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Unreported anatomical variation of septum pellucidum.

During gross anatomy dissections of the brain, a developmental abnormality of the septum pellucidum was found in a 31-year-old male cadaver. Other parts of the central nervous system in this cadaver were normal in every aspect. Histological samples were taken from the neighboring areas of this abnormality, and they were examined under light microscope and scanning electron microscope. In this abnormality of the septum pellucidum, the two laminae of the septum pellucidum were fused together and there was a hole located 1 cm anterior to its apex. The maximum diameter of the hole was 0.5 cm in the sagittal plane and 0.6 cm in the vertical plane. In the light microscopic and scanning electron microscopic examinations, the free margin of this foramen was regular, and the surrounding tissue was intact and histologically unique to the septum pellucidum. Ependymal cells were present at the free margin of the foramen. Cavum vergae, cavum septum pellucidum, and agenesis of the septum pellucidum are described in the literature. These three abnormalities are seen in cadavers usually with histories of schizophrenia and other psychiatric or neurologic disorders. In a retrospective study, the cadaver with this abnormality had a history of schizophrenia and no history or signs of any kind of brain or head operation. As far as we could ascertain, the abnormality described here has not been reported previously.

Adult↗

Anatomical variations of the splenic artery and its clinical implications.

The variations in orgin, course, and terminal branching pattern of the splenic artery were studied in 320 cadavers. The artery originated from the coeliac trunk in the majority of cadavers (90.6%), followed by abdominal aorta (8.1%), and other sights (1.3%). A suprapancreatic course of the artery was commonly observed (74.1%) followed by enteropancreatic (18.5%), intrapancreatic (4.6%), and retropancreatic (2.8%) courses. In two cases (0.63%) the proximal part of the splenic artery made a loop that was embedded in the substance of the pancreas, which is an interesting and rare finding. In five cases (1.5%) the proximal part of the artery divided into two or more branches that had suprapancreatic and enteropancreatic courses. The splenic artery divided into terminal branches in 311 (97%) cadavers. In nine (2.8%) cadavers it passed through the hilum of spleen without dividing. Two terminal branches were the most common (63.1%) followed by four (18.8%), six (9.7%), and more than six (5.6%) branches. The present study clearly indicates that there is variation in origin, course, and terminal distribution pattern of the splenic artery. The knowledge of these variations are of significant importance during surgical and radiological procedure of upper abdominal region to avoid any catastrophic complications.

Aorta, Abdominal↗

Do sagittal plane anatomical variations (angulation) of the cervical facets and C2 odontoid affect the geometrical configuration of the cervical lordosis?

Anthropometric and statistical evaluation of measurements from digitization of 252 lateral cervical radiographs were used to investigate any correlation between radiographic measurements of cervical lordosis with sagittal plane facet angulation, articular pillar height, and inclination of the C2 odontoid with respect to the body of C2. Some researchers have hypothesized that facet and odontoid architecture variations can cause a reduction in cervical lordosis. To evaluate this hypothesis, the posterior aspect of the C2 dens, vertebral body corners, and superior and inferior facet surfaces of C2-C7 were digitized on 252 lateral cervical X-rays to calculate global angle, segmental angles, dens angle, facet angles, and facet height. No correlation between facet angle, articular pillar height, and cervical curve was found. Similarly, no correlation between the sagittal angle of the dens and any angle of cervical curvature was identified. There was correlation between the global ARA C2-C7 angle and the Cobb angles at C1-C7 (r = 0.71) and C2-C7 (r = 0.82). There was correlation between the global inclination of the atlas vertebral angle (APL) and the Cobb angle at C1-C7 (r = 0.66), Cobb angle at C2-C7 (r = 0.39), ARA C2-C7 (r = 0.42), and anterior translation of C2 compared to C7 (r = -0.46). Because no correlation between cervical facet and odontoid architecture and any segmental or global angle of cervical lordosis was found, conservative and surgical rehabilitative techniques aimed at the reduction of sagittal cervical deformities do not need to account for a patient's architecture of the cervical facets nor odontoid.

Adult↗

Anatomical variations of the cutaneous innervation patterns of the sural nerve on the dorsum of the foot.

The present study attempts to determine the cutaneous pattern of distribution of the sural nerve on the dorsum of the foot to note the predominant pattern present and whether there was any association between the innervation pattern and sex or side. A total of 260 Indian feet (78 adult feet: 60 male, 18 female; 52 fetal feet: 20 male, 32 female) were dissected. The results showed six patterns of innervation of the toes by the sural nerve. In Type I, the lateral side of the little toe was supplied by the sural nerve alone and the adjacent sides of the 2nd, 3rd, 4th, and 5th toes by the superficial peroneal nerve alone (35.38%). In Type II the lateral side of the little toe was supplied by the sural nerve alone and the adjacent sides of the 4th and 5th toes by the sural nerve along with the superficial peroneal nerve (10%). In Type III the lateral side of the little toe was supplied by the sural nerve alone and the adjacent sides of the 3rd, 4th, and 5th toes by the sural nerve along with the superficial peroneal nerve (21.15%). In Type IV the lateral 1(1/2) toes were supplied by the sural nerve alone and the adjacent sides of the 3rd and 4th toes by the superficial peroneal nerve alone (3.85%). In Type V the lateral 1(1/2) toes were supplied by the sural nerve alone and the adjacent sides of the 3rd and 4th toes were supplied by the sural nerve along with the superficial peroneal nerve (5%). In Type VI the lateral 2(1/2) toes were supplied by the sural nerve alone (24.61%). The predominant patterns were Type I (35.38%), Type VI (24.61%), and Type III (21.15%). There was no association between the innervation pattern of the sural nerve and sex or side. The pattern, which is usually described, was found in only 35.38% of feet. Considering the variation in the pattern of cutaneous distribution of the sural nerve in Indian feet, the function of the sural nerve may be to supply a wider area of skin than is usually described.

Adult↗

Anatomic variation of portal venous anatomy in the porta hepatis: ultrasonographic evaluation.

The appearance of the portal vein as it crosses anterior to the inferior vena cava and enters the liver at the porta hepatis was evaluated on 100 longitudinal and 100 transverse ultrasonograms. Three major variations were noted on the parasagittal scans, while four major variations were evident on the transverse images. These variations were primarily related to the size of the left portal vein and the angle at which the left portal vein coursed away from the main portal vein. The appearance and course of the proximal right portal vein was extremely constant and may therefore be used as a landmark to detect pathologic processes in the porta hepatis. Detection of altered anatomy in this region may be especially helpful in correctly differentiating dilated intrahepatic bile ducts from normal portal veins.

Diagnostic Errors↗

Temporal and anatomical variations of brain water apparent diffusion coefficient in perinatal cerebral hypoxic-ischemic injury: relationships to cerebral energy metabolism.

Cerebral apparent diffusion coefficients (ADCs) were determined in nine newborn piglets before and for 48 h after transient hypoxia-ischemia. Phosphorus MRS revealed severely reduced cerebral energy metabolism during the insult and an apparently complete recovery 2 h after resuscitation commenced. At this time, mean ADC over the imaging slice (ADCglobal) was 0.88 (0.04) x 10(-9) m2 x s(-1) (mean (SD)), which was close to the baseline value of 0.92 (0.4) x 10(-9) m2 x s(-1). In seven of the animals, a "secondary" failure of energy metabolism then evolved, accompanied by a decline in ADCglobal to 0.64 (0.17) x 10(-9) m2 x s(-1) at 46 h postresuscitation (P < 0.001 versus baseline). For these seven animals, ADCglobal correlated linearly with the concentration ratio [phosphocreatine (PCr)]/[inorganic phosphate (Pi)] (0.94 < r < 0.99; P < 0.001). A nonlinear relationship was demonstrated between ADCglobal and the concentration ratio [nucleotide triphosphate (NTP)]/[Pi + PCr + 3 NTP]. The ADC reduction commenced in the parasagittal cortex before spreading in a characteristic pattern throughout the brain. ADC seems to be closely related to cerebral energy status and shows considerable potential for the assessment of hypoxic-ischemic injury in the newborn brain.

Animals↗

Anatomical variations of the median nerve in the carpal tunnel.

The median nerve was explored in 100 hands and the variations classified by the Lanz system. Only 47.7% of hands showed the standard anatomy described in textbooks. Rare variations were also found. Knowledge of the variable anatomy of the nerve could help to avoid incomplete decompression at operations for carpal tunnel entrapment and injury to the thenar branch of the nerve. The possibility of double thenar innervation must be considered in preoperative evaluation and in the follow up of median nerve injuries.

Carpal Bones↗

Anatomical variation of the oestrogen receptor in the non-neoplastic myometrium of fibromyomatous uteri.

Myometrial tissues from a total of 30 normal and 30 fibromyomatous uteri were compared in order to assess whether the oestrogen receptor distribution is similar for both types. All patients concerned were premenopausal with no history of exogenous hormone usage. Material taken from the subserosal, midmyometrial and subendometrial regions of both the fundus and the lower segment was stained by immunocytochemistry for the oestrogen receptor. No significant difference in the oestrogen receptor content was noted between the fundus and the lower segment in either the normal or the fibromyomatous myometria. Similarly, the phase of the menstrual cycle did not affect the total receptor content of either group of tissue. The oestrogen receptor content in the non-neoplastic portion of the fibromyomatous myometria was highest in the subendometrial and lowest in the subserosal region. The differences in receptor content between normal and fibromyomatous myometria were minimal in the subendometrial region but marked in the subserosal region. The myometrium of fibromyomatous uteri thus expresses significantly increased levels of oestrogen receptor, and the pathogenesis of fibromyomata may be related to an inherent abnormality in the myometrium.

Adult↗

Anatomical variation of the oestrogen receptor in normal myometrium.

Tissue from 20 surgically resected uteri was examined in order to test the hypothesis that the oestrogen receptor content of the myometrium may not be uniform throughout the uterus. All patients were premenopausal, had no history of any exogenous steroid hormone use and were in the proliferative phase of the menstrual cycle. Material was taken from the subserosal, midmyometrical and subendometrial regions of both the fundal and lower uterine segments. Care was taken to remove all endometrium. Suitable samples were analysed by radioimmunoassay (RIA) for oestrogen receptors. An adjacent block from each area was fixed in formalin and stained immunocytochemically for oestrogen receptors. The results of the RIA show a significantly higher receptor content in the subendometrial region than in either the midmyometrial or the subserosal region. No significant difference was demonstrated between the numbers of receptors in the fundus and in the lower uterine segments. The differences were also well demonstrated by immunocytochemistry, according to which 83% of all cells counted in the subendometrial region were positive, while only 61% of cells in the middle and 47% of those in the subserosal region were positive.

Adult↗

Interposition of the colon between the kidney and the psoas muscle: a normal anatomic variation studied by CT.

The position of the bowel in the pararenal space was examined in relation to the kidney and the psoas muscle in 1203 abdominal computed tomographic (CT) examinations. The ascending colon was found between the lower kidney pole and the psoas muscle in 1.7% and the descending colon in 0.7% of the patients. This variation appeared more frequently in women, young adults, and individuals with less intrabdominal fat. Lateral displacement of the lower kidney pole was observed in 40% of the patients with this normal variation. These findings may be of value when interpreting urographic and abdominal CT examinations.

Adult↗