Scalenus Minimus Muscle: Overestimated or Not? An Anatomical Study

Natsis, Konstantinos; Totlis, Trifon; Didagelos, Matthaios; Tsakotos, George; Vlassis, Konstantinos; Skandalakis, Panagiotis

doi:10.1177/000313481307900425

Cited by 13 publications

(6 citation statements)

References 8 publications

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“…Compression is often relieved surgically by cutting the anterior scalene muscle. Another important etiology of TOS is hypertrophy and/or fibrosis of the scalenus minimus muscle, which is a separate fibrous band, often arises from seventh and/or sixth cervical vertebrae and insert to the first rib, and occurs in 71.7% of TOS patients [ 19 ]. This population often combine with cervical ribs or elongated C7 transverse processes, which change the shape of the scalenus minimus muscle (in our patients, mostly behind the subclavian artery and the lower trunk of the brachial plexus), elevate the lower trunk, and cause the nerve to be compressed against the anterior scalene muscle.…”

Section: Discussionmentioning

confidence: 99%

Diagnosis of thoracic outlet syndrome with the lower trunk compression of brachial plexus by high-frequency ultrasonography

Chen,

Gong,

Wang

et al. 2023

BMC Musculoskelet Disord

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Background Thoracic outlet syndrome (TOS) with the lower trunk compression of brachial plexus (BP) is difficult to diagnosis. This study aimed to summarize the features of thoracic outlet syndrome (TOS) with the lower trunk compression of brachial plexus observed on high-frequency ultrasonography (HFUS). Methods The ultrasound data of 27 patients who had TOS with the lower trunk compression of brachial plexus were collected and eventually confirmed by surgery. The imaging data were compared, and the pathogenesis of TOS was analyzed on the basis of surgical data. Results TOS occurred predominantly in females (70.4%). Most cases had unilateral involvement (92.6%), mainly on the right side (66.7%). The HFUS features of TOS can be summarized as follows: (1) Lower trunk compression. HFUS revealed focal thinning that reflected compression at the level of the lower trunk; furthermore, the distal part of the nerve was thickened for edema (Affected side: 0.49 ± 0.12 cm vs. Healthy side: 0.38 ± 0.06, P = 0.009), and the cross-sectional area of brachial plexus cords was markedly greater on the injured side than on the healthy side (0.95 ± 0.08 cm² vs. 0.65 ± 0.11 cm², P = 0.004). (2) Hyperechoic fibromuscular bands behind the compressed nerve (mostly the scalenus minimus muscle). (3) Abnormal bony structures: cervical ribs or elongated transverse processes of the 7th cervical vertebra (C7). Surgical results showed that the etiological factors contributing to TOS were (1) muscle hypertrophy and/or fibrosis (100%) and (2) cervical ribs/elongated C7 transverse processes (20.7%). Conclusion TOS with the lower trunk compression of brachial plexus can be diagnosed accurately and reliably by high-frequency ultrasound.

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Section: Discussionmentioning

confidence: 99%

Diagnosis of thoracic outlet syndrome with the lower trunk compression of brachial plexus by high-frequency ultrasonography

Chen,

Gong,

Wang

et al. 2023

BMC Musculoskelet Disord

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“…In another study, Natsis et al (2013) observed the presence of scaleneus minimus muscle in 4.11% cases of cadavers and mentioned it as another predisposing factor for TOS. We also found the presence of scalenus minimus muscle in some of our dissected cadavers.…”

Section: Graphic 1-comparison Of Values Between Male and Female Cadavers On Right Sidementioning

confidence: 96%

Cadaveric Measurement and Analysis of Interscalene Triangle and Costo-Clavicular Spaces in Relation to Thoracic Outlet Syndrome

Chaudhury

Ghosh

2020

Rev Arg de Anat Clin

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Objectives: Thoracic outlet syndrome (TOS) is an upper extremity disorder resulting from compression of brachial plexus structures and subclavian vessels within thoracic outlet region at any of the three primary sites- interscalene triangle, costoclavicular space and retro-pectoralis minor space. This study focused on detailed anatomic exploration and measurement of normal anatomic variability within interscalene triangle and costoclavicular space. Material and Method: We examined 49 cadavers (22 male and 27 female) and dissected both sides to explore and examine 98 dissected areas. We measured the base width, height, angle within interscalene triangle and the vertical distance within costoclavicular space. We also calculated the area of interscalene triangle. Results: The mean values of base width, height, interscalene angulation of interscalene triangle and height of costoclavular space was 10.18±4.31 mm, 45.19±0.07mm, 10.85±0.06 degrees and 10.22±0.07 mm respectively. The mean area of interscalene triangle was 214.82±5.22sqmm. Conclusion: We have found clinically significant differences between the interscalene and costiclavicular space vertical heights; the height of costoclavicular space was clinically significantly lower than the interscalene space (p< 0.001). No clinical significant difference was found between male and female measurements. These ranges of dataset could be useful for planning treatment approaches in TOS.

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“…SMM is relatively rare among the population. Natsis et al, in their cadaveric study, write about 4.11% of its occurrence, while George et al note 3% [52,53]. Over the years, many papers have reported a prevalence between 7.8% and even 71.7% [54,55].…”

Section: Scalenus Minimus Musclementioning

confidence: 99%

Congenital, Acquired, and Trauma-Related Risk Factors for Thoracic Outlet Syndrome—Review of the Literature

Maślanka,

Zielinska,

Karauda

et al. 2023

JCM

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Thoracic outlet syndrome is a group of disorders that affect the upper extremity and neck, resulting in compression of the neurovascular bundle that exits the thoracic outlet. Depending on the type of compressed structure, the arterial, venous, and neurogenic forms of TOS are distinguished. In some populations, e.g., in certain groups of athletes, some sources report incidence rates as high as about 80 cases per 1000 people, while in the general population, it is equal to 2–4 per 1000. Although the pathogenesis of this condition appears relatively simple, there are a very large number of overlapping risk factors that drive such a high incidence in certain risk groups. Undoubtedly, a thorough knowledge of them and their etiology is essential to estimate the risk of TOS or make a quick and accurate diagnosis.

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Scalenus Minimus Muscle: Overestimated or Not? An Anatomical Study

Cited by 13 publications

References 8 publications

Diagnosis of thoracic outlet syndrome with the lower trunk compression of brachial plexus by high-frequency ultrasonography

Diagnosis of thoracic outlet syndrome with the lower trunk compression of brachial plexus by high-frequency ultrasonography

Cadaveric Measurement and Analysis of Interscalene Triangle and Costo-Clavicular Spaces in Relation to Thoracic Outlet Syndrome

Congenital, Acquired, and Trauma-Related Risk Factors for Thoracic Outlet Syndrome—Review of the Literature

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