Try out PMC Labs and tell us what you think. Learn More. Language: English Portuguese. To determine the frequency and features of the arcade of Struthers, and to assess its clinical implication in ulnar nerve compression. Forty arms from 26 cadaver specimens were dissected in the Anatomy Laboratory of this institution.
The extension of the arcade, distance from the medial epicondyle, and relation with ulnar nerve were recorded. In 29 The extension of the arcade ranged from 3. The arcade of Struthers is a musculoaponeurotic canal that represents an important site of entrapment or compression of the ulnar nerve. The arcade, the intermuscular septum, and the internal brachial ligament should be released in patients submitted to ulnar nerve anterior transposition surgery. It may be observed even in the absence of the supracondylar process; even when present, it may not cause the compression of these structures.
The supracondylar process of the humerus has been described by anatomists and anthropologists; it is phylogenetically considered as a vestige of the supracondylar foramen, found in reptiles, marsupials, and some mammals. In contrast, the arcade of Struthers was first described in by Kane et al. The arcade of Struthers can cause compression of the ulnar nerve. Controversy exists in the literature regarding the existence of the arcade of Struthers.
Some anatomical studies have found an anatomical formation consistent with the arcade of Struthers. Conversely, other studies have reported that the arcade of Struthers does not exist; rather, that there are only anatomical variations of the intermuscular septum and the forearm fascia. This study aimed to analyze the anatomical structures that relate to the ulnar nerve in the medial aspect of the arm, such as the brachial fascia, the medial intermuscular septum, the internal brachial ligament, and the medial head of the triceps brachii muscle, and to assess the possibility of these structures being responsible for the compressive syndrome of the ulnar nerve or even whether they can interfere after surgical procedures of anterior transposition of the ulnar nerve at the elbow.
Of the corpses, 22 were male and four were female, 15 were white and 11 were non-white. Cadavers whose forearms were deformed by traumas, malformations, and scars were excluded. The dissection was performed through an incision in the anteromedial aspect of the arm from the axilla to the middle third of the forearm. Two flaps that included the skin and the subcutaneous tissue were pulled away, exposing the entire medial surface of the arm.
The brachial fascia, basilic hiatus, basilic vein, and the medial cutaneous nerve of the forearm were identified. The brachial fascia was incised longitudinally in the medial margin of the triceps brachii muscle in the same manner that the skin was folded, one anterior flap and one posterior flap Fig.
The ulnar nerve was identified in the axillary region and dissected distally to the medial intermuscular septum, which it crosses, passing from the anterior to the posterior compartment of the arm.
In this location, the internal brachial ligament can also be identified. Then, the ulnar nerve was identified distally in the epicondilar-olecranon groove and dissected proximally until it was covered by the medial head of the triceps brachii muscle or by its aponeurosis which corresponds to the distal edge of the arcade of Struthers. The distance from the arcade to the medial epicondyle and the length of the arcade were measured.
Four limbs of two stillborns were dissected as a pilot for familiarization with the structures of the medial aspect of the arm, and were not included in this study Fig.
A Keller brand 2. This study was approved by the Research Ethics Committee of the institution under the number 1. The brachial fascia was incised longitudinally in the medial margin of the triceps brachii muscle and in the same way in which the skin was folded, with an anterior flap and a posterior flap. Stillborn arm dissected as a pilot, showing the ulnar nerve surrounded by the medial head of the triceps.
In this study, the arcade of Struthers was defined as a fibrous canal on the medial aspect of the middle- and lower-third of the arm, consisting of the medial head of the triceps brachii muscle and its aponeurotic expansion, which extends into the intermuscular septum and internal brachial ligament and covers part of the ulnar nerve Fig. In 29 limbs The length of the arcade ranged from 3.
The internal brachial ligament Fig. The authors believe that, in most cases, it represents an unfolding of the intermuscular septum Fig. The intermuscular septum divides the arm into anterior and posterior compartments. The ulnar nerve passes from the anterior to the posterior compartment at the opening of the Struthers arcade.
When tractioning the nerve proximally and distally, it was observed that it moved easily within the arch, which was sectioned at the end of the dissection, and it was not possible to identify any points within it that showed any signs of nerve compression.
In two limbs, an additional fibrous band was identified near the medial epicondyle Fig. In one limb, an accessory portion of the medial triceps head that was inserted into the intermuscular septum was identified; another limb presented the anconeus epitrochlearis muscle Fig.
It passed posteriorly to the ulnar nerve. In nine limbs The ulnar nerve passes from the anterior to the posterior compartment at the opening of the arcade of Struthers. In one limb, the presence of epitrochlear anconeus muscle was observed. Medial epicondyle a.
Al-Quattan and Murray[ 1 ] suggested:. It is recommended that the ligaments, which pass deep to the ulnar nerve, including the internal brachial ligament, should be released at their insertions. This can be done without extending the skin incision, since the insertion of such ligaments is located at the same level as the arcade.
If the ulnar nerve is found buried in the medial head of the triceps, the overlying muscular roof should be incised. Proximal extension of the skin incision may be needed to mobilize the ulnar nerve fully from the deep groove in the muscle. The anterior border of the slit differed from the arcade of Struthers, which is a tendinous structure connecting the medial head of the triceps brachii muscle to the medial intermuscular septum, because the former was anterior to the ulnar nerve while the latter was posterior to the nerve.
The arcade was described as a fibrous canal with an average length of 5. Kim et al. Some authors have also implicated the arcade of Struthers in cases of failed cubital tunnel surgery. Regarding the classical description of the arcade of Struthers,[ 21 ] our type II most coincides with this anatomy, which is consistent with the so-called internal BL and was found in We believe that an arcade of Struthers as described by multiple authors does exist, and based on our study, it exists in the majority of individuals.
However, why some individuals become symptomatic and others do not is yet to be elucidated. As the ulnar nerve traverses this structure, this area may necessitate surgical evaluation for proximal ulnar neuropathies. This later notion is supported by case reports of patients with ulnar nerve palsy that improved following transection of this connective tissue.
On the majority of sides, the arcade was found to be due to a thickening of the brachial fascia. Each of these structures could be easily evaluated with a more proximal skin incision and exploration for routine decompressive procedures of the ulnar nerve at the medial epicondyle. Based on our study, this could be up to almost 20 cm proximal to the medical epicondyle.
Therefore, in order to better localize the site of compression, adjuncts to surgical decompression could include electrophysiology and ultrasound. National Center for Biotechnology Information , U.
Journal List Surg Neurol Int v. Surg Neurol Int. Published online Dec Shoja , 1 Martin M. Mortazavi , Marios Loukas , 2 and Aaron A.
Shane Tubbs. Mohammadali M. Martin M. Aaron A. Author information Article notes Copyright and License information Disclaimer. George's University, Grenada. Shane Tubbs: lgro. Shoja: moc. Mortazavi: gro. Cohen-Gadol: moc. Received Oct 5; Accepted Nov This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
This article has been cited by other articles in PMC. Abstract Background: Significant controversy exists regarding the existence of the so-called arcade of Struthers and whether this structure is involved in some cases of proximal ulnar nerve entrapment.
Methods: Fifteen cadavers 30 sides underwent dissection of the medial arm with special attention to the course of the ulnar nerve and its relationships to the soft tissues of this region. Results: We identified a thickening in the inferior medial arm that crosses the ulnar nerve and is consistent with the so-called arcade of Struthers in Conclusions: Based on our findings, the arcade of Struthers is an anatomical band of connective tissue in the medial distal arm that crosses the ulnar nerve.
Keywords: Anatomy, entrapment, neurosurgery, peripheral nerve, ulnar nerve. RESULTS We identified a thickening in the inferior medial arm that crossed the ulnar nerve and was consistent with the so-called arcade of Struthers in Open in a separate window. Figure 1. Figure 2. In most cases this structure is due to a thickening of brachial fascia 3.
NB: This structure should not be confused with the ligament of Struthers. The arcade of Struthers was not actually documented by Sir John Struthers who described the ligament of Struthers. Later researchers found the structure, however, the discovery was not without controversy, with some groups claiming it did not exist 3,4.
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