Although patients who have an AA variant are often asymptomatic, they compose a significant portion of the population of patients and pose a greater risk of hemorrhage and ischemia during surgery in the thorax. Because of the possibility of encountering such variants, it is prudent for surgeons to consider potential variations in planning procedures, especially of an endovascular nature, in the thorax.

The sciatic nerve has varying anatomy with respect to the piriformis muscle. Understanding this variant anatomy is vital to avoiding iatrogenic nerve injuries. A comprehensive electronic database search was performed to identify articles reporting the prevalence of anatomical variations or morphometric data of the sciatic nerve. The data found was extracted and pooled into a meta-analysis. A total of 45 studies (n = 7068 lower limbs) were included in the meta-analysis on the sciatic nerve variations with respect to the piriformis muscle. The normal Type A variation, where the sciatic nerve exits the pelvis as a single entity below the piriformis muscle, was most common with a pooled prevalence of 85.2% (95%CI: 78.4-87.0). This was followed by Type B with a pooled prevalence of 9.8% (95%CI: 6.5-13.2), where the sciatic nerve bifurcated in the pelvis with the exiting common peroneal nerve piercing, and the tibial nerve coursing below the piriformis muscle. In morphometric analysis, we found that the pooled mean width of the sciatic nerve at the lower margin of the piriformis muscle was 15.55 mm. The pooled mean distance of sciatic nerve bifurcation from the popliteal fossa was 65.43 mm. The sciatic nerve deviates from its normal course of pelvic exit in almost 15% of cases. As such we recommend that a thorough assessment of sciatic nerve variants needs to be considered when performing procedures in the pelvic and gluteal regions in order to reduce the risk of iatrogenic injury. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1820-1827, 2016.

PurposeSeveral variations in the anatomy and injury of the lateral femoral cutaneous nerve (LFCN) have been studied since 1885. The aim of our study was to analyze the available data on the LFCN and find a true prevalence to help in the planning and execution of surgical procedures in the area of the pelvis, namely inguinal hernia repair.MethodsA search of the major medical databases was performed for LFCN anatomy. The anatomical data were collected and analyzed.ResultsTwenty-four studies (n = 1,720) were included. The most common pattern of the LFCN exiting the pelvis was medial to the Sartorius as a single branch. When it exited in this pattern, it did so on average 1.90 cm medial to the anterior superior iliac spine (ASIS).ConclusionsThe LFCN and its variations are important to consider especially during inguinal hernia repair, abdominoplasty, and iliac bone grafting. We suggest maintaining a distance of 3 cm or more from the ASIS when operating to prevent injury to the LFCN.Electronic supplementary materialThe online version of this article (doi:10.1007/s10029-016-1493-7) contains supplementary material, which is available to authorized users.

The PA most commonly divides below the knee into the anterior tibial artery and the common trunk of the posterior tibial artery and the peroneal artery. Knowledge of the prevalence of possible variations in this anatomy as well as morphometric data is crucial in the planning and execution of any surgical intervention in the area of the knee.

The aim of this study was (a) to examine the anatomy of the sural nerve (SN) in a sample of 30 patients and (b) to analyze the incidence of different origins of the SN, and the distance of the SN from planned arthroscopic portals. An ultrasound (USG) examination of the SN was performed bilaterally on thirty healthy patients with no history of surgery or trauma of the lower limb. The SNs were classified into six main types of pattern, with an additional category for new and unclassified types. Each of Types 1 and 3 had two subdivisions. The distances from the superior border of the calcaneal tuberosity to the three simulated arthroscopy portal sites (Z1, Z1.5, Z2) to the SN were measured. A total of 30 patients (n = 60 limbs) with an average age of 27 ± 7.5 years were examined and the SN was visualized in all cases. The most common origin was Type 3A, accounting for 30% of limbs. Type 2 was the second most common seen in 18.3%. The distances of the SN from arthroscopic portal placement sites above the lateral malleolus were 2.07 ± 0.39 cm at the Z1 portal, 2.15 ± 0.38 cm at Z1.5, and 2.28 ± 0.33 cm at Z2. The variability in the anatomy of the SN warrants the use of USG to locate it accurately, thus preventing iatrogenic injury when portals are placed for arthroscopy, improving proper administration of anesthesia, and helping to localize the nerve for graft harvesting. Clin. Anat. 31:450-455, 2018. © 2017 Wiley Periodicals, Inc.

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ObjectivesThe goal of our study was to analyze the prevalence of variations, branching patterns, and histology of the ulnar nerve (UN) in Guyon’s canal to address its importance in hand surgery, particularly decompression of the UN.MethodsFifty fresh cadavers were dissected bilaterally, and the nerve in the area of Guyon’s canal was visualized. Samples for histology were also taken and prepared. The collected data were then analyzed.ResultsMorphometric measurements of the hands and histological studies were not found to have significant differences when compared by left or right side or by sex. Three major branching patterns were found, with division into deep and superficial UN being the most common (85%). Additional findings included a majority (70%) presenting with a cutaneous branch within the canal and/or with an anastomosis of its distant branches with those of the median nerve (57%).ConclusionThe UN is most commonly found to divide into a superficial and deep ulnar branch within Guyon’s canal. However, additional branches and anastomoses are common and should be taken into careful consideration when approached during surgery in the area, particularly during decompression procedures of Guyon’s canal.

The clinical anatomy of the infrapatellar branch of the saphenous nerve (IPBSN) is of particular importance during operations in the area of the knee, especially when material for anterior cruciate ligament reconstruction is harvested. The nerve can easily be injured during the harvesting procedure, leading to postoperative complications that reduce quality of life. Three different skin incisions are commonly used during hamstring tendon harvesting: horizontal, vertical, and oblique. The aim of this ultrasound simulation study was to assess the risk of IPBSN injury associated with the type of skin incision and the point-of-emergence of the IPBSN relative to the sartorius muscle. Thirty healthy volunteers (60 lower limbs) were recruited for identification of the IPBSN. When it was found, using a high-frequency ultrasound probe, three different 3 cm skin incisions over the pes anserinus were simulated. Vertical, horizontal, or oblique lines simulating incisions were marked over the pes anserinus and ultrasound was used to visualize the structures that could be injured during the marked incisions. The IPBSN was visualized in 58 lower limbs (96.7%). The results of the simulation study indicated that the vertical incision should be avoided during hamstring tendon harvesting, as it is associated with a significantly higher risk of injury (25.9%) to the IPBSN than the horizontal (3.5%) or oblique (8.6%) incisions. We recommend that a preoperative ultrasound assessment of IPBSN anatomy be performed to minimize the risk of iatrogenic injury to the nerve and associated complications. Clin. Anat. 30:868-872, 2017. © 2017 Wiley Periodicals, Inc.