Unusual origin of the levator scapulae muscle from mastoid process

Levator Scapulae Stiffness Measurement Reliability in Individuals with and without Chronic Neck Pain by Experienced and Novel Examiners

The levator scapulae muscle is a key structure in the etiopathology of neck and shoulder musculoskeletal pain. Although previous studies used shear-wave elastography (SWE) for characterizing this muscle elasticity, limited evidence assessed the inter-examiner reliability of this procedure. This study aimed to analyze the inter-examiner reliability for calculating Young's modulus and shear wave speed in a cohort of participants with and without chronic neck pain. A diagnostic accuracy study was conducted, acquiring a set of SWE images at the C5 level in participants with and without neck pain (n = 34 and 33, respectively) by two examiners (one experienced and one novel). After blinding the participants' identity, examiner involved, and side, the stiffness indicators were calculated by an independent rater in a randomized order. Intra-class correlation coefficients (ICC), standard error of measurement, minimal detectable changes, and coefficient of variation were calculated. Both cohorts had comparable sociodemographic characteristics (p > 0.05). No significant levator scapulae elasticity differences were found between genders, sides, or cohorts (all, p > 0.05). Inter-examiner reliability for calculating Young's modulus and shear wave speed was moderate-to-good for assessing asymptomatic individuals (ICC = 0.714 and 0.779, respectively), while poor-to-moderate in patients with neck pain (ICC = 0.461 and 0.546, respectively). The results obtained in this study support the use of this procedure for assessing asymptomatic individuals. However, reliability estimates were unacceptable to support its use for assessing elasticity in patients with chronic neck pain. Future studies might consider that the shear wave speed is more sensitive to detect real changes in comparison with Young's modulus.

Unusual insertion of the levator scapulae muscle: a case report

The current case report describes an uncommon insertion of the levator scapulae (LS), which broadly attaches to multiple structures, including the serratus posterior superior, ligamentum nuchae, and the 6th and 7th spinous processes of the cervical vertebrae. The most superior portion of this aponeurosis merged with the ligamentum nuchae at the C7 level. The middle and inferior portions of the head were inserted (or fused) into the tendon of the rhomboid minor as well as the fibers of the serratus posterior superior muscle. Consequently, recognizing this anatomical variation, characterized by an additional slip of the LS attaching to the 7th vertebra and other muscular structures, is crucial not only for anatomists but also for surgeons performing procedures on the posterior neck related to cervical or shoulder pain and cervical dystonia.

A Rare Variation of the Levator Scapulae Muscle: A Case Report and Review of Literature

Muscle variations in the posterior neck region are mainly categorized as variations in the origin and insertion of the muscles and the presence of accessory slips or rudimentary muscles. The levator scapulae muscle is a variable muscle with several different types of variations described throughout the literature. Herein, we report a rare unilateral case of an accessory slip from the levator scapulae. Aberrant muscle slip originates from the distal one-third of the levator scapulae. Then, it passes upwards and outwards above a vascular bundle containing a superficial branch of the transverse cervical artery and vein. The deviant muscle slip inserts onto the superior nuchal line. Muscle variations in the neck's posterior region and the levator scapulae's variations, as per se, have the utmost clinical significance since they might be mistaken for tumor mass. Moreover, such variations might be deceptive during surgical procedures in the region. Therefore, detailed knowledge of such complex muscular variations in the posterior region of the neck is paramount for surgeons and radiologists alike.

A Possible Accessory Muscle of the Serratus Posterior Superior Muscle

Anatomical variation is defined as the normal range of possibilities in the topography and morphology of body structures. In contrast, an anomaly is any structural or functional anatomical finding beyond the normal range of possibilities. This case study describes a muscular anomaly found in a 73-year-old preserved Caucasian male. We observed a left-sided anomalous muscle originating from the transverse process of the C1 (Atlas) vertebra and inserting onto the proximal attachment of the serratus posterior superior (SPS) muscle at the C7 level. We suggest that this anomaly is a result of early embryological development and hypothesize that the atypical neck muscle may reinforce the action of the SPS. This finding is rare and no reference of it can be found in the literature. Reporting anatomical anomalies is important for the medical literature and education.

Classification of the superior angle of the scapula and its correlation with the suprascapular notch: a study on 303 scapulas

PURPOSE

The aims of this study had been to classify the superior angle of the scapula based on morphological features, and to investigate its correlation with the suprascapular notch.

METHODS

303 samples of Chinese dried scapular specimens were collected from the Department of anatomy, Southwest Medical University. According to the anatomical morphological characteristics of the superior angle of the scapula, the morphological classification was performed to explore its correlation with the suprascapular notch (SSN).

RESULTS

The superior angle of the scapula was classified into three types (Hilly shape, Mountain Peak shape and Chimney shape). There were 143 cases of Hilly shape (47.20%), 144 cases of Mountain shape (47.52%), and 16 cases of Chimney shape (5.28%). The angle of Hilly shape (93.36° ± 7.76°) was significantly larger than the Mountain Peak shape (86.60° ± 6.61°) and the Chimney shape (86.22° ± 7.20°), and the difference was statistically significant (P < 0.05). The type I-III of Rengachary's classification to SSN was low risk of suprascapular nerve entrapment, while the type IV-VI was high risk of suprascapular nerve entrapment. Compared with the Mountain Peak shape and the Chimney shape, the Hilly shape corresponds to more types I-III of suprascapular notch but to fewer types IV-VI (P < 0.05).

CONCLUSIONS

The superior angle of the scapula was divided into three types: Hilly shape (47.20%), Mountain Peak shape (47.52%) and Chimney shape (5.28%). The Mountain Peak shape might be more likely to result in inability of the levator muscle with acute or chronic overload mechanisms, and the risk of suprascapular nerve entrapment in Mountain peak shape was higher than that of Hilly shape. And, it might have a potential effect on neck pain.

Variant Prevertebral Muscle: Unique Cadaveric Findings

The levator scapulae muscle typically runs from the transverse process of the atlas to the superior angle of the scapula. In this paper, we describe a rare finding identified during a dissection of a male cadaver, wherein a continuation of the right levator scapulae ran past its normal attachment to the C1 transverse process, fusing with the inferior attachment of the rectus capitis lateralis muscle. No variants were found on the opposite side, and the innervation of the levator scapulae muscle variant was typical of that of a normal levator scapulae. We also describe other related variants of the cranial levator scapulae muscle, hypothesize the embryologic origin of our finding, and finally discuss potential clinical relevance of levator scapulae muscle variants.

Anatomic variations of levator scapulae in a normal cohort: an MRI study

PURPOSE

Accessory attachments of the levator scapulae (LS) muscle have been described in the literature in previous cadaveric studies, but there is little knowledge about the incidence and distribution. Knowledge of LS accessory attachments is relevant to clinicians working in the fields of radiology, surgery, neurology, and musculoskeletal medicine. The purpose of this study was to explore the incidence and spectrum of LS caudal accessory attachments in vivo using magnetic resonance (MR) imaging in a young cohort.

METHODS

MR images of the cervical spine were obtained from 37 subjects (13 males and 24 females) aged 18-36 years using an axial T1-weighted spin echo sequence acquired from a 3-Tesla MR scanner. The LS muscle was identified, and the presence of caudal accessory attachments was recorded and described.

RESULTS

LS caudal accessory attachments were identified in 16 subjects (4 right, 6 left, and 6 bilateral; 12 female). Ten had unilateral accessory attachments to the serratus anterior, serratus posterior superior or the first/second rib. Four had bilateral accessory attachments to serratus anterior. One had bilateral accessory attachments to serratus posterior superior and unilateral accessory attachment to serratus anterior. One had bilateral attachments to both muscles.

CONCLUSIONS

Both unilateral and bilateral LS caudal accessory attachments were present in nearly half of the subjects examined. They were relatively more frequent in females than males. The findings indicate that these accessory attachments are common, and in some cases, those accessory attachments can occur bilaterally and to more than one site.