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STUDY DESIGN: Immunohistochemistry labeled pre- and postsynaptic structural markers to quantify excitatory and inhibitory synapses in the spinal superficial dorsal horn at 14 days after painful facet joint injury in the rat. OBJECTIVE: The objective of this study was to investigate the relationship between pain and synapse density in the spinal cord after facet injury. SUMMARY OF BACKGROUND DATA: Neck pain is a major contributor to disability and often becomes chronic. The cervical facet joints are susceptible to loading-induced painful injury, initiating spinal central sensitization responses. Although excitatory synapse plasticity has been reported in the superficial dorsal horn early after painful facet injury, whether excitatory and/or inhibitory synapse density is altered at a time when pain is maintained is unknown. METHODS: Rats underwent either a painful C6/C7 facet joint distraction or sham surgery. Mechanical hyperalgesia was measured and immunohistochemistry techniques for synapse quantification were used to quantify excitatory and inhibitory synapse densities in the superficial dorsal horn at day 14. Logarithmic correlation analyses evaluated whether the severity of facet injury correlated with either behavioral or synaptic outcomes. RESULTS: Facet joint injury induces pain that is sustained until day 14 (P <0.001) and both significantly greater excitatory synapse density (P = 0.042) and lower inhibitory synapse density (P = 0.0029) in the superficial dorsal horn at day 14. Injury severity is significantly correlated with pain at days 1 (P = 0.0011) and 14 (P = 0.0002), but only with inhibitory, not excitatory, synapse density (P = 0.0025) at day 14. CONCLUSION: This study demonstrates a role for structural plasticity in both excitatory and inhibitory synapses in the maintenance of facet-mediated joint pain, and that altered inhibitory, but not excitatory, synapse density correlates to the severity of painful joint injury. Understanding the functional consequences of this spinal structural plasticity is critical to elucidate mechanisms of chronic joint pain. LEVEL OF EVIDENCE: N /A.

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Ten forelimbs of five Myrmecophaga tridactyla were examined to study the anatomy of the brachial plexus. The brachial plexuses of the M. tridactyla observed in the present study were formed by the ventral rami of the last four cervical spinal nerves, C5 through C8, and the first thoracic spinal nerve, T1. These primary roots joined to form two trunks: a cranial trunk comprising ventral rami from C5-C7 and a caudal trunk receiving ventral rami from C8-T1. The nerves originated from these trunks and their most constant arrangement were as follows: suprascapular (C5-C7), subscapular (C5-C7), cranial pectoral (C5-C8), caudal pectoral (C8-T1), axillary (C5-C7), musculocutaneous (C5-C7), radial (C5-T1), median (C5-T1), ulnar (C5-T1), thoracodorsal (C5-C8), lateral thoracic (C7-T1) and long thoracic (C6-C7). In general, the brachial plexus in the M. tridactyla is similar to the plexuses in mammals, but the number of rami contributing to the formation of each nerve in the M. tridactyla was found to be larger than those of most mammals. This feature may be related to the very distinctive anatomical specializations of the forelimb of the anteaters.

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BACKGROUND: In complete brachial plexus palsy, we have hypothesized that grafting to the musculocutaneous nerve should restore some hand sensation because the musculocutaneous nerve can drive hand sensation directly or via communication with the radial and median nerves. OBJECTIVE: To investigate sensory recovery in the hand and forearm after C5 root grafting to the musculocutaneous nerve in patients with a total brachial plexus injury. METHODS: Eleven patients who had recovered elbow flexion after musculocutaneous nerve grafting from a preserved C5 root and who had been followed for a minimum of 3 years were screened for sensory recovery in the hand and forearm. Six matched patients who had not undergone surgery served as controls. Methods of assessment included testing for pain sensation using Adson forceps, cutaneous pressure threshold measurements using Semmes-Weinstein monofilaments, and the static 2-point discrimination test. Deep sensation was evaluated by squeezing the first web space, and thermal sensation was assessed using warm and cold water. RESULTS: All grafted patients recovered sensation in a variable territory extending from just over the thenar eminence to the entire lateral forearm and hand. Seven patients were capable of perceiving 2-0 monofilament pressure on the thenar eminence, palm, and dorsoradial aspect of the hand. All could differentiate warm and cold water. None recovered 2-point discrimination. None of the patients in the control group recovered any kind of sensation in the affected limb. CONCLUSION: Grafting the musculocutaneous nerve can restore nociceptive sensation on the radial side of the hand.

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Ansa cervicalis is a loop of nerves found in the anterior wall of the carotid sheath in the carotid triangle of neck innervating infrahyoid muscles. Its superior root has fibres from the first cervical nerve that leaves the hypoglossal nerve and joins the inferior root formed by the branches from the second and third cervical nerves. The two roots join to form ansa cervicalis. The ansa cervicalis nerve formation is relatively complex, as its course and location along the great vessels of the neck vary. In the present case on the left side of an adult male cadaver the inferior root was absent and the contributions from C2 and C3 were joining independently with the superior root of ansa to form ansa cervicalis. However no such variation was found in the ansa cervicalis formation on the right side.

El asa cervical es un loop de nervios que se encuentra en la pared anterior de la vaina carotídea, en el triángulo carotídeo del cuello, que inerva los músculos infrahioideos. Su raíz superior tiene fibras del primer nervio cervical que sale del nervio hipogloso y se une a la raíz inferior formada por las ramas de los nervios cervicales segundo y tercero. Las dos raíces se unen para formar el asa cervical. La formación del asa cervical del nervio es relativamente compleja, ya que su curso y ubicación varía a lo largo de los grandes vasos del cuello. En el lado izquierdo del cuello de un cadáver adulto de sexo masculino, la raíz inferior del asa cervical estaba ausente y las contribuciones de los ramos de C2 y C3 se unieron, de forma independiente, con la raíz superior del asa y así formar el loop.

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Cervicogenic headache (CeH) is a well-recognized headache syndrome, distinguishable from other primary and secondary headaches. Although in some cases a cervical lesion may be detected in connection with the headache, many CeH patients have no demonstrable lesion. Besides, most of the frequent cervical diseases, such as spondylosis and disc herniations, do not present with headache of the cervicogenic type. This suggests that the neck is not an independent headache generator. CeH may depend in addition on a central predisposition counterpart, leading to the activation of the trigeminovascular system and pain generation.

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La generación de dolor de cabeza desde estructuras cervicales no es un concepto nuevo. Aunque no existe consenso en grupos expertos, muchos estudios han tratado de dar luz al asunto y establecer criterios clínicos para el diagnóstico diferencial, como también proveer un tratamiento adecuado. Es entonces imperativo disponer de bases anatomofisiológicas para su mejor comprensión. La emergencia de los nervios, su distribución cutánea, y sus relaciones anatómicas conforman un esquema de distribución sensitiva cérvico-cráneo-facial que nos permitiría explicar y asociar a algunos síndromes dolorosos de esta región. Este estudio incluyó una muestra de doce disecciones (n=12) de la región posterior cervical efectuada hasta el plano de los músculos semiespinosos. Diferentes estructuras anatómicas que se relacionan o podrían generar dolor de cabeza son descritas. Es así, como por ejemplo, comprobamos que el nervio occipital mayor, en su recorrido, puede estar sometido a tensión, atrapamiento o presiones en el paso a través del músculo semiespinoso, en el ojal fascio-muscular o bien al pasar entre las inserciones téndino musculares del esplenio y trapecio respectivamente. De este modo podría postularse una correlación anatomopatológica dentro de las posibles etiologías del síndrome cervicooccipital.

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Pacientes com queixas de sofrimento das raízes cervicais são freqüentes na prática diária de qualquer especialidade médica. Doenças degenerativas e herniações nas junções de C5-C6 e C6-C7 são as causas mais comuns de acontecimento radicular cervical. Os autores defendem aqui a idéia "low tech high touch" na avaliação das radiculopatias cervicais, lançando mão de um exame físico acurado e dando ênfase a aspectos tais como: a simples inspeção, o exame da força muscular, dos reflexos profundos e da sensibilidade, além de algumas manobras embasadas no conhecimento da inervação segmentar. A dor localizada e as alterações da sensibilidade em faixa são as manifestações mais freqüentemente encontradas. Para cada raiz com exceção de C1 e C2, encontramos um músculo sentinela que pode evidenciar sinais de fraqueza ou atrofia. Os testes que comprovam dano raticular como, por exemplo, o sinal de Bickele, os testes de Spurling (com 100% de especificidade) e de Tensão do Membro Superior entre outros, quando positivos, são denunciadores de acometimento destes pequenos segmentos neurais aos quais denominamos raízes nervosas.

Patients with complaints of suffering in the cervical roots are frequent in the daily practice of any medical specialty. Degenerative diseases and disk herniations from C5-C6 and C6-C7 are the most common causes for cervical roots lesions. The authors defend the idea of "low tech high touch" in the evaluation of the cervical root diseases using an accurate physical examination and highlighting to aspects such as: simple inspection, examination of muscular strength, deep reflexes, and sensitivity, additionally to some maneuvers based on the knowledge of segmentar innervation. The localized pain and the alterations of dermatomes' sensitivity are the most frequently found manifestations. For each root, with exception of C1 and C2, one can see a sentinel muscle that could show signs of weakness or atrophy. The root suffering tests such as, for example, the Bickele and Spurling (the latter with 100% of specificity) and Upper Limb Tension Test, between others, when positive, show suffering of these small neural segments which we call nervous roots.

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Desde comienzos del siglo XX se sabe, por experimentos en gatos, que el cuello juega un papel significativo en la postura y el equilibrio. Investigaciones en animales demuestran la existencia de sensores provenientes de las cápsulas sinoviales de las articulaciones cervicales. El rol exacto de éstas en el equilibrio se dificulta por la posible participación conjunta de otros órganos del cuello como el muscular, vascular y sistema simpático. Se intenta demostrar, mediante métodos de exámenes clínicos diferentes, que las reacciones obtenidas con estimulaciones funcionales son sólo propias, y diferentes de las articulaciones cervicales. Para ello se estimularon los sensores propioceptivos de las articulaciones facéticas de los huesos cervicales usando: 1. un martillo de 900 gr, con una gruesa punta de goma; 2. una plataforma vibrante, para realizar el test de posturografía; 3. una electronistagmografía; y 4. una herramienta en vibración con una gruesa punta de goma. De un total de 2.304 pacientes que consultaron en vértigo, y a quienes se les hicieron estos tests, el 9,8 por ciento demostró que se trataba de un vértigo cervical, pues el resto de los enfermos no mostraron alteración alguna. La articulación atlanto-axoídea fue la más frecuentemente afectada. Los síntomas de consulta más comunes fueron el desequilibrio, seguido por el vértigo giratorio, la oscilopsia y drop attacks.

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Cranial sensory innervation is supplied mainly by the trigeminal nerves and by the first cervical nerves. Excitatory and inhibitory interactions among those nerve roots may occur in a mechanism called nociceptive convergence, leading to loss of somato-sensory spatial specificity. Three volunteers in an experimental trial had sterile water injected over their greater occipital nerve on one side of the neck. Pain intensity was evaluated 10, 30 and 120 s after the injection. Two of the patients reported intense pain. Trigeminal autonomic features, suggestive of parasympathetic activation, were seen associated with trigeminally distributed pain. These data add to and reinforce previous evidence of convergence of cervical afferents on the trigeminal sensory circuit.

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The authors study the vertebral artery from its origin to termination, especially in its course inter and intra transverse process and show its relation to venous and nervous structures, as well as its behavior toward adjacent conjunctive tissue. They discuss the relation of the anatomy to the physiopathology of the vertebral artery and come to the conclusion that the vertebral artery is fixed to adjacent structures in the fibrous osteomuscular tunnel by means of a continuous lamina of collagen along its entire course and that there is considerable independence between the artery and the branches of these final nerves

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The authors study the vertebral artery from its origin to termination, especially in its course inter and intra transverse process and show its relation to venous and nervous structures, as well as its behavior toward adjacent conjunctive tissue. They discuss the relation of the anatomy to the physiopathology of the vertebral artery and come to the conclusion that the vertebral artery is fixed to adjacent structures in the fibrous osteomuscular tunnel by means of a continuous lamina of collagen along its entire course and that there is considerable independence between the artery and the branches of these final nerves.

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A produçäo de cefaléias a partir de anormalidades no pescoço nunca foi sistematizada a ponto de permitir o estudo de sua patogenia, embora fosse fato conhecido há muitos anos. Sjaastad et al. descreveram, em 1983, grupo de pacientes com uma cefaléia uniforme e estereotipada. Os ataques se caracterizam por dor moderada, unilateral sem mudança de lado, de longa duraçäo, recorrendo em poucas semanas. A cefaléia podia ser provocada por certos movimentos do prescoço ou por commpressäo de pontos desencadeadores ali localizados. A dor se iniciava na regiäo cervical, irradiando-se para as áreas órbito-fronto-temporal e/ou facial. A denominaçäo "cefaléia cervicogênica" (CC) foi proposta para esta entidade. Sua fisiopatogenia näo é completamente conhecida. Bloqueios da raiz C2 e do nervo grande occipital eliminam a dor. Apresentamos um caso de CC, fazendo alguns comentários acerca do seu quadro clínico, fisiopatologia e tratamento

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