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Nerve Territories (nerve + territory)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Excess target-derived neurotrophin-3 alters the segmental innervation of the skin

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2001
Amy M. Ritter
Abstract It is thought that dermatomes are established during development as a result of competition between afferents of neighbouring segments. Mice that overexpress neurotrophins in the skin provide an interesting model to test this hypothesis, as they possess increased numbers of sensory neurons, and display hyperinnervation of the skin. When dermatomal boundaries were mapped in adult mice, it was found that those in nerve growth factor and brain-derived neurotrophic factor overexpressers were indistinguishable from wild-type animals but that overlap between adjacent segments was greatly reduced in neurotrophin-3 (NT-3) overexpressers. However, dermatomes in heterozygous NT-3 knockout mice displayed no more overlap than wild-types. In order to quantify differences across strains, innervation territories of thoracic dorsal cutaneous nerves were mapped and measured in adult mice. Overlap between adjacent dorsal cutaneous nerves was normal in nerve growth factor overexpressing mice, but much reduced in NT-3 overexpressers. However, this restriction was not reflected in the central projection of the dorsal cutaneous nerve, creating a mismatch between peripheral and central projections. Dorsal cutaneous nerve territories were also mapped in neonatal mice aged postnatal day 7,8. In neonates, nerve territories of NT-3 overexpressers overlapped less than wild-types, but in neonates of both strains the amount of overlap was much greater than in the adult. These results indicate that substantial separation of dermatomes occurs postnatally, and that excess NT-3 enhances this process, resulting in more restricted dermatomes. It may exert its effects either by enhancing competition, or by direct effects on the stability and formation of sensory endings in the skin. [source]

Speed of onset of ,corner pocket supraclavicular' and infraclavicular ultrasound guided brachial plexus block: a randomised observer-blinded comparison

ANAESTHESIA, Issue 7 2009
M. J. Fredrickson
Summary This prospective, randomised, observer blinded study compared the onset time of brachial plexus block using 2% lidocaine 25,30 ml with adrenaline 5 ,g.ml,1 into the ,corner pocket' inferolateral/lateral to the subclavian artery (supraclavicular, n = 30) or to a triple point injection around the axillary artery (infraclavicular, n = 30). Mean (SD) onset time for complete pinprick sensory blockade assessed by a blinded observer in all four distal nerves was similar in both groups: supraclavicular = 22 (9.4) min, infraclavicular = 21 (7.1) min, p = 0.59. Complete sensory blockade in all four nerve territories at 30 min was achieved in 57% in group supraclavicular and 70% in group infraclavicular (p = 0.28). Painless surgery without the requirement for block supplementation was higher in group infraclavicular (28/30, 93%) compared with group supraclavicular (19/30, 67%; p = 0.01). Of the 11 failures in group supraclavicular, nine were due to incomplete ulnar nerve territory anaesthesia. These results do not support the concept of rapid onset successful supraclavicular block via a simple ultrasound-guided local anaesthetic injection inferolateral to the subclavian artery. [source]

Facial and glossal distribution of anaesthesia after inferior alveolar nerve block

JOURNAL OF ORAL REHABILITATION, Issue 2 2003
H.-K. Kim
summary, The aim of this study was to subjectively determine the distribution of anaesthesia by mapping areas of sensory loss following inferior alveolar nerve block. Fifty healthy dental students were the subjects of this study (men 32, women 18). They were asked to draw the anaesthetized area on a diagram of the face and tongue 20 min after inferior alveolar nerve block. They evaluated the degree of anaesthesia by touching their faces and moving their tongues. All of the 50 subjects reported anaesthesia in the facial area. Of these, 21 (42%) reported the cutaneous distribution of anaesthesia on mental nerve territory only. Seventeen subjects (34%) reported anaesthesia on mental and buccal nerve territory. Nine subjects (18%) reported anaesthesia on mental, buccal, and auriculotemporal nerve territory. Two subjects (4%) reported anaesthesia on mental and auriculotemporal nerve territory and one subject (2%) on mental, buccal and infra-orbital nerve territory. Forty-seven of the 50 subjects (94%) reported anaesthesia of the tongue with the various degree of anaesthesia according to the area. Of these, 17 subjects (34%) reported strong anaesthesia on the anterior area and weak anaesthesia on the middle part of the tongue. Nineteen subjects (38%) reported strong anaesthesia of the lateral area and weak anaesthesia on the medial area, and 11 subjects (22%) reported anaesthesia on only the lateral side of the tongue. Three subjects (6%) reported no anaesthesia of the tongue. The distribution of anaesthesia of the facial and glossal regions determined subjectively after inferior alveolar nerve block, varies significantly between individuals. [source]