An anatomical investigation of rare upper limb neuropathies due to the Struthers' ligament or arcade: a meta-analysis.

BACKGROUND: The Struthers' ligament (SL) is a fibrous band that originates fromthe supracondylar humeral process and inserts into the medial humeral epicondyle, potentially compressing both the median nerve and brachial artery. The controversial Struthers' arcade (SA) is a musculotendinous band found in the distal end of the arm that might compress the ulnar nerve. This study aimed to evaluate the pooled prevalence estimate of the SL and SA, and their anatomical features. MATERIALS AND METHODS: A meticulous search of major electronic medical databases was carried out regarding both structures. Applicable articles (and all relevant references) were analysed. Data from the eligible articles was extracted and evaluated. The quality and the potential risk of bias in the included studies were assessed using the AQUA tool. RESULTS: The arcade was reported in 13 studies (510 arms), whereas the ligament in 6 studies (513 arms). The overall pooled prevalence estimate of the ligament was 1.8%, and 52.6% for the arcade. Most frequently, the ulnar nerve was covered by a tendinous arcade (42.2%). In all cases, the ligament inserted into the medial humeral epicondyle, but had various origins. Only 1 study reported compression of the median nerve by the ligament, whilst another contradicted this view. CONCLUSIONS: Although the SL is rare, and the SA is a valid anatomical entity (though with a variable presentation), clinically meaningful neurovascular entrapments caused by these structures are infrequent. Nonetheless, a better understanding of each may be beneficial for the best patient outcomes.

The anatomical landmarks effective in the localisation of the median nerve during orthopaedic procedures.

BACKGROUND: The aim of this study was to create a safe zone for surgeons who perform procedures in the wrist to avoid iatrogenic damage to the median nerve (MN) by identifying anatomical landmarks using ultrasound (USG). MATERIALS AND METHODS: We measured the distances between the MN and two easily identifiable anatomical landmarks at the level of the proximal border of carpal ligament using USG. RESULTS: A total of 57 volunteers (n = 114 upper limbs) were included in this study. Our main findings revealed that the distance from the flexor carpi radialis tendon to MN (FCR-MN) was 7.87 mm (95% confidence interval 7.37-8.37) and the distance from flexor carpi ulnaris tendon to MN (FCU-MN) was 19.09 mm (95% confidence interval 18.51-19.67). CONCLUSIONS: The tendons of FCR and FCU are easily identifiable landmarks that can be distinguished using simple palpation. Based on our USG findings, the area around FCR should be carefully navigated to avoid iatrogenic injury to the MN during surgical procedures around the carpal tunnel.

Erratum: The Achilles tendon and the retrocalcaneal bursa: An anatomical and radiological study.

[This corrects the article DOI: 10.1302/2046-3758.67.BJR-2016-0340.R1.].

The Achilles tendon and the retrocalcaneal bursa: An anatomical and radiological study.

OBJECTIVES: Inflammation of the retrocalcaneal bursa (RB) is a common clinical problem, particularly in professional athletes. RB inflammation is often treated with corticosteroid injections however a number of reports suggest an increased risk of Achilles tendon (AT) rupture. The aim of this cadaveric study was to describe the anatomical connections of the RB and to investigate whether it is possible for fluid to move from the RB into AT tissue. METHODS: A total of 20 fresh-frozen AT specimens were used. In ten specimens, ink was injected into the RB. The remaining ten specimens were split into two groups to be injected with radiological contrast medium into the RB either with or without ultrasonography guidance (USG). RESULTS: In specimens injected with ink, diffusion outside the RB was observed with staining of the anterior portion of the AT. In eight contrast-injected specimens (five USG, three non-USG), a similar localised diffusion pattern was observed, with the contrast identified superiorly and anteriorly. In two contrast-injected specimens (non-USG), the diffusion pattern was more extensive. CONCLUSION: This study confirmed the existence of connections between the RB and the AT, especially rich in the anteroinferior portion of the tendon, which should be considered a weak zone for substances injected into the RB. We hypothesise that this part of the AT might be most vulnerable to rupture after corticosteroid injections.Cite this article: P. A. Pekala, B. M. Henry, J. R. Pekala, K. Piska, K. A. Tomaszewski. The Achilles tendon and the retrocalcaneal bursa: An anatomical and radiological study. Bone Joint Res 2017;6:446-451. DOI:10.1302/2046-3758.67.BJR-2016-0340.R1.

The twisted structure of the Achilles tendon unraveled: A detailed quantitative and qualitative anatomical investigation.

The Achilles tendon (AT) consists of fibers originating from the soleus muscle (SOL), which lies deep, and the medial (GM) and lateral (GL) heads of the gastrocnemius muscle, which lie superficial. As the fibers descend toward the insertion of the AT, the individual subtendons twist around each other. The aim of this study was to investigate the twisted structure of the AT and its individual subtendons. Specimens of the AT, with preserved calcaneal bone and a fragment of the triceps surae muscle, were obtained from 53 fresh-frozen, male cadavers (n=106 lower limbs). The angle of torsion of each of the AT's subtendons was measured using a specially designed and 3D-printed tool. The mean distance between the most distal fibers of the triceps surae muscle and the superior border of the calcaneal bone was 60.77±14.15 mm. The largest component of the AT at the level of its insertion into the calcaneal bone is the subtendon from the GL (44.43%), followed by the subtendon from SOL (27.89%), and the subtendon from GM (27.68%). The fibers originating from the GM rotate on average 28.17±15.15°, while the fibers originating from the GL and SOL twist 135.98±33.58° and 128.58±29.63°, respectively. The torsion of superficial fibers (GM) comprising the AT is significantly lower than that of deeper fibers (GL and SOL). The cross-sectional area of the AT is smaller at the level of the musculo-tendinous junction than at the level of its insertion. This study illustrates the three types of the AT with differently twisting subtendons, as well as a generalized model of the AT. Types of AT torsion may potentially alter the biomechanical properties of the tendon, thus possibly influencing the pathophysiologic mechanisms leading to the development of various tendinopathies.

The variable origin of the lateral circumflex femoral artery: a meta-analysis and proposal for a new classification system.

The lateral circumflex femoral artery (LCFA) is responsible for vascularisation of the head and neck of the femur, greater trochanter, vastus lateralis and the knee. The origin of the LCFA has been reported to vary significantly throughout the literature, with numerous branching patterns described and variable distances to the mid-inguinal point reported. The aim of this study was to determine the estimated population prevalence and pooled means of these anatomical characteristics, and review their associated clinical relevance. A search of the major electronic databases was performed to identify all articles reporting data on the origin of the lateral circumflex femoral artery and its distance to the mid-inguinal point. Additionally, an extensive search of the references of all relevant articles was performed. All data on origin, branching, and distance to mid-inguinal point was extracted and pooled into a meta-analysis. A total of 26 articles (n = 3731 lower limbs) were included in the meta-analysis. Lateral circumflex femoral artery most commonly originates from the deep femoral artery with a pooled prevalence of 76.1% (95% confidence interval 69.4-79.3). The deep femoral artery-derived lateral circumflex femoral artery was found to originate with a mean pooled distance of 51.06 mm (95% confidence interval 44.61-57.51 mm) from the mid-inguinal point. Subgroup analysis of both gender and limb side data were consistent with these findings. Due to variability in the lateral circumflex femoral artery's origin and distance to mid-inguinal point, anatomical knowledge is crucial for clinicians to avoid iatrogenic injuries when performing procedures in the femoral region, and thus radiographic assessment prior to surgery is recommended. Lastly, we propose a new classification system for origin of the lateral circumflex femoral artery.

Superficial fibular nerve variations of fascial piercing: A meta-analysis and clinical consideration.

The superficial fibular (peroneal) nerve (SFN) is one of the successive branches of the common fibular (peroneal) nerve and goes on to bifurcate into the medial dorsal cutaneous (MDN) and intermediate dorsal cutaneous (IDN) nerves. The SFN is a main contributor to sensory innervation of the foot and lower leg. It varies widely in its penetrance of the deep (crural) fascia, and differences in its subsequent course can result in iatrogenic injuries. Articles on the prevalence of this anatomical variation were identified by a comprehensive database search. The data collected were extracted and pooled into a meta-analysis. A total of 14 articles (n = 665 lower limbs) were included on the meta-analysis of SFN variations in fascial piercing. The normal Type 1 variation, where the SFN pierces the deep fascia as a single entity and later bifurcates into the MDN and IDN, had a pooled prevalence of 82.7% (95%CI: 74.0-89.4). The Type 2 variant, where the SFN bifurcates early and then pierces the fascial layer separately as the MDN and IDN, had a pooled prevalence of 15.6% (95%CI: 8.9-23.6). Type 3, when the SFN penetrates the deep fascia and courses similar to the MDN with absent IDN was noted in 1.8% (95%CI: 0.0-4.9) of cases. A substantial portion of the population has a pattern of SFN piercing that deviates from the normal Type 1 anatomy. It is recommended that possible SFN variants in patients should be addressed thoroughly to help prevent iatrogenic injuries and postoperative complications. Clin. Anat. 30:120-125, 2017. © 2016 Wiley Periodicals, Inc.