Quadrilateral Space Research Articles

A rare case of acute traumatic complicated right axillary artery pseudoaneurysm with quadrangular space syndrome

Axillary artery pseudoaneurysms are relatively rare, with few reported cases found in the literature. There have been high rates of rupture and compression-related complications in trauma-related pseudoaneurysms of the upper limb. Prompt diagnosis with non-invasive imaging modalities such as ultrasound, magnetic resonance imaging, and computed tomography. Angiography is required for immediate intervention and prevention of complications. Here, we present a case of an extremely rare right-sided acute traumatic axillary artery pseudoaneurysm with compression, resulting in quadrangular space syndrome in a 31-year-old male patient. We performed a critical literature review of the same and identified only a few previously reported cases.

Transfer of Motor Fascicle From the Ulnar Nerve to the Axillary Nerve by Posterior Access. New Approach.

We describe a new technique of transferring the motor branch ulnar nerve (UN) to the axillary nerve (AN) by posterior approach. Three patients with C5, C6, and C7 brachial plexus injury were operated. By supraclavicular approach, the spinal accessory was transferred to the suprascapular nerve. By posterior approach in the arm, the AN was identified within the quadrilateral space, and the UN was identified medially with intrafascicular dissection of a motor fascicle, which is lifted to 4 cm in length and transferred to AN. By medial approach, a motor branch from the median nerve is transferred to the biceps nerve. At a follow-up minimum of 10 months, the maximum abduction was 160 and the minimum 90 degrees. This technique, neurotization of the AN with fascicles of the UN, spinal accessory to suprascapular nerve, and median nerve branch to biceps nerve are indicated in C5-C7 avulsion when there is no radial nerve available. Level IV.

American English diphthong transitions and the acoustic vowel space: A pilot comparison of two tasks

The purpose of the present study is to evaluate the potential relationship(s) between diphthong transitions and the acoustic vowel space parameters in two speaking tasks. Diphthongs are associated with acoustic changes that reflect changes in vocal tract configurations, affording unique opportunities for investigating the articulatory-acoustic link. The acoustic vowel space, a representation of monophthong vowels in a two-dimensional plane defined by the first and second formant frequencies (F1 and F2), has been widely used to interpret articulatory-acoustic consequences and to index articulatory integrity. Nevertheless, limited is known as to how diphthongs and monophthong vowels account for the acoustic working space together [Lee et al., JASA 136(4), 1880–1894 (2014)]. To add to this inquiry, transitions of American English diphthongs /ei/, /ɑɪ/, /ɑʊ/, /oʊ/, and /ɔi/, defined by the primary F2 transition, are examined with respect to the quadrilateral vowel space anchored by /i/, /æ/, /ɑ/, and /u/. The speech sounds were obtained from four male speakers in two tasks, sentence reading and connected speech, that have been shown to elicit vowel space changes. It is hypothesized that greater diphthong transitions are associated with parameters corresponding to a larger vowel space. Findings will be discussed within the framework of the acoustic theory.

Anatomical considerations for nerve transfer in axillary nerve injury

This study investigated the anatomical details of the axillary and radial nerves in 50 upper limbs from 29 adult formalin-embalmed cadavers, and ten fresh upper limbs. The focus was on understanding the course, division, and ramifications of these nerves to improve treatment of shoulder dysfunction caused by axillary nerve damage. The axillary nerve divided anteriorly and posteriorly before passing the quadrangular space in all specimens, with specific distances to the first ramifications. It was found that the deltoid muscle's clavicular and acromial parts were always innervated by the anterior division of the axillary nerve, whereas the spinous part was variably innervated. The longest and thickest branches of the radial nerve to the triceps muscles were identified, with no statistically significant differences in fiber numbers among triceps branches. The study concludes that nerve transfer to the anterior division of the axillary nerve can restore the deltoid muscle in about 86% of shoulders, and the teres minor muscle can be restored by nerve transfer to the posterior division. The medial head branch and long head branch of radial nerve were identified as the best donor options.

Approximation properties of primal discontinuous Petrov-Galerkin method on general quadrilateral meshes

We consider the approximation properties of primal discontinuous Petrov-Galerkin (DPG) method on quadrilateral meshes. We show how the previous convergence results as well as the Aubin-Nitsche type duality arguments can be extended to cover arbitrary convex quadrilateral elements with bilinear isomorphisms. The arguments are based on the approximation theory of quadrilateral vector finite element spaces associated to the numerical flux variable of the DPG approximation. The theoretical results are validated by a numerical experiment that features also a comparison between the primal DPG method and a conventional least squares finite element method with the same number of degrees of freedom.

Bilateral Long Head of the Triceps Brachii Muscle Innervation via Axillary Nerve: A Case Report

The radial nerve has traditionally been considered the innervation of the long head of the triceps brachii (LHT). However, cadaveric studies have discovered LHT innervation via the axillary nerve in roughly 6-15 % of shoulders. A cadaver with exclusive axillary nerve innervation to the LHT bilaterally was discovered during cadaveric dissection in a graduate course at Samford University. This anatomical variation may have clinical implications for surgeries, shoulder dislocations, and quadrilateral space syndrome. Axillary nerve injuries may additionally present with shoulder extension and elbow extension weakness if this variation is present.

Arthroscopic Removal of Extra-Articular Foreign Bodies From the Shoulder: Inside-Out Technique

Arthroscopic shoulder surgery can be performed for retrieval of bullets and retained metallic fragments in the glenohumeral and subacromial spaces. Previous case reports and case series have demonstrated the effectiveness of an arthroscopic approach over an open procedure, as it is less invasive, allows for improved inspection and documentation of the joint surfaces and periarticular structures, and potentially leads to a faster recovery. An arthroscopic approach for extracting foreign bodies from both the quadrilateral space and the posterior extra-articular space by first accessing the glenohumeral space has yet to be described. This inside-out technique may afford surgeons the potential for improved visualization and less morbidity compared with a traditional open posterior approach. We report a technique for an arthroscopic inside-out approach for removal of extra-articular foreign bodies retained in either the quadrilateral space or the posterior extra-articular space.

The surgical anatomy of the axillary approach for nerve transfer procedures targeting the axillary nerve

PurposeThe exact relational anatomy for the anterior axillary approach, targeting the axillary nerve for nerve transfers/grafts, has not been fully investigated. Therefore, this study aimed to dissect and document the gross anatomy surrounding this approach, specifically regarding the axillary nerve and its branches.MethodsFifty-one formalin-fixed cadavers (98 axilla) were bilaterally dissected simulating the axillary approach. Measurements were taken to quantify distances between identifiable anatomical landmarks and relevant neurovascular structures encountered during this approach. The musculo-arterial triangle, described by Bertelli et al., to aid in identification on localization of the axillary nerve, was also assessed.ResultsFrom the origin of the axillary nerve till (1) latissimus dorsi was 62.3 ± 10.7 mm and till (2) its division into anterior and posterior branches was 38.8 ± 9.6 mm. The origin of the teres minor branch along the posterior division of the axillary nerve was recorded as 6.4 ± 2.9 mm in females and 7.4 ± 2.8 mm in males. The musculo-arterial triangle reliably identified the axillary nerve in only 60.2% of the sample.ConclusionThe results clearly demonstrate that the axillary nerve and its divisions can be easily identified with this approach. The proximal axillary nerve, however, was situated deep and therefore challenging to expose. The musculo-arterial triangle was relatively successful in localising the axillary nerve, however, more consistent landmarks such as the latissimus dorsi, subscapularis, and quadrangular space have been suggested. The axillary approach may serve as a reliable and safe method to reach the axillary nerve and its divisions, allowing for adequate exposure when considering a nerve transfer or graft.

P1$$ {P}_1 $$–Nonconforming quadrilateral finite element space with periodic boundary conditions: Part I. Fundamental results on dimensions, bases, solvers, and error analysis

AbstractThe –nonconforming quadrilateral finite element space with periodic boundary conditions is investigated. The dimension and basis for the space are characterized by using the concept of minimally essential discrete boundary conditions. We show that the situation is different based on the parity of the number of discretizations on coordinates. Based on the analysis on the space, we propose several numerical schemes for elliptic problems with periodic boundary conditions. Some of these numerical schemes are related to solving linear equations consisting of non‐invertible matrices. By courtesy of the Drazin inverse, the existence of corresponding numerical solutions is guaranteed. The theoretical relation between the numerical solutions is derived, and it is confirmed by numerical results. Finally, the extension to the three dimensions is provided.

High-Resolution Ultrasound Imaging of Axillary Nerve and Relevant Injury.

To evaluate the feasibility of axillary nerve (AN) visualization in healthy volunteers and the diagnostic value of AN injury via high-resolution ultrasonography (HRUS). AN was examined by HRUS on both sides of 48 healthy volunteers and oriented the transducer according to three anatomical landmarks: quadrilateral space, anterior to subscapular muscle, and posterior to axillary artery. The maximum short-axis diameter (SD) and cross-sectional area (CSA) of AN were measured at different levels, and AN visibility was graded by using a five-point scale. The patients suspected of having AN injury were assessed by HRUS, and the HRUS features of AN injury were observed. AN can be visualized on both sides in all volunteers. There was no significant difference in SD and CSA of AN at the three levels between the left and right sides or in SD between males and females. However, the CSA of males at different levels was slightly larger than those of females (P < .05). In most volunteers, AN visibility at different levels was excellent or good, and AN was best displayed anterior to subscapular muscle. Rank correlation analysis revealed that the degree of AN visibility had correlation with height, weight, and BMI. A total of 15 patients diagnosed with AN injury, 12 patients showed diffuse swelling or focal thickening in AN, and 3 patients showed AN discontinuity. HRUS is able to reliably visualize AN, and it could be considered as the first choice for diagnosing AN injury.

A Surgical Framework for the Management of Incomplete Axillary Nerve Injuries.

Axillary nerve injury is the most common nerve injury affecting shoulder function. Nerve repair, grafting, and/or end-to-end nerve transfers are used to reconstruct complete neurotmetic axillary nerve injuries. While many incomplete axillary nerve injuries self-resolve, axonotmetic injuries are unpredictable, and incomplete recovery occurs. Similarly, recovery may be further inhibited by superimposed compression neuropathy at the quadrangular space. The current framework for managing incomplete axillary injuries typically does not include surgery. This study is a retrospective analysis of 23 consecutive patients with incomplete axillary nerve palsy who underwent quadrangular space decompression with additional selective medial triceps to axillary end-to-side nerve transfers in 7 patients between 2015 and 2019. Primary outcome variables included the proportion of patients with shoulder abduction M3 or greater as measured on the Medical Research Council (MRC) scale, and shoulder pain measured on a Visual Analogue Scale (VAS). Secondary outcome variables included pre- and postoperative Disabilities of the Arm, Shoulder, and Hand Questionnaire (DASH) scores. A total of 23 patients met the inclusion criteria and underwent nerve surgery a mean 10.7 months after injury. Nineteen (83%) patients achieved MRC grade 3 shoulder abduction or greater after intervention, compared with only 4 (17%) patients preoperatively (p = 0.001). There was a significant decrease in VAS shoulder pain scores of 4.2 ± 2.5 preoperatively to 1.9 ± 2.4 postoperatively (p < 0.001). The DASH scores also decreased significantly from 48.8 ± 19.0 preoperatively to 30.7 ± 20.4 postoperatively (p < 0.001). Total follow-up was 17.3 ± 4.3 months. A surgical framework is presented for the appropriate diagnosis and surgical management of incomplete axillary nerve injury. Quadrangular space decompression with or without selective medial triceps to axillary end-to-side nerve transfers is associated with improvement in shoulder abduction strength, pain, and DASH scores in patients with incomplete axillary nerve palsy.

Quadrangular Space Syndrome: a systematic review of surgical and medical therapeutic advances.

The axillary nerve and posterior circumflex humeral artery are compressed in Quadrangular Space Syndrome (QSS), which can be treated with conservative approaches or surgical decompression in recalcitrant instances. There are no clear guidelines for determining which surgical method is optimal for treating QSS and other disorders that mirror QSS. The goal of this study is to grade and review past, current, and planned medicinal and surgical care modalities for QSS. The review protocol is registered with PROSPERO (ID: CRD42022332766). To identify recent advances in the methods/techniques of medical and surgical management of QSS, PubMed and Medline databases were searched until March 2022 for publications, including case studies, case reports, and review articles, using medical subject headings terms like quadrilateral space syndrome, surgical management, and medical management. Throughout the study, all the authors scrupulously followed a well-developed registered review process and the risk of bias in systematic reviews guidance tool. Data on proposed medical and surgical management methods/techniques were compiled, and each was analyzed based on the underlying neuro-vascular systems. There were 88 items found in the first search. Following applying the inclusion and exclusion criteria, 16 papers were chosen for synthesis in the review study after a thorough assessment. Three studies (conservative and advanced) focused on medical care of QSS, while 12 articles (prior, current, and newer) focused on surgical management of QSS. Only four of the 15 studies reviewed proposed different surgical approaches/techniques for surgical decompression in QSS. There were two regularly used surgical procedures discovered, one anterior/delto-pectoral and the other posterior/ scapular. The anterior route is more technically straightforward and can be employed for surgical QSS decompression.

The Posterior Circumflex Humeral Artery with Variant Origin and Course

The posterior circumflex humeral artery (PCHA) typically emanates from the axillary artery (AxA) that supplies the shoulder region and surrounding structure. During routine dissection, we noticed that a truncus profundocircumflexus arose as a branch of Brachial Artery distal to teres major (TM), which branches into profunda brachii, besides PCHA. This circumflex humeral artery, winding around the TM muscle, coursed superolaterally and reached the quadrangular space for its usual vascular territory. Adequate awareness of such rare variations observed in the present study is pertinent for physicians for quadrangular space syndrome, radiologists to avert misreading of angiographs, and orthopedics in case of trauma to the axilla, shoulder region, and upper arm or during invasive vascular procedures.

Destruction of Vowel Space Area in Patients with Dysphagia after Stroke.

Dysphagia is associated with dysarthria in stroke patients. Vowel space decreases in stroke patients with dysarthria; destruction of the vowel space is often observed. We determined the correlation of destruction of acoustic vowel space with dysphagia in stroke patients. Seventy-four individuals with dysphagia and dysarthria who had experienced stroke were enrolled. For /a/, /ae/, /i/, and /u/ vowels, we determined formant parameter (it reflects vocal tract resonance frequency as a two-dimensional coordinate point), formant centralization ratio (FCR), and quadrilateral vowel space area (VSA). Swallowing function was assessed using the videofluoroscopic dysphagia scale (VDS) during videofluoroscopic swallowing studies. Pearson’s correlation and linear regression were used to determine the correlation between VSA, FCR, and VDS. Subgroups were created based on VSA; vowel space destruction groups were compared using ANOVA and Scheffe’s test. VSA and FCR were negatively and positively correlated with VDS, respectively. Groups were separated based on mean and standard deviation of VSA. One-way ANOVA revealed significant differences in VDS, FCR, and age between the VSA groups and no significant differences in VDS between mild and moderate VSA reduction and vowel space destruction groups. VSA and FCR values correlated with swallowing function. Vowel space destruction has characteristics similar to VSA reduction at a moderate-to-severe degree and has utility as an indicator of dysphagia severity.

Selective Suprascapular and Axillary nerve (SSAX) block – A diaphragm sparing regional anesthetic technique for shoulder surgeries

Interscalene block, the gold standard for shoulder surgeries is inevitably associated with phrenic nerve palsy, even at low volumes. The major innervation of the shoulder joint is by suprascapular nerve and axillary nerve. Suprascapular nerve block has been used commonly for postoperative analgesia in shoulder surgeries done under GA. Combining axillary block with suprascapular nerve block was found to provide superior analgesia when compared to suprascapular block alone. Selective Suprascapular and Axillary nerve (SSAX) block provides effective analgesia in shoulder surgeries without causing diaphragm palsy, but has limited published literature. We performed ultrasound guided suprascapular block in the supraspinous fossa (posterior approach) using 10 ml of 0.25% Ropivacaine and axillary block in the quadrangular space using 6ml of 0.25% Ropivacaine before administration of general anaesthesia (GA) in 4 cases. Among four cases, 2 were closed shoulder manipulation with intra-articular steroid injection for periarthritis, 1 was closed reduction and K-wire fixation for chronic shoulder subluxation and the 4th was Latarjet procedure for recurrent shoulder dislocation. All patients received paracetamol 1g at the end of the procedure and every 6 h postoperatively. No patient experienced pain during recovery and the analgesia lasted for a mean duration of 347.5 minutes. Tramadol was required for rescue analgesia in only one patient (Latarjet surgery). We found that SSAX block provided effective analgesia in all patients, but needs randomized controlled trials with larger sample size comparing with interscalene block.

Teres Intermedius: An Accessory Rotator Cuff Muscle Discovered During Routine Cadaveric Dissection

The teres minor is a unipennate intrinsic shoulder muscle that arises on the lateral border of the scapula and runs obliquely to insert on the greater tubercle of the humerus. It stabilizes and contributes to external rotation of the glenohumeral joint. Teres major, while resembling the teres minor in origin and fiber direction, ultimately diverges from the teres minor as it passes anterior to the humerus and acts predominantly as a medial rotator and adductor of the shoulder. Described variants in the teres musculature are rare. We found a unilateral accessory muscle in the teres region of the right shoulder in an 81‐year‐old Caucasian male cadaver in a traditional anatomy lab. The accessory muscle arises from the lateral aspect of the scapula and travels parallel and posterior to the teres minor to insert onto the posterior head of the deltoid. The variant muscle is of similar size to the teres minor (also present), but its fibers are encapsulated in their own distinct fascial sheath, entirely separate from that of the anatomically normal teres muscles. We provide a detailed description of the accessory muscle and propose that similar variants may be clinically important due to their proximity to the anatomical quadrangular space, as compression of the structures traversing this area may result in pain, tenderness, paresthesia, and cyanosis in the shoulder region.

The Quadrangular Space, Endonasal Access to the Meckel Cave: Technical Considerations and Clinical Series

An anteromedial corridor via an expanded endoscopic endonasal approach to the Meckel cave (MC) was described more than a decade ago. However, few clinical series or endoscopic endonasal technical contributions exist concerning this type of approach to this complex region. We present a detailed description of the surgical technique for this approach reviewing the original technique and adding clarifying conceptual notions. We conducted a multicenter retrospective study selecting patients who underwent endonasal endoscopic surgery for lesions exclusively limited to the MC in the past 6 years. Intraoperative and postoperative complications were analyzed. The study of 10 cadaveric specimens provides additional information. We performed a fully endoscopic anteromedial corridor to the MC in 18 patients. The most prevalent pathologic finding was schwannoma of the V nerve in 4 patients. Sixth cranial nerve palsy (13 patients) and trigeminal dysfunction (10 patients) were the predominant preoperative clinical signs. There were no remarkable intraoperative complications. Corneal keratopathy caused by dry eye syndrome affected 3 patients and V2 residual neuralgia appeared postoperatively in 2 patients. Six patients recovered from sixth cranial nerve palsy, and 2 showed improvement in preoperatively referred facial pain. The front door to the MC via the endonasal anteromedial corridor could be a good option. Understanding of the anatomy and the concept of the quadrangular space is crucial to performing this technique safely, which has few complications in experienced hands. Recovery from sixth nerve palsy is possible with this approach. Corneal keratopathy in these patients is a potential complication.

Quadrangular Space Decompression

Background: The quadrangular (or quadrilateral) space is defined by its anatomical borders and is the passageway for the axillary nerve and posterior circumflex humeral artery (PCHA). Quadrangular space syndrome (QSS) can present due to various compressive pathologies but is commonly seen in overhead athletes. Quadrangular space syndrome can present with neurogenic symptoms including pain and paresthesias, as well as vascular complications from compression of the PCHA including thrombosis, aneurysm formation, and distal emboli. Indications: Surgical decompression of the quadrangular space is indicated for severe neurogenic or vascular compromise in the case of QSS refractory to nonoperative treatment. Technique Description: After appropriate preoperative physical examination findings and trial of nonoperative treatment, including physical therapy and injections, surgical decompression was indicated. The posterior border of the deltoid was marked, and an incision centered over the posterior border of the deltoid lateral to the axillary fold was made. Posterior border of deltoid was identified and retracted, revealing the interval of the teres minor and major. The nerve to the teres minor was identified, protected, and fibrous bands compressing the nerve were released. The nerve to the teres minor was tracked deep to find the axillary nerve. This was identified and fibrous bands around the nerve were decompressed. The circumflex vessels were protected throughout. Following decompression of the nerves, there was free movement of the nerves indicating adequate surgical decompression. Results: Adequate surgical decompression of the axillary nerve and PCHA achieved with resolution of neurogenic symptoms of pain and paresthesias at first postoperative visit. Discussion/Conclusion: Quadrangular space syndrome is a rare disorder, can be difficult to diagnose, and is the cause of significant morbidity, particularly in overhead athletes. If symptoms persist after nonoperative treatment, operative decompression of the quadrangular space may be indicated. Adequate surgical decompression results in relief of neurogenic and vascular symptoms.

Revisiting the Surgical Approaches to Decompression in Quadrilateral Space Syndrome: A Cadaveric Study.

BackgroundQuadrangular space syndrome involves compression of the axillary nerve and posterior circumflex humeral artery. In a few cases, its management requires surgical decompression. The current study reviews the surgical approaches used in the decompression of neurovascular structures and presents our reflections and recommendations.MethodologyIn this study, four human cadavers were used for dissection of the axillae and the scapular region by the senior residents of the Department of Anatomy and Department of Orthopedics. The residents dissected the quadrangular space in the eight upper limbs using anterior and posterior surgical approaches.ResultsTo identify the quadrangular space and secure its contents, the posterior approach was recognized as the easier and quicker method by both Anatomy and Orthopedic residents; however, it may result in increased postoperative morbidity. Although the anterior (deltopectoral) approach involves more skill, it reduces postoperative morbidity.ConclusionsThe anterior (deltopectoral) approach with suggested modifications can be an effective method in the surgical decompression of quadrangular space syndrome. The authors suggest more cadaveric studies to provide anatomists and surgeons with the opportunity to practice and evaluate older and newer surgical approaches.

Arthroscopic Axillary Nerve Neurolysis From the Anteroinferior Glenoid Through the Quadrilateral Space to the Terminal Deltoid Branches

Axillary nerve compression is a rare cause of posterolateral shoulder pain. Once the diagnosis is confirmed and after failure of conservative measures, open procedures have been the mainstay of treatment for several decades. More recently, arthroscopic techniques have been proposed, which offer several advantages, including improved access to difficult locations, better visualization, and less surgical morbidity. The objective of this Technical Note is to describe an arthroscopic neurolysis of the axillary nerve from the inferior humeral pouch, through the quadrilateral space and into the subdeltoid recess.