No abstract

Our morphometric findings may help clarifying the detailed anatomy of the MC and its topographical relations for the planning of dental implantation.

The cutaneous ligaments of the human digits are delicate functional structures essential for normal skin stability during digital movements. These ligaments extend bilaterally between the phalanx and the finger dermis, either posteriorly (Cleland's ligaments) or anteriorly (Grayson's ligaments) to the digital neurovascular bundles. We have performed a series of detailed anatomical dissections of the human digits so as to investigate morphometrically Cleland's and Grayson's ligaments and their topographic arrangements. Data were statistically compared between fingers, respecting both side (left or right) and sex, in an attempt to clarify some of the morphologic variations of these structures. The cutaneous ligaments of the human digits have been analyzed bilaterally both in 30 fixed cadavers (300 adult human digits) and in 10 nonfixed human cadaveric digits. A computerized morphometrical investigation of the human digits and their Cleland's and Grayson's ligaments has been performed and the resulting quantitative data have been statistically assessed, comparing groups according to finger, phalanx, side (left or right hands), and sex. The ratio between the origin and insertion (O:I) of these ligaments indicate a divergent arrangement of fibers, with values varying from 0.52 to 0.84, depending on the phalanx and finger analyzed. Our morphometrical data provide normal reference values, mainly for Grayson's ligaments, that can be useful in the comparison with the respective measurements obtained in Dupuytren's disease. Morphological bases are also provided, which may be relevant either in computerized tomography or magnetic resonance imaging involving the hand region and in their application in surgical procedures of the human hand.

Tracheal wall thickening in PITS is due to a deranged collagen remodeling that is related to myofibroblast activation.

Entrapment neuropathy is a group of clinical disorders involving compression of a peripheral nerve and interference with nerve function mostly through traction injury. We have investigated the chronic compression of peripheral nerves as an experimental procedure for detecting changes in ultrastructural nerve morphology. Adult hamsters (Mesocricetus auratus, N = 30) were anesthetized with a 25% pentobarbital solution and received a cuff around the right sciatic nerve. Left sciatic nerves were not operated (control group). Animals survived for varying times (up to 15 weeks), after which they were sacrificed and both sciatic nerves were immediately fixed with a paraformaldehyde solution. Experimental nerves were divided into segments based upon their distance from the site of compression (proximal, entrapment and distal). Semithin and ultrathin sections were obtained and examined by light and electron microscopy. Ultrastructural changes were qualitatively described and data from semithin sections were morphometrically analyzed both in control and in compressed nerves. We observed endoneurial edema along with both perineurial and endoneurial thickening and also the existence of whorled cell-sparse structures (Renaut bodies) in the subperineurial space of compressed sciatic nerves. Morphometric analyses of myelinated axons at the compression sites displayed a remarkable increase in the number of small axons (up to 60%) in comparison with the control axonal number. The distal segment of compressed nerves presented a distinct decrease in axon number (up to 40%) comparatively to the control group. The present experimental model of nerve entrapment in adult hamsters was shown to promote consistent histopathologic alterations analogous to those found in chronic compressive neuropathies.