Relationship between the Branching Patterns of the Radial Nerve and Supinator Muscle

The posterior interosseous nerve (PIN) innervates the posterior compartment muscle of the forearm and is a continuation of the deep branch of the radial nerve. The anatomic descriptions of PIN vary among different authors. This study investigated the distribution patterns of PIN and its relationships to the supinator muscle. This study investigated which nerves innervate the posterior compartment muscles of the forearm, the radial nerve, and the PIN, using 28 nonembalmed limbs. Also, the points where the muscle attaches to the bone were investigated. The measured variables in this study were measured from the most prominent point of the lateral epicondyle of the humerus (LEH) to the most distal point of the radius styloid process. For each specimen, the distance between the above two points was assumed to be 100%. The measurement variables were the attachment area of the supinator and branching points from the radial nerve. The attachment points of the supinator to the radius and ulna were 47.9 % ± 3.6 % and 31.5 % ± 5.2 % , respectively, from the LEH. In 67.9% of the specimens, the brachioradialis and extensor carpi radialis longus (ECRL) were innervated by the radial nerve before superficial nerve branching, and the extensor carpi radialis brevis (ECRB) innervated the deep branch of the radial nerve. In 21.4% of the limbs, the nerve innervating the ECRB branched at the same point as the superficial branch of the radial nerve, whereas it branched from the radial nerve in 7.1% of the limbs. In 3.6% of the limbs, the deep branch of the radial nerve branched to innervate the ECRL. PIN was identified as a large branch without divisions in 10.7% and as a deep branch innervating the extensor digitorum in 14.3% of the limbs. The anatomic findings of this study would aid in the diagnosis of PIN syndromes.

Novel Classification of the Branching Patterns of the Superficial Branch and the Deep Branch of the Superficial Circumflex Iliac Artery and the Superficial Inferior Epigastric Artery on Computed Tomographic Angiography

Background Recent advances in the superficial circumflex iliac artery (SCIA) perforator flap transfer emphasized the necessity to comprehensively understand the lower abdominal vasculature. This study aimed to clarify the relationship among the superficial inferior epigastric artery (SIEA), the superficial branch (SCIAs), and the deep branch (SCIAd) of the SCIA. Methods Computed tomographic angiography was retrospectively reviewed in 312 hemiabdomens in 161 female patients who underwent abdominal flap breast reconstruction. We assessed the presence, caliber, and branching patterns of the SCIA branches and the SIEA. Results The SIEA-SCIA common trunk was present in 40.1% of the hemiabdomen and was identified in either side of the abdomen in 63.6% of patients. At least one superficial vessel larger than 1.5 mm was found in 61.5% of hemiabdomens. Seven branching patterns of the SCIA-SIEA system were noted: (1) the SCIA and the SIEA originated together (17.0%); (2) the SIEA and the SCIAs shared an origin (22.8%), (3) the SCIA and the SIEA branched separately (17.0%), (4) each artery originated separately (8.0%); (5) the SCIAs and the SCIAd emerged together with the SIEA absent (17.3%); (6) the SCIAs and the SCIAd originated separately with the SIEA absent (13.1%); (7) the SIEA and SCIAd originated separately with the SCIAs absent (3.5%). Conclusion SCIA-SIEA branching patterns were classified into seven distinctive patterns. This novel classification may help surgeons to choose the optimal pedicle when using the hemi-abdomen region as the donor site.

Morphological Classification of Arch of Frohse and Its Implication in Compression of Deep Branch of Radial Nerve

BACKGROUND Arcade of Frohse (AF) is a tendinous superior margin of superficial layer of supinator muscle which was first described by Frohse and Frankel in 1908. Since then it has been studied by many authors and held accountable as one of the essential components for compression of deep branch of radial nerve (DBRN) which leads to radial tunnel syndrome. Considering AF as an important element of compression, we made an attempt to classify it on the basis of its shape and to find out if any particular shape has a predominant role in compression of the nerve. We also observed the structure of superior and inferior margin of the supinator muscle. METHODS This study was conducted among 80 (70 males and 10 females) formalin fixed upper limbs present in the Department of Anatomy. The limbs were maintained in supine with slightly flexed position and dissection was performed to expose the supinator muscle. The proximal and distal borders of supinator muscles were examined meticulously with the help of magnified lens. The morphometric measurements were taken with the help of a digital caliper. RESULTS The FA is classified into four categories as loop, high arc, low arch and linear shaped. The most frequent shape observed was arch shaped (high and low arch) about 66%, followed by loop shaped (30%) and least was linear shaped (2.5%). On the basis of structure, the proximal and distal margin of supinator muscle was reported to be tendinous in majority of the cases. The distance of the AF from the fixed reproducible anatomical landmark like inter epicondylar line (IEL) was measured and the average distance found was 3.36 cm. CONCLUSIONS Knowledge of different shapes would aid surgeons and radiologists for better approach towards diagnosis and management of supinator syndrome. The morphometric finding can be useful for surgeons to locate the superior margin of supinator (AF) in surgical procedures for decompression of DBRN in supinator syndrome. KEY WORDS Arcade of Frohse, Inter Epicondylar Line, Supinator Muscle, Deep Branch of Radial Nerve and Radial Tunnel Syndrome

Topographical, anatomical and neurosurgical aspects of "end-to-side" nerve repair

The article presents the results of a comprehensive anatomical and experimental study of individual variability in the structure and topography of motor branches of peripheral nerves in relation to the justification of methods for selective reinnervation of tissues by the "end-to-side" neurorrhaphy. It was found that relatively longer branches of peripheral nerves with a small number of connecting inter-arm collaterals characteristic of narrow and long limbs create conditions for less traumatic mobilization of motor branches. In cases with relatively wide and short extremities mobilization of peripheral nerves is complicated by the presence of a large number of collateral branches and intra-trunk connections, which are often damaged when separate bundles that make up the mobilized branches of the donor or recipient nerve are isolated from the main nerve trunk. It has been shown that potential recipient nerves should be motor branches of peripheral nerves, the preservation of which is of fundamental importance for the function of the corresponding segment of the limb. To create conditions conducive to selective reinnervation of functionally significant muscle groups of the upper limb, we have developed, justified from anatomical positions, and tested in an experiment on anatomical material methods for connecting the distal motor branches of peripheral nerves by the "end-to-side" neurorrhaphy. The main idea of accelerated recovery of the thumb opposition in injuries of the median nerve is to reinnervate the muscles of the elevation of the I finger due to nerve fibers that are part of the deep branch of the ulnar nerve. For this purpose, surgical techniques have been developed for connecting the recurrent motor branch of the damaged median nerve mobilized at the level of the wrist with the edges of a surgically formed perineurium defect on the lateral surface of the bundles that make up the deep branch of the ulnar nerve. In another clinical situation, in patients with radial nerve injuries, for the muscle reinnervation, а method is proposed for neurotisation of the deep motor branch of the radial nerve by the end-to-side suture to the lateral surface of the median nerve. We assume that performing the "end-to-side" nerve suture at the level of the base of the hand in the cases of proximal damage to the median nerve will reduce the time of reinnervation of the muscles of the thumb elevation by 400450 days. Transposition of the deep branch of the damaged at the proximal level radial nerve with "end-to-side" neurorrhaphy to the median nerve by 250300 days (based on the total length of the shoulder and forearm, which is about 50 cm and the rate of regeneration of nerve fibers 1 mm per day). Accordingly, with higher injuries (brachial plexus), the gain in the time of reinnervation of the distal segments will be even greater. In our opinion, the results can be used as a basis for further clinical research on the development of methods for selective tissue reinnervation in cases with isolated injuries of the peripheral nerves.

Use of Preoperative High-Resolution Ultrasound System to Facilitate Elevation of the Superficial Circumflex Iliac Artery Perforator Flap

Background During elevation of the superficial circumflex iliac artery (SCIA) perforator (SCIP) flaps, the flap pedicle must often be converted from the superficial branch to the deep branch of the SCIA, complicating and prolonging the procedure. The goal of the present study was to demonstrate the effectiveness of high-resolution ultrasonography to decrease the conversion rate on which no previous report has focused, by making a comparison with a conventional method. Patients and Methods Forty-five consecutive cases where free SCIP flap transfer was performed for reconstruction were retrospectively reviewed. To preoperatively mark the course of the superficial branch, handheld Doppler ultrasonography was used in 27 cases (group 1) and a high-resolution ultrasound system in 18 cases (group 2). Results The conversion rate was significantly greater in group 1 than in group 2 (10/27 [37%] vs. 0/18 [0%], p = 0.003]. The frequency of use of multiple venous anastomoses was significantly higher in group 1 than in group 2 (21/27 [78%] vs. 2/18 [11%], p < 0.001). The operative time was significantly longer in group 1 than in group 2 (p = 0.038). There were no significant differences in postoperative complication rates (1/27 [4%] versus 0/18 [0%], p = 1.0). Conclusion The use of a preoperative high-resolution ultrasound system significantly decreased the rate from of intraoperative conversion from the superficial branch to the deep branch of the SCIA. It also resulted in significantly fewer venous anastomoses and a shorter operative time, while maintaining a low incidence of postoperative complications.

The Brewer-Dobson circulation in CMIP6

The Brewer-Dobson circulation (BDC) is a key feature of the stratosphere that models need to accurately represent in order to improve the representation of surface climate variability. For the first time, the Climate Model Intercomparison Project includes in its phase 6 (CMIP6) a set of diagnostics that allow for careful evaluation of the BDC. Here, the BDC is evaluated against observations and reanalyses using historical simulations. CMIP6 results confirm the well-known inconsistency in BDC trends between observations and models in the middle and upper stratosphere. The increasing CO2 simulations feature a robust acceleration of the BDC but also reveal large uncertainties in the deep branch trends. The very close connection between the shallow branch and surface temperature is highlighted, which is absent in the deep branch. The trends in mean age of air are shown to be more robust throughout the stratosphere than those in the residual circulation. The paper reflects the current knowledge and main uncertainties regarding the BDC.