Cervical coupling during lateral head translations creates an S-configuration

OBJECTIVE: To determine cervical coupling during the posture of lateral head translation relative to a fixed thoracic cage. DESIGN: Digitized measurements from anteroposterior cervical radiographs of 20 volunteers were obtained in neutral, left, and right lateral translation posture of the head compared to a fixed thorax. BACKGROUND DATA: Clinically, lateral translation of the head is a common posture. Ranges of motion and spinal coupling have not been reported for this movement. METHODS: Vertebral body corners, mid-lateral articular pillars and the superior spinous-lamina junction of C3-T4 were digitized on 60 radiographs. Using the orthogonal axis of positive x-direction to the left, vertical as positive y and anterior as positive z, digitized points were used to measure projected segmental z-axis rotation, y-axis rotation, and segmental lateral translations of each vertebra. RESULTS: Subjects translated their heads laterally a mean of 51 mm. The major coupled motion was lateral bending (z-axis rotation), which changed direction at the C4-C5 disc space creating an S-shape. Upper cervical (C3-C4) lateral bending was contralateral to the main motion of head translation direction. Lower cervical and upper thoracic lateral bending were ipsilateral. Other segmental motions averaged less than 1 mm and 1 degrees. CONCLUSIONS: Lateral head translations (x-axis) compared to a fixed thoracic cage can be large with a mean of 51 mm to one side. The major spinal coupling was lateral bending which changed direction at C4-C5 resulting in an S-configuration. This might have application in side impacts. All other segmental movements were small, less than 1 mm and 1 degrees. RELEVANCE: The clinically common posture of lateral head translation results in an S-shaped cervical spine and may occur in side impact trauma. This posture has not been studied for cervical coupling patterns or range of motion (ROM).     

Normal global motion of the cervical spine: an electrogoniometric study.

OBJECTIVE: Establishment of a normal database and clinical reference of active global cervical spine motion ranges and patterns using a commercial electrogoniometer. DESIGN: Three-dimensional cervical motion ranges and patterns were analyzed in 250 asymptomatic volunteers. BACKGROUND: In vivo out-of-plane motion patterns of the cervical spine have not yet been reported in large populations, but could be of clinical interest. METHODS: In 250 subjects (aged 14-70 yr), motion range and patterns between the first thoracic vertebra and the head were analyzed for flexion-extension, lateral bending, rotation in neutral sagittal plane position and in full flexion using the CA 6000 Spine Motion Analyzer. RESULTS AND CONCLUSIONS: Average motion range in the sagittal plane was 122 degrees (SD: 18 degrees ). Flexion was slightly more important than extension. Out-of-plane components were negligible. Global bending range averaged 88 degrees (SD: 16 degrees ), left and right bending being comparable. Homolateral rotation was associated to lateral bending. Its extent was approximately 40% of the bending range. Global rotation range in neutral sagittal plane position was 144 degrees (SD: 20 degrees ), without significant difference between right and left rotations. Associated motion components were small. During rotation in flexed head position, global range (134 degrees, SD: 24 degrees ) was comparable to the one in neutral flexion. But heterolateral bending, averaging 60% of the primary motion, was associated to flexed rotation. Significant reduction of all primary (but not conjunct) motions with age were obtained. Sex had no influence on cervical motion range. RELEVANCE: Our results agreed with previous observations, validating the methodology used. They thus constitute reference data of cervical out-of-plane motion for clinical applications.     

Three-dimensional analysis of active head and cervical spine range of motion: effect of age in healthy male subjects

OBJECTIVE: To assess the effect of age on active head-cervical range of motion in healthy men. DESIGN: Three-dimensional cervical motion ranges and patterns were measured in 70 men. BACKGROUND: The effect of age on cervical range of motion is still discussed. METHOD: Twenty adolescent (mean age 16 year), 30 young adult (mean age 23 year), and 20 mid-aged (mean age 37 year) men performed maximal head and cervical spine flexion-extension, lateral bending, and axial rotation. Movements were detected using a digital optoelectronic instrument. Maximum head-cervical spine and thoracic motions were separated. RESULTS: Flexion and extension were larger in the adolescents and young adults (130-132 degrees ) than in the mid-aged men (117 degrees ). Thoracic movement increased as a function of age. Lateral bending was symmetric, associated with head-cervical rotation and extension, and larger in adolescents (85 degrees ) than in young (77 degrees ) and mid-aged adults (79 degrees ). Axial rotation was symmetric, associated with flexion-extension and lateral bending, and similar in the three age groups (respectively, 160 degrees, 155 degrees, 153 degrees ). CONCLUSIONS: Active head-cervical range of motion reduced between 15 and 45 years of age in men.Relevance The present data can be used as a reference for cervical range in motion in men between 15 and 45 years.     

The flexion-rotation test and active cervical mobility--a comparative measurement study in cervicogenic headache

A single blind, age and gender matched, comparative measurement study was designed to assess active range of cervical motion and passive range of rotation in cervical flexion in asymptomatic and cervicogenic headache subjects. Both procedures are commonly used in clinical practice to evaluate patients with cervicogenic headache. We studied 20 women and eight men with side dominant cervicogenic headache (mean age 43.3 years) matched with 28 asymptomatic subjects. Two experienced manipulative therapists, who were blind to each other's measurement, noted active ranges of cervical motion and passive cervical rotation performed in the flexion-rotation test using the Cervical Range of Motion Device. Headache severity was assessed by a questionnaire. Additionally, one therapist prior to neck motion assessment determined the dominant symptomatic cervical motion segment. Active cervical motion in each direction was identical between the cervicogenic and control groups. In contrast, average rotation in flexion was 44 degrees to each side in the asymptomatic group and 28 degrees towards the headache side in the symptomatic group. C1-2 was deemed to be the dominant segmental level of headache origin in 24 of 28 subjects. In those 24 subjects range of rotation during the flexion-rotation test was inversely correlated to headache severity.     

The Immediate Effects of Upper Thoracic Translatoric Spinal Manipulation on Cervical Pain and Range of Motion: A Randomized Clinical Trial

This study examined the effect of translatoric spinal manipulation (TSM) on cervical pain and cervical active motion restriction when applied to upper thoracic (T1-T4) segments. Active cervical rotation range of motion was measured re- and post-intervention with a cervical inclinometer (CROM), and cervical pain status was monitored before and after manipulation with a Faces Pain Scale. Study participants included a sample of convenience that included 32 patients referred to physical therapy with complaints of pain in the mid-cervical region and restricted active cervical rotation. Twenty-two patients were randomly assigned to the experimental group and ten were assigned to the control group. Pre- and post-intervention cervical range of motion and pain scale measurements were taken by a physical therapist assistant who was blinded to group assignment. The experimental group received TSM to hypomobile upper thoracic segments. The control group received no intervention. Paired t-tests were used to analyze within-group changes in cervical rotation and pain, and a 2-way repeated-measure ANOVA was used to analyze between-group differences in cervical rotation and pain. Significance was accepted at p = 0.05. Significant changes that exceeded the MDC₉₅ were detected for cervical rotation both within group and between groups with the TSM group demonstrating increased mean (SD) in right rotation of 8.23° (7.41°) and left rotation of 7.09° (5.83°). Pain levels perceived during post-intervention cervical rotation showed significant improvement during right rotation for patients experiencing pain during bilateral rotation only (p=.05). This study supports the hypothesis that spinal manipulation applied to the upper thoracic spine (T1-T4 motion segments) significantly increases cervical rotation ROM and may reduce cervical pain at end range rotation for patients experiencing pain during bilateral cervical rotation.     

Active range of motion in the cervical spine increases after spinal manipulation (toggle recoil)

BACKGROUND: It has generally been assumed that spinal manipulation has the biomechanical effect of increasing spinal range of motion. Past research has shown that there are likely no lasting changes to passive range of motion, and it is unclear whether there is an increase in active range of motion after manipulation. OBJECTIVE: To study changes in active cervical range of motion after spinal manipulation of the cervical spine. DESIGN: A double-blind randomized controlled trial at the outpatient clinic Phillip Chiropractic Research Centre, RMIT University, Melbourne, Australia. METHODS: One hundred five patients with cervicogenic headache were randomized into 2 groups. After a baseline observation period, Group 2 received manipulation (toggle recoil) to the cervical spine, whereas Group 1 received sham manipulation. In the next trial phase, Group 1 received manipulation, whereas Group 2 received no treatment. This was followed by the final trial phase, in which Group 2 received sham manipulation and Group 1 received no treatment. After each trial phase, active range of cervical motion was measured with a strap-on head goniometer by 2 blinded examiners. RESULTS: After receiving spinal manipulation, active range of motion in the cervical spine increased significantly (P < .0006) in Group 2 compared with Group 1, and this difference between the treatment groups disappeared after the third trial phase in which Group 1 also received manipulation, as expected. CONCLUSION: Spinal manipulation of the cervical spine increases active range of motion.     

Assessment of the cervical range of motion over time, differences between results of the Flock of Birds and the EDI-320: a comparison between an electromagnetic tracking system and an electronic inclinometer

The objective of this study was to analyse cervical range of motion, assessed over time by means of a digital inclinometer (EDI-320) and a three-dimensional electromagnetic tracking device (Flock of Birds). The maximum active cervical range of motion was assessed with two measurement devices in three sessions over time, with 6-week intervals. In total, 26 women and 24 men (mean age: 44.4, SD: 9.9) without known pathology of the cervical spine participated. Four movements were measured axial rotation with the cervical spine in a flexed and in an extended position, flexion-extension, and lateral bending. The results showed that the factor time was significant for rotation in extension and rotation in flexion. The factor device was significant for all movements measured, and the interaction term between time and device was significant for all movements except rotation in extension. The Flock of Birds measured significantly higher ranges of motion on all motions except for lateral bending. A substantial variation in cervical range of motion was observed over time (ranging from -5.6 to 8.1) as well as between devices (ranging from -13.1 to 29.9). Substantial and significant differences in cervical range of motion were found over time as well as differences between the Flock of Birds and the EDI-320.     

Global and regional kinematics of the cervical spine during upper cervical spine manipulation: A reliability analysis of 3D motion data

Studies reporting spine kinematics during cervical manipulation are usually related to continuous global head–trunk motion or discrete angular displacements for pre-positioning. To date, segmental data analyzing continuous kinematics of cervical manipulation is lacking. The objective of this study was to investigate upper cervical spine (UCS) manipulation in vitro. This paper reports an inter- and intra-rater reliability analysis of kinematics during high velocity low amplitude manipulation of the UCS. Integration of kinematics into specific-subject 3D models has been processed as well for providing anatomical motion representation during thrust manipulation.Three unembalmed specimens were included in the study. Restricted dissection was realized to attach technical clusters to each bone of interest (skull, C₁–C₄ and sternum). During manipulation, bone motion data was computed using an optoelectronic system. The reliability of manipulation kinematics was assessed for three experimented practitioners performing two trials of 3 repetitions on two separate days.During UCS manipulation, average global head–trunk motion ROM (±SD) were 14 ± 5°, 35 ± 7° and 14 ± 8° for lateral bending, axial rotation and flexion-extension, respectively. For regional ROM (C₀–C₂), amplitudes were 10 ± 5°, 30 ± 5° and 16 ± 4° for the same respective motions. Concerning the reliability, mean RMS ranged from 1° to 4° and from 3° to 6° for intra- and inter-rater comparisons, respectively.The present results confirm the limited angular displacement during manipulation either for global head–trunk or for UCS motion components, especially for axial rotation. Additionally, kinematics variability was low confirming intra- and inter-practitioners consistency of UCS manipulation achievement.     

Spinal manipulation causes variable spine kinematic and trunk muscle electromyographic responses

STUDY DESIGN: Analytic cohort with a convenience sample in a research clinic. OBJECTIVES: To determine the influence of a spinal manipulation on trunk kinematics and associated trunk myoelectric activity. SUMMARY OF BACKGROUND: While the mechanism of spinal manipulation is unknown, it has been theorized to influence spinal range of motion and trunk muscle activity. METHODS: Trunk kinematics were measured in low back pain patients (n = 14) during simple range of motion tasks in three planes, while trunk muscle electromyogram signals were recorded bilaterally from paraspinal and abdominal musculature. Kinematics and electromyogram signals were assessed pre-post manipulation. Electromyogram activity was also assessed pre-post manipulation during quiet stance. RESULTS: While no consistent kinematic or electromyographic changes occurred following manipulation across the population, individual changes were observed. The largest changes (> 6 degrees ) in range of motion occurred in the sagittal plane of three patients experiencing the greatest amount of pain. During quiet stance 17 muscles across all subjects exhibited changes in muscle activity following manipulation. Sixteen of those changes were decreases in muscle amplitude. CONCLUSIONS: This study offers some preliminary data on the short-term effects of manipulation on lumbar range of motion and dynamic electromyogram. The findings suggest that the response to manipulation is variable and dependent on the individual, with no change in some to the largest changes seen in the more pained patients. Relevance. Basic science investigations into the mechanisms and biomechanical influences of spinal manipulation are few. This study attempts to address issues of measureable functional change with manipulative therapy.     

Biomechanics of the Thorax: A Clinical Mode of in Vivo Function

Abstract

A clinical model of the in vivo biomechanics within the thorax is proposed. The relative motion of the thoracic vertebrae and the associated ribs both as moving bones (osteokinematics) and moving joints (arthrokinematics) is considered during sagittal, coronal and transverse motion of the trunk. Flexion and extension of the thorax induces anterior/posterior translation together with slight vertical translation of the vertebral elements. Simultaneously the ribs anteriorly/posteriorly rotate at the costotransverse joints. Sideflexion and rotation can occur both to the same side and to the opposite side in the midthorax and the lower thorax. The first pattern of motion occurs during axial rotation of the trunk while the latter occurs during lateral bending. The ribs rotate anteriorly on one side and posteriorly on the other during both lateral bending and axial rotation of the trunk. A clinical hypothesis of the mechanism which produces these coupling movement patterns is discussed.     

Effects of acupuncture, cervical manipulation and NSAID therapy on dizziness and impaired head repositioning of suspected cervical origin: a pilot study

In a single-subject experiment undertaken on 14 consecutive patients, the effects of acupuncture, cervical manipulation, no therapy, and NSAID-percutan application on kinesthetic sensibility, dizziness/vertigo and pain were studied in patients with dizziness/vertigo of suspected cervical origin. The ability to perceive position of the head with respect to the trunk was studied. The effects of different forms of therapy-and none-on dizziness and neck pain were compared, using a 100 mm visual analogue scale (VAS). Active head relocation by subjects with dizziness was significantly less precise than in the control group. Manipulation was the only treatment to diminish the duration of dizziness/vertigo complaints during the past 7 days and increased the cervical range of motion. Both acupuncture and manipulation reduced dizziness/vertigo on the VAS scale and had positive effects on active head repositioning. Ketoprofen percutan application and acupuncture both alleviated pain. The results of this study would suggest that spinal manipulation may impact most efficiently on the complex process of proprioception and dizziness of cervical origin.     

Lumbar motion trends and correlation with low back pain. Part II. A roentgenological evaluation of quantitative segmental motion in lateral bending.

OBJECTIVE: A radiographic study was undertaken to describe the relationship between the magnitude of coupled lumbar motion in lateral bending and the presence of low back pain: correlation between pain and motion, relationship between motion category and motion and symmetry of lumbar motion. DESIGN: Survey. SETTING: Chiropractic college student health center and private chiropractic clinic. PARTICIPANTS: 249 subjects: 114 with low back pain, 29 asymptomatic with no history and 106 asymptomatic with history. Of these, 194 were freshman volunteers and 55 were new private clinic low back pain patients. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Net lumbar segmental tilt and rotation in lateral bending: corrected and uncorrected for segmental malposition with the patient standing in the upright neutral position. RESULTS: Statistical analysis demonstrated no significant relationship between coupled lumbar motion and low back pain (p greater than .01). The presence of type II motion could account for, on average, less than 5% loss of segmental tilt in the lumbar spine. Asymmetries between left and right side motion averaged 45 to 100% of unilateral range of motion. CONCLUSIONS: This study suggests that back pain is not an indication for the routine use of lateral bending films for the identification of alterations in the magnitude of lumbar segmental motion in lateral bending. It further indicates that type II motion cannot be ruled out as a normal variant. The paucity of symmetrical lumbar motion suggests that segmental tilt or coupled rotation asymmetry, in and of itself, should not be considered an indication for spinal manipulation.     

Quantifying strain in the vertebral artery with simultaneous motion analysis of the head and neck: A preliminary investigation

BackgroundSpontaneous vertebral artery dissection has significant mortality and morbidity among young adults. Unfortunately, causal mechanisms remain unclear.The purpose of this study was to quantify mechanical strain in the vertebral artery while simultaneously capturing motion analysis data during passive movements of the head and neck relative to the trunk during spinal manipulation and cardinal planes of motion.MethodsEight piezoelectric crystals (four per vertebral artery) were sutured into the lumen of the left and right vertebral arteries of 3 cadaveric specimens. Strain was then calculated as changes in length between neighboring crystals from a neutral head/neck reference position using ultrasound pulses. Simultaneously, passive motion of the head and neck on the trunk was captured using eight infrared cameras. The instantaneous strain arising in the vertebral artery was correlated with the relative changes in head position.FindingsStrain in the contralateral vertebral artery during passive flexion-rotation compared to that of extension-rotation is variable ([df = 32]: − 0.61 < r < 0.55). Peak strain does not coincide with peak angular displacement during spinal manipulation and cardinal planes of motion. Axial rotation displayed the greatest amount of strain. The greatest amount of strain achieved during spinal manipulation was comparably lower than strains achieved during passive end range motions and previously reported failure limits.InterpretationThe results of this study suggest that vertebral artery strains during head movements including spinal manipulation, do not exceed published failure strains. This study provides new evidence that peak strain in the vertebral artery may not occur at the end range of motion, but rather at some intermediate point during the head and neck motion.     

Accuracy and reliability of a new,protractor-based neck goniometer

OBJECTIVES: To assess the reliability of the SpinT, a new protractor-based device, for measuring active cervical spine ranges of motion. In addition, to compare the accuracy of the Cervical Ranges of Motion (CROM) instrument and SpinT measurements of rotation about the Y axis with and without tilt, the former motion occurring during natural rotation of the head. Study Design: Interexaminer reliability, intraexaminer reliability, and accuracy trials were conducted. METHODS: Two examiners made 2 individual measurements of each of the individual cervical ranges of motion of 23 patients (15 men, 8 women; aged 21 to 42 years) with no cervical symptoms. The patients were asked to move their necks to end range while they sat upright. The accuracy of the CROM instrument and SpinT goniometers was assessed with a testing instrument capable of rotating and/or tilting to preset angles and upon which either device could be positioned. RESULTS: There was excellent agreement between the SpinT measurements of rotation about the Y axis compared with the readings from the testing platform regardless of the angle of tilt, whereas the CROM instrument displayed poor concordance when the tilt exceeded 5 degrees. The reliability trials generally yielded close agreement between the examiners, especially regarding measurements of rotation left and right and extension and revealed higher concordance regarding intraexaminer results. CONCLUSION: This study indicates that SpinT measurements of active cervical ranges of motion are reliable and that the SpinT goniometer accurately measures rotation with associated tilt.     

Neurophysiologic response to intraoperative lumbosacral spinal manipulation

BACKGROUND: Although the mechanisms of spinal manipulation are poorly understood, the clinical effects are thought to be related to mechanical, neurophysiologic, and reflexogenic processes. Animal studies have identified mechanosensitive afferents in animals, and clinical studies in human beings have measured neuromuscular responses to spinal manipulation. Few, if any, studies have identified the basic neurophysiologic mechanisms of spinal manipulation in human beings or animals. OBJECTIVES: The purpose of this clinical investigation was to determine the feasibility of obtaining intraoperative neurophysiologic recordings and to quantify mixed-nerve root action potentials in response to lumbosacral spinal manipulation in a human subject undergoing lumbar spinal surgery. METHODS: An L4-L5 laminectomy was performed in a 62-year-old man. Short-duration (<0.1 ms) mechanical force, manually assisted spinal manipulative thrusts (150 N) were delivered to the lumbosacral spine with an Activator II Adjusting Instrument. With the spine exposed, spinal manipulative thrusts were delivered internally to the L5 mammillary process, L5-S1 joint, and the sacral base with various force vectors. This protocol was repeated by contacting the skin overlying respective anatomic landmarks. Mixed-nerve root recordings were obtained from gas-sterilized platinum bipolar hooked electrodes attached to the S1 nerve root at the level of the dorsal root ganglion during the spinal manipulative thrusts and during a 30-second baseline period during which no spinal manipulative thrusts were applied. RESULTS: During the active trials, mixed-nerve root action potentials were observed in response to both internal and external spinal manipulative thrusts. Differences in the amplitude and discharge frequency were noted in response to varying segmental contact points and force vectors, and similarities were noted for internally and externally applied spinal manipulative thrusts. Amplitudes of mixed-nerve root action potentials ranged from 200 to 2600 mV for internal thrusts and 800 to 3500 mV for external thrusts. CONCLUSIONS: Monitoring mixed-nerve root discharges in response to spinal manipulative thrusts in vivo in human subjects undergoing lumbar surgery is feasible. Neurophysiologic responses appeared sensitive to the contact point and applied force vector of the spinal manipulative thrust. Further study of the neurophysiologic mechanisms of spinal manipulation in humans and animals is needed to more precisely identify the mechanisms and neural pathways involved.     

Defining the Neutral Zone of sheep intervertebral joints during dynamic motions: an in vitro study

OBJECTIVE: To make an experimental assessment of the Neutral Zone of intervertebral joints during dynamic spinal motion in flexion/extension, lateral bending and axial rotation and to develop a criterion for its definition. DESIGN: Dynamic mechanical testing of sheep intervertebral joints with a six-degree of freedom robotic facility under position control. BACKGROUND: The Neutral Zone is defined as a region of no or little resistance to motion in the middle of an intervertebral joint's range of movement. Previous studies have used quasi-static loading regimes that do not model physiological activity. This study simulated physiological movements using a robotic testing facility to address this issue. METHODS: Five spines from mature sheep were used and three motion segments were tested from each spine. The robotic facility enabled the testing regime to be defined for each individual joint based on its geometry. The joints were tested by cycling through the full range of physiological movement in flexion/extension, lateral bending and axial rotation. RESULTS: A Neutral Zone was found to exist during dynamic movements only in flexion/extension. The results suggested that a Neutral Zone does not exist in lateral bending or axial rotation. The zygapophysial joints were shown to be significant in determining the mechanics of the intervertebral joints as their removal increased the Neutral Zone in all cases. A new criterion for defining the size of the Neutral Zone during dynamic motion was proposed and its implications for spinal movements in life discussed. CONCLUSIONS: A Neutral Zone exists in flexion/extension during dynamic movements of intervertebral joints and is a feature of the natural range of joint motion. This has important implications for the muscular control of the spine consisting of several intrinsically lax joints stacked on one another. RELEVANCE: The existence of a Neutral Zone is a feature of the natural range of joint motion and requires complex control of intervertebral joints by the spinal muscles. Defining the biomechanical response throughout the physiological range of motion (RoM) is important in understanding possible injury and rehabilitation mechanisms.     

Changes in Vertebral Artery Blood Flow in Different Head Positions and Post–Cervical Manipulative Therapy

ObjectiveThe objective of this study was to investigate the hemodynamics of blood flow through the V3 region of the vertebral artery contralateral to the side manipulated during different rotary head positions and post–cervical spinal manipulation.MethodsThis quasi-experimental study was performed on 25 healthy, asymptomatic participants, both male and female, between 20 and 30 years of age. Each participant presented with a C0/C1 or C1/C2 cervical facet restriction (as determined by motion palpation). Participation was voluntary, and participants had no symptoms of vertebrobasilar artery insufficiency or contraindications to cervical spinal manipulation. Doppler ultrasound was used to measure vertebral artery blood flow (V3 region) hemodynamics, contralateral side of manipulation, as close to C1/C2 region as possible in 4 positions of cervical rotation (neutral, 45°, maximum, and post-manipulation neutral). Doppler ultrasound parameters included peak systolic flow velocity, end diastolic flow velocity, mean flow velocity, vessel diameter, and flow rate. The nonparametric Friedman test was used for analysis across each head and neck position, and post manipulation.ResultsNo clinical or statistically significant results (P > .05) were found for any of the hemodynamic parameters in any of the head positions.ConclusionsHemodynamic measurements of the V3 region of the vertebral artery do not show significant changes in the measured head positions or following manipulation of the upper cervical spine in patients without pre-existing risk factors.     

Manual fixation versus locking during upper cervical segmental mobilization. Part 2: an in vitro three-dimensional arthrokinematic analysis of manual axial rotation and lateral bending mobilization of the atlanto-axial joint

BackgroundThree-dimensional kinematic aspects of coupled motion during manual cervical mobilization have not previously been studied. Using an in vitro 3D-motion analysis method, the kinematic effects of two different segmental techniques for axial rotation and lateral bending mobilization of the upper cervical spine were investigated as a second part of the study (in part one, kinematic effects of flexion-extension mobilization have been investigated).MethodsAxial rotation and lateral bending mobilization of the atlanto-occipital and atlanto-axial segments were analysed in vitro using an electromagnetic tracking device. Local reference frames were defined based on bony reference points that were registered using a 3D-digitizing stylus.Five embalmed and one fresh specimen were analysed. Segmental motion was registered simultaneously in the atlanto-occipital and the atlanto-axial joints during manual mobilization through the full range of axial rotation and lateral bending mobility. The 3D-kinematic aspects during regional mobilization were compared with those during segmental mobilization with manual fixation and during segmental mobilization using a locking technique.ResultsDuring both segmental axial rotation techniques of the atlanto-axial joint, a significant reduction of the coupled lateral bending and flexion-extension motion was observed. The locking technique also induced an increase in the main axial rotation component. During lateral bending mobilization of the atlanto-axial joint, the manual fixation technique reduced the effect on the coupled flexion-extension component significantly.InterpretationsThese results suggest that for manual segmental axial rotation and lateral bending mobilization of the upper cervical spine segmental manual fixation or locking may be preferred in different situations depending on the desired effects. This study brings additional information to the data provided by part 1 of this study on the 3D-arthrokinematic effects of flexion-extension mobilization.