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At least 829 records · Page 46Linked to original sources
PubMed2000

The expression of androgen receptors in human neck and limb muscles: effects of training and self-administration of androgenic-anabolic steroids.

The purpose of this study was to investigate the immunohistochemical expression of androgen receptors (AR) in human vastus lateralis and trapezius muscles and to determine whether long-term strength training and self-administration of androgenic-anabolic steroids are accompanied by changes in AR content. Biopsy samples were taken from eight high-level power-lifters (P), nine high-level power-lifters who used anabolic steroids (PAS) and six untrained subjects (U). Myonuclei and AR were visualised in cross-sections stained with the monoclonal antibody against AR and 4',6-diamidino-2-phenylindole. The proportion of AR-containing myonuclei per fibre cross-section was higher in the trapezius than in the vastus lateralis (P<0.05). In the trapezius, the proportion of AR-containing myonuclei was higher in P compared to U and in PAS compared to both P and U (P<0. 05). On the contrary, in the vastus lateralis, there were no differences in AR content between the three groups. Myonuclear number in both muscles was higher in P compared to U and in PAS compared to both P and U (P<0.05). In conclusion, AR content differs greatly between human neck and limb muscles. Moreover, the regulation of AR-containing myonuclei following training and self-administration of androgenic-anabolic steroids is muscle dependent.

Adult↗
PubMed2002

Spatiotemporal consistency of human mandibular and head-neck movement trajectories during jaw opening-closing tasks.

Previous studies of spatial and temporal coordination between human mandibular and head-neck movements during single as well as rhythmic jaw opening-closing tasks suggest that these movements are regulated by central nervous commands common for jaw and neck muscles. The present study evaluated the spatiotemporal consistency of concomitant mandibular and head-neck movements during repeated single jaw opening-closing tasks, in short- as well as long-term perspectives and at different speeds. The subjects were seated in an upright position without head support. They were instructed to perform single maximal jaw opening-closing movements, repeated ten times for fast and slow speed, respectively. Recordings were made at two sessions. A wireless optoelectronic technique was used to record three-dimensional mandibular and head-neck movements. The spatiotemporal consistency of repeated movement trajectories of the mandible (both in relation to the head and in space) and of the head-neck was quantitatively assessed by a spatiotemporal index (STI). In addition, mean movement trajectory patterns were compared for speed and recording sessions (expressed as correlation coefficient, r). The results showed relatively small STI (high degree of spatiotemporal consistency) and high r (reproducible trajectory patterns) values, both in short- and long-term perspectives, for concomitant mandibular and head-neck movements. The data were not generally speed related. In conclusion, the present results suggest a high degree of spatiotemporal consistency of the kinematic patterns of mandibular and head-neck movements during jaw opening-closing, in short- as well as long-term perspectives. They also indicate that underlying neural processes are invariant in nature. The results give further support to the notion of a tight functional coupling between the human jaw and the neck motor systems during natural jaw function.

Adult↗
PubMed2001

Aggressive fibromatosis of the neck in a patient with Gardner's syndrome.

We report a patient with Gardner's syndrome who, in addition to a total colectomy, had multiple excisions of desmoid tumors in both thighs. He presented with left-sided neck swelling and pain. MRI was highly suggestive of desmoid tumors in multiple neck muscles. To our knowledge this is the first description of diffuse fibromatosis of the neck in association with Gardner's syndrome.

Adult↗
PubMed1975

Macular input to neurons of the spinoreticulocerebellar pathway.

The present report summarizes the results obtained in previous experiments in which the responses to lateral tilt of both reticulocerebellar neurons located in the lateral reticular nucleus (NRL) and ascending spinoreticular tract axons, located in the lateral funiculi of the cervical segments C2-C3, had been recorded in precollicular decerebrate cats. Steady changes in unit activity were evoked by 15-20 degrees tilts which lasted as long as the position of the cat was maintained. Most of the units responsive to tilting showed an increase in discharge rate during tilt in one direction and a decrease in discharge rate during tilt in the opposite direction. Moreover the magnitude of the unitary responses was clearly related to the degree of tilt. The responses of the NRL neurons to tilt were attributed in part to direct efferent vestibuloreticular projections from the Deiters' nucleus, in part to some indirect influence of the lateral vestibulospinal tract on neurons of the cervical ascending spinoreticular pathway. Since most of these ascending units affected by tilt were influenced by stimulation of both ipsilateral and contralateral forelimb nerves, and some of them also by stimulation of high threshold neck muscle afferents, it was postulated that these neurons projected to the forelimb and the neck region of the cerebellar cortex of the anterior lobe. This corticocerebellar region may therefore integrate from time to time not only the signal input originating from macular receptors but also the somatosensory input which originates from neck receptors as a result of the actual displacement in head position induced by the vestibulospinal reflex.

Action Potentials↗
PubMed1998

Oesophageal impaction in a Canada goose (Branta canadensis).

An oesophageal impaction, consisting of plant material and nylon fishing line, and alimentary parasitism were diagnosed and treated in a Canada goose. At presentation the bird was non-ambulatory with flaccid neck muscles, lethargic, emaciated, dehydrated and had watery brown to green faeces. Palpation of the neck revealed a solid tubular mass ventrally in the mid-cervical region with gritty material cranial to it. Radiographs disclosed an oesophageal mass containing seed or grit-like radio-opaque material, and dilated cranial oesophagus containing radio-opaque material. Laboratory investigations revealed non-regenerative anaemia, heterophilia, lymphopenia, hypoproteinaemia, and many strongyle eggs in faeces. Treatment included supportive therapy, oesophageal gavage, oesophagotomy and drug therapy. The bird recovered and was released 27 days after initial presentation.

Animal Feed↗
PubMed1992

[X-ray computed tomographic scans of lower limb and trunk muscles in facioscapulohumeral muscular dystrophy].

X-rays computed tomographic (CT) scans of muscles of the lower limbs and the trunk in 14 patients with facioscapulohumeral muscular dystrophy (FSH) were studied. The CT scans showed that the affected muscles were decreased in density and size. The laterality of muscular involvement was sometimes observed. The muscular lesions in the lower limbs showed proximal distribution. In the thigh, the hamstrings were affected first, the adductor muscles second, and then the muscular involvement progressed to the quadriceps femoris muscle. In the lower leg, the gastrocnemius and soleus muscles were relatively spared as compared with the tibialis anterior muscle. In the lumbar girdle, the abdominal muscles were involved first, the gluteal muscles second, the back muscles third, and the psoas major muscle were relatively spared. The muscular weakness of this distribution exacerbated lumbar lordosis. The neck muscles were less affected than those of the lumbar girdle. The CT scans in FSH demonstrated the characteristic pattern of muscular involvement, which differed from the inherited muscular diseases such as Duchenne muscular dystrophy, myotonic dystrophy, and others.

Adolescent↗
PubMedDate not supplied

Perception of horizontal head and trunk rotation in patients with loss of vestibular functions.

In patients with loss of vestibular functions, we studied psychophysically the self-motion perception for 'trunk in space' and 'head in space' during various combinations of horizontal head and trunk rotation in the dark. The results were compared to those of normal subjects. For their 'trunk in space' perception, the subjects relied on their internal image of space, derived from the vestibular receptors in the head, and referred their trunk to this as a reference by adding to it a nuchal trunk-to-head signal. The patients, by contrast, always considered the trunk as stationary. Obviously because they were devoid of any space cues, they abandoned or suppressed a neck contribution to their 'trunk in space' perception, which, in fact, would yield an erroneous perception in almost all conditions in the dark. Both the patients and the subjects based their 'head in space' perception on their internal representation of 'trunk in space' and added to this a nuchal head-to-trunk signal. However, the patients' head-to-trunk signal, unlike that of the subjects, was considerably larger than the actual head-to-trunk rotation at low stimulus frequency. We relate this finding to some unconscious modification of their neck muscle activity during passive head rotation. It appears that the patients' gain of the neck input per se is not increased, but rather that subsets of this input are modified according to the particular function they serve.

Adolescent↗
PubMedDate not supplied

The effects of spastic cerebral palsy on occlusion.

This research paper compares dental casts and lateral cephalometric radiographs of thirty children with spastic cerebral palsy with those of a control group to determine what effect spasticity and cerebral palsy have on dental occlusion and skeletal formation. Muscle spasticity can retard bone growth. Variations in the normal tonus of head and neck muscles can cause malocclusion and arch deformity.

Adolescent↗
PubMedDate not supplied

[The surgical anatomy of the long muscles of the neck and head and the potentials for their use in reconstructive operations on the palatopharyngeal sphincter].

The authors analyze the results of topographoanatomic studies of the prevertebral muscles of the neck, carried out in 37 nonfixed human corpses. They substantiate the possibility of leaving intact the vasculonervous branches in cutting and translocating towards the soft palate of the grafts on an upper peduncle from long muscles of the neck and head.

Adult↗
PubMed1993

Suboccipital muscles in the cat neck: morphometry and histochemistry of the rectus capitis muscle complex.

The morphometry, histochemistry, and biomechanical relationships of rectus capitis muscles were examined in adult cats. This family of muscles contained six members on the dorsal, ventral, and lateral aspects of the upper cervical vertebral column. Three dorsal muscles (rectus capitis posterior major, medius, and minor) formed a layered complex spanning from C1 and C2 to the skull. Rectus capitis posterior major was composed predominantly of fast fibers, but the other two deeper muscles contained progressively higher proportions of slow fibers. One ventral muscle, rectus capitis anterior major, was architecturally complex. It originated from several cervical vertebrae and appeared to be divided into two different heads. In contrast, rectus capitis anterior minor and rectus capitis lateralis were short, parallel-fibered muscles spanning between the skull and C1. The ventral muscles all had nonuniform distributions of muscle-fiber types in which fast fibers predominated. Dorsal and ventral muscle groupings usually had cross-sectional areas of 0.5 cm2 or more, reflecting a potential capacity to generate maximal tetanic force in excess of 9 N. Biomechanical analyses suggested that one muscle, rectus capitis lateralis, had its largest moment in lateral flexion, whereas the other muscles had large, posturally dependent moment arms appropriate for actions in flexion-extension. The observation that most rectus muscles have relatively large cross-sectional areas and high fast-fiber proportions suggests that the muscles may have important phasic as well as postural roles during head movement.

Animals↗
PubMed1977

Changes in fine structure of rat skeletal muscle related to cold acclimation.

Mitochondria became larger and some numerous in the internal red fibers of M. quadriceps femoris and neck muscle in cold-acclimated rats than in warm-acclimated ones, while they became less in number in spite of remarkable increase of size in the external white fibers of the former muscle. Mitochondrial cristae and sarcoplasmic reticuli developed better in the muscles of cold-acclimated rats.

Acclimatization↗
PubMedDate not supplied

Whiplash injuries: clinical picture and diagnostic work-up.

The term "whiplash" commonly refers to symptoms and signs associated with a mechanical event such as a sudden acceleration and deceleration of the neck (due, in the majority of cases, to a road accident), instead of to the mechanism itself. The recent Quebec Classification of Whiplash Associated Disorders (WAD) contributed to define nosographically all the clinical manifestations usually grouped under the terms acute/post-traumatic and late "syndrome". In the late phase of WAD, neck pain and neck muscle contraction have been reported in all cases, together with headache in over 50%. "Headache stemming from the neck", despite numerous attempts to classify this entity (i.e. cervicogenic headache) according to the IASP classification (headache associated with neck disorders), is still a subject of debate. An adequate multiparametric procedure is required to study WAD, which takes into account: the patient's principal details; an exact reconstruction of the event; description and analysis of the signs and symptoms, with various complications and correlated dysfunctions; an objective neurological and neck-shoulder examination; and a battery of complementary instrumental tests which are described in this study. These investigations include evaluation of muscle tension (manual palpation, algometry, EMG recording), kinematic analysis of the cervical spine, neuropsychological and psychological evaluation, and evaluation of disability. In order to assess cervical spine mobility in WAD patients, a 3D kinematic analysis by means of the ELITE system and clinical evaluation were performed in our setting. Seventy patients with whiplash injury and 46 healthy volunteers were enrolled in the study. Patients were tested at the time of first consultation and again 6 months and 12 months later. Clinical evaluation of the range of motion was performed both in patients and in 41 healthy volunteers. Furthermore, patients diagnosed according to the WAD Classification as grade 2 (n = 68) or grade 3 (16) underwent a Quality of life (QoL) evaluation, measured using the short form (36-item) Health Survey (SF36) and the migraine-specific questionnaire (MSQ). According to our data, whiplash patients showed an impairment of cervical spine mobility, as well as a poor QoL, compared to a control group population, even though we observed a trend towards improvement over time in cervical ROM.

Biomechanical Phenomena↗
PubMed2001

[A case with upper limb dominant Guillain-Barré syndrome and serum IgG anti-GT1a antibodies: sparing oropharyngeal palsy].

We report a 78-year-old man with Guillain-Barré syndrome (GBS) who showed upper limb dominant muscle weakness following an upper respiratory infection. He had no weakness in extraocular, oropharyngeal and neck muscles. Tendon reflexes were absent in his upper limbs. Electrophysiological studies suggested demyelination of motor nerves in his upper and lower extremities. He had serum IgG antibodies to GM1 and GT1a but not to GQ1b. Anti-GT1a antibodies did not cross-react to GM1 by means of the absorption test. Titers of the antibodies decreased after recovering from muscle weakness of upper limbs. Since the presence of serum antibodies to GT1a but not to GQ1b were reported in patients with pharyngeal-cervical-brachial weakness of Guillain-Barré syndrome, it has been suggested that anti-GT1a antibodies play a role in acute oropharyngeal neuropathy. This is the first report of a patient with GBS lacking oropharyngeal palsy who had serum IgG antibodies to GT1a but not to GQ1b. Our case suggests that anti-GT1a antibodies are related not only with acute oropharyngeal neuropathy but also with upper limb dominant motor neuropathy.

Aged↗
PubMed1995

Trisynaptic inhibition from the contralateral vertical semicircular canal nerves to neck motoneurons mediated by spinal commissural neurons.

1. Neck motoneurons usually receive disynaptic excitation and inhibition from individual semicircular canal nerves. However, in motoneurons of some neck muscles, trisynaptic inhibition is evoked by stimulation of the contralateral vertical canal nerves. The present study was performed to analyze this pathway and the location and properties of the last-order interneurons responsible for mediating this trisynaptic inhibition from the contralateral vertical canal nerves to neck motoneurons in anesthetized cats. 2. Bipolar stimulating electrodes were implanted on the contralateral anterior (ACN), lateral (LCN), and posterior canal nerve (PCN), and postsynaptic potentials (PSPs) evoked by electrical stimulation of individual canal nerves were intracellularly recorded from motoneurons of the obliquus capitis inferior (OCI), longus capitis (LC), and rectus capitis posterior (RCP) muscles. Stimulation of the contralateral ACN evoked trisynaptic inhibitory PSPs (IPSPs) in OCI and LC motoneurons and disynaptic excitatory PSPs (EPSPs) in RCP motoneurons. Stimulation of the contralateral PCN evoked di- and trisynaptic IPSPs in OCI and RCP motoneurons and disynaptic EPSPs in LC motoneurons. Stimulation of the contralateral LCN evoked disynaptic EPSPs in all of the motoneurons examined. 3. To determine the pathway that mediates these trisynaptic IPSPs from the vertical canal nerves to neck motoneurons, a lesion was made in the lower medulla, and the patterns of PSPs evoked by stimulation of the three contralateral canal nerves were compared before and after the lesion. Interruption of the ipsilateral medial longitudinal fascicle (MLF) abolished all disynaptic EPSPs and IPSPs from the three contralateral canal nerves in OCI, LC, and RCP motoneurons. In contrast, trisynaptic IPSPs evoked by stimulation of the contralateral ACN or PCN remained unaffected by sectioning the MLFs bilaterally. Sectioning of the contralateral lateral vestibulospinal tract (LVST) eliminated the trisynaptic IPSPs in OCI and LC motoneurons evoked by contralateral ACN stimulation and trisynaptic IPSPs in OCI and RCP motoneurons evoked by contralateral PCN stimulation but did not affect disynaptic EPSPs and IPSPs. 4. Stimulation of the contralateral LVST in the lower medulla after sectioning the bilateral MLFs evoked disynaptic IPSPs in OCI, LC, and RCP motoneurons. Because the LVST only projects ipsilaterally, this finding indicates that the last-order interneurons that mediate the trisynaptic inhibition through the LVST are most likely commissural neurons located in the spinal cord. 5. To determine the locations of last-order commissural neurons terminating on OCI motoneurons, wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) was injected into the OCI muscle nerve at C1.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2005

Morphology, architecture, and biomechanics of human cervical multifidus.

STUDY DESIGN: Cadaveric dissections and biomechanical modeling were used to study the human cervical multifidus muscle. OBJECTIVES: To describe attachment patterns of the multifidus in the cervical region, to quantify the muscle's architecture, and to use a biomechanical model to calculate the moment-generating capacity of the cervical multifidus. SUMMARY OF BACKGROUND DATA: Deep neck muscles such as the multifidus may play an important role in cervical spine stability and neck pain. However, there are limited data regarding the fascicular attachments or architecture parameters necessary to calculate force and moment. METHODS: The multifidus spinae was studied by dissection of nine cadaveric specimens. Fascicles were grouped according to attachment, and architecture parameters (musculotendon length, fascicle length, and physiologic cross-sectional area) were quantified. The data were used in a biomechanical model to calculate moment arm, force-, and moment-generating capacity of the multifidus. RESULTS: The multifidus originates from the facet capsules of lower cervical vertebrae and the transverse processes of upper thoracic vertebrae. The fascicles span 2 to 5 vertebral segments from origin to insertion, and they insert on the spinous processes and laminae of superior cervical vertebrae. For each fascicular subgroup, musculotendon lengths ranged from 2.0 to 6.9 cm, fascicle lengths ranged from 1.2 to 3.7 cm, and physiologic cross-sectional area ranged from 0.1 to 1.0 cm2. The total moment-generating capacity of the cervical multifidus in the neutral posture was predicted to be approximately 0.7 Nm for extension and lateral bending and 0.3 Nm for axial rotation. CONCLUSIONS: The fascicular attachment pattern of the multifidus spinae in the cervical region appears to be unique to that region. The direct attachment to cervical facet capsules supports a possible role in neck pain and injury. Characterizing the biomechanical function of the multifidus is important for the analysis of normal and pathologic conditions.

Adult↗