Biomedical subjects

R C Hallgren

Publications and source records attributed to R C Hallgren.

12 recordsLinked to original sources

PubMed1999

Visualization technology in medical education.

Visualization technology offers the possibility of profoundly changing the way in which osteopathic medical students assimilate basic osteopathic principles by giving them the ability to interactively explore biomechanical components of the musculoskeletal system, and to investigate the effects that changes in physical properties can have on functionality. The authors are developing a multiple-volume series of computer-assisted learning modules that use three-dimensional, visualization technology to enhance the acquisition of knowledge and skills necessary for clinical evaluation and treatment of the lumbar and cervical spines. These materials, designed to serve as an adjunct to teaching strategies that faculty are currently using, are available to students on campus through the Kobiljak Resource Center at Michigan State University College of Osteopathic Medicine (MSUCOM) and via the Internet (http://hal.bim.msu.edu/EdTech) to individuals and groups who are physically removed from the Michigan State University campus. In addition to addressing needs in undergraduate and graduate medical education, these osteopathic materials, delivered to users via CD-ROM, have been approved for obtaining Category 1-B CME credits (http://hal.bim.msu.edu/cme). It is anticipated that the use of these materials will facilitate understanding of static and dynamic relationships among physical components of the musculoskeletal system, thus contributing to ongoing efforts to develop and maintain physician, faculty, and student expertise in areas that are uniquely osteopathic. Although initial efforts were restricted to the cervical and lumbar spines, future modules will include other regions of the body. The ultimate goal is to enable students to visualize the effects of pathologic processes as they interactively control an articulation in three-dimensional space.

Cervical Vertebrae↗

PubMed1997

Chronic neck pain, standing balance, and suboccipital muscle atrophy--a pilot study.

OBJECTIVE: To study the relationship between chronic neck pain, standing balance and suboccipital muscle atrophy. We hypothesize that patients with chronic neck pain have more somatic dysfunction in the cervical spine than control subjects without neck pain. We also hypothesize that patients with chronic neck pain and somatic dysfunction exhibit more atrophy of suboccipital muscles. Lastly, because suboccipital muscles have a high density of proprioceptors, we hypothesize that chronic pain patients exhibit a loss in standing balance. DESIGN: Randomized, controlled, partially blind study examining chronic neck pain patients and control subjects for differences in degree of upper cervical somatic dysfunction, standing balance and suboccipital muscle atrophy. SETTING: Subjects were recruited from a clinical practice at Michigan State University; controls were recruited from the faculty, staff and students. PARTICIPANTS: Seven chronic neck pain patients and seven asymptomatic control subjects. MAIN OUTCOME MEASURES: Palpation was used to diagnose somatic dysfunction in the upper cervical spine. Balance parameters were calculated using a force platform; muscle atrophy was judged with magnetic resonance images. RESULTS: Chronic neck pain patients had almost twice as many somatic dysfunctions as controls (p = .028). Force platform results showed a decrease in standing balance in patients compared with control subjects (p = .004). MRI showed that chronic neck pain subjects had marked atrophy of the rectus capitis posterior major and minor muscles, including fatty infiltration. CONCLUSIONS: This study suggests that there is a relationship between chronic pain, somatic dysfunction, muscle atrophy and standing balance. We hypothesize a cycle initiated by chronic somatic dysfunction, which may result in muscle atrophy, which can be further expected to reduce proprioceptive output from atrophied muscles. The lack of proprioceptive inhibition of nociceptors at the dorsal horn of the spinal cord would result in chronic pain and a loss of standing balance.

Adult↗

PubMed1995

Anatomic relation between the rectus capitis posterior minor muscle and the dura mater.

STUDY DESIGN: Anatomic study of the suboccipital region, specifically the deep muscles of the suboccipital triangle, was performed in cadaveric specimens. OBJECTIVE: To observe and describe the relationship between the deep suboccipital musculature and the spinal dura. SUMMARY OF BACKGROUND DATA: A review of the literature revealed no reports describing a physical connection between suboccipital musculature and the spinal dura. METHODS: Dissections of the suboccipital region were performed in 10 embalmed and one fresh sagittally hemisected head and neck specimens. RESULTS: A connective tissue bridge between the rectus capitis posterior minor muscle and the dorsal spinal dura at the atlanto-occipital junction was observed in every specimen. The fibers of the connective tissue bridge were oriented primarily perpendicular to the dura. This arrangement of fibers appears to resist movement of the dura toward the spinal cord. CONCLUSIONS: Awareness of the physical relation between the rectus capitis posterior minor muscle and spinal dura via this connective tissue bridge should lessen the potential risk of dural damage during surgery. This connective tissue bridge may help resist dural infolding during head and neck extension.

Adult↗

PubMed1994

Atrophy of suboccipital muscles in patients with chronic pain: a pilot study.

Magnetic resonance imaging studies were performed in six patients with chronic head and neck pain and in five control subjects to determine whether irreversible atrophic changes resulting in destruction of muscle fibers have a role in patients with chronic pain specific to the cervical spine. Both groups of subjects had medical history obtained and underwent physical examination and proton density-weighted (PD-weighted) magnetic resonance imaging. Subjects with chronic pain had substantial restriction of motion. Axial proton density-weighted images of the rectus capitis major and minor muscles were examined. In the subjects with chronic pain, the muscles had high signal intensity, indicating replacement of dead suboccipital skeletal muscle with fatty tissue. This infiltration was not observed in the control subjects who were free of significant motion restrictions and had no history of recurring neck and head pain. Analysis of pixel intensity values confirmed this finding. The reduction in proprioceptive afferent activity in affected muscles may cause increased facilitation of neural activity that is perceived as pain. At least mean squares algorithm was used to define a linear estimating equation for each subject. Linear regression analysis, using an alpha level < .005, was used to determine how well each subject's data fit the estimating equation. This preliminary work indicates substantial infiltration of fatty tissue into suboccipital muscles of some subjects being treated for chronic head and neck pain.

Adult↗

PubMed1993

Quantifying passive resistance to motion in the straight-leg-raising test on asymptomatic subjects.

The clinician needs an objective way to measure limb motion in the straight-leg-raising test. A biomechanical algorithm was used to quantify resistance to motion in 15 asymptomatic subjects. Measurements from a pendulum electrogoniometer and hand-held load cell were used to calculate a moment representing passive resistance to motion. After three measurement trials, significant increases in range of motion (4.7%) and moment (8.4%) occurred. Then, an isometric contraction-relaxation of the hip extensors produced a highly significant increase in motion (8.8%) but decrease in moment (< 14.3%). A third order polynomial fit of moment per angle stratified the sample into two groups according to their change in moment. Motion in group 1 increased 8.0%, and in group 2, 9.5%. However, group 1 had no change in moment whereas group 2 had a highly significant decrease in moment (22.9%). The measured change in resistance demonstrated that a simple biomechanical algorithm quantified properties in a clinical test that were not observed in range of motion alone.

Adolescent↗

PubMed1992