Interscalene triangle compression. Pain in hand is common, not in shoulder and neck .
Interscalene triangle compression The interscalene triangle is the most medial compartment, and its borders are cre-ated by the anterior scalene muscle anteriorly, middle scalene muscle posteriorly, and first rib inferiorly. Comprehensive explanation of neck structures, cervical fascia, muscles, vessels and nerves. [ 1 ] Jan 9, 2021 · BACKGROUND: Scalenus syndrome is a collection of symptoms as the consequences of nerve and vascular compression within the scalene triangle. During extreme shoulder abduction, the costoclavicular space is naturally narrowed. The artery and brachial plexus together pass As they travel from the upper mediastinum to the upper extremity, these structures run through three important spaces: the interscalene triangle, the costoclavicular space, and the subpectoral space. thoracic outlet where compression of nerves or vasculature occurs include the interscalene tri-angle, costoclavicular space, and subcoracoid space [7]. 18 A more recent study aimed at characterizing the interscalene triangle identified the width of the base of the triangle ranged between 0 and 2. Download scientific diagram | Brachial plexus anatomy: interscalene triangle. TOS is one such general term used for problems stemming from nerve or blood vessel compression in their passage from the cervical area toward the axilla and proximal arm either at the interscalene triangle, the costoclavicular triangle, or the subcoracoid space. 16 Oct 25, 2011 · interscalene base, both of which were measured in the current study. 1016/j. The interscalene triangle is usually the main entrapment point (culprit), and will often stand for 60-80% of the patients’ symptoms. Jun 1, 2012 · Magnetic resonance and computed tomographic imaging studies suggest that, of the 3 potential locations for constriction, the costoclavicular space is the most susceptible to compression. 1 Three major anatomic locations are common for such neurogenic entrapment of the BP owing to their congenital or acquired narrowing: the interscalene triangle, the costoclavicular space, and the space beneath the pectoralis minor Mar 1, 2010 · SUMMARY: The BPL is a part of the peripheral nervous system. Brachial plexus compression findings such as numbness, pain, paresthesia, vasomotor changes, and weakness (with muscle wasting in extreme cases) 3. Thoracic outlet syndrome (TOS) is a frequently overlooked peripheral nerve compression that creates difficulties for the clinician regarding diagnosis and management. May 17, 2012 · Neurovascular compression may be observed most commonly in the interscalene triangle, but it also has been described in the costoclavicular space and in the subcoracoid space. There are three distinct anatomic areas where compression can occur: the interscalene triangle (or scalene interval), the costoclavicular space, and the subcoracoid space. 1) [3•, 6]. However, the entity has long been forgotten in May 9, 2024 · There are three common sites of compression: scalene triangle: between scalenus anterior and scalenus medius muscles. 1 I Oct 29, 2019 · The scalene triangle (also known as the interscalene triangle) is located laterally at the root of the neck and is the space through which the roots and trunks of the brachial plexus and the third part of the subclavian artery exit the neck. Mar 26, 2020 · Figure 1 Representative sketch of potential brachial plexus compression sites at the (A) interscalene triangle, (B) costoclavicular space, and (C) retropectoralis minor space. The subclavian artery always passed through the lower part of this space. Nov 19, 2016 · Unlike neurogenic and arterial TOS, in which compression occurs within the interscalene triangle formed by the anterior and middle scalene muscles and first rib, venous TOS arises in the costoclavicular space bordered by the costoclavicular ligament/subclavius muscle, clavicle, and first rib (1,37,39). Thoracic outlet syndrome classically results from constrictions in 1 or more of 3 specific anatomical locations: the interscalene triangle, costoclavicular space, and coracopectoral tunnel. Diagnosis involves physical exam maneuvers like Adson's test and imaging. The costoclavicular space is the most frequent site of arterial compression 1 and is mainly a result of anatomical variations and masses occupying the costoclavicular space Aug 2, 2016 · Thoracic outlet syndrome (TOS) is a group of conditions caused by compression of the neurovascular structures that serve the upper extremity. 2,7,8 Cervical ribs are a rarity; most are asymptomatic. Inter-Scalene Triangle. Jun 4, 2021 · Thoracic outlet syndrome is a neurovascular disorder resulting from compression of the brachial plexus and/or subclavian vessels in the interval between the neck and axilla. : Kuhn J, Lebus G, Bible J, Thoracic Outlet Syndrome, Journal of the American Academy of Orthopaedic Surgeons All three neurovascular structures pass through this space. As alleviation of symptoms will only occur if the Non-surgical techniques to decrease compression in the interscalene triangle have included injections of anaesthetic agents , steroids and BTX-A [3,37,38,39]. 1990;159:231-236. Sep 24, 2023 · The interscalene triangle, the costoclavicular space, and the sub-pectoral space are the three areas of compression that lead to thoracic outlet syndrome. There are 3 main areas where the Brachial Plexus nerves can get compromised. 13 The vast majority of cases of TOS involve neural and/or vascular compression within the interscalene triangle. 125-1B) is the most common site of brachial plexus compression. 2. ) This interscalene triangle transmits all trunks of the brachial plexus, but only the subclavian artery traverses this triangle, not the The presence of cervical ribs cause problems either through interscalene triangle narrowing or through a concurrent fibrous band causing direct compression, elongation, or angulation of the brachial plexus (14,16,18,44). Sites of neurovascular compression within the thoracic outlet include the interscalene triangle, costoclavicular space, and subcoracoid space . It contains important structures, i. 4 Anomalous bands may arise Jul 10, 2020 · The interscalene triangle is a space between the anterior and middle scalene muscles and first rib, forming the anterior, posterior, and inferior borders of the triangle, respectively. These lesions almost always occur in association with a congenital cervical rib or other bony anomaly. The brachial plexus roots and the third segment of the subclavian artery both pass across it. retropectoralis minor space: between pectoralis minor and coracoid process May 25, 2014 · TOS is the clinical result of constriction or compression of neurovascular structures in the interscalene triangle, costoclavicular space, or retropectoral (coracopectoral) space . Many disease processes affect the BPL. Arch Surg. This compression may be caused by several anatomical structures in one or more of the following three compartments: the interscalene triangle, the Dec 1, 2019 · No patient had compression located only in the costoclavicular space or retro-pectoralis minor space (Table 1). MRI showed compression at more than one site in 10 (21%) cases, compression in the scalene triangle only in 21 (44%) cases, and compression in the costoclavicular space in 3 (6%) cases. Compression may be due to one or more of the following factors: congenital variations in anatomy – such as anomalous scalene musculature, aberrant fibrofascial bands, or cervical ribs See full list on physio-pedia. Aetiology Thoracic outlet syndrome (TOS) is often caused by compression at the interscalene triangle, costoclavicular, or subcoracoid spaces. 125-3 ) also compress the plexus in this location. Anterior triangle of the neck (submandibular triangle, carotid triangle, muscular triangle, submental triangle), interscalene triangle, and vertebral triangle is also discussed. These spaces are in continuity from the cervical spine, extending into the superior mediastinum and up to the lateral border of the pectoralis minor muscle. Other possible sources of compression include anomalous first rib, C7 transverse process or post-traumatic changes from prior clavicular or rib fractures. 2 cm with an average of 1. 2 – 4 This triangle is bordered by the anterior scalene muscle anteriorly, the middle and the posterior scalene muscles posteriorly, and the first rib inferiorly. , the brachial plexus and the third part of the subclavian artery. The costoclavicular space is the most frequent site of arterial compression and is mainly a result of anatomical variations and …. 29,30 Therefore, the anatomy of the scalene triangle and relative proximity of vessels to the sites of compression support the belief that scalene triangle pathology is more likely to create VTOS. Nov 9, 2022 · The interscalene triangle (sometimes termed simply the scalene triangle) is a region of the neck with fundamental importance to the function of the upper limbs, as the roots of the brachial plexus and the third part of the subclavian artery pass through it. (See Figure 22-1, A. Different varieties of BPL lesions are discussed. 017 Corpus ID: 10490114; Descriptive anatomy of the interscalene triangle and the costoclavicular space and their relationship to thoracic outlet syndrome: a study of 60 cadavers. Sep 1, 2024 · Thoracic outlet syndrome (TOS) is a group of symptoms caused by the compression of neurovascular structures of the superior thoracic outlet. 70 Because the subclavian vein is anterior to the subclavian artery (Figs. from Neurogenic thoracic outlet syndrome is caused by compression and subsequent irritation of the brachial plexus nerves as they pass through the scalene triangle at the base of the neck, between the clavicle and first rib, or in the infraclavicular pectoralis minor space (Fig. The 3 sites of compression causing thoracic outlet syndrome are the interscalene triangle, the costoclavicular space, and the sub-pectoral space. T horacic outlet syndrome (TOS) is a condition with compression of the neurovascular structures of the superior thoracic aperture, including the brachial plexus (BP). 1986 Oct;121(10):1141-4. Feb 18, 2018 · Compression directly to the brachial plexus is the most common driver of thoracic outlet syndrome. 79. The thoracic outlet is located within the lower part of the neck, behind the clavicle and above the first rib, extending into the axilla, and it is often described by several closely related anatomic spaces, including the scalene triangle, the Thoracic outlet syndrome is caused by compression of the neurovascular structures crossing the interscalene triangle, costoclavicular space or retropectoralis minor space. When present, cervical ribs ( Fig. The interscalene triangle is the most medial compartment, and its borders are created by the anterior scalene Oct 25, 2011 · Thoracic outlet syndrome classically results from constrictions in 1 or more of 3 specific anatomical locations: the interscalene triangle, costoclavicular space, and coracopectoral tunnel. thoracic outlet area is made up of several distinct spaces. It is comprised of two main entrapment zones, which are the interscalene triangle and the costoclavicular passage. 2). Figures 7a-b show the root/trunk junctions of the BP (arrows) with surrounding fat as they extend between the anterior (short arrows) and middle scalene muscles (arrowhead in 7b) and superior to the subclavian artery (red asterisk). (A) Schematic drawing illustrates the trunks as they exit the interscalene space, a passageway delimited by the Download scientific diagram | The three main sites implicated in neurovascular compression in the thoracic outlet. Numerous factors, such as extra scalene muscles, congenital anomalies of the first rib, cervical ribs, fibrous bands, aneurysms, and trauma, might contribute to this illness. 78. (Klassen et al, 2013). 2 Fibrous bands are more likely than rib anomalies to cause constrictions. Aug 23, 2023 · Scalene triangle compression can result in occipital headaches (referred pain), neck, and supraclavicular pain. Some authors further classify the thoracic outlet on the basis of three anatomical apertures within this broader space: the interscalene triangle, costoclavicular space, and subpectoral space. Isolated NPMS is usually associated with fewer head and neck symptoms. 1 to 2. 1, the areas within the thoracic outlet where compression of nerves or vasculature occurs include the interscalene triangle, costoclavicular space, and subcoracoid space . AA : axillary artery ABD : abduction ADs : anterior divisions AS : anterior scalene muscle AV : axillary vein BPL : brachial This variation would likely modify the presentation of thoracic outlet syndrome; for example by sparing the C5 nerve root from compression in the interscalene triangle, and hence sparing, for example, deltoid muscle strength, At the same time, however such superficial passage might render the C5 nerve root vulnerable to forces applied during Causes of interscalene triangle compression. Presence of a supernumerary cervical rib, as demonstrated in this figure, may constrict this space Arterial TOS is caused by subclavian artery compression within the scalene triangle leading to the development of occlusions or aneurysms. In this space, the nerve structures appeared as oval hypoechoic structures arranged above the subclavian artery, which lies at the bottom of the interscalene I have this condition and can verify it sucks hard. 125-2 ) and anomalous first ribs ( Fig. 1 I Compression may occur at three distinct areas in the thoracic outlet: retropectoralis minor space, the costoclavicular space, and the interscalene triangle. Neurogenic TOS is most frequently characterized by compression of the brachial plexus nerve roots (C5 to T1) within the scalene triangle. The sciatic nerve (roots L4-S3) is classically described as traveling inferior to the piriformis muscle and branches into the common fibular (peroneal) (roots L4 The scalene triangle is therefore one of the principal sites for nerve and blood vessel compression that causes TOS. Symptoms from compression of neurovascular bundle at thoracic outlet; Neuro complications most common (95%), then venous compression (3%), and then arterial (1%) Scalene triangle most often involved area: borders are anterior scalene, middle scalene and first rib; Clinical Features Coronal T1-weighted (7a) and sagittal T2-weighted (7b) images through the lateral interscalene triangle. Hypertrophy of scalene muscles, elevation of first rib. This study of human Magnetic resonance and computed tomographic imaging studies suggest that, of the 3 potential locations for constriction, the costoclavicular space is the most susceptible to compression. Three different compartments in the cervicoaxillary canal are related to the genesis of neurovascular compression syndrome: the interscalene triangle, the costoclavicular space, and the pectoralis Aug 1, 2021 · Clinical manifestations of complications relating to the interscalene triangle include thoracic outlet syndrome, which can result in vascular or neurological compromise of the upper limb following compression at the interscalene triangle. Aug 22, 2024 · Compression of neurovascular structures at the brachial plexus occurs in three key areas: the interscalene triangle, costoclavicular space, and subcoracoid space, each with specific boundaries and components. Am J Surg. , In patients who perform activities that require repetitive upper-extremity movement, such as swimming or throwing, or in patients In neurogenic TOS, compression occurs equally in the interscalene triangle and in the costoclavicular space. Described in Table 1 and diagrammatically represented in Fig. 2 Interscalene triangle surface area can be decreased by cervical ribs, fibrous bands, and kyphotic musculoskeletal anatomy. These spaces are (1) interscalene space or triangle, (2) costoclavicular space, and (3) subpectoralis minor space (less often encountered and less important). The interscalene triangle consists of the anterior scalene muscle, middle scalene muscle, and first rib. It can occur in the interscalene triangle, costoclavicular space, or subcoracoid area. Thompson RW. Neurovascular compression may be seen in the interscalene triangle, costoclavicular space, or posterior to the pectoralis minor, although any cause of abnormalities of shoulder girdle alignment may c … Nov 1, 2006 · The thoracic outlet includes three compartments (the interscalene triangle, costoclavicular space, and retropectoralis minor space), which extend from the cervical spine and mediastinum to the lowe Another testing modality suggested by the Society for Vascular Surgery is to inject the scalene and pectoralis minor muscles with local anaesthetic to check for alleviation of symptoms, the rationale being that the scalene triangle and pectoralis minor space are common sites of compression . Sep 14, 2024 · Thoracic outlet syndrome (TOS) is a condition with compression of the neurovascular structures of the superior thoracic aperture, including the brachial plexus (BP). In arterial TOS, the costoclavicular space is the most frequent site of compression, followed by the interscalene triangle. As opposed to the subclavian artery and the brachial plexus that get compressed in the interscalene triangle between the anterior and middle scaleneus muscles, the subclavian vein gets compressed in the costoclavicular triangle, which is bordered by the medial aspect of the clavicle superiorly, the first rib inferiorly and the insertion of the May 9, 2024 · There are three common sites of compression: scalene triangle: between scalenus anterior and scalenus medius muscles. showing anatomic causes of compression. 1 I Mar 1, 2024 · The space in the interscalene triangle is reduced when a cervical rib is present, resulting in compression of the neurovascular structures [11] (Fig. 2012. in 2001 it has a sensitivity of 79% and specificity of 76%. Contents of the interscalene triangle. 15), it has only recently been recognized that nerve compression at the level of the pectoralis minor muscle tendon can make a substantial contribution to symptoms in neurogenic TOS, and that in many cases nerve compression at this level may dominate over that occurring at the level of the scalene Jul 30, 2016 · The scalene triangle (Fig. With respect to the subclavian arteries, they typically ascend into the neck before arching laterally. 6 The most medial aperture that can result in neurovascular compression is within the interscalene triangle. retropectoralis minor space: between pectoralis minor and coracoid process Aug 1, 2003 · The interscalene triangle was well identified, bordered anteriorly by the anterior scalene muscle and posteriorly by the middle and posterior scalene muscles (Figs 4B and C, and 5B and C). A, Illustration; B, photograph. 70 Because the subclavian vein is anterior to the subclavian artery (Figure 1, Figure 2) and dynamic compression in the costoclavicular space primarily Mar 28, 2020 · The thoracic outlet is the region from the intervertebral foramina to the coracoid process and contains the brachial plexus, subclavian artery, and vein []. Thoracic cervical rib can cause narrowing of the scalene triangle. Pain in hand is common, not in shoulder and neck Machleder HI, Moll F, Verity MA. Surgery for neurogenic TOS is based on removing one or more of the structures considered responsible for brachial plexus nerve root compression at the level of the scalene triangle, including: The anterior and middle scalene muscles; Any additional scalene muscle or fascial band anomalies that may be encountered The presence of cervical ribs cause problems either through interscalene triangle narrowing or through a concurrent fibrous band causing direct compression, elongation, or angulation of the brachial plexus (14,16,18,44). 1 cm. Neurogenic thoracic outlet syndrome (nTOS) makes up roughly 90% of all thoracic outlet syndrome (TOS) cases and typically features an anatomical susceptibility with The interscalene triangle is bordered by the anterior scalene muscle anteriorly, the middle scalene posteriorly, and the medial surface of the first rib inferiorly. According to Gillard et al. The interscalene triangle is the most medial compartment, and its borders are created by the anterior scalene Jun 1, 2012 · Early descriptions of the interscalene triangle suggest the width of the base of the interscalene triangle to range from 0. Scalene muscle abnormalities in traumatic thoracic outlet syndrome. Physical examination includes investigation for brachial plexus compression at the scalene triangle and under the pectoralis minor muscle. They cross under the clavicle and over the first rib. Jordan et al. 04. Causes of costoclavicular space compression. This study of human cadavers aims to expand on the descriptive anatomy of the interscalene triangle and associated costoclavicular space. The anterior scalene muscle in thoracic outlet compression syndrome. In this article, on the basis of 60 patients, we reviewed MR imaging findings of subjects with brachial plexopathy. Sanders RJ, Jackson CG, Banchero N, et al. Fig 2. Symptoms include pain, numbness, and weakness in the arm. 15 Notably, the trunks of the brachial plexus and subclavian artery mised (Fig. These signs include both tenderness and Tinel’s sign in each location (Table 2 and Table 3). Oct 29, 2019 · The scalene triangle (also known as the interscalene triangle) is located laterally at the root of the neck and is the space through which the roots and trunks of the brachial plexus and the third part of the subclavian artery exit the neck. Adapted with permission from Wolters Kluwer Health, Inc. B, Anatomy of thoracic outlet, identifying the three potential regions of compression: interscalene triangle, costoclavicular space, and retropectoralis minor (subcoracoid) space. The peak of the paired inter-scalene triangle points superiorly in the direction of the base of Thoracic outlet syndrome (TOS) is an often misdiagnosed cause of neck, shoulder, and arm disability. There is a wide spectrum of clinical presentations with symptoms of pain, weakness, paresthesia, numbness, coldness, tingling, and discoloration in the upper extremity. The knowledge of its clinical presentation with specific symptoms, as well as proper imaging examinations, ranging from plain radiographs to ultrasound, computed tomography and magnetic resonance imaging, may help achieve a precise diagnosis. Nerve (yellow) compression can occur at the scalene triangle or pectoralis minor space, whereas venous compression most often occurs at the costoclavicular space. Anatomical variants such as a cervical rib can cause narrowing of the scalene triangle. The borders of the triangle are the latera … Described in Table 1 and diagrammatically represented in Fig. This may require surgical decompression if the effects of the condition are sufficiently deleterious on the As the scalene contraction draws the first rib superiorly, compression is placed on the subclavian vein in the costoclavicular space and the subclavian artery in the scalene triangle . Jul 19, 2015 · The thoracic outlet consists of three areas; the interscalene triangle, the costoclavicular space, and the pectoralis minor space or the subcoracoid space. com In patients with a significant component of symptoms attributable to brachial plexus compression at the level of the pectoralis minor muscle, division of the pectoralis minor muscle tendon (a tenotomy) may also be performed, either as an isolated procedure or in combination with decompression at the scalene triangle. e. Table 2. It is surmised that only up to 20% of NTOS cases are solely due to the presence of a cervical rib. 1, 2) and dynamic compression in the costoclavicular space primarily occurs anteriorly Nov 30, 2016 · The interscalene triangular space is bordered anteriorly by the scalene anticus muscle, posteriorly by the scalene medius muscle, and inferiorly by the medial border of the first rib. This area is between the Anterior and Middle Scalene muscles in the side of the neck. 1 Three major anatomic locations are common for such neurogenic entrapment of the BP Thoracic Outlet Syndrome is defined as a neurovascular symptom complex associated with compression of the brachial bundle, which includes the brachial plexus and/or subclavian vessels. Oct 24, 2024 · Compression most often occurs at the interscalene triangle. costoclavicular space: between the clavicle and 1 st rib. degrees of compression similar to the costoclavicular space. jmpt. 9 cm. Compression can occur in any of these three spaces because of structural anomalies or trauma. Once TOS is May 17, 2012 · Magnetic resonance and computed tomographic imaging studies suggest that, of the 3 potential locations for constriction, the costoclavicular space is the most susceptible to compression. 1. Diagnosis can be suspected clinically with specific provocative tests and supplemented with radiographs or vascular studies. The boundaries of the scalene triangle are as follow; medially the lateral border of the anterior scalene, laterally the medial border of the middle scalene, and inferiorly the first rib. brachial plexus at the level of the interscalene triangle. Costoclavicular Space This type of compression occurs under the pectoralis minor tendon when the arm is in positions of abduction and external rotation. Additionally, evidence is sought for nerve compression at the elbow, forearm, and wrist. Typical features include (9-16, 25): Subjective. 1: interscalene triangle; 2: costoclavicular space; 3: subpectoral tunnel. The underlying mechanism is an ongoing process of Thoracic outlet syndrome is caused by compression of the neurovascular bundle in the thoracic outlet. Methods Oct 20, 2015 · The thoracic outlet area is made up of several distinct spaces. Aug 13, 2024 · Introduction The region of the neck known as the Inter-scalene triangle, or scalene triangle, is crucial to the operation of the upper limbs. May 27, 2024 · Location Of Nerve Compression; Causes; Tests; Thoracic Outlet Syndrome Exercises; Common Questions; Location Of Nerve Compression. The posterior scalene muscle was rarely identified as a separate structure from the middle scalene muscle on MR images. Jan 26, 2021 · Compression in the scalene triangle is usually associated with occipital headaches and significant neck pain due to trauma to the scalene muscles, while headaches and neck pain are absent or minimal when compression is in the other two spaces. Magnetic resonance and computed tomographic imaging studies suggest that, of the 3 potential locations for constriction, the costoclavicular space is the most susceptible to compression. Arterial injury is most often due to bone trauma at the scalene triangle. Neurogenic thoracic outlet syndrome symptoms typically involve the ulnar digits, but do not follow a radicular pattern, distinguishing it from other differential As highlighted elsewhere by Sanders (Chap. Symptoms consistent with irritation at the site of compression; scalene triangle in the case of TOS and pectoralis muscle site in the case of PMS and pain on palpation of the affected area. 1 The term ‘thoracic outlet syndrome’ was originally coined in 1956 by Peet to indicate compression of the neurovascular structures in the interscalene triangle corresponding to the possible etiology of the symptoms. (Modified from Sanders RJ, Haug CE. What worked best for me is 1) scalene stretches from the neck series of active isolated stretching, with the second rib being pinned down to make room for first rib. Narrowing of this space tends to cause venous symptoms, frequently denoted venous TOS (vTOS), with varying degrees of additional symptoms due to arterial or brachial plexus compression. The Adson test is designed to decrease the space in the interscalene triangle. 5 cm, with an average of 0. The elements of the interscalenetriangle includingthe brachialplexusand subclavian artery can be seen here traveling between the anterior and middle scalene muscles through the interscalene triangle. [ 7 ] reported that anesthetic block of the anterior scalene muscle could be used to help predict which patients may potentially benefit from decompressive surgery for the Involves compression of brachial plexus nerve roots (C5-T1), typically in the interscalene triangle or under pec minor tendon in subcoracoid space About us About Quizlet Three spaces within the thoracic outlet region are potentially responsible for compression of the neurovascular structures as they travel to the upper extremity (). As the anterior scalene muscle goes from rest (A) to contracted (B), it pulls the first thoracic rib cranially and compresses the brachial plexus and subclavian within the costoclavicular space. This study of human Jul 1, 2023 · As the scalene contraction draws the first rib superiorly, compression is placed on the subclavian vein in the costoclavicular space and the subclavian artery in the scalene triangle (Fig. TOS is the clinical result of constriction or compression of neurovas- cular structures in the interscalene triangle, costoclavicular space, or retropectoral (coracopectoral) space (Figure 1 Scalene Triangle. Of note, the C8/T1 roots and inferior trunk are the closest components of the brachial plexus to the first rib and C7 Compression with movement of the scalene muscle. May 27, 2014 · Thoracic outlet syndrome is caused by compression of the neurovascular structures crossing the interscalene triangle, costoclavicular space or retropectoralis minor space. Other possible sources of compression include anomalous first rib, C7 transverse process, or post-traumatic changes Sep 11, 2022 · Importantly, the interscalene triangle is 1 of 3 sites where compression of the critical neurovascular structures traveling between the neck and the upper limb can be compressed. The interscalene triangle is bordered anteriorly by the anterior scalene muscle, posteriorly by the middle scalene muscle, and inferiorly by the first rib. After passing over the first rib, the brachial plexus nerves, subclavian artery, and subclavian vein all pass together underneath the clavicle. It results in similar arterial compression symptoms as subclavian compression in the interscalene triangle (5,32). Histochemical and morphometric studies. Jun 1, 2012 · DOI: 10. Cervical ribs can vary in size and attachment, resulting in anatomic variations that range from a length of <1 cm to complete fusions with the first rib [13] . rat kyohk ksqlt acfduoh xosiy rqh ijbwmwe hnr oxrkpc fxrd