Craniocervical instability treated by contoured loop fixation.
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Rigid posterior fixation of the skull to the third, fourth and fifth cervical vertebrae was achieved in three patients who, as a result of operation, had gross instability of the craniocervical junction. An anatomically contoured steel loop was secured to the occiput via small burr holes and to the vertebrae by sublaminar wiring. This technique has the advantage over bone grafting, either alone or with cement, in that it affords rigid stabilisation, allows early mobilisation and may contribute to eventual bony fusion. (+info)
Bulbar symptoms and episodic aphonia associated with atlanto-occipital subluxation in ankylosing spondylitis.
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A patient with intermittent aphonia associated with atlanto-occipital subluxation due to ankylosing spondylitis is presented and discussed. The only other case from the literature is reviewed and compared with our patient, where symptoms and signs of episodic low bulbar disease, presumably due to intermittent vascular insufficiency, were relieved by external bracing. (+info)
Persistent proatlantal artery.
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A case of persistent proatlantal artery is described and the developmental anatomy reviewed. This vessel, arising from the internal carotid artery in the neck, is liable to be confused with the hypoglossal artery, but unlike the latter it forms the vertebral artery outside the skull and enters through the foramen magnum. (+info)
Experimental production of forward dislocation in the human cervical spine.
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Entire human cadaveric cervical spines with the basiocciput were subjected to load in a compression apparatus to simulate the clinical situation of forward dislocation. The movements were recorded by lateral cineradiography. Vertical load was measured by a potentiometric transmitter synchronised with each frame of the cineradiograph. The lower part of the spine was flexed and fixed, and the upper extended and free to move forward. Vertical compression then produced bilateral dislocation of the facets without fracture. If lateral tilt or axial rotation occurred as well, a unilateral dislocation was produced. The maximum vertical load was only 145 kilograms, and coincided with the rupture of the posterior ligament and capsule and the stripping of the anterior longitudinal ligament, but this occurred before dislocation. The low vertical load indicates a peculiar vulnerabiity of the cervical spine in this position and correlates well with the minor trauma often seen in association with forward dislocation. (+info)
Cytology of equine cerebrospinal fluid.
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The cytology of cerebrospinal fluid samples from horses is described. The samples were obtained from 24 normal horses, 35 horses with axonal degeneration and/or spinal cord compression, 29 horses with encephalomyelitis, 14 horses with other lesions of the nervous system, and eight horses with signs of neurologic dysfunction of undetermined origin. (Three of the latter were suspected botulinum intoxications.) Fluid was aspirated from the atlanto-occipital space following general anesthesia or immediately after a lethal dose of barbiturate. In two horses, fluid also was aspirated from the lumbosacral space. Small mononuclear cells were predominant in normal horses, and in most horses with axonal degeneration and encephalomyelitis. Several horses with encephalomyelitis also had neutrophils, eosinophils, and some mitotic figures. Although the cytologic findings were abnormal in many of the horses with disease of the central nervous system, in most horses the cytologic findings were normal. (+info)
The human vertebral column at the end of the embryonic period proper. 2. The occipitocervical region.
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The present investigation of the cervical region of the vertebral column at eight post-ovulatory weeks is the first such study based on precise reconstructions of staged embryos. At the end of the embryonic period proper, a typical vertebra is a U-shaped piece of cartilage characterized by spina bifida occulta. The notochord ascends through the centra and leaves the dens to enter the basal plate of the skull. The median column of the axis comprises three parts (designated X, Y, Z) which persist well into the fetal period. They are related to the first, second and third cervical nerves, respectively. Part X may project into the foramen magnum and form an occipito-axial joint. Part Z appears to be the centrum of the axis. The articular columns of the cervical vertebrae are twofold, as in the adult: an anterior (atlanto-occipital and atlanto-axial) and a posterior (from the lower aspect of the axis downwards). Alar and transverse ligaments are present. Cavitation is not found in the embryonic period in either the atlanto-occipital or zygapophysial joints, and is generally not present in the median atlanto-axial joint either. Most of the transverse processes exhibit anterior and posterior tubercles. An 'intertubercular lamella' may or may not be present, i.e. the foramina transversaria are being formed around the vertebral artery. The spinal ganglia are generally partly in the vertebral canal and partly on the neural arches, medial to the articular processes. During the fetal period, the articular processes shift to a coronal position and this alteration appears to be associated with a corresponding change in the location of the spinal ganglia. (+info)
Abrupt change in head position and cerebral infarction.
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Eight patients are described who developed infarctions in the vertebral-basilar artery distribution following chiropractic neck manipulation or spontaneous head turning. The angiographic and autopsy findings indicate that injury to the intima of the vertebral artery at the atlantoaxial joint forms a nidus for thrombus formation which may propogate or embolize to involve other vessels in the vertebral-basilar system and result in progressive brainstem infarction. The role of anticoagulation in these patients is discussed. (+info)
Osteochondrosis in feedlot cattle.
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Beginning in summer 1977 and continuing through four consecutive seasons, we examined lame limb joints from 106 partially fattened cattle and 28,235 pairs of occipital condyles from fully fattened cattle for osteochondrosis. Of the 106 lame cattle, nine (8.5%) had characteristic lesions, usually in their stifle joints, and of the 28,235 atlanto-occipital joints, 1063 (3.8%) had lesions on their condyles. Slices of affected articular cartilage and subjacent bone were studied radiographically and histologically. Radiographs showed subchondral defects and epiphyseal "cyst-like" lesions, and histologic sections showed disarrayed and degenerated chondrocytes. Splits occurred along osteochondral junctions or in adjacent cartilage or bone. Some bone trabeculae had been replaced by fibrous tissue that, in some areas, extended deep into epiphyses. (+info)