Morphometric analysis of the phrenic nerve in male and female Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR)

Ventilatory differences between rat strains and genders have been described but the morphology of the phrenic nerve has not been investigated in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. A descriptive and morphometric study of the phrenic nerves of male (N = 8) and female (N = 9) SHR, and male (N = 5) and female (N = 6) WKY is presented. After arterial pressure and heart rate recordings, the phrenic nerves of 20-week-old animals were prepared for epoxy resin embedding and light microscopy. Morphometric analysis performed with the aid of computer software that took into consideration the fascicle area and diameter, as well as myelinated fiber profile and Schwann cell nucleus number per area. Phrenic nerves were generally larger in males than in females on both strains but larger in WKY compared to SHR for both genders. Myelinated fiber numbers (male SHR = 228 ± 13; female SHR = 258 ± 4; male WKY = 382 ± 23; female WKY = 442 ± 11 for proximal right segments) and density (N/mm²; male SHR = 7048 ± 537; female SHR = 10355 ± 359; male WKY = 9457 ± 1437; female WKY = 14351 ± 1448) for proximal right segments) were significantly larger in females of both groups and remarkably larger in WKY than SHR for both genders. Strain and gender differences in phrenic nerve myelinated fiber number are described for the first time in this experimental model of hypertension, indicating the need for thorough functional studies of this nerve in male and female SHR.

Complex distribution of renal vessels

The retroperitoneal lumbar vessels should be immediately recognized during urological, vascular and radiologicalmedical procedures. Few studies have tried to define an exact pattern for the lumbar vasculature andmost of the anatomical descriptions suggest the presence of a regular pattern. Nevertheless, for the renal bloodvessels, despite the described regular pattern, several anatomical variations have interested anatomists for morethan a century. Taking into account that there is a constant need for reviewing this anatomy due to the advancesin surgical and/or uroradiological procedures techniques, we describe a complex variation of the renalblood vessels found during the dissection routine in our laboratory. A male cadaver, aged 65 years, embalmedwith 10% formalin solution presented, on the left side, two renal arteries arising from the abdominal aorta,both of them entering the kidney on the hilar region. From the hilar region of the left kidney, there were alsotwo tributary renal veins, which join together 3.0 cm from the hilus, before draining into the inferior venacava. These two tributary veins were large in diameter, and made a loop around the two renal arteries and alsothe ureter. No anatomical variations were found on the right side. This is a complex anatomical variation of therenal vessels which might have functional implications once the venous loop described might be a compressionfactor for the renal arteries and for the ureter.

Tortuosity of the internal carotid artery cervicalcourse: case reports and literature review

Variations in the course of the internal carotid arteries (ICA) are reported in the literature as coiling, looping,kinking or tortuosities of the vessels. Nevertheless, the definitions between these variants are confusing. Also, the clinical relevance of morphological anomalies of extracranial ICA is a matter of debate because of up to date the natural history of kinking, coiling and tortuosities of this artery is not well known. However, some authors consider that these conditions are burdened with disabling, even fatal neurological complications.Also, variations of the ICA cervical course may lead to direct contact of the artery with the pharyngeal wall, being of great clinical relevance due to the large number of routine procedures performed in this region. In the present study, we describe two cases of ICA tortuosities and review the current literature regarding the causes, symptoms and clinical significances of the variations of the cervical ICA course. Tortuosity of the cervical ICA is not a rare condition and they can easily be mistaken clinically for an aneurysm, a tumor or an abscess and subsequently injured during an attempted biopsy or excision. Thus, regardless the controversy of its causes (congenital or acquired) it should be included in the differential diagnosis of cervical soft tissue widening. Also, they should be taken into consideration on the diagnostic procedures for ischemic transitory attacks and/or stroke.