Layer Of Loose Connective Tissue Research Articles

An echogenic mass on the aortic valve.

An asymptomatic 64-year-old patient came for a routine check-up following inferior wall myocardial infarction (MI) and stent insertion in France 6 months previously. He had no cardiovascular risk factors or significant past medical history. Systemic examination was normal as were his haematological and biochemical parameters. A routine echocardiogram (TTE) revealed a mass on the non-coronary leaflet of the aortic valve (AV) with normal left ventricular function and no other valvular abnormalities. Subsequent transoesophageal echocardiography confirmed a pedunculated echogenic mobile mass 0.5–1 cm in diameter attached to the aortic side of AV (Fig. 1a and online video files). Further imaging with cardiac MR described the hypointense mobile mass as possible fibroelastoma. The patient underwent excision of the tumour (Fig. 1b) and AV replacement. Histopathology revealed a central fibrous core surrounded by a layer of loose connective tissue with variable elastic tissue with the surface covered by endothelial cells, consistent with papillary fibroelastoma (Fig. 2). His post-operative recovery was uneventful and was later discharged. Papillary fibroelastoma is a rare, benign cardiac tumour accounting for 10 % of all cardiac tumours [1]. They are generally found on aortic and mitral valves. Patients may present with neurological events, stroke, angina, myocardial infarction, sudden death or as incidental findings on autopsy or at surgery. TTE is useful in making the diagnosis. Treatment in asymptomatic patients is controversial. However, left-sided tumours may be considered for surgery as they can embolise causing strokes, MI, peripheral ischaemia and even vascular obstruction. Though rightsided tumours follow a more benign course, they can interfere with cardiac output if bulky enough.

Morphology of the female genital ducts of the blue land crab Cardisoma guanhumi (Crustacea: Brachyura: Gecarcinidae)

AbstractThis is a histological and histochemical analysis of the terminal portion of the female reproductive system and genital ducts of the blue land crab (Cardisoma guanhumi). Animals were collected in the Jaguaribe estuary (Ceará, Brazil) and dissected. Genital duct fragments were fixed and submitted to different staining techniques. The female reproductive system consists of a pair of ovaries and a pair of genital ducts. In the mid‐posterior portion of each lobe, the ovaries communicate with the genital ducts, which are subdivided into oviduct, spermatheca, vagina, and gonopore. Histologically, the spermatheca of C. guanhumi is composed of columnar secretory epithelium and is divided into a dorsal zone and a ventral zone, the latter covered internally by a cuticle layer. Both zones are enveloped by a thin layer of loose connective tissue. Histological cross sections revealed the vagina to be concave, a pattern considered phylogenetically more advanced than the simple, tubular form. Our findings suggest fertilization is internal, favoring sperm from the most recent copulation.

Left Ventricles of the Mature Camel Heart (Camelus dromedaries) with Special References to the Structure and Distribution of the Purkinje Cardiomyocytes:Microanatomy

The present investigation was performed to clarify the histological features of the left ventricles in the heart of the mature dromedary camel. This investigation was carried out on the left ventricles of six healthy mature camels. Microscopically, the left ventricles is consisted of three major layers or tunics; the internal endocardium, the middle myocardium, and the external epicardium. The endocardium is consisted of three layers; the endothelial layer of simple squamous epithelium, sub-endothelial layer of loose connective tissue and the sub-endocardial layer that connecting the endocardium with the myocardium and housing bundles of the purkinje cardiomyocytes; purkinje fibers. The myocardium, is the middle layer of the ventricular wall, is sandwiched between an outer epicardium, that covers the ventricular wall, and an inner endocardium, that lines the chamber, containing two bundles of cardiac fibers; the working cardiac myocytes (myocardiocytes) and the purkinje bundles. The epicardium is the outer most layer of the ventricular wall. This layer is a relatively thin in comparison with the myocardium and is consisted of a sub-epicardial layer of loose connective tissue which housing many blood vessels, lymph vessels, nerves and adipocytes and mesothelium of simple squamous epithelium.

Structural conformation and mechanical testing of human crural fascia

Chronic exertional compartment syndrome (CECS) is a condition in which chronic increased pressure within a closed osteofascial compartment compromises blood flow to the muscles and nerves within that compartment, resulting in pain and disability. It is frequent in athletes that occur in repetitive loading, as in competitive athletes, long-distance runners, skiers, basketball and soccer players. It is known that one of the possible cause is that the aponeurotic fasciae, as the crural fascia, in some subjects are not able to adapt to the variation of tension. Really, the mechanical behaviour of the fasciae is actually unknown. Ten dissections of inferior limbs were performed to analyze the crural fascia from an histological (H-E, azan Mallory, van Gieson stains) and mechanical point of view (Planar Biaxial TestBench Test Instrument of Bose® Electro-Force), to understand its structural conformation and mechanical behaviour. The samples were cut along both the proximal- distal direction and the medial-lateral direction, in order to obtain evidence of possible anisotropy of the tissue. Both the anterior and the posterior compartments of the crural fascia were object of investigation. The samples had width of about 3 mm, a free ‘gauge’ length of 10 mm and variable thickness according to the location. The mechanical characterization of the elastic response of the crural fascia was made by considering tensile tests at a strain rate of 120%/s. The visco-elastic response of the fascia was evaluated by incremental relaxation tests at nominal strain of 7%, 9% and 11%, respectively. The stress decay of the relaxation tests was monitored for 240 s. In crural fascia the collagen fibres are disposed to form three distinct sub-layers (mean thickness 115μm), separated by a layer of loose connective tissue (mean thickness 43μm). Inside a single sub-layer, the fibres are all parallel, whilst the angle between the fibres of adjacent layers is about 78°. Elastic fibres are less than 1%. The tissue of the anterior compartment was found stiffer than the tissue of the posterior compartment, both along the proximal-distal and the medial-lateral direction. The tissue was found stiffer along the proximal-distal direction than along the medial-lateral direction. The stress decay during the relaxation tests was found similar for the anterior and the posterior compartment. The preliminary results show that the crural fascia has structural conformation and mechanical properties that well adapt to the geometric variation of enveloped muscles. This is due above all to the spatial arrangement of collagen fibers. Besides, this fascia is not an homogeneous tissue, but it is stiffer anteriorly. This finding well corresponds to the clinical practice, indeed the anterior compartment syndrome is more frequent than the posterior one.

Histology and Mucous Histochemistry of the Integument and Body Wall of a Marine Polychaete Worm,Ophryotrochan. sp. (Annelida: Dorvilleidae) Associated with Steelhead Trout Cage Sites on the South Coast of Newfoundland

Histology and mucous histochemistry of the integument and body wall of a marine polychaete worm,Ophryotrochan. sp. (Annelida: Dorvilleidae) associated with Steelhead trout cage sites on the south coast of Newfoundland. A new species of polychaete (Ophryotrochan. sp. (Annelida: Dorvilleidae)) was identified from sediment below Steelhead trout cages on the south coast of Newfoundland, Canada. The organisms were observed to produce a network of mucus in which groups of individuals would reside. Questions regarding the nature and cellular source of the mucus were addressed in this study. Samples of worms were taken from below cages and transported to the laboratory where individuals were fixed for histological study of the cuticle and associated mucus histochemistry. The body wall was organized into segments with an outer cuticle that stained strongly for acid mucopolysaccharides. The epidermis was thin and supported by loose fibrous connective tissue layers. Channels separating individual segments were lined with cells staining positive for Alcian blue. Mucoid cellular secretions appeared thick and viscous, strongly staining with Alcian blue and Periodic Acid Schiff Reagent. It was noted that lateral channels were connected via a second channel running through the anterior/posterior axis. The role of mucus secretion is discussed.

Morphology and morphometry of the reproductive system of female Saguinus midas (Linnaeus, 1758)

In this article, the reproductive system's morphology of three young animals of the species Saguinus midas, from the bauxite mine in Paragominas, is described. The specimens were fixed and preserved in a solution of 10% aqueous formaldehyde, followed by dissection, measurement of the genital organs (uterus, vagina, ovaries, and uterine tubes), and histological processing. The vulva is delimited by the labia, with a clitoris. It is lined by keratinized stratified squamous epithelium with sebaceous glands of holocrine secretion. The vagina is an elongated tube with an average length of 26 mm and diameter of 1 mm, presenting a non-keratinized squamous epithelium, disposed between the vestibule of the vagina and cervix, the latter being relatively short. The uterus is simple, has globular shape and is located in the caudal portion of the abdominal cavity, with an average length of 14 mm and average width of 7 mm. It is formed by vascular and serous layers of muscles, and undergoes a bifurcation to form two structures on the bottom of blind sac. The uterine tubes are long and convoluted with an average length of 35 mm (right) and 36 mm (left), consisting of loose connective tissue and muscle layer lined by simple ciliated columnar epithelium. The ovaries are large and ellipsoid with smooth surface. Histologically, one animal showed ovulation fosse.

Hyaluronan within fascia in the etiology of myofascial pain

The layers of loose connective tissue within deep fasciae were studied with particular emphasis on the histochemical distribution of hyaluronan (HA). Samples of deep fascia together with the underlying muscles were taken from neck, abdomen and thigh from three fresh non-embalmed cadavers. Samples were stained with hematoxylin-eosin, Azan-Mallory, Alcian blue and a biotinylated HA-binding protein specific for HA. An ultrasound study was also performed on 22 voluntary subjects to analyze the thickness of these deep fasciae and their sublayers. The deep fascia presented a layer of HA between fascia and the muscle and within the loose connective tissue that divided different fibrous sublayers of the deep fascia. A layer of fibroblast-like cells that stained prominently with Alcian blue stain was observed. It was postulated that these are cells specialized for the biosynthesis of the HA-rich matrix. These cells we have termed "fasciacytes", and may represent a new class of cells not previously recognized. The ultrasound study highlighted a mean thickness of 1.88 mm of the fascia lata, 1.68 mm of the rectus sheath, and 1.73 mm of the sternocleidomastoid fascia. The HA within the deep fascia facilitates the free sliding of two adjacent fibrous fascial layers, thus promoting the normal function associated with the deep fascia. If the HA assumes a more packed conformation, or more generally, if the loose connective tissue inside the fascia alters its density, the behavior of the entire deep fascia and the underlying muscle would be compromised. This, we predict, may be the basis of the common phenomenon known as "myofascial pain."

Reduced thoracolumbar fascia shear strain in human chronic low back pain

BackgroundThe role played by the thoracolumbar fascia in chronic low back pain (LBP) is poorly understood. The thoracolumbar fascia is composed of dense connective tissue layers separated by layers of loose connective tissue that normally allow the dense layers to glide past one another during trunk motion. The goal of this study was to quantify shear plane motion within the thoracolumbar fascia using ultrasound elasticity imaging in human subjects with and without chronic low back pain (LBP).MethodsWe tested 121 human subjects, 50 without LBP and 71 with LBP of greater than 12 months duration. In each subject, an ultrasound cine-recording was acquired on the right and left sides of the back during passive trunk flexion using a motorized articulated table with the hinge point of the table at L4-5 and the ultrasound probe located longitudinally 2 cm lateral to the midline at the level of the L2-3 interspace. Tissue displacement within the thoracolumbar fascia was calculated using cross correlation techniques and shear strain was derived from this displacement data. Additional measures included standard range of motion and physical performance evaluations as well as ultrasound measurement of perimuscular connective tissue thickness and echogenicity.ResultsThoracolumbar fascia shear strain was reduced in the LBP group compared with the No-LBP group (56.4% ± 3.1% vs. 70.2% ± 3.6% respectively, p < .01). There was no evidence that this difference was sex-specific (group by sex interaction p = .09), although overall, males had significantly lower shear strain than females (p = .02). Significant correlations were found in male subjects between thoracolumbar fascia shear strain and the following variables: perimuscular connective tissue thickness (r = -0.45, p <.001), echogenicity (r = -0.28, p < .05), trunk flexion range of motion (r = 0.36, p < .01), trunk extension range of motion (r = 0.41, p < .01), repeated forward bend task duration (r = -0.54, p < .0001) and repeated sit-to-stand task duration (r = -0.45, p < .001).ConclusionThoracolumbar fascia shear strain was ~20% lower in human subjects with chronic low back pain. This reduction of shear plane motion may be due to abnormal trunk movement patterns and/or intrinsic connective tissue pathology. There appears to be some sex-related differences in thoracolumbar fascia shear strain that may also play a role in altered connective tissue function.

Histological Structure of the Integument in Mastacembelus mastacembelus (Solander)

The histological structure of integument in Mastacembelus mastacembelus have been investigated from skin fragments cut from nine regions at body surface. The results revealed that the integument of the fish investigated comprises three principal layers- the epidermis, the dermis (corium) and the subcutis-All the three principal layers may further be divided into secondary layers according to the function performed by their cells. The epidermis may further divided into three layers- the outermost epithelial coverage, the middle layer and the basal layer (stratum germinatiuum)-The dermis consists of a relatively thin upper layer of loose vascular connective tissue called the stratum laxum and a thick lower compact layer- the stratum compactum. The upper loose layer contains blood capillaries, nerve fibers and scale pockets. The subcutis is the innermost and the thinnest layer of the skin and is situated in between the stratum compactum and the muscles. All the above main layers showed great extend in their thickness.

Histological Structure of the Integument in Mastacembelus mastacembelus (Solander)

The histological structure of integument in Mastacembelus mastacembelus have been investigated from skin fragments cut from nine regions at body surface. The results revealed that the integument of the fish investigated comprises three principal layers- the epidermis, the dermis (corium) and the subcutis-All the three principal layers may further be divided into secondary layers according to the function performed by their cells. The epidermis may further divided into three layers- the outermost epithelial coverage, the middle layer and the basal layer (stratum germinatiuum)-The dermis consists of a relatively thin upper layer of loose vascular connective tissue called the stratum laxum and a thick lower compact layer- the stratum compactum. The upper loose layer contains blood capillaries, nerve fibers and scale pockets. The subcutis is the innermost and the thinnest layer of the skin and is situated in between the stratum compactum and the muscles. All the above main layers showed great extend in their thickness.

3D reconstruction of the crural and thoracolumbar fasciae

To create computerized three-dimensional models of the crural fascia and of the superficial layer of the thoracolumbar fascia. Serial sections of these two fasciae, stained with Azan-Mallory, van Gieson and anti-S100 antibody stains, were recorded. The resulting images were merged (Image Zone 5.0 software) and aligned (MatLab Image Processing Toolkit). Color thresholding was applied to identify the structures of interest. 3D models were obtained with Tcl/Tk scripts and Paraview 3.2.1 software. From these models, the morphometric features of these fasciae were evaluated with ImageJ. In the crural fascia, collagen fibers represent less than 20% of the total volume, arranged in three distinct sub-layers (mean thickness, 115 μm), separated by a layer of loose connective tissue (mean thickness, 43 μm). Inside a single sub-layer, all the fibers are parallel, whereas the angle between the fibers of adjacent layers is about 78°. Elastic fibers are less than 1%. Nervous fibers are mostly concentrated in the middle layer. The superficial layer of the thoracolumbar fascia is also formed of three thinner sub-layers, but only the superficial one is similar to the crural fascia sub-layers, the intermediate one is similar to a flat tendon, and the deep one is formed of loose connective tissue. Only the superficial sub-layer has rich innervation and a few elastic fibers. Computerized three-dimensional models provide a detailed representation of the fascial structure, for better understanding of the interactions among the different components. This is a fundamental step in understanding the mechanical behavior of the fasciae and their role in pathology.

Analysis of the presence of the hyaluronic acid inside the deep fasciae and in the muscles

Recent works have demonstrated that the deep fascia is a multilayer structure, formed by different layers of collagen fibers and loose connective tissue (LCT). The aim of this work was to study the layers of LCT inside the deep fasciae, and in particular to evaluate the presence of Hyaluronic acid (HA). Three fresh not embalmed cadavers were studied. Samples of the deep fascia together with the underlying muscles were taken from the neck over the SCOM, from the abdomen over the rectus muscle and from the thigh over the sartorius muscle. Samples were stained with hematoxylin-eosin, azan-Mallory, Alcian blue and a biotinylated HA-binding protein that has high specificity for HA. At the microscopic evaluation, the deep fascia was formed of two or three layers of parallel collagen fibre bundles, densely packaged. Each collagen layer presented a mean thickness (± SD) of 277.6 ± 86.1 µm. Between the different layers, a thin layer of loose connective tissue could be recognized, having mean thickness 43 ± 12 µm. Staining with the Alcian Blue and with the highly specific HA-binding peptide documented a layer of hyaluronan between fascia and muscle and inside deep fascia, in particular inside the loose connective tissue separating the fibrous sub-layer of the fascia. In some samples, some fibroblast-like cells that stained very well at the Alcian Blue stain were observed. It was postulated that these were specialized cells for the biosynthesis of the HA-rich matrix, that we’ll call “fasciacyte”. This means that the fascia thus provides an extracellular matrix that is a gliding lubricant over muscle, permitting the free contraction of muscles, but also a unique matrix for its repair and regeneration. Besides, the HA inside the deep fascia facilitates the free sliding of two adjacent fibrous fascial layers, guaranteed the normal functionality of the deep fascia. If the HA assumes a more packed conformation, or more generally if the loose connective tissue inside the fascia alters its density, the behavior of the whole deep fascia and of the underlying muscle could be compromised. This could be at the origin of many myofascial pains.

Vascular Supply to the Acetabular Labrum

The acetabular labrum plays an important role in hip joint stability and protection of the articular cartilage of the hip. Despite this, few investigators have evaluated its microscopic vasculature and, to our knowledge, none has assessed its macroscopic blood supply. The purposes of this study were to identify the origin and course of the vascular supply to the acetabular labrum to determine if this blood supply is affected by a labral tear. Colored silicone was injected into the vascular tree proximal to thirty-five hips in twenty-eight fresh cadavers. Twenty-four hours after injection, anatomic dissection was performed and the vessels supplying the labrum were followed from their origin to their final distribution. Additionally, labral segments of fifteen randomly selected hips were resected to assess the acetabular rim's vascular contribution, and fifteen hips were dislocated for complete intra-articular inspection of the labrum. Radial branches of a previously described periacetabular periosteal vascular ring were identified as the source of labral blood supply in all thirty-five hips. These branches coursed toward the hip joint on the periosteal surface, penetrated the joint capsule near its innominate insertion, and continued within a loose connective-tissue layer on the capsular surface of the labrum. No contribution from the hip capsule, synovial lining, or osseous acetabular rim could be demonstrated. An intact vascular supply was identified in all seven hips with a labral tear. The acetabular labrum receives its blood supply from radial branches of a periacetabular periosteal vascular ring that traverses the osseolabral junction on its capsular side and continues toward the labrum's free edge. The hip capsule, the synovial lining, and the osseous acetabular rim do not appear to provide substantial contributions to the labral blood supply.

Branch Blockade of the Dorsal Sacral Rami

The recent original research article by Dreyfuss and colleagues [1], presents an interesting perspective on a potential technique to diagnose sacroiliac joint pain of extra-articular origin. However, some questions arise out of the described methodology, which we believe may merit further discussion. Recent morphological and histological study of the posterior sacroiliac region [2] indicate a specialized and metameric arrangement of a deep fascial layer that is related to a number of adjacent structures in the region. These include the individual dorsal sacral foramen, the associated lateral and medial branches of the dorsal sacral rami, and the long posterior sacroiliac ligament. The delicate neurovascular lateral branches of the dorsal sacral rami form a variable network of interconnected lateral branches from L5 to S4 dorsal rami [2–4], which lie immediately posterior to the dorsal sacral surface. Significantly, the lateral branches lie within a protective and continuous layer of loose connective and adipose tissue, as they wend their variable path between the …

Weshalb ist die Lunge trocken?

The extremely thin blood-gas barrier, the high blood perfusion rate and the deformability of the lung required for ventilation call for safety measures in order to keep the peripheral airspaces dry. The protective factors are provided in part by the particular structural organization of the lung, in part by physiological safeguards. Amongst the structural safety factors the extremely low permeability of the alveolar epithelial cell layer, the effective drainage system of interstitial spaces, and the loose connective tissue layers which surround vessels and bronchi, and which can act as transient fluid reservoirs, should be mentioned. The physiologic safety factors include the low hemodynamic pressures in the pulmonary vessels, the high colloid-osmotic pressure of blood, the decrease in perimicrovascular colloid-osmotic pressure on increased transcapillary fluid filtration, the interstitial pressure gradient between peripheral and central parts of the lung, and the minimal mechanical forces acting on the fine lung parenchyma owing to the low surface tensions provided by alveolar surfactant. Whether the active pumping mechanism improving reabsorption of edema fluid is also operative under normal conditions has not yet been clarified.

Mechanics of crural fascia: from anatomy to constitutive modelling

Ten dissections of inferior limbs and histological studies were performed to describe the structural conformation of the muscular fascia of the leg (crural fascia) and to propose a constitutive model to be adopted for the analysis of its biomechanical behaviour. The crural fascia had a mean thickness of 924 microm and was composed of three layers (mean thickness 277.6 microm) of parallel, collagen fibre bundles separated by a thin layer of loose connective tissue (mean thickness 43 microm). Only a few elastic fibres were highlighted. The disposition of the collagen fibres gives the crural fascia anisotropic characteristics. In addition, their crimped conformation is the cause of the non-linear elastic behaviour of the tissue. Both these aspects are included in the constitutive model. The constitutive modelling of the crural fascia represents a useful tool to rationally interpret the correlation between functional behaviour and structural conformation.

Neovascularization of Porous Silk Fibroin Films(PSFFs) as Dermis Substitutes Implanted in Rats

Neovascularization in biomaterials plays a key role in wound healing. In this paper, porous silk fibroin films (PSFFs) whose structure was optimized, as dermis substitutes, were implanted in the back skin of rats for recovery of dermis loss. Results showed that a thin layer of loose connective tissue had formed at the interface between PSFFs and subcutaneous tissues, in which abundant blood vessels could be observed at 24 h after surgery. Whereafter the newly formed connective tissue thickened and the number of microvessels in the tissue increased. Furthermore, a few microvessels could be seen in PSFFs at day 5, most of which were capillaries. By day 10, the density of microvessels in PSFFs increased to a peak while the percentage of capillary decreased. At day 23, both the density of microvessels and the percentage of capillary was almost equal to those of normal tissues. In summary, wound healing with PSFFs as dermis substitutes is the neovascularization process of PSFFs. The process includes three major steps: (1) new formation and growth of loose connective tissue into the pores of PSFFs, (2) proliferation and migration of fibroblasts and endothelial cells, and (3) formation of functional microvessels and their networks.

Exencephaly in a live, full term fetus

Sir, Exencephaly is a rare malformation of the neural tube with a large amount of protruding brain tissue and absence of calvarium. It is considered to be an embryological precursor of anencephaly where the facial structures and the base of brain are always present. Most cases are stillborn. We report a case of Exencephaly in a live full term fetus which succumbed after 3 hours. A 21 yr old gravid, primipara was admitted with a history of post maturity. Ultrasound of the abdomen revealed a single live fetus with breech presentation and a suspicion of anencephaly. She was given a trial labour with no response. Hence an elective caesarean section was performed. Intra-operatively minimal liquor was detected and the presentation was complete breech. The female infant was 3kgs in weight and had an APGAR score of 6 to 8. The infant expired after 3 hours. At autopsy the fetal skull vault was absent and the brain was covered by a thick membrane with visible tortuous blood vessels [Figure 1]. Three other swellings were noted in the occipital region, one extending up to the cervical vertebrae [Figure 2]. The fetus had a normal forehead and the eyes were protruding. The ears, oral cavity and nasal cavity were normal. No other external anomalies were seen [Figure 3]. Figure 1 Cerebrum covered by highly vascularized tissue Figure 2 Three occipital masses composed of cerebellar tissue Figure 3 Exencephalic fetus with protruding eyeballs and no other external anomalies Internal autopsy showed the brain and overlying tissue being covered by a highly vascular layer below which was a layer of loose connective tissue 2 to 4 cms thick [Figure 1]. When this layer was removed, two roughly symmetrical cerebral hemispheres were seen. In the cerebral cortex the gyri were flattened, sulci were shallower and all surfaces were highly vascular. Cut sections of the cerebrum showed a single large ventricular chamber lined by numerous multi lobular soft tissue masses with a vague corpus callosum like white area. The average cortical thickness of the cerebrum was 2cms. The occipital nodules also showed similar findings. All thoracic and abdominal organs were normal and well formed. Lungs floatation test was positive. On microscopic examination, the layer between the cortical surface and meninges was composed of loose connective tissue containing numerous tortuous vascular channels and focal nodules of dysplastic neural elements. The cerebral tissue contained scattered neurons, neuroblasts and glial elements with a thinned out layer of cortical tissue. The nodules in the occipital region showed cerebellar tissue composed of nodules of dysplastic neural elements and was also covered by a highly vascular layer. Spinal subarachnoid space also showed foci of dysplastic neural tissue. Exencephaly is characterized by the absence of cranial cavity and scalp with a large amount of protruding brain tissue covered by a membrane, and with prominent bulging eyeballs. Exencephaly is considered to lie somewhere on the spectrum between anencephaly and encephalocoele.[1 2] It is much less common than anencephaly but it has the same etiology and recurrence risk as other neural tube defects.[3] Exencephaly is an uncommon malformation of the cranium that characteristically involves a large disorganized mass of brain tissue. The flat bones of calvaria are absent and the brain mass is left uncovered .It is a clinical entity which is incompatible with life.1Neural tube defects account for most CNS malformations. Failure of a portion of neural tube to close or reopening of a region of the tube after successful closure, may lead to one of the several deformities. In our case the primary diagnosis of anencephaly was ruled out on the basis that the flat bones of calvarium were absent. The marked dysplasia and disorganized development of cerebrum were atypical of meningoencephalocoele.[3] Exencephaly is rarely reported in human embryos. Anencephaly occurs in 1 in 5 per 1000 live births, more commonly in females.[4] It is thought to develop at 28 wks of gestation. As with anencephaly, exencephaly is also incompatible with life.[1 2] Forebrain development is disrupted and all that remains is the area cerebrovasculosa with a flattened remnant of disorganized brain tissue admixed with ependymal, choroid plexus and meningothelial cells.[4] Exencephaly is a rare precursor of anencephaly in which a large amount of brain tissue is present despite the absence of the calvaria. The brain in these cases consist of a disorganized, anarchic outgrowth of nervous tissue with polymicrogyria and nodules of heterotopias. In our case all the macroscopic and microscopic findings were as described in literature, although we could not explain the persistence of exencephaly late in pregnancy and survival of the fetus for 3 hours.

The long posterior sacroiliac ligament: A histological study of morphological relations in the posterior sacroiliac region

Objectives To investigate the morphology of the long posterior sacroiliac ligament (LPSL) and its potential relationship to adjacent structures in the posterior sacroiliac region, and to consider any possible functional anatomical implications that may arise. Methods Four large cadaveric tissue blocks of the posterior sacroiliac region were utilised in this qualitative histological study. The blocks underwent demineralisation in ethyl-diamine-tetra-acetic acid (EDTA). The end-point was determined radiographically. The demineralised tissue blocks were subsequently processed and a base sledge microtome used to section the blocks. Sequential sections were stained with Harris haematoxylin and alcoholic eosin (H&E) and mounted on glass slides prior to viewing under a light microscope. Results The LPSL was observed to have proximal and distal regions of osseous attachment. Between these regions of attachment the middle LPSL was observed as a confluence of three layers: the erectores spinae aponeurosis, the ‘deep fascial layer’ and the gluteal aponeurosis. Deep to the ‘deep fascial layer’ a layer of adipose and loose connective tissue was observed. Lateral branches of the dorsal sacral rami were identified within this layer. Conclusions The middle long posterior ligament appears to provide a pathway for the lateral branches of the dorsal sacral rami between the posterior sacral region and the gluteal region. This histological study provides a morphological basis for the proposal that putative sacroiliac joint pain may be due to an entrapment neuropathy of the lateral branches of the dorsal sacral rami at the long posterior sacroiliac ligament.

Pectoral and femoral fasciae: common aspects and regional specializations

The aim of this study was to analyse the organization of the deep fascia of the pectoral region and of the thigh. Six unembalmed cadavers (four men, two women, age range 48-93 years old) were studied by dissection and by histological (HE, van Gieson and azan-Mallory) and immunohistochemical (anti S-100) stains; morphometric studies were also performed in order to evaluate the thickness of the deep fascia in the different regions. The pectoral fascia is a thin lamina (mean thickness +/- SD: 297 +/- 37 mum), adherent to the pectoralis major muscle via numerous intramuscular fibrous septa that detach from its inner surface. Many muscular fibres are inserted into both sides of the septa and into the fascia. The histological study demonstrates that the pectoral fascia is formed by a single layer of undulated collagen fibres, intermixed with many elastic fibres. In the thigh, the deep fascia (fascia lata) is independent from the underlying muscle, separated by the epimysium and a layer of loose connective tissue. The fascia lata presents a mean thickness of 944 mum (+/-102 mum) and it is formed by bundles of collagen fibres, arranged in two to three layers. In each layer, the fibres are parallel to each other, whereas the orientation of the fibres varies from one layer to the adjacent one. The van Gieson elastic fibres stain highlights the presence of elastic fibres only in the more external layer of the fascia lata. In the thigh the epimysium is easily recognizable under the deep fascia and presents a mean thickness of 48 mum. Both the fascia lata and pectoral fascia result innerved, no specific differences in density or type of innervations is highlighted. The deep fascia of the pectoral region is morphologically and functionally different from that of the thigh: the fascia lata is a relatively autonomous structure with respect to the underlying muscular plane, while the pectoralis fascia acts as an additional insertion for the pectoralis major muscle. Different portions of the pectoralis major muscle are activated according to the glenohumeral joint movements and, consequently, selective portions of the pectoral fascia are stretched, activating specific patterns of proprioceptors. So, the pectoralis muscle has to be considered together with its fascia, and so as a myofascial unit, acting as an integrated control motor system.