Splenius Cervicis Research Articles

Inferior Trapezius Muscle Agenesis and Scapular Dyskinesis in a 58 Year-Old Black Male Donor: A Cadaveric Case Report

A functionally significant abnormality was observed in a 58 year-old Black male donor with a cause of death of thyroid cancer. He exhibited left inferior trapezius muscle agenesis as well as scapular dyskinesis. The left scapula is shown pressing into the adjacent vertebral bodies of C7 and T1, which resulted in deviations in the location of the left semispinalis capitis, semispinalis cervicis, and splenius cervicis muscles. This resulted in compromise of the left levator scapulae muscle. It is suspected that these abnormalities would have resulted in functional limitations in arm movement, particularly in adduction. A literature review was completed to understand the significance of these abnormalities.

Analysis of abnormal muscle activities in patients with loss of cervical lordosis: a cross-sectional study

BackgroundThis study aimed to detect the differences in cervical muscle activation patterns in people with versus without cervical lordosis and explore the possible mechanism of cervical pain originating therein.MethodsThis cross-sectional design included 39 participants without and 18 with normal cervical lordosis. Muscular activation was measured for 5 s in both groups using surface electromyography. Subsequently, the root mean square (RMS) of muscle amplitude was obtained at the bilateral splenius capitis, upper and lower parts of the splenius cervicis, upper and lower parts of the semispinalis cervicis, sternocleidomastoid, upper trapezius, and rhomboid muscles in five cervical positions: 0° (resting), 30° of flexion, 30° of extension, 60° of extension, and upon a 1-kg load on the head in a resting posture.ResultsThe RMS values of the upper trapezius muscle at all postures and the rhomboid muscles at 60° of extension were significantly lower in the loss of lordosis than control group. Comparing the RMS ratio of each posture to the resting position, the ratio of the upper trapezius at flexion was significantly higher and that of the rhomboids at 60° of extension and upon loading was significantly lower in the loss of lordosis than control group. Moreover, the pattern changes in the RMS values according to posture showed a similar shape in these two muscles, and lower in the loss of lordosis than the normal group.ConclusionsThe loss of normal cervical alignment may correlate with predisposed conditions such as reduced muscle activation of the trapezius and rhomboid muscle, and may also provoke over-firing of the upper trapezius muscle, possibly increasing neck musculoskeletal pain.Trial registration.Clinicaltrials.gov, registration number: NCT03710785.

The Morphological Evaluation of the Cervical Muscle in Patients With Basilar Invagination: A Magnetic Resonance Imaging-Based Study.

To investigate the characteristics of functional muscle and muscle size in patients with basilar invagination (BI) and explore the effects of atlantoaxial dislocation. Eighty BI patients (BI group) and eighty age- and sex-matched asymptomatic people (control group) were included. Axial T2 MRI image was used to measure the cross-sectional area (CSA) and functional CSA (FCSA). The sternocleidomastoid (SCM), longus capitis and longus colli (LCap & LC), trapezius (Trap), splenius capitis (SpCap), splenius cervicis (SpC), semispinalis capitis (SSCap), semispinalis cervicis (SSC), multifidus (MS), levator scapulae (LS) and posterior deep layer muscles (PDLM) were evaluated. Correlations between age, atlantodental interval (ADI), Chamberlain distance and muscles were observed. BI group (39.4±18.4 yr old, 33M/47F) exhibited significantly lower FCSA/CSA ratios than the control group in all extensor and flexor muscles, and presented smaller CSAs on the right and left Trap, SSC, LS, SCM and left LCap & LC. FCSA/CSA ratios were significantly lower in BI patients with dislocation on the right Trap, SpCap, SpC, SSCap, MS, LS, LCap & LC and PDLM, and the left SSCap, MS and LCap & LC than in patients without. Additionally, functional muscles of all parameters decreased with age in BI patients. Excluding children, the Trap, SpC, MS and LS muscle sizes of BI patients tended to increase with age. ADI and Chamberlain distance tended to correlate negatively with FCSA/CSA ratio. The BI patients, especially those with atlantoaxial dislocation, had less functional muscles compared with the control group. Moreover, their functional muscles decreased with age more obviously.

Greater muscle volume and muscle fat infiltrate in the deep cervical spine extensor muscles (multifidus with semispinalis cervicis) in individuals with chronic idiopathic neck pain compared to age and sex-matched asymptomatic controls: a cross-sectional study

Muscle size and composition (muscle volume and muscle fat infiltrate [MFI]) may provide insight into possible mechanisms underpinning chronic idiopathic neck pain, a common condition with no definitive underlying pathology. In individuals with chronic idiopathic neck pain > 3 months and age- and sex-matched asymptomatic controls, muscle volumes of levator scapulae, multifidus including semispinalis cervicis (MFSS), semispinalis capitis, splenius capitis including splenius cervicis (SCSC), sternocleidomastoid and longus colli from C3 through T1 were quantified from magnetic resonance imaging. Between-group differences were determined using linear mixed models, accounting for side (left or right), muscle, spinal level, sex, age, and body mass index (BMI). Individuals with pain had greater muscle volume (mean difference 76.8mm3; 95% CI 26.6–127.0; p = .003) and MFI (2.3%; 0.2–4.5; p = .034) of the MFSS compared to matched controls with no differences in relative volume, accounting for factors associated with the outcomes: muscle, spinal level, side (left had smaller volume, relative volume and MFI than right), sex (females had less volume and relative volume than males), age (older age associated with less relative volume and greater MFI), and BMI (higher BMI associated with greater muscle volume and MFI). Greater MFI in individuals with chronic idiopathic neck pain suggests a possible underlying mechanism contributing to neck pain. Perspective: These findings suggest MFI in the MFSS may be radiologic sign, potentially identifying patients with a less favourable prognosis. Future studies are needed to confirm this finding and determine if MFI is a contributor to the development or persistence of neck pain, or consequence of neck pain.

Association Between the Cervical Extensor Musculature and the Demographic Features, Symptoms, and Sagittal Balance in Patients with Multilevel Cervical Spondylotic Myelopathy

To obtain the quantitative measurements of the muscle morphology of cervical extensors in patients with multilevel cervical spondylotic myelopathy, and determine whether the morphological parameter of each muscle correlates with the patients' demographic features, symptoms, and cervical sagittal balance. We retrospectively evaluated 100 hospitalized patients scheduled to undergo surgery for multilevel cervical spondylotic myelopathy. Demographic data, including age, sex, and body mass index, were recorded, and symptoms were evaluated using the visual analog scale (VAS), neck disability index (NDI), and modified Japanese Orthopedic Association scale scores. The cross-sectional area (CSA) of the multifidus, semispinalis capitis, semispinalis cervicis, splenius capitis and splenius cervicis were measured on magnetic resonance imaging. The CSA of the total extensor muscles, deep extensor muscles (DEM, consisting of multifidus and semispinalis capitis), and superficial extensor muscles (consisting of semispinalis cervicis, splenius capitis and splenius cervicis) were calculated. The adjusted CSA (aCSA) was calculated as the CSA of the muscle/CSA of the corresponding vertebral body. The fat infiltration ratio (FIR) of the posterior extensor muscles was assessed using a pseudocoloring technique. Sagittal parameters, including cervical lordosis (CL), C2-7 cervical sagittal vertical axis (SVA), T1-slope, mismatch between T1-slope and CL (T1S-CL), and range of motion, were measured. The measured parameters were compared between the males and the females, between the patients with higher muscle aCSA and the patients with lower muscle aCSA, and between the patients with and without sagittal balance. A Pearson correlation analysis was conducted to determine the correlations between the paraspinal muscle measurements, and the clinical and radiographic parameters. There were 67 males and 33 females in this study, and the mean age was 59.22±9.54years. Compared with females, male patients showed higher CSA and aCSA of extensor muscles. Patients with lower muscle aCSA were significantly older and had worse NDI scores, with significantly greater C2-7 SVA and T1S-CL. Patients with sagittal imbalance showed significantly lower aCSA of total extensor muscles and DEM, as well as a significantly higher FIR. Age was significantly correlated with the aCSA of each measured muscle and the FIR. The aCSA of the DEM was correlated with the NDI score, the visual analog scale score, the SVA, the T1-slope, and the T1S-CL. In patients with multilevel CSM, age and sex were demographic factors that were highly correlated with muscle morphology changes. Extensor muscles, especially DEM, play important roles in maintaining cervical sagittal balance and are associated with the severity of neck symptoms.

Functional Modularization in the Neck Muscles of the Gerenuk (Litocranius walleri)

The gerenuk (Litocranius walleri) is an African ruminant that feeds on high growing foliage by standing erect on its hindlimbs and extending its long neck. We hypothesize that extensive myological adaptation would be present in the muscles that facilitate head stability and movement, as well as muscles that anchor the neck. The vertebral musculature from the atlas to the thoracic vertebrae of a gerenuk specimen was dissected and compared to that of other ruminants. Several muscles were found to have narrowed or shifted caudally along the vertebral column, resulting in their cranial‐most attachment point being the fifth cervical vertebrae (C5). Similarly, two muscles were found to have shifted cranially, resulting in their caudal‐most attachment point also being C5. Caudally shifted muscles include m. serratus ventralis cervicis, the scalene muscles, m. rhomboideus cervicis, and the cervical part of the trapezius. Cranially shifted muscles include m. splenius cervicis and m. longissimus capitis. These shifts indicate a significant degree of modularization occurring between head movement muscles and neck stability muscles, with C5 being the boundary. Further adaptation that was not part of modularization around C5 was found in the segmental muscles attaching between vertebral processes. Segments of m. intertransversarii and m. multifidi have elongated and undergone specialization at the cranial attachments. The segments of m. spinalis cervicis were found to have a complex configuration that interdigitates with the multifidi. Additionally, m. levator claviculae and m. iliocostalis cervicis were present, neither of which have been previously described in ruminants. Previously published work reported that osteological adaptation in the gerenuk neck is especially pronounced in C1 – C4, which is consistent with our findings of myological modularization occurring with C5 as the boundary.

Changes in deep neck muscle length from the neutral to forward head posture. A cadaveric study using Thiel cadavers.

Forward head posture (FHP) is one of the most common postural deviations. Deep neck muscle imbalance of individuals with FHP is of primary concern in clinical rehabilitation. However, there is scarce quantitative research on changes in deep neck muscle length with the head moving forward. This study aimed to investigate changes in deep neck muscle length with different severity levels of FHP. Six Thiel‐embalmed cadavers (four males and two females) were dissected, and 16 deep neck muscles in each cadaver were modeled by a MicroScribe 3D Digitizer in the neutral head posture, slight FHP, and severe FHP. The craniovertebral angle was used to evaluate the degrees of FHP. Quantitative length change of the deep neck muscles was analyzed using Rhinoceros 3D. In slight FHP significant changes in length occurred in four muscles: two shortened (upper semispinalis capitis, rectus capitis posterior minor) and two lengthened (longus capitis, splenius cervicis). In severe FHP all occipital extensors were significantly shortened (10.6 ± 6.4%), except for obliquus capitis superior, and all cervical extensors were significantly lengthened (4.8 ± 3.4%), while longus capitis (occipital flexor) and the superior oblique part of the longus colli (cervical flexor) were lengthened by 8.8 ± 3.8% and 4.2 ± 3.1%, respectively. No significant length change was observed for the axial rotator. This study presents an alternate anatomical insight into the clinical rehabilitation of FHP. Six muscles appear to be important in restoring optimal head posture, with improvements in FHP being related to interventions associated with the occipital and cervical extensors.

Electromyographic Responses of Neck, Back, and Limb Outlet Muscles Associated With High-Velocity, Low-Amplitude Manual Cervical and Upper Thoracic Spinal Manipulation of Individuals With Mild Neck Disability: A Descriptive Observational Investigation

ObjectivesThe purpose of this study was to investigate the extent of electromyographic responses associated with manual high-velocity, low-amplitude (HVLA) spinal manipulation systematically applied to the upper and lower cervical and upper thoracic spines in a cohort with mild neck disability. MethodsThe study was a descriptive observational investigation, with all participants receiving the same interventions. Nineteen participants with mild neck disability received 6 manual HVLA manipulations to the cervical and upper thoracic spine. Bipolar surface electromyography electrode pairs were used to measure responses of 16 neck, back, and limb outlet muscles bilaterally. The number of electromyographic responses was then calculated. ResultsElectromyographic responses associated with cervical and thoracic manipulation occurred in a median of 4 of the 16 (range: 1-14) recorded muscles. Cervical spinal manipulation was associated with the highest rates of electromyographic responses in neck muscles, whereas responses in back muscles were highest after upper thoracic manipulation. ConclusionCervical spinal manipulation was associated with the highest rate of electromyographic responses in muscles of the cervical spine (sternocleidomastoid and splenius cervicis), whereas responses in back muscles (upper and middle trapezius, latissimus dorsi, and longissimus thoracis) were highest after upper thoracic manipulations. This result suggests that electromyographic muscular responses associated with spinal manipulation primarily occur locally (close to the target segment) rather than distally.

Anatomo-sonographic identification of the longissimus capitis and splenius cervicis muscles: principles for possible application to ultrasound-guided botulinum toxin injections in cervical dystonia

ObjectiveThe main objective of this study was to define and verify anatomo-sonographic landmarks for ultrasound-guided injection of botulinum toxin into the longissimus capitis (LC) and splenius cervicis (SC) muscles.Methods and resultsAfter a preliminary work of anatomical description of the LC and SC muscles, we identified these muscles on two cadavers and then on a healthy volunteer using ultrasound and magnetic resonance imaging (MRI) to establish a radio-anatomical correlation. We defined an anatomo-sonographic landmark for the injection of each of these muscles. The correct positioning of vascular glue into the LC muscle and a metal clip into the SC muscle of a fresh cadaver as verified by dissection confirmed the utility of the selected landmarks.DiscussionFor the LC muscle, the intramuscular tendon of the cranial part of the muscle appears to be a reliable anatomical landmark. The ultrasound-guided injection can be performed within the cranial portion of the muscle, between the intra-muscular tendon and insertion into the mastoid process at dens of the axis level. For the SC muscle, the surface topographic landmarks of the spinous processes of the C4–C5 vertebrae and the muscle body of the levator scapulae muscle seem to be reliable landmarks. From these, the ultrasound-guided injection can be carried out laterally by transfixing the body of the levator scapulae.ConclusionThe study defined two cervical anatomo-sonographic landmarks for injecting the LC and SC muscles.

Intramuscular innervation patterns of the splenius capitis and splenius cervicis and their clinical implications for botulinum toxin injections.

The purpose of this study was to clearly characterize the intramuscular nerve distributions of the splenius capitis and splenius cervicis muscles that are both responsible for the onset of a chronic tension type headache and to use this information to identify the effective botulinum toxin (BoNT) injection sites. Ten splenius capitis and splenius cervicis specimens were subjected to Sihler's staining to reveal intramuscular nerve arborization patterns and determined the optimal location for BoNT injection. Nerve distribution patterns in the splenius capitis were identified as nerve pathways that travel down toward the origin point and others that travel up toward the insertion point. This neuromuscular innervation from the central (50%) point was distributed evenly in these two directions. The neural pathways of splenius cervicis traveled vertically from the insertion point to the origin point. If the length from the muscle origin point to the insertion point is normalized to 100%, motor neurons innervate the muscle from around the 30% to the 70% point. The safest and most-effective BoNT injection sites for the splenius capitis and splenius cervicis were found at around the 50% point and the 30% to the 70% point, respectively.

Classifying neck pain status using scalar and functional biomechanical variables – development of a method using functional data boosting

BackgroundIndividuals with neck pain have different movement and muscular activation (collectively termed as biomechanical variables) patterns compared to healthy individuals. Incorporating biomechanical variables as covariates into prognostic models is challenging due to the high dimensionality of the data. Research questionWhat is the classification performance of neck pain status of a statistical model which uses both scalar and functional biomechanical covariates? MethodsMotion capture with electromyography assessment on the sternocleidomastoid, splenius cervicis, erector spinae, was performed on 21 healthy and 26 individuals with neck pain during walking over three gait conditions (rectilinear, curvilinear clockwise (CW) and counterclockwise (CCW)). After removing highly collinear variables, 94 covariates across the three conditions were used to classify neck pain status using functional data boosting (FDboost). ResultsTwo functional covariates trunk lateral flexion angle during CCW gait, and trunk flexion angle during CW gait; and a scalar covariate, hip jerk index during CCW gait were selected. The model achieved an estimated AUC of 80.8 %. For hip jerk index, an increase in hip jerk index by one unit increased the log odds of being in the neck pain group by 0.37. A 1° increase in trunk lateral flexion angle throughout gait alone reduced the probability of being in the neck pain group from 0.5 to 0.15. A 1° increase in trunk flexion angle throughout gait alone increased the probability of being in the neck pain group from 0.5 to 0.9. SignificanceInterpreting the physiological significance of the extracted covariates, with other biomechanical variables, suggests that individuals with neck pain performed curvilinear walking using a stiffer strategy, compared to controls; and this increased the risk of being in the neck pain group. FDboost can produce clinically interpretable models with complex high dimensional data and could be used in future prognostic modelling studies in neck pain research.

Morphologic Characteristics of the Deep Cervical Paraspinal Muscles in Patients with Single-Level Cervical Spondylotic Myelopathy

This study aimed to compare morphologic changes of deep paraspinal muscles at C4-7 in patients with C5-6 single-level cervical spondylotic myelopathy (CSM), and to evaluate the relationship between morphologic changes and the level of spinal cord compression. The study included 15 patients with C5-6 single-level CSM and 15 age- and sex-matched healthy subjects. Cross-sectional area (CSA) and functional CSA of the bilateral longus capitis (LCap), longus colli (LC), multifidus (MF), semispinalis cervicis (SSC), semispinalis capitis, splenius capitis, and splenius cervicis were measured on preoperative magnetic resonance images at C4-7, and calculated as ratios with respect to the corresponding vertebral body CSA. The mean maximum spinal cord compression was 22.30% in the CSM group. At the cranial level (C4-5), the CSM group had more fat infiltration in the MF and SSC (P < 0.05). At the spinal cord compression segment and caudal adjacent segment (C5-6 and C6-7), the degree of fat infiltration of all paravertebral muscles was aggravated, accompanied by atrophy of LCap, LC, and MF (P < 0.05). Compared between different levels, fat infiltration in the MF at C5-6 was greater than adjacent levels. In patients with C5-6 single-level CSM, fat infiltration and atrophy of deep paraspinal muscles, especially the Lcap, LC, and MF, mainly occurred in the level of spinal cord compression and caudal adjacent level. In the cranial adjacent segment, the degree of MF and SSC fat infiltration in patients with CSM was also aggravated. This may suggest that multiple mechanisms are involved in paraspinal muscles degeneration in CSM.

Reliability of cervical muscle volume quantification using magnetic resonance imaging

BackgroundMagnetic resonance imaging (MRI) is used to quantify the size and structure of the architecturally complex cervical spine musculature of individuals with traumatic and idiopathic neck pain. However, to our knowledge, no scan-rescan reliability data is available on neck muscle volumes. ObjectivesThis study investigates the intra- and inter-rater reliability and scan-rescan reliability in cervical muscle volume investigations. DesignClinical Measurement, Reliability study. MethodsMRI scans were performed and repeated (within 1 h) for five asymptomatic individuals. Two raters manually traced levator scapulae, multifidus including semispinalis cervicis, semispinalis capitis, splenius capitis including splenius cervicis, and sternocleidomastoid using Analyze software (v12.0). Reliability was determined using intra-class correlation coefficients, Lin's concordance coefficient and Bland-Altman plots, with interpretation of reliability coefficients using the criteria from Fleiss. ResultsIntra-rater reliability of muscle quantification was excellent (ICCs ranging from 0.78 to 0.96). Inter-rater reliability was excellent for sternocleidomastoid(ICC 0.92, 95% CI 0.80, 0.97) and splenius capitis (ICC 0.77, 0.51, 0.90), and ranged from fair to good for levator scapulae (0.63, 0.18, 0.85), multifidus (0.73, 0.44, 0.88), and semispinalis capitis (0.50, 0.08, 0.77). The scan-rescan reliability was excellent for all muscles (ICCs ranging from 0.94 to 0.98). ConclusionThreats to reliability appear to be more related to manual quantification of muscles on images rather than protocols related to re-positioning a participant in the scanner and repeating the same protocol.The current findings suggest that the proposed methods can be used in establishing normative data for cervical muscle volume and comparing individuals with and without neck pain.

Cervical muscle volume in individuals with idiopathic neck pain compared to asymptomatic controls: A cross-sectional magnetic resonance imaging study

BackgroundNeck muscle compositional changes may represent potential biomarkers contributing towards chronic neck-related pain and disability. ObjectivesTo determine differences in muscle volume in the cervical muscles of individuals with chronic idiopathic neck pain compared with age- and sex-matched asymptomatic individuals, and to determine if these muscle variables relate to spinal level, side (left or right), age, sex, body mass index (BMI) or muscle strength. Study designCross-sectional magnetic resonance imaging (MRI) study. MethodsMuscle volume of five muscle (groups) from cervical levels C3-T1 in 20 pain and 17 asymptomatic participants were quantified using MRI: levator scapulae, multifidus including semispinalis cervicis, semispinalis, splenius capitus including splenius cervicis, and sternocleidomastoid. Isometric extensor and flexor muscle strength were assessed with a dynamometer. Linear mixed modelling determined differences between groups in muscle volume accounting for participant characteristics. ResultsIndividuals with pain had greater muscle volume (adjusted mean difference 71.2 mm3 (95% CI 14.2–128.2, p = .015) of the sternocleidomastoid, accounting for spinal level, side, muscle group (extensors vs flexor), sex, age, body mass index and strength. Modelling indicated muscle volume differed between spinal levels (p < .001); greater extensor muscle strength was associated with greater volume (p = .011); female sex (p < .001) and older age (p = .012) were associated with less volume. ConclusionBetween-group differences in cervical flexor muscle volume, and volume differences across spinal levels and muscles suggest the contribution of cervical muscles to chronic idiopathic neck pain is multifaceted and complex.

Experimental and Numerical Study of Cervical Muscle Contraction in Frontal Impact

In a crash situation, drivers typically make evasive maneuvers before an upcoming impact, which can affect the kinematics and injury during impact. The purpose of the current study was to investigate the response and effect of drivers’ cervical muscles in a frontal impact. A crash scenario was developed using a vehicle driving simulator, and 10 volunteers were employed to drive the simulator at 20 km/h, 50 km/h, 80 km/h and 100 km/h. Electromyography (EMG) was recorded from the sternocleidomastoideus (SCM), splenius cervicis (SPL) and trapezium (TRP) muscles using a data acquisition system, and the level of muscle activation was calculated. A numerical study was conducted using data collected in the experiment. The results revealed that the cervical muscles were activated during drivers’ protective action. EMG activity of cervical muscles before impact was greater than that during normal driving. EMG activity increased with driving speed, with the SCM and TRP exhibiting larger increases than the SPL. The kinematics and load of the driver were influenced by muscle activation. Before the collision, the head of an active model stretched backward, while the passive model kept the head upright. In low-speed impact, the torque and shear of the cervical muscle in the active model were much lower than those in the passive model, while the tension of the cervical muscle was higher in the active model compared with the passive model. The results indicated that the incidence of cervical injury in high-speed impact is complex.

Precise application of Traditional Chinese Medicine in minimally-invasive techniques

Precise application of Traditional Chinese Medicine in minimally-invasive techniques

The subatlantic triangle: gateway to early localization of the atlantoaxial vertebral artery.

OBJECTIVE Exposure of the vertebral artery (VA) between C-1 and C-2 vertebrae (atlantoaxial VA) may be necessary in a variety of pathologies of the craniovertebral junction. Current methods to expose this segment of the VA entail sharp dissection of muscles close to the internal jugular vein and the spinal accessory nerve. The present study assesses the technique of exposing the atlantoaxial VA through a newly defined muscular triangle at the craniovertebral junction. METHODS Five cadaveric heads were prepared for surgical simulation in prone position, turned 30°-45° toward the side of exposure. The atlantoaxial VA was exposed through the subatlantic triangle after reflecting the sternocleidomastoid and splenius capitis muscles inferiorly. The subatlantic triangle was formed by 3 groups of muscles: 1) the levator scapulae and splenius cervicis muscles inferiorly and laterally, 2) the longissimus capitis muscle inferiorly and medially, and 3) the inferior oblique capitis superiorly. The lengths of the VA exposed through the triangle before and after unroofing the C-2 transverse foramen were measured. RESULTS The subatlantic triangle consistently provided access to the whole length of atlantoaxial VA. The average length of the VA exposed via the subatlantic triangle was 19.5 mm. This average increased to 31.5 mm after the VA was released at the C-2 transverse foramen. CONCLUSIONS The subatlantic triangle provides a simple and straightforward pathway to expose the atlantoaxial VA. The proposed method may be useful during posterior approaches to the craniovertebral junction should early exposure and control of the atlantoaxial VA become necessary.

Changes in neck and upper trunk muscle activities according to the angle of movement of the neck in subjects with forward head posture.

[Purpose] This study investigated changes in neck and upper trunk muscle activities according to the angle of movement of the neck in subjects with Forward Head Posture. [Subjects and Methods] Twenty subjects with forward head postures were recruited. The activities of the sternocleidomastoid muscle, splenius capitis and splenius cervicis muscles, upper trapezius muscle, and middle trapezius muscle during flexion and extension were assessed. [Results] The activity of the sternocleidomastoid muscle showed significant differences between the 30° flexed position and the full range of motion position, and between the neutral position and the full ROM position. The activity of the middle trapezius muscle showed a significant reduction in the 30° extended position and the full ROM position as compared to the neutral position. [Conclusion] In the full flexed position, sternocleidomastoid muscle activity increased significantly, and during extension position, the middle trapezius muscle reduced its activities.

Trunk Posture Influences Neck Angle When Reading A Tablet Computer

In 2013, 64% of American households owned a handheld computer device (e-reader, tablet, smartphones, etc.). The presence of these devices has grown more quickly than our understanding of their effects on musculoskeletal disorders. Their use on a tabletop or a person’s lap causes increased head and neck flexion, as well as an inreased gravitational moment produced by the weight of the head (Straker et al., 2009, Young et al., 2012, Vasavada et al., 2015). A limitation to these studies is that they keep a standard trunk position throughout all tasks; however, people can also assume a semi-reclined position when reading a tablet. The purpose of this study was to determine the influence of a semi-reclined trunk position on neck and head flexion angle, and cervical erector spinae muscle activity. Nineteen participants (10 male, 9 female) read off of a tablet in four postures: with the tablet in their lap, on a tabletop, off of a standard computer monitor, and semi-reclined to an angle of 30 degrees from the vertical. Having the tablet on the lap ( M=16%MVC, SD=8%MVC) significantly increased muscle activity of the cervical erector spinae ( p=.0023) compared to reading off of a monitor or in the semi-reclined position (approximately 10%MVC). Neck and head flexion angles significantly increased ( p&lt;.001) when reading the tablet off the lap (neck M=56.8o, SD=17.3o; head M=53.4o, SD=12.9o) versus the computer (neck M=6.4o, SD=6.4o; head M=8.2o, SD=7.4o), however, the head angle during semi-reclined reading stayed more vertical despite having the highest increase in neck flexion angle (neck M=71.6o, SD=14.0o; head M=19.7o, SD=9.2o). In the semi-reclined position, the gravitational moment of the head is second smallest for the four reading positions. In theory, this is desired as the moment that must be produced by the musculature and surround tissues would be less. The downside to this posture is that many of the neck extensor muscles may still not be in optimal force and moment production position. Many of the neck muscles that assist with extension originate from C5 to T5 and insert on C5 and above (Vasavada et al., 1998). At 30 degrees of neck flexion, the moment generating capability of the spenius and semispinalis muscles are decreased compared to when at a neutral position and fascicle length of splenius cervicis, capitis, and semispinalis capitis muscles experience changes of more than 70% of optimal length (Vasavada et al., 1998). While many of the extensor muscles only show moment arms that vary by 1 cm or less, for some there can be about a 2-3 cm changes as one goes from a flexed to extended neck posture (Vasavada et al., 1998). These combined changes mean that the force producing capabilities of the neck extensor muscles may be compromised a semi-reclined position. Future studies should report torso angle to properly analyze biomechanical risk factors during handheld computer use and compare results between studies.

Prevalence of Myofascial Pain Syndrome in Chronic Non-Specific Neck Pain: A Population-Based Cross-Sectional Descriptive Study.

Chronic non-specific neck pain is a frequent complaint. It is a recognized medical and socioeconomic problem and a frequent cause of job absenteeism. In recent years, case reports about myofascial pain syndrome (MPS) are emerging among patients suffering from pain. MPS is a regional pain syndrome characterized by myofascial trigger points (MTrP) in palpable taut bands of skeletal muscle that refer pain to a distance, and that can cause distant motor and autonomic effects. To assess the prevalence of active and latent MTrPs in subjects suffering from chronic non-specific neck pain. A population-based cross-sectional descriptive study was carried out from January 2012 to December 2014. Three primary healthcare centers in Alcalá de Henares, Madrid (Spain). Two hundred and twenty-four participants diagnosed by their family doctor with chronic non-specific neck pain. Participants were examined by a physical therapist to determine the presence of MPS. Pain descriptions from the subjects and pain body diagrams guided the physical examination. The subjects were not given any information concerning MPS or other muscle pain syndromes. All participants presented with MPS. MTrPs of the trapezius muscles were the most prevalent, in 93.75% of the participants. The most prevalent active MTrPs were located right (82.1%) and left (79%) in the nearly-horizontal fibers of the upper trapezius muscle. Furthermore, active MTrPs in the levator scapulae, multifidi, and splenius cervicis muscles reached a prevalence of 82.14%, 77.68%, and 62.5%, respectively. MPS is a common source of pain in subjects presenting chronic non-specific neck pain.