Neck retractions, cervical root decompression, and radicular pain.

 Abdulwahab SS, Sabbahi M

1: J Orthop Sports Phys Ther 2000 Jan;30(1):4-9; discussion 10-2

Texas Woman's University, School of Physical Therapy, Houston 77030-2897, USA.

STUDY DESIGN: Two-group repeated measures. OBJECTIVES: To evaluate the changes in the flexor carpi radialis H reflex after reading and neck retraction exercises and to correlate reflex changes with the intensity of radicular pain.

BACKGROUND: Repeated neck retraction movements have been routinely prescribed for patients with neck pain. METHODS AND MEASURES: Ten nonimpaired subjects (mean age, 27 +/- 4 years) and 13 patients (mean age, 35 +/- 9 years) with C7 radiculopathy volunteered for the study. The flexor carpi radialis H reflex was elicited by electrical stimulation of the median nerve at the cubital fossa before and after 20 minutes of reading and after 20 repetitive neck retractions.

Subjective intensity of the radicular pain was reported before and after each condition using an analog scale. RESULTS: For patients with radiculopathy, a repeated-measures analysis of variance showed a significant decrease in the H reflex amplitude (from 0.81 +/- 0.4 to 0.69 +/- 0.39 mV), an increase in radicular symptoms after reading (from 4.2 +/- 1.3 to 5.6 +/- 1.4 on the visual analog scale), an increase in the H reflex amplitude (from 0.69 +/- 0.39 to 1.01 +/- 0.49 mV), and a decrease in pain intensity (from 5.6 +/- 1.4 to 1.5 +/- 1.3) after repeated neck retractions. There was an association between cervical root compression (smaller H reflexes) and increased pain during reading and between cervical root decompression (larger H reflex) and reduced pain (r = -0.86 to -0.60). Exacerbation of symptoms was found with a reading posture. There were no significant changes in the H reflex amplitude in the nonimpaired group. No

changes were found in reflex latency for either groups. CONCLUSIONS: Neck retractions appeared to alter H reflex amplitude. These exercises might promote cervical root decompression and reduce radicular pain in patients with C7 radiculopathy. The opposite effect (an exacerbation of symptoms) was found with the reading posture.

PMID: 10705591, UI: 20169769

EMG support of breig

@@1: Spine 1999 Jan 15;24(2):137-41

Cervical root compression monitoring by flexor carpi radialis H-reflex in

healthy subjects.

Sabbahi M, Abdulwahab S

School of Physical Therapy, Texas Woman's University, Houston, USA.

STUDY DESIGN: One-group, pretest-postest experimental research with repeated

measures. OBJECTIVE: To determine the effect of head postural modification on

the flexor carpi radialis H-reflex in healthy subjects. SUMMARY OF BACKGROUND

DATA: H-reflex testing has been reported to be useful in evaluating and treating

patients with lumbosacral and cervical radiculopathy. The idea behind this

technique is that postural modification can cause further H-reflex inhibition,

indicating more compression of the impinged nerve root, or recovery, indicating

decompression of the root. Such assumptions cannot be supported unless the

influence of normal head postural modification on the H-reflex in healthy

subjects is studied. METHODS: Twenty-two healthy subjects participated in this

study (14 men, 8 women; mean age, 39 +/- 9 years). The median nerve of the

subjects at the cubital fossa was electrically stimulated (0.5 msec; 0.2 pulses

per second [pps] at H-max), whereas the flexor carpi radialis muscle H-reflex

was recorded by electromyography. The H-reflexes were recorded after the subject

randomly maintained the end range of head-forward flexion, backward extension,

rotation to the right and the left, lateral bending to the right and the left,

retraction and protraction. These were compared with the H-reflex recorded

during comfortable neutral positions. Data were recorded after the subject

maintained the position for 30 seconds, to avoid the effect of dynamic postural

modification on the H-reflex. Four traces were recorded in each position. During

recording, the H-reflex was monitored by the M-response to avoid any changes in

the stimulation-recording condition. RESULTS: Repeated multivariate analysis of

variance was used to evaluate the significance of the difference among the

H-reflex, amplitude, and latency, in various head positions. The H-reflex

amplitude showed statistically significant changes (P < 0.001) with head

postural modification. All head positions, except flexion, facilitated the

H-reflex. Extension, lateral bending, and rotation toward the side of the

recording produced higher reflex facilitation than the other positions. These

results indicate that H-reflex changes may be caused by spinal root

compression-decompression mechanisms. It may also indicate that relative spinal

root decompression occurs in most head-neck postures except forward flexion.

CONCLUSIONS: Head postural modification significantly influences the H-reflex

amplitude but not the latency. This indicates that the H-reflex is a more

sensitive predictor of normal physiologic changes than are latencies. The

H-reflex modulation in various head positions may be-caused by relative spinal

root compression-decompression mechanisms.

PMID: 9926383, UI: 99125206

Surgical treatment of cervical spondylotic myelopathy: time for a  controlled trial.

Rowland LP

Neurology 1992 Jan;42(1):5-13

Neurological Institute, Columbia-Presbyterian Medical Center, New York, NY 10032-3784.

Surgical procedures on the cervical spine are accepted therapies for the myelopathy of cervical

spondylosis. However, reported improvement rates vary widely, and many reports indicate

improvement in about one-half of the cases. It has not been proven that outcome after surgery is

better than the natural history or conservative therapy. Radiographic or imaging evidence of cord

impingement or compression may be seen in asymptomatic people. There are no clear guides to

the selection of patients who may benefit from the operation and there has been no

standardization of preoperative evaluation, trials of conservative therapy, ascertainment of

progressive disability, or assessment of outcome. A multicenter controlled trial might answer

these questions.

Analysis of the cervical spine alignment following laminoplasty and  laminectomy.

Matsunaga S, Sakou T, Nakanisi K

Spinal Cord 1999 Jan;37(1):20-4

Department of Orthopaedic Surgery, Faculty of Medicine, Kagoshima University, Sakuragaoka,

                       Japan.

Very little detailed biomechanical examination of the alignment of the cervical spine following

laminoplasty has been reported. We performed a comparative study regarding the buckling-type

alignment that follows laminoplasty and laminectomy to know the mechanical changes in the

alignment of the cervical spine. Lateral images of plain roentgenograms of the cervical spine were

put into a computer and examined using a program we developed for analysis of the

buckling-type alignment. Sixty-four patients who underwent laminoplasty and 37 patients who

underwent laminectomy were reviewed retrospectively. The subjects comprised patients with

cervical spondylotic myelopathy (CSM) and those with ossification of the posterior longitudinal

  ligament (OPLL). The postoperative observation period was 6 years and 7 months on average

  after laminectomy, and 5 years and 6 months on average following laminoplasty. Development of

the buckling-type alignment was found in 33% of patients following laminectomy and only 6%

after laminoplasty. Development of buckling-type alignment following laminoplasty appeared

  markedly less than following laminectomy in both CSM and OPLL patients. These results favor

  laminoplasty over laminectomy from the aspect of mechanics.

Atrophy of the nuchal muscle and change in cervical curvature after  expansive open-door laminoplasty.

Fujimura Y, Nishi Y

Arch Orthop Trauma Surg 1996;115(3-4):203-5

Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.

We analyzed computed tomography (CT) images and plain X-ray films of 53 patients who had

undergone expansive open-door laminoplasty, in a 3-year study. The relationship between the

postoperative changes in the nuchal muscles and those in the cervical curvature was investigated.

On postoperative CT images, the cross-sectional area of all nuchal muscles was reduced to

approximately 80% of its preoperative size. This atrophic change was especially intense in the

multifidus muscle and the semispinalis cervicis muscle. Postoperative cross-sectional area of the

deep nuchal muscles was reduced approximately 30% from its preoperative size. No significant

correlation was found between the all cross-sectional area of the nuchal muscles and the cervical

curvature. However, a weak correlation was found between the deep nuchal muscles area and

the curve index (correlation coefficient 0.29).

support of breig

Lordotic alignment and posterior migration of the spinal cord following en bloc open-door laminoplasty for cervical myelopathy: a magnetic  resonance imaging study.

Baba H, Uchida K, Maezawa Y, Furusawa N, Azuchi M, Imura S

J Neurol 1996 Sep;243(9):626-32

We investigated lordotic alignment and posterior migration of the spinal cord following en bloc

open-door laminoplasty for cervical myelopathy. Fifty-five patients (32 men and 23 women)

were studied, with an average follow-up of 2.4 years. Radiological examination included

evaluation of lordosis of the cervical spine and spinal cord, degree of enlargement of bony spinal

canal, and the magnitude of posterior cord migration. We also correlated these changes with

neurological improvement. Postoperatively, there was an average of 5% loss of cervical spine

lordosis (P > 0.01) on radiographs and 12% reduction in the lordotic alignment of the spinal cord

(P > 0.05) on magnetic resonance imaging. Postoperatively, the size of the bony spinal canal

increased by 48%. Posterior cord migration showed a significant correlation with the

preoperative cervical spine and spinal cord lordosis (P < 0.05). Thirty-seven (67%) patients with

  neurological improvement exceeding 50% showed significant posterior cord migration following

laminoplasty compared with those demonstrating less than 50% improvement (P = 0.01). Our

results suggest that a significant neurological improvement is associated with posterior cord

migration after cervical laminoplasty.

                       PMID: 8892062, UI: 97047142

Multilevel cervical spondylosis. Laminoplasty versus anterior  decompression.

Hirabayashi K, Bohlman HH

Spine 1995 Aug 1;20(15):1732-4

Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.

Poor overall outcome and a high incidence of postoperative kyphosis and progressive

myelopathy have driven surgeons away from decompressive laminectomy as a treatment for

multilevel cervical spondylosis. Dr. Henry Bohlman advocates anterior decompression and fusion

as the best approach to the pathophysiology of this disorder, while Dr. Kiyoshi Hirabayashi

believes that laminoplasty represents an excellent strategy for patients with degenerative disease,

as well as those with ossification of the posterior longitudinal ligament.

Preoperative and postoperative magnetic resonance image evaluations of  the spinal cord in cervical myelopathy.

Yone K, Sakou T, Yanase M, Ijiri K

 Spine 1992 Oct;17(10 Suppl):S388-92

Department of Orthopaedic Surgery, Faculty of Medicine, Kagoshima University, Japan.

To evaluate the morphologic changes of the spinal cord in patients with cervical myelopathy due

to cervical spondylosis and ossification of the posterior longitudinal ligament, the authors

measured the thickness and signal intensity of the cervical cord with magnetic resonance imaging

in healthy adults and patients with cervical myelopathy, and compared these findings. In patients

with cervical myelopathy, the preoperative and postoperative magnetic resonance imaging

 findings were compared with the severity of myelopathy and postoperative results. In healthy

adults, the anteroposterior diameter of the cervical cord was 7.8 mm at the C3 level and

decreased at lower levels. In the patients with cervical myelopathy, the preoperative spinal

 anteroposterior diameter was significantly reduced at various levels corresponding to the stenosis

site within the vertebral canal. In the group with ossification of the posterior longitudinal ligament,

  the minimal anteroposterior diameter of the cervical cord tended to decrease with increasing

  severity of myelopathy. However no relationship was observed between the two parameters in

   the cervical spondylotic myelopathy group. In the group with ossification of the posterior

longitudinal ligament, surgical results were good when the postoperative anteroposterior diameter

was increased, whereas in the cervical spondylotic myelopathy group there was no relationship

between the two parameters. In the patients with myelopathy, a high intensity area was observed

  in about 40% of all patients before operation and about 30% after operation. However, the

  presence or absence of a high intensity area did not correlate with the severity of myelopathy or

with surgical results in the group with ossification of the posterior longitudinal ligament and the

cervical spondylotic myelopathy groups.

                       PMID: 1440032, UI: 93068549

Neck and shoulder pain after laminoplasty. A noticeable complication.

Hosono N, Yonenobu K, Ono K

Spine 1996 Sep 1;21(17):1969-73

Department of Orthopaedic Surgery, Japan.

STUDY DESIGN: The authors retrospectively analyzed the prevalence and features of neck and

shoulder pain (axial symptoms) after anterior interbody fusion and laminoplasty in patients with

cervical spondylotic myelopathy. OBJECTIVES: To reveal the difference in prevalence of

postoperative axial symptoms between anterior interbody fusion and laminoplasty and to clarify

the pathogenesis of axial symptoms after laminoplasty. SUMMARY OF BACKGROUND

DATA: Outcome of the cervical surgery is evaluated on neurologic status alone; axial symptoms

after laminoplasty rarely have been investigated. Such symptoms, however, are often severe

enough to interfere with a person's daily activity. METHODS: Ninety-eight patients had surgery

for their disability secondary to cervical spondylotic myelopathy. Of those patients, 72 had

laminoplasty, and 26 had anterior interbody fusion. The presence or absence of axial symptoms

was investigated before and after surgery. The duration, severity, and laterality of symptoms were

also recorded. RESULTS: The prevalence of postoperative axial symptoms was significantly

higher after laminoplasty than after anterior fusion (60% vs. 19%; P < 0.05). In 18 patients

(25%) from the laminoplasty group, the chief complaints after surgery were related to axial

 symptoms for more than 3 months, whereas in the anterior fusion group, no patient reported

having such severe pain after surgery. CONCLUSIONS: The prevalence and severity of axial

symptoms after laminoplasty proved to be higher and more serious than has been believed. Such

  symptoms should be considered in the evaluation of the outcome of cervical spinal surgery.

Related Articles, Books, LinkOut

Postural imbalance and vibratory sensitivity in patients with idiopathic scoliosis: implications for treatment.

Byl NN, Holland S, Jurek A, Hu SS

 J Orthop Sports Phys Ther 1997 Aug;26(2):60-8

University of California, San Francisco, USA.

Sporadic research reports of decreased proprioception and balance problems have been

reported in subjects with idiopathic scoliosis, yet these sensory motor deficits have not been

addressed in conservative clinical management programs. The purpose of this study was to

compare both balance reactions and vibratory sensitivity (as an estimate of proprioception) in

patients with idiopathic scoliosis (N = 24) and age-matched controls (N = 24). Balance was

measured by the ability to pass a series of simple static and complex sensory-challenged balance

tasks. Vibratory thresholds were measured with the Bio-Thesiometer at the cervical spine, wrist,

and foot. Compared with age-matched controls, regardless of curve severity or spinal fusion, the

subjects with idiopathic scoliosis had similar simple static balance responses when the

 somatosensory system was stable (with or without vision or head turning), but they were

significantly more likely to fail the complex, sensory-challenged balance tasks when the

somatosensory system was challenged by an unstable position of the feet, particularly when the

eyes were closed. The vibratory thresholds were similar in subjects with scoliosis and their

  age-matched controls, but individuals with moderate to severe scoliosis (> 25 degrees) had

significantly higher vibratory thresholds than those with mild curves. These findings suggest there

may be problems with postural righting in patients with idiopathic scoliosis, particularly when the

  balance task challenges the vestibular pathways. Although vibration sensitivity did not distinguish

normal healthy individuals from individuals with idiopathic scoliosis, those with more severe

scoliotic curves appear to have a high threshold to vibration. These balance and vibratory

 differences could either be interpreted as etiologic risk factors or as consequences of spinal

   asymmetry. In either case, given that curves can continue to progress even into the adult years,

  improving the ability to right the body with gravity could help maintain the balance of the spine

 despite structural asymmetry.

                       PMID: 9243403, UI: 97387370

Kinematics of cervical spine injury. A functional radiological hypothesis.

 Penning L

Eur Spine J 1995;4(2):126-32

Department of Diagnostic Radiology, University Hospital of Groningen AZG, The Netherlands.

This paper, based on functional radiological knowledge of normal cervical spine kinematics,

   develops the hypothesis that compressive vertebral injury can be produced by abrupt reversal of

curve between hyperflexed and hyperextended parts of the cervical spine. Reversal of curve

occurs when the main vector of a compressive force passes between two centers of

  flexion-extension motion. The hypothesis more clearly explains reverse dislocation of fractured

vertebrae than the current concept of Whitley and Forsyth of motion of the head through an arc.

The mechanism of injuries with characteristics of hyperflexion of one segment and hyperextension

of an adjacent segment, e.g., in certain types of hangman's fractures, is better understood. The

hypothesis is expected to be helpful in guiding experimental cervical spine injury, as it relates

direction of force to level and type of the resulting vertebral injury.

                       PMID: 7600151, UI: 95323521

support of breig

1: J Orthop Sports Phys Ther 1993 Mar;17(3):155-60

Reliability of measuring forward head posture in a clinical setting.

Garrett TR, Youdas JW, Madson TJ

Physical Therapy Program, Mayo School of Health-Related Sciences, Rochester, MN.

We believe there is a need to identify a practical method for determining

objective measurement of forward head posture. In our study, we determined the

within-tester and between-tester reliabilities for clinical measurements of

static, sitting, forward head posture using the cervical range of motion (CROM)

instrument. Repeated measurements were made using a standardized protocol on 40

patients seated in a standardized position. The seven testers had from 1 to 8

years of clinical experience. All measurements were recorded by the same

investigator. The intraclass correlation coefficient (ICC[1,1]) was used to

quantitate within-tester and between-tester reliability. Measurements of forward

head position performed by the same physical therapist had high reliability (ICC

= 0.93). Good reliability (ICC = 0.83) was demonstrated when different physical

therapists measured the forward head posture of the same patient. We concluded

that measurements of forward head posture made by physical therapists trained in

the correct use of the CROM instrument are reliable. This reliability is

important for determining the effectiveness of treatment programs. On the basis

of our data, the CROM instrument will assist clinicians in the objective

evaluation and reassessment of the patient population demonstrating forward head

posture.

PMID: 8472080, UI: 93230304

1: Spine 1998 Apr 15;23(8):921-7

The correlation between surface measurement of head and neck posture and the

anatomic position of the upper cervical vertebrae.

Johnson GM

School of Physiotherapy, University of Otago, Dunedin, New Zealand.

STUDY DESIGN: Repeated measurements were made of surface postural angles

registering the relative positions of the head and neck in photographs and of

angles of the upper cervical vertebrae recorded in lateral cephalometric

radiographs in the same subjects. For all registrations, subjects assumed the

natural head rest position. OBJECTIVES: To examine the correlation between

external measurement of head and neck posture and the anatomic positions of the

upper four cervical vertebrae. SUMMARY OF BACKGROUND DATA: Interpretation of

surface cervical posture measurement is confounded by lack of knowledge about

the extent of the underlying compensatory adjustments among the upper cervical

vertebrae that may accompany variation in head and neck posture. The correlation

between surface measurement and postural characteristics of the upper cervical

spine has not been reported to date. METHODS: The association between a set of

angles describing the anatomic position of the four upper cervical vertebrae on

lateral cephalometric radiographs and a surface measurement of head and neck

posture, the craniovertebral angle, was studied in 34 young adult women aged

between 17.2 and 30.5 years, mean age, 24.5 years. Anatomic positions of the

upper four cervical vertebrae were expressed by angles relative to the true

vertical or horizontal. Surface angles registering head and neck position for

each subject were obtained from photographs recorded on two occasions. RESULTS:

No strong correlation could be established between the angles taken from the

lateral cephalometric radiographs measuring the extent of upper cervical

lordosis, orientation of the atlas, vertebral inclination, or odontoid process

tilt and surface angles recording head and neck position. This finding was

attributed principally to the much greater positional variability demonstrated

within the upper cervical spine when compared with the surface measurements of

head and neck position. CONCLUSION: Anatomic alignment of the upper cervical

vertebrae cannot be inferred from variation in surface measurement of head and

neck posture. This is the case even in those people identified with more extreme

head and neck postural tendencies.

PMID: 9580960, UI: 98242061

1: Spine 1996 Nov 1;21(21):2435-42

The effect of initial head position on active cervical axial rotation range of

motion in two age populations.

Walmsley RP, Kimber P, Culham E

School of Rehabilitation Therapy, Queen's University, Kingston, Ontario, Canada.

STUDY DESIGN: This study analyzed cervical axial rotation initiated from five

different starting positions in asymptomatic subjects. The results were analyzed

to ascertain if rationale for certain clinical assessment methods could be

justified. SUMMARY OF BACKGROUND DATA: In the assessment of the cervical spine,

many clinicians use assessment techniques that propose to isolate anatomic

structures by using various permutations and combinations of the three gross

rotational movements, for example, evaluation of axial rotation in flexion and

extension. OBJECTIVES: The primary purpose of this study was to compare the

magnitude of cervical axial rotation when started from neutral, flexion,

extension, protraction, and retraction, and the protraction-retraction range of

motion also was determined. METHODS: Two groups of 30 subjects, one group aged

18-30 years and the other group aged 50-65 years and stratified by gender,

participated in the study. The 3Space Tracker system (Polhemus, A Kaiser

Aero-space and Electronics, Co., Colchester, VT), art electromagnetic tracking

device, was used to determine the angular and linear position of the head

relative to the sternum by detecting the position and orientation of two sensors

attached to the forehead and sternum. RESULTS: Analysis of variance of the data

revealed a statistically significant difference (p < 0.05) in axial rotation

between all of the five starting positions. The younger age group demonstrated

greater range of motion when rotation was initiated from neutral and extension,

whereas the older group had greater range when the motion was initiated from

protraction, retraction, and flexion. CONCLUSIONS: The results suggest that

varying the starting sagittal head position may affect the anatomic structures

involved in restraining axial rotation. This supports the clinical approach to

range of motion assessment in combined movement patterns.

PMID: 8923628, UI: 97082392

Incidence of common postural abnormalities in the cervical, shoulder, and

thoracic regions and their association with pain in two age groups of healthy

subjects.

Griegel-Morris P, Larson K, Mueller-Klaus K, Oatis CA

1: Phys Ther 1992 Jun;72(6):425-31

Philadelphia Institute for Physical Therapy, PA 19104.

The purposes of this study were to identify the incidence of postural

abnormalities of the thoracic, cervical, and shoulder regions in two age groups

of healthy subjects and to explore whether these abnormalities were associated

with pain. Eighty-eight healthy subjects, aged 20 to 50 years, were asked to

answer a pain questionnaire and to stand by a plumb line for postural assessment

of forward head, rounded shoulders, and kyphosis. Subjects were divided into two

age groups: a 20- to 35-year-old group (mean = 25, SD = 63) and a 36- to

50-year-old group (mean = 47, SD = 2.6). Interrater and intrarater reliability

(Cohen's Kappa coefficients) for postural assessment were established at .611

and .825, respectively. Frequency counts revealed postural abnormalities were

prevalent (forward head = 66%, kyphosis = 38%, right rounded shoulder = 73%,

left rounded shoulder = 66%). No relationship was found between the severity of

postural abnormality and the severity and frequency of pain. Subjects with more

severe postural abnormalities, however, had a significantly increased incidence

of pain, as determined by chi-square analysis (critical chi 2 = 6, df = 2, P

less than .05). Subjects with kyphosis and rounded shoulders had an increased

incidence of interscapular pain, and those with a forward-head posture had an

increased incidence of cervical, interscapular, and headache pain.

PMID: 1589462, UI: 92270665

1: J Manipulative Physiol Ther 1999 Jan;22(1):26-8

The ability to reproduce the neutral zero position of the head.

Christensen HW, Nilsson N

Nordic Institute of Chiropractic & Clinical Biomechanics, Odense, Denmark.

OBJECTIVE: To determine how precisely asymptomatic subjects can reproduce a

neutral zero position of the head. STUDY DESIGN: Repeated measures of the active

cervical neutral zero position. SETTING: Institute of Medical Biology (Center of

Biomechanics) at Odense University. PARTICIPANTS: Thirty-eight asymptomatic

students from the University of Odense, male/female ratio 20:18 and mean age

24.3 years (range, 20 to 30 years). INTERVENTION: Measurements of the location

of the neutral zero head position by use of the electrogoniometer CA-6000 Spine

Motion Analyzer. Each subject's neutral zero position with eyes closed was

measured 3 times. The device gives the localization of the neutral zero as

coordinates in 3 dimensions (x, v, z) corresponding to the 3 motion planes.

RESULTS: The mean difference from neutral zero in 3 motion planes was found to

be 2.7 degrees in the sagittal plane, 1.0 degree in the horizontal plane, and

0.65 degree in the frontal plane. CONCLUSION: We found that young adult

asymptomatic subjects are very good at reproducing the neutral zero position of

the head. This suggests the existence of some advanced neurologic control

mechanisms.

Publication Types:

Clinical trial

PMID: 10029946, UI: 99154208

1: Spine 1997 Apr 15;22(8):865-8

Ability to reproduce head position after whiplash injury.

Loudon JK, Ruhl M, Field E

Department of Physical Therapy Education, University of Kansas Medical Center,

Kansas City, USA.

STUDY DESIGN: A two-group design with repeated measures. OBJECTIVES: To

determine if there is loss of the ability to reproduce target position of the

cervical spine individuals who have sustained a whiplash injury. SUMMARY OF

BACKGROUND DATA: The ability to sense position is a prerequisite for functional

movement. Injury may have a deleterious effect on this ability, resulting in

inaccurate positioning of the head and neck with respect to the body coordinates

and to the environment. METHODS: Eleven subjects with history of whiplash injury

(age, 42 +/- 8.7 years) and 11 age-matched asymptomatic subjects (age, 43 +/-

3.1 years) participated in the study. Effects of whiplash injury on the ability

to replicate a target position of the head were assessed. Maximum rotation of

the neck and ability to reproduce the target angle were measured using a

standard cervical range-of-motion device. Subjects' perception of "neutral"

position was also assessed. RESULTS: Analysis of variance indicated the whiplash

subjects were less accurate in reproducing the target angle than were control

subjects. These whiplash subjects tended to overshoot the target. In addition,

the subjects in the whiplash group were often inaccurate in their assessment of

neutral position. CONCLUSIONS: Subjects who have experienced a whiplash injury

demonstrate a deficit in their ability to reproduce a target position of the

neck. These data are consistent with the hypothesis that these subjects possess

an inaccurate perception of head position secondary to their injury. This study

has implications for the rehabilitation of individuals with whiplash injury.

PMID: 9127919, UI: 97273529

1: Acta Odontol Scand 1989 Apr;47(2):105-9

Natural head position recording on frontal skull radiographs.

Huggare J

Institute of Dentistry, University of Oulu, Finland.

This paper sets out to evaluate the variability and reproducibility of frontal

head position in healthy young adults. Two posteroanterior skull radiographs of

22 dental students and 2 frontal photographs of these and 24 other students,

taken at a 1-week interval, were analyzed with regard to head position and

cervical spine inclination. Head position varied in the range of +/- 5 degrees

with regard to the vertical. The cervical spine was more often inclined to the

right than to the left. The reproducibility of the head position with regard to

the craniovertical angle was 1.15 degrees and that of the craniocervical and

cervicohorizontal angles 0.93 degrees and 1.45 degrees, respectively. Any

deviation in the frontal head position tended to be spontaneously corrected on

looking in a mirror. It is concluded that the frontal head position is slightly

more accurately reproducible than the sagittal head position. The use of a

mirror in front of the patient when recording the frontal natural head position

is not to be recommended.

PMID: 2718757, UI: 89244136

1: J Orthop Res 1992 Mar;10(2):217-25

Trunk positioning accuracy in children 7-18 years old.

Ashton-Miller JA, McGlashen KM, Schultz AB

Department of Mechanical Engineering and Applied Mechanics, University of

Michigan, Ann Arbor 48109-2125.

Trunk proprioception was measured in 253 healthy children 7-18 years of age

using infrared markers placed on the back of the head and on the skin over the

T1, T8, and S1 spinous processes. The children were tested for their accuracy in

sensing return of the head and trunk to a centered, neutral position in the

frontal plane. Whole-body sway was also quantified during 10 s of relaxed

standing by measuring mean amplitudes of trunk marker and foot center of

pressure (CP) movements. The results show that trunk positioning accuracy

improved significantly with age (p = 0.000). Subjects could position their trunk

in the frontal plane to within a mean (+/- SD) of 2.5 (+/- 1.1) and 0.9 (+/-

0.6) degrees of the neutral position at ages 7 and 18 years, respectively. No

statistically significant gender differences were found. At every age trunk

positioning accuracy was diminished in the presence of a continuous external

trunk moment (equivalent to 0.01 x body weight x height), although not

significantly so. Neither mean trunk sway nor CP amplitudes were significantly

correlated with age or sex. The overall results suggest that spine

decompensation is only abnormal when it exceeds 20 mm in healthy children and

adolescents.

PMID: 1740740, UI: 92156965

1: J Orthop Res 1991 Jul;9(4):576-83

Trunk positioning accuracy in the frontal and sagittal planes.

McGlashen K, Ashton-Miller JA, Green M, Schultz AB

Department of Mechanical Engineering and Applied Mechanics, University of

Michigan, Ann Arbor 48109-2125.

The accuracy with which the head and spine could be positioned in the frontal

and sagittal planes relative to the pelvis was measured and compared in ten

healthy adult males. Subjects were tested with eyes closed, while standing with

their pelvis externally restrained. The positions of markers, attached to the

back of the head and over each of the T1, T6, T11, and L3 spinous processes,

were measured to the nearest mm using strain-gaged flexible beam transducers.

Subjects were tested for their accuracy in sensing return of the trunk to an

initial neutral position under different test conditions. Results showed that