Search

The supracochlear cartilage is known as an accessory cartilage of the chondrocranium situated between the otic capsule and the trigeminal ganglion. Although claimed to appear regularly during human development, its incidence and development have been reported only scarcely in the literature. The aim of this study was to describe the position and relationships of the supracochlear cartilage during its development. This study was made in 96 human specimens of 7-17 weeks of development, belonging to a collection of the Embryology Institute of Complutense University of Madrid. In addition, three-dimensional reconstruction of the supracochlear cartilage was made from 1 specimen. This cartilage, spherical in shape, appeared bilaterally in 23 specimens and unilaterally (left side) in 5. In our results, the supracochlear cartilage was found in 26.5% of the cases and was related to the trigeminal ganglion, the dura mater of the trigeminal cavity and the otic capsule. In 4 specimens, bilaterally, the supracochlear cartilage was continuous with the otic capsule. This work suggests that, based on the structures to which the supracochlear cartilage is related, it could be derived from the cranial neural crest. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The superior cervical ganglion (SCG) provides sympathetic input to the head and neck, its relation with mandible, submandibular glands, eyes (second and third order control) and pineal gland being demonstrated in laboratory animals. In addition, the SCG’s role in some neuropathies can be clearly seen in Horner’s syndrome. In spite of several studies published involving rats and mice, there is little morphological descriptive and comparative data of SCG from large mammals. Thus, we investigated the SCG’s macro- and microstructural organization in medium (dogs and cats) and large animals (horses) during a very specific period of the post-natal development, namely maturation (from young to adults). The SCG of dogs, cats and horses were spindle shaped and located deeply into the bifurcation of the common carotid artery, close to the distal vagus ganglion and more related to the internal carotid artery in dogs and horses, and to the occipital artery in cats. As to macromorphometrical data, that is ganglion length, there was a 23.6% increase from young to adult dogs, a 1.8% increase from young to adult cats and finally a 34% increase from young to adult horses. Histologically, the SCG’s microstructure was quite similar between young and adult animals and among the 3 species. The SCG was divided into distinct compartments (ganglion units) by capsular septa of connective tissue. Inside each ganglion unit the most prominent cellular elements were ganglion neurons, glial cells and small intensely fluorescent cells, comprising the ganglion’s morphological triad. Given this morphological arrangement, that is a summation of all ganglion units, SCG from dogs, cats and horses are better characterized as a ganglion complex rather than following the classical ganglion concept. During maturation (from young to adults) there was a 32.7% increase in the SCG’s connective capsule in dogs, a 25.8% increase in cats and a 33.2% increase in horses. There was an age-related increase in the neuronal profile size in the SCG from young to adult animals, that is a 1.6-fold, 1.9-fold and 1.6-fold increase in dogs, cats and horses, respectively. On the other hand, there was an age-related decrease in the nuclear profile size of SCG neurons from young to adult animals (0.9-fold, 0.7-fold and 0.8-fold in dogs, cats and horses, respectively). Ganglion connective capsule is composed of 2 or 3 layers of collagen fibres in juxtaposition and, as observed in light microscopy and independently of the animal’s age, ganglion neurons were organised in ganglionic units containing the same morphological triad seen in light microscopy. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The ganglionic eminence (GE) is a transient but conspicuous structure of the developing forebrain which not only gives rise to a large number of precursor neurons and glial cells for various structures of the forebrain, but in addition serves as an intermediate target for growing axons to the cerebral cortex. To investigate the roles of the highly polysialylated isoform of the neural cell adhesion molecule (PSA-NCAM) in cell migration and axonal growth within the GE and its neighbouring structures, the spatio-temporal expression pattern of PSA-NCAM was examined in human fetal forebrains between 14 and 36 weeks of gestation with a specific immunohistochemical method. Scattered PSA-NCAM-positive cells were found in the centre but more frequently in the marginal zone of the GE. Intensely labelled cells were also identified in the gangliothalamic body, basolateral nuclei of the amygdala and the subventricular and intermediate zone adjacent to the GE. This cellular immunoreactivity started to appear in various structures during the period from 14 to 19 weeks and gradually diminished after 25–28 weeks. Strong immunoreactivity was also detected in fibres running from the intermediate zone of the neocortex to the internal capsule from 16 weeks onwards, and after 24 weeks, the immunoreactivity was gradually decreased. In the vicinity of the GE, between 16 and 22 weeks, short fibre bundles were observed to leave the longitudinally oriented axons of the internal capsule to reach the marginal zone of the GE. Our results suggest a close relationship between PSA-NCAM expression and neuronal migration (over short distances) and transitory axonal projections (target recognition and axonal fasciculation) in the region of the GE. Copyright © 2004 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]