuse with the posterior divisions of the middle and lower trunk and gives out four branches independently.

Electrophysiological study of the dominant motor innervation to the extensor digitorum communis muscle and long head of triceps brachii at posterior divisions of brachial plexus

Restoration of elbow and finger extension function is still challenging in management of complete brachial plexus avulsion injury, mainly because of fewer available donor nerves for transfer to the radial nerve. Selective neurotization could be a potentially alternative for overcoming this dilemma. This study was designed to identify the innervation dominance of the extensor digitorum communis muscle (EDCM) and long head of the triceps brachii (LTB) at the level of division of brachial plexus. From February 2008 to October 2009, 17 patients with complete brachial plexus avulsion injury underwent the procedure of contralateral C7 nerve root transfer. The posterior divisions of brachial plexus on the healthy donor side were intraoperatively stimulated and the compound muscle action potentials (CMAPs) from the extensor digitorum communis muscle and long head of triceps brachii were recorded by an electrophysiological device. In 13 out of 17 patients (76.5%), the maximal amplitude of CMAP from EDCM was induced by stimulation of the posterior division of lower trunk (PDLT). The mean amplitudes of CMAP from EDCM with stimulation of the posterior division of upper trunk (PDUT), middle trunk (PDMT), and PDLT were 0.64 ± 0.95, 1.64 ± 1.56, and 5.32 ± 4.67 mV (P < 0.05), respectively. The maximal amplitude of CMAP from LTB was induced mainly by stimulation of the PDMT) and PDLT (6 out of 11 and 5 out of 11 patients). The mean amplitudes of CMAP from LTB with stimulation of the PDUT, PDMT, and PDLT were 0.15 ± 0.24, 5.20 ± 4.27, and 7.48 ± 9.90 mV, respectively. The differences of CMAPs between stimulation of PDUT and other two divisions were significant (P < 0.05). From the electrophysiological point of view, this study showed that the PDLT was the major motor division innervating EDCM, and the PDMT and PDLT shared the similar proportion of LTB innervation.