Anconeus Epitrochlearis Muscle Research Articles

The Ulnar Nerve at Elbow Extension and Flexion: Assessment of Position and Signal Intensity on MR Images.

Purpose To assess the position and signal intensity of the ulnar nerve at elbow extension and flexion by using magnetic resonance imaging. Materials and Methods Institutional review board approval and written informed consent were obtained. Transverse T2-weighted images were obtained perpendicular to the upper arm in 100 healthy elbows of 50 volunteers (23 men, 27 women; age range, 21-57 years) and nine elbows with ulnar neuropathy (five men, four women; age range, 24-59 years) with extension and 130° of flexion. Ulnar nerve position was classified into three types: no dislocation, subluxation, or dislocation. One-way analysis of variance, paired t tests, Student t tests, and multiple regression analysis were used to analyze correlations between ulnar nerve movement angle during flexion and age, sex, presence of the anconeus epitrochlearis muscle, and ulnar neuropathy and to compare the contrast-to-noise ratio of nerve to muscle between extension and flexion. Results Nerve positions in healthy elbows were as follows: All had no dislocation at extension, and at flexion, 51 of 100 elbows (51.0%) had no dislocation, 30 of 100 elbows (30.0%) had subluxation, and 19 of 100 elbows (19.0%) had dislocation. Nerve movement angle was smaller in elbows with the anconeus epitrochlearis muscle than in those without the muscle (P = .045, .015). Presence of the muscle was the only significant factor associated with nerve movement angle (P = .047, .013). Only dominant elbows with nerve movement angle of less than 15° and nondominant elbows with nerve movement angle of less than 10° showed contrast-to-noise ratio increase at flexion (P = .021-.030). Conclusion Ulnar nerve movement during flexion was apparent in approximately half of healthy elbows and was similar between healthy elbows and elbows with ulnar neuropathy. Nerve signal intensity increased during flexion only in elbows without apparent nerve movement. (©) RSNA, 2016 Online supplemental material is available for this article.

The anconeus epitrochlearis muscle may protect against the development of cubital tunnel syndrome: a preliminary study.

OBJECTIVE The authors hypothesized that when the anatomical variant of an anconeus epitrochlearis is present, the risk of developing cubital tunnel syndrome would be reduced by replacing the normal roof of the cubital tunnel (Osborne's ligament) with a more forgiving muscular structure, the anconeus epitrochlearis. The authors further hypothesized that when the presence of an anconeus epitrochlearis contributes to ulnar neuropathy, it would be secondary to muscular hypertrophy, thereby making it more likely to occur in the dominant arm. Therefore, the goal of the present study was to evaluate these hypotheses. METHODS This retrospective cohort study was performed by reviewing the records of all adult patients who underwent operative intervention for cubital tunnel syndrome between 2005 and 2014 as the experimental group and all asymptomatic patients in the medical literature who were part of a series reporting the prevalence of an anconeus epitrochlearis as the control group. The primary outcome of interest was the presence of an anconeus epitrochlearis in asymptomatic individuals versus patients with cubital tunnel syndrome. RESULTS During the study period, 168 patients underwent decompression of the ulnar nerve for cubital tunnel syndrome, and an anconeus epitrochlearis was found at surgery in 9 (5.4%) patients. The control group consisted of 634 asymptomatic patients from the medical literature, and an anconeus epitrochlearis was present in 98 (15.5%) of these patients. An anconeus epitrochlearis was present significantly less frequently in the symptomatic patients than in asymptomatic individuals (p < 0.001). Among patients undergoing surgical decompression, an anconeus epitrochlearis was associated with symptoms in the dominant arm (p = 0.037). CONCLUSIONS The authors found that an anconeus epitrochlearis was present significantly less often in patients with cubital tunnel syndrome than in asymptomatic controls. The mechanism of protection may be that this muscle decreases the rigidity of the entrance into the cubital tunnel. When an anconeus epitrochlearis does contribute to cubital tunnel syndrome, it is significantly more likely to occur in the dominant arm, possibly due to repetitive use and hypertrophy of the anconeus epitrochlearis. The presence of an anconeus epitrochlearis may be protective against the development of cubital tunnel syndrome, although this is a preliminary finding.

A rare cause of ulnar nerve entrapment at the elbow area illustrated by six cases: The anconeus epitrochlearis muscle

Ulnar nerve entrapment is the second most common compressive neuropathy after carpal tunnel syndrome. The accessory anconeus epitrochlearis muscle – present in 4% to 34% of the general population – is a known, but rare cause of ulnar nerve entrapment at the elbow. The aim of this article was to expand our knowledge about this condition based on six cases that we encountered at our hospital between 2011 and 2015. Every patient had a typical clinical presentation: hypoesthesia or sensory deficit in the fourth and fifth fingers; potential intrinsics atrophy of the fourth intermetacarpal space; loss of strength and difficulty with fifth finger abduction. Although it can be useful to have the patient undergo ultrasonography or MRI to aid in the diagnosis, only electromyography (EMG) was performed in our patients. EMG revealed clear compression in the ulnar groove, with conduction block and a large drop in nerve conduction velocity. Treatment typically consists of conservative treatment first (splint, analgesics). Surgical treatment should be considered when conservative treatment has failed or the patient presents severe neurological deficits. In all of our patients, the ulnar nerve was surgically released but not transposed. Five of the six patients had completely recovered after 0.5 to 4years follow-up. Ulnar nerve entrapment at the elbow by the anconeus epitrochlearis muscle is not common, but it must not be ignored. Only ultrasonography, MRI or, preferably, surgical exploration can establish the diagnosis. EMG findings such as reduced motor nerve conduction velocity in a short segment of the ulnar nerve provides evidence of anconeus epitrochlearis-induced neuropathy.

Acute Cubital Tunnel Syndrome Secondary to Anconeus Epitrochlearis Muscle: 由肘肌滑車上肌導致的急性肘管綜合症

Cubital tunnel syndrome is the most common type of ulnar nerve entrapment that usually associates with chronic sensory and motor symptoms. Having anconeus epitrochlearis muscle is an uncommon cause of cubital tunnel syndrome. In this paper, the author introduces a case of cubital tunnel syndrome due to anconeus epitrochlearis muscle presenting with acute sensory, motor, and sympathetic symptoms. For such cases, there has been much controversy over the choices of surgical treatment, which can be excision of the muscle alone or together with ulnar nerve anterior transposition.

An Anatomical Basis for Endoscopic Cubital Tunnel Release and Associated Clinical Outcomes

To study the ulnar nerve in fresh-frozen cadavers as related to endoscopic release of the cubital tunnel and to present a retrospective review of patients treated with decompression via endoscopic visualization. To further our understanding of relevant anatomy, we dissected 26 cadaver limbs. We paid special attention to fascial membranes as potential sites of constriction as well as the position of nerves, vessels, and aberrant anatomy. These findings facilitated our understanding of the extent of release in 80 patients (92 cases) with endoscopic cubital tunnel simple decompression. Outcome measures included Disabilities of the Arm, Shoulder, and Hand score, Gabel and Amadio score, and grip and pinch strengths. We noted fascial bands proximal to the medial epicondyle in 12 of 26 cadaver specimens, 2 of which could be the so-called arcade of Struthers. We observed a high degree of variability in the anatomy of the flexor pronator aponeurosis distal to the medial epicondyle. Where present (n= 10), medial antebrachial cutaneous nerve branches crossed the ulnar nerve at an average distance of 2.9 cm from the medial epicondyle (range, 1.0-4.5 cm). Aberrant structures were noted in 8 of the 26 specimens, including an anconeus epitrochlearis muscle in 2 specimens, a basilic vein crossing the ulnar nerve in 4 specimens, and an accessory origin of the medial head of the triceps from the medial intermuscular septum in 2specimens. In the clinical portion of this study, the average Disabilities of the Arm, Shoulder, and Hand score before surgery was 49 (n= 34) and after surgery was 25 (n= 56). The Gabel and Amadio outcome scores were 24 excellent, 40 good, 25 fair, and 3 poor (n=92). Average follow-up was 8.2 months (range, 0.1-35 mo). Cadaveric dissections shed light on vulnerable anatomical structures during release, including branches of the medial antebrachial cutaneous nerve, ulnar nerve, brachial artery, fascial bands, and basilic vein. The high degree of anatomical variability in this study highlights the advantage of endoscopic visualization in allowing surgeons to minimize surgical trauma. Therapeutic IV.

Cubital Tunnel Syndrome by Anconeus Epitrochlearis in an Adolescent

Compression neuropathy of the ulnar nerve due to anconeus epitrochlearis muscle is rare in adolescents. It is usually known that the hypertrophied muscle in adult or weightlifting athletes compresses the ulnar nerve. There were only few case reports in children and adolescent relevant to athletic activities. In this case, a non-athlete 15-year-old girl developed compression ulnar nerve neuropathy caused by an anconeus epitrochearis muscle. This case is remarkable as an anconeus epitrochearis muscle is uncommon in non-athlete children and adolescent since a literature review revealed no previous report.

Feasibility of 3D Ultrasound to Evaluate Upper Extremity Nerves

This study investigates the performance of a 3 D Ultrasound (US) system in imaging elbow and wrist nerves. Twenty healthy volunteers with asymptomatic median, ulnar and radial nerves were prospectively investigated. Bilateral 3DUS scans of the elbows and wrists were acquired by using a commercially available US scanner (18 MHz, AplioXG, Toshiba) and stored as a 3 D volume by a dedicated software (CURE, Robarts Research Institute). Retrospectively, qualitative (image quality, atypical nerve location, findings potentially associated with compression neuropathy) and quantitative (cross-sectional area measurements) evaluations were performed. In all 200 nerves 3DUS was feasible (100%). Image quality was insufficient in 13.5% (25 ulnar nerve elbow, 2 radial nerve) and sonomorphology was not assessable in those nerves. Measurement of cross sectional areas was feasible in all nerves (100%). Median cross-sectional area (range) were: median nerve elbow 7 mm2 (6-9), radial nerve 3 mm2 (1-4), ulnar nerve elbow 8 mm2 (5-11), median nerve wrist 8 mm2 (5-10), and ulnar nerve wrist 4 mm2 (2-6). No significant changes in nerve cross-sectional area along each nerve was found. Ulnar nerve subluxation was found in 2 nerves (6.7%). No anconeus epitrochlearis muscle or osteophytes were found. 3DUS is a feasible method for assessing nerves of the upper extremity and has been shown to provide a good overview of the median, ulnar and radial nerve at the elbow and wrist, but is limited for evaluation of the ulnar nerve in the cubital tunnel. This technique enables reliable measurements at different locations along the nerve.

Anconeus Epitrochlearis as a Source of Medial Elbow Pain in Baseball Pitchers

Medial elbow pain is reported in 18% to 69% of baseball players aged of 9 and 19 years. This is due to the large valgus stresses focused on the medial side of the elbow during overhead activities. In overhead throwers and pitchers, pain can be attributed to valgus extension overload with resultant posteromedial impingement, overuse of the flexor-pronator musculature resulting in medial epicondylitis, or occasional muscle tears or ruptures. The anconeus epitrochlearis is a known cause of cubital tunnel syndrome and has been postulated as a source of medial elbow pain in overhead athletes. This article describes the cases of 3 right-handed baseball pitchers with persistent right-sided medial elbow pain during throwing despite a prolonged period of rest, physical therapy, and nonsteroidal anti-inflammatory drugs. Two patients had symptoms of cubital tunnel syndrome as diagnosed by electromyogram and nerve conduction studies and the presence of the anconeus epitrochlearis muscle per magnetic resonance imaging. All patients underwent isolated release of the anconeus muscle without ulnar nerve transposition and returned to their previous levels of activity. The diagnosis and treatment of pitchers who present with medial-sided elbow pain can be complex. The differential should include an enlarged or inflamed anconeus epitrochlearis muscle as a possible cause. Conservative management should be the first modality. However, surgical excision with isolated release of the muscle can be successful in returning patients with persistent pain despite a trial of conservative management to their previous levels of function.

Malformation musculaire associée à une variation anatomique de l’avant-bras révélées par des compressions étagées du nerf ulnaire (Double Crush syndrome)

This article describes the concomitant presence of two anomalous muscles on a left forearm in a 40-year-old man. The anconeus epitrochlearis muscle was responsible for a cubital tunnel syndrome and the unusual origin of the flexor digiti minimi brevis muscle was responsible for a compartment syndrome with ulnar nerve compression at the level of Guyon's canal during effort diagnosed by MRI. Resection of these muscles relieved the symptoms and allowed the patient to return to work.

Cubital Tunnel Syndrome – A Review and Management Guidelines

Cubital tunnel syndrome (CuTS) is the second most common peripheral nerve compression syndrome. In German-speaking countries, cubital tunnel syndrome is often referred to as sulcus ulnaris syndrome (retrocondylar groove syndrome). This term is anatomically incorrect, since the site of compression comprises not only the retrocondylar groove but the cubital tunnel, which consists of 3 parts: the retrocondylar groove, partially covered by the cubital tunnel retinaculum (lig. arcuatum or Osborne ligament), the humeroulnar arcade, and the deep flexor/pronator aponeurosis. According to Sunderland , cubital tunnel syndrome can be differentiated into a primary form (including anterior subluxation of the ulnar nerve and compression secondary to the presence of an anconeus epitrochlearis muscle) and a secondary form caused by deformation or other processes of the elbow joint. The clinical diagnosis is usually confirmed by nerve conduction studies. Recently, the use of ultrasound and MRI have become useful diagnostic tools by showing morphological changes in the nerve within the cubital tunnel. A differential diagnosis is essential in atypical cases, and should include such conditions as C8 radiculopathy, Pancoast tumor, and pressure palsy. Conservative treatment (avoiding exposure to external noxes and applying of night splints) may be considered in the early stages of cubital tunnel syndrome. When nonoperative treatment fails, or in patients who present with more advanced clinical findings, such as motor weakness, muscle atrophy, or fixed sensory changes, surgical treatment should be recommended. According to actual randomized controlled studies, the treatment of choice in primary cubital tunnel syndrome is simple in situ decompression, which has to be extended at least 5-6 cm distal to the medial epicondyle and can be performed by an open or endoscopic technique, both under local anesthesia. Simple decompression is also the therapy of choice in uncomplicated ulnar luxation and in most post-traumatic cases and other secondary forms. When the luxation is painful, or when the ulnar nerve actually "snaps" back and forth over the medial epicondyle of the humerus, subcutaneous anterior transposition may be performed. In cases of severe bone or tissue changes of the elbow (especially with cubitus valgus), the anterior transposition of the ulnar nerve may again be indicated. In cases of scarring, submuscular transposition may be preferred as it provides a healthy vascular bed for the nerve as well as soft tissue protection. Risks resulting from transposition include compromise in blood flow to the nerve as well as kinking of the nerve caused by insufficient proximal or distal mobilization. In these cases, revision surgery is necessary. Epicondylectomy is not common, at least in Germany. Recurrence of compression on the ulnar nerve at the elbow may occur. This review is based on the German Guideline "Diagnose und Therapie des Kubitaltunnelsyndroms" ( www.leitlinien.net ).

활차상 주근에 의한 지연성 척골신경 마비 - 2예 보고 -

Materials and Methods: A 37 year old female patient presented with tardy ulnar nerve palsy findings for the elbow. During surgery, an atypical anconeus epitrochlearis muscle was observed, which originated from the triceps aponeurosis and inserted into the medial intermuscular septum. Muscle resection, nerve decompression and ulnar nerve anterior transposition were done. A 35 year old male patient presented with tardy ulnar nerve palsy findings for the elbow. During surgery, a typical anconeus epitrochlearis muscle was found. Muscle resection, nerve decompression and ulnar nerve anterior transposition were done. Results and Conclusion: Tardy ulnar nerve palsy can be associated with and caused by either an atypical or a typical anconeus epitrochlearis muscle.

Elbow Nerves: MR Findings in 60 Asymptomatic Subjects—Normal Anatomy, Variants, and Pitfalls

To prospectively evaluate the signal intensity (SI), course, and diameter of elbow nerves and to identify anatomic variants that are potentially associated with nerve compression syndromes on magnetic resonance (MR) images of asymptomatic elbows. This study was approved by the institutional review board. Informed consent was obtained from each volunteer. Sixty subjects with asymptomatic elbows (age range, 22.4-51.7 years; median age, 32.8 years) underwent MR imaging. Increased SI compared with surrounding muscles on fluid-sensitive MR images, anatomic course, anatomic nerve and muscle variants potentially associated with nerve compression syndromes, and qualitative changes in nerve diameters were evaluated. Quantitative data on the shortest and longest nerve diameters were obtained. Increased SI on fluid-sensitive MR images was seen in the ulnar nerve in 60% (36 of 60) of subjects but was never observed in the median and radial nerves. An atypical intermuscular course of the median nerve between the brachialis and pronator muscles was detected in 17% (10 of 60) of subjects. Ulnar nerve subluxation at the level of the cubital tunnel was seen in 2% (one of 60) of subjects; an anconeus epitrochlearis muscle, in 23% (14 of 60); and a hypertrophic leash of Henry, in 15% (nine of 60). Median nerve dimensions were 2.4 x 4.0 mm (range, 1.0-4.0 x 3.0-7.0 mm) for the ulnar nerve, 1.0 x 1.9 mm (range, 0.8-2.0 x 0.9-5.0 mm) for the radial nerve, and 3.0 x 5.4 mm (range, 1.0-5.0 x 3.0-9.0 mm) for the median nerve. Increased SI of the ulnar nerve on fluid-sensitive images (60%), an atypical intermuscular course of the median nerve (17%), and an anconeus epitrochlearis muscle (23%) are common MR findings in asymptomatic elbows.

Diagnostic ultrasonography of the ulnar nerve in cubital tunnel syndrome

Thirty-two elbows in 31 patients diagnosed as having cubital tunnel syndrome underwent ultrasonographic examination to assess morphological changes in the ulnar nerve and its surrounding tissues. On longitudinal images, the site of constriction due to the fibrous band and proximal swelling of the nerve were observed by ultrasonography and were confirmed intraoperatively. On axial images, the lengths of the major axis [7.2 (SD 1.6) mm] and the minor axis [3.7 (0.9) mm] of the nerve at the medial epicondyle were greater than those in normal subjects. There was a correlation between the stage of ulnar nerve palsy and the diameter of the major axis. Preoperatively, ganglia were detected by ultrasonography in the cubital tunnel in three cases and an anconeus epitrochlearis muscle in two.

Diagnostic Ultrasonography of the Ulnar Nerve in Cubital Tunnel Syndrome

Thirty-two elbows in 31 patients diagnosed as having cubital tunnel syndrome underwent ultrasonographic examination to assess morphological changes in the ulnar nerve and its surrounding tissues. On longitudinal images, the site of constriction due to the fibrous band and proximal swelling of the nerve were observed by ultrasonography and were confirmed intraoperatively. On axial images, the lengths of the major axis [7.2 (SD 1.6) mm] and the minor axis [3.7 (0.9) mm] of the nerve at the medial epicondyle were greater than those in normal subjects. There was a correlation between the stage of ulnar nerve palsy and the diameter of the major axis. Preoperatively, ganglia were detected by ultrasonography in the cubital tunnel in three cases and an anconeus epitrochlearis muscle in two.

Ulnar nerve compression at the elbow caused by a prominent medial head of the triceps and an anconeus epitrochlearis muscle

A number of musculo-tendinous variations around the medial epicondyle have been alleged to cause ulnar nerve compression. Subluxation of the ulnar nerve, a "snapping" separate medial head of triceps, a prominent medial head of triceps covering the ulnar nerve, anconeus epitrochlearis, Osborne's band, and the ligament of Struthers have been implicated. We present a case of clearcut compression of the ulnar nerve at two levels just at and posterior to the epicondyle by a tightly applied prominent head of the triceps, and at a more distal level beneath an anconeus epitrochlearis muscle.

The cubital tunnel and ulnar neuropathy

The anatomy of the cubital tunnel and its relationship to ulnar nerve compression is not well documented. In 27 cadaver elbows the proximal edge of the roof of the cubital tunnel was formed by a fibrous band that we call the cubital tunnel retinaculum (CTR). The band is about 4 mm wide, extending from the medial epicondyle to the olecranon, and perpendicular to the flexor carpi ulnaris aponeurosis. Variations in the CTR were classified into four types. In type 0 (n = 1) the CTR was absent. In type Ia (n = 17), the retinaculum was lax in extension and taut in full flexion. In type Ib (n = 6) it was tight in positions short of full flexion (90 degrees to 120 degrees). In type II (n = 3) it was replaced by a muscle, the anconeus epitrochlearis. The CTR appears to be a remnant of the anconeus epitrochlearis muscle and its function is to hold the ulnar nerve in position. Variations in the anatomy of the CTR may explain certain types of ulnar neuropathy. Its absence (type 0 CTR) permits ulnar nerve displacement. Type Ia is normal and does not cause ulnar neuropathy. Type Ib can cause dynamic nerve compression with elbow flexion. Type II may be associated with static compression due to the bulk of the anconeus epitrochlearis muscle.

Ulnar compression neuropathy secondary to the anconeus epitrochlearis muscle

The treatment of the five arms of four patients with ulnar neuropathy at the elbow and an associated anconeus epitrochlearis muscle is presented. Two of these patients had unilateral involvement, one had bilateral neuropathy and bilateral anconeus epitrochlearis muscles, and one had bilateral symptoms, with an anconeus epitrochlearis muscle on the side that was treated by operation. All patients were treated with excision of the anconeus epitrochlearis muscle and cubital tunnel release without anterior transposition of the nerve. All five arms were clinically normal at follow-up 16 to 29 months after operation. Postoperative electrodiagnostic studies on four arms at an average of 9 months after operation showed marked improvement in conduction velocities across the elbow. We recommend simple excision of the anomalous anconeus epitrochlearis muscle when no other cause of ulnar nerve neuropathy at the elbow is identified. Anterior transposition of the nerve seems unnecessary.