Search

Radiculopathy is diagnosed using a combination of history, physical examination, and imaging. Unfortunately, well-established dermatomal and myotomalmaps are an oversimplification of the convoluted nature of spinal sensory and motor innervation. When clinical presentation and imaging seemingly contradict one another, it is important to consider variant innervation patterns. This article presents three patients with objective dermatomal and/or myotomal deficits due to disc herniations whose clinical presentations are "textbook" for nerve root pathology that is adjacent to the nerve root that is actually compromised. In addition, the literature is reviewed to discuss the history of dermatomal and myotomal maps, the effectiveness of a clinician's ability to determine the precise pathologic disc and nerve root level in patients presenting with radiculopathy, and anatomical explanations as to why inconsistencies such as those seen in the patients in these cases exist. [ABSTRACT FROM AUTHOR]

• Study shows important inter-individual variability in myotome innervation among patients. • Most muscles have multi-radicular innervation. • Root territories strongly overlap, not only under dorsal but also ventral stimulation at threshold. Most of knowledge on muscle radicular innervation was from explorations in root/spinal cord pathologies. Direct and individual access to each of the lumbar-sacral -ventral and dorsal- nerve roots during dorsal rhizotomy for spastic diplegia allows precise study of the corresponding muscle innervation. Authors report the lumbo-sacral segmental myotomal organization obtained from recordings of muscle responses to root stimulation in a 20-children prospective series. Seven key-muscles in each lower limb and anal sphincter were Electromyography (EMG)-recorded and clinically observed by physiotherapist during L2-to-S2 dorsal rhizotomy. Ventral roots (VR), for topographical mapping, and dorsal roots (DR), for segmental excitability testing, were stimulated, just above threshold for eliciting muscular response. In 70% of the muscles studied, VR innervation was pluri-radicular, from 2-to-4 roots, with 1 or 2 roots being dominant at each level. Overlapping was important. Muscle responses to DR stimulation were 1.75 times more extended compared to VR stimulation. Inter-individual variability was important. Accuracy of root identification and stimulation with the used method brings some more precise information to radicular functional anatomy. Those neurophysiological findings plead for performing Intra-Operative Neuromonitoring when dealing with surgery in the lumbar-sacral roots. [ABSTRACT FROM AUTHOR]

Background: Accurate prediction of walking function after a traumatic spinal cord injury (SCI) is crucial for an appropriate tailoring and application of therapeutical interventions. Long-term outcome of ambulation is strongly related to residual muscle function acutely after injury and its recovery potential. The identification of the underlying determinants of ambulation, however, remains a challenging task in SCI, a neurological disorder presented with heterogeneous clinical manifestations and recovery trajectories., Objectives: Stratification of walking function and determination of its most relevant underlying muscle functions based on stratified homogeneous patient subgroups., Methods: Data from individuals with paraplegic SCI were used to develop a prediction-based stratification model, applying unbiased recursive partitioning conditional inference tree (URP-CTREE). The primary outcome was the 6-minute walk test at 6 months after injury. Standardized neurological assessments ≤15 days after injury were chosen as predictors. Resulting subgroups were incorporated into a subsequent node-specific analysis to attribute the role of individual lower extremity myotomes for the prognosis of walking function., Results: Using URP-CTREE, the study group of 361 SCI patients was divided into 8 homogeneous subgroups. The node specific analysis uncovered that proximal myotomes L2 and L3 were driving factors for the differentiation between walkers and non-walkers. Distal myotomes L4-S1 were revealed to be responsible for the prognostic distinction of indoor and outdoor walkers (with and without aids)., Conclusion: Stratification of a heterogeneous population with paraplegic SCI into more homogeneous subgroups, combined with the identification of underlying muscle functions prospectively determining the walking outcome, enable potential benefit for application in clinical trials and practice.

Study Design. Cross-sectional study. Objective. The purpose of this study is to compare pressure pain threshold (PPT) values between patients with chronic nonspecific low back pain (CLBP) and healthy individuals and correlate PPT values of the structures investigated with demographic and clinical data from patients with CLBP. Summary of Background Data. Chronic pain may decrease pain tolerance of almost the entire spinal cord segment; however, previous studies on PPT in patients with low back pain have limited their focus to evaluating only patient complaints. Methods. Forty subjects participated in the study: 20 with a clinical diagnosis of CLBP and 20 healthy individuals. Outcome measures were PPT values of myotomes, sclerotomes, and dermatomes corresponding to segments L1 to S3; demographic, clinic, and social data; visual analogue scale, and Roland and Morris Questionnaire. Results. Most analyzed structures had lower PPT values in patients with CLBP than in healthy individuals on both sides (bilaterally). PPT correlated positively with height and pain duration (P < 0.05) and negatively with body mass index in the suprainterspinous ligament between L2 and L3 and dermatomes L5 to S2 (P < 0.05). Conclusion. Our results showed that individuals with CLBP have lower PPT values than healthy individuals in almost all assessed structures. We propose a simple approach that can differentiate patients with CLBP whose hyperalgesia in the painful area may be the result of several mechanisms that should be further investigated, such as sensitization of the central nervous system. [ABSTRACT FROM AUTHOR]

Stretch injuries of the C5-C7 roots of the brachial plexus traditionally have been associated with palsies of shoulder abduction/external rotation, elbow flexion/extension, and wrist, thumb, and finger extension. Based on current myotome maps we hypothesized that, as far as motion is concerned, palsies involving C5-C6 and C5-C7 root injuries should be similar. In 38 patients with upper-type palsies of the brachial plexus, we examined for correlations between clinical findings and root injury level, as documented by CT tomomyeloscan. Contrary to commonly held beliefs, C5-C7 root injuries were not associated with loss of extension of the elbow, wrist, thumb, or fingers, but residual hand strength was much lower with C5-C7 vs C5-C6 lesions. [ABSTRACT FROM PUBLISHER]

Abstract: In spina bifida aperta (SBA), spinal MRI provides a surrogate marker to estimate muscle damage caudal to the myelomeningocele (MMC). This muscle damage by the MMC can be quantified by intra-individual comparison of muscle ultrasound density (MUD) caudal versus cranial to the MMC (dMUD = [MUDcaudal-to-the-MMC] − [MUDcranial-to-the-MMC]). Quantitative dMUD assessment requires time, equipment and expertise, whereas it could also be visually determined by differences in muscle echodensity caudal vs. cranial to the MMC (visual-dMUD). If visual and quantitative dMUD correspond, visual dMUD assessment could provide a clinical screening parameter. In 100 SBA muscle ultrasound recordings of patients with various MMC levels, we aimed to compare quantitative dMUD (dMUD = [MUDcalf-muscle/S1] − [MUDquadriceps-muscle/L2-L4]) with visual dMUD assessments by 20 different observers. Results indicate that quantitative dMUD can be visually detected (sensitivity 86%; specificity 57%), implicating that visual dMUD screening could provide a quick, clinical screening tool for muscle impairment by the MMC. [Copyright &y& Elsevier]

Due to rapid depletion of wild stocks, the necessity to cultivate fish is eminent. Current fish farming practices seek to improve flesh quality. The notion that white muscles are the main target of the fishing industry is emphasized. A novel approach is suggested based on the development of white muscles in wild fish from eggs to adults. A compilation of facts about white muscle structure, function and ontogeny is followed by an account of the changes in swimming behaviour and performance related to the use of white muscle during growth from larva to adult. Ecological data narrate early swimming performance with white muscle development and growth, unveiling some of the important natural selection factors eliminating weak swimmers and poor growers from the breeding stock. A comparison between fish culture practise and natural conditions reveals fundamental differences. New approaches following wild breeding processes promise several important advantages regarding the quality of white muscle. [ABSTRACT FROM AUTHOR]

Knowledge of segmental innervation of skeletal muscles is essential for diagnosing lumbar radiculopathy. Myotomes and dermatomes are traditionally thought to be innervated by a single spinal segment, but experimental studies have shown that this pattern of segmental innervation allows considerable overlap. This implies that muscles (or dermatomes) are innervated not only by axons of one spinal segment, but also partially by axons of adjacent spinal levels. We describe a patient in whom overlap in segmental innervation complicated adequate diagnosis of a recurrent lumbar hernia. Further, we present an outline of electrophysiological and anatomical studies on segmental innervation. [ABSTRACT FROM AUTHOR]

Localization of the acetylcholine (nicotinic) receptor sites was investigated in the developing cervical myotomes of the early chick embryo by radioautography at the light and electron microscope level, using I-α-bungarotoxin. The presence of cholinergic receptor sites was detected in situ as early as 60 hours of incubation (stage 17); their relative density increased in the myotome during the differentiation of the somite. Specific labeling of these receptor sites was detected in the myotomal tissue but not in the notochord, spinal cord or periaxial mesenchyme. The distribution of the receptor sites was uniform in the myotome at 3 days in ovo. An anterior-posterior asymmetry of the density appeared at 4 days in ovo and developed up to the 6th day. The highest density of these toxin-binding receptor sites was observed near the spinal motor nerve bundle as revealed by silver staining. These observations, made in situ, are discussed with respect to the possible neurotrophic or physical effects of the early motor innervation. [ABSTRACT FROM AUTHOR]

Abstract: There are 31 pairs of spinal nerves: eight cervical, 12 thoracic, five lumbar, five sacral and one coccygeal. They form by fusion of a posterior sensory spinal root (bearing its posterior root ganglion) with an anterior motor root. These join at each intervertebral foramen. Typically, the nerve then divides into a posterior and an anterior primary ramus. The former supplies the vertebral muscles and dorsal skin. The anterior primary ramus in the thoracic region bears a white ramus communicans to the sympathetic ganglion. Each spinal nerve receives a grey ramus from the sympathetic chain. The nerves T2–T12 supply the skin and muscles of the trunk sequentially. The other nerves are arranged into the cervical, brachial, lumbar and sacral plexuses. The cervical plexus supplies the skin and anterior muscles of the neck and form the phrenic nerve (C3–C5), while the brachial plexus supplies the skin and muscles of the upper limb, and the lumbar and sacral plexuses supply the skin of the lower limb and perineum and the muscles of the posterior abdominal wall, pelvis, perineum and lower limb. The segmental nerves are arranged to supply the skin (dermatomes), while the segmental supply to the limb muscles, the myotomes, is more complex. [Copyright &y& Elsevier]

Abstract: There are 31 pairs of spinal nerves: eight cervical, 12 thoracic, five lumbar, five sacral and one coccygeal. They form by fusion of a posterior sensory spinal root (bearing its posterior root ganglion) with an anterior motor root. These join at each intervertebral foramen. Typically, the nerve then divides into a posterior and an anterior primary ramus. The former supplies the vertebral muscles and dorsal skin. The anterior primary ramus in the thoracic region bears a white ramus communicans to the sympathetic ganglion. Each spinal nerve receives a grey ramus from the sympathetic chain. The nerves T2–T12 supply the skin and muscles of the trunk sequentially. The other nerves are arranged into the cervical, brachial, lumbar and sacral plexuses. The cervical plexus supplies the skin and anterior muscles of the neck and forms the phrenic nerve (C3–C5), while the brachial plexus supplies the skin and muscles of the upper limb, and the lumbar and sacral plexuses supply the skin of the lower limb and perineum and the muscles of the posterior abdominal wall, pelvis, perineum and lower limb. The segmental nerves are arranged to supply the skin (dermatomes), while the segmental supply to the limb muscles, the myotomes, is more complex. [Copyright &y& Elsevier]