Subarachnoid hemorrhage is bleeding in the space between your brain and the surrounding membrane (subarachnoid space). Bleeding usually results from the rupture of an abnormal bulge in a blood vessel in your brain (brain aneurysm). Sometimes an abnormal tangle of blood vessels in your brain (arteriovenous malformation), trauma or other events cause bleeding. A subarachnoid hemorrhage may lead to permanent brain damage or death if not treated.

A video showing the examination of femoral hernia.

The complex circuitry interconnecting different areas in the brain, known collectively as white matter, is composed of millions of axons organized into fascicles and bundles. Upon macroscopic examination of sections of the brain, it is difficult to discern the orientation of the fibers. The same is true for conventional imaging modalities. However, recent advancements in magnetic resonance imaging (MRI) make such task possible in a live subject. By sensitizing an otherwise typical MRI sequence to the diffusion of water molecules it is possible to measure their diffusion coefficient in a given direction1. Normally, the axonal membrane and myelin sheaths pose barriers to the movement of water molecules and, thus, they diffuse preferentially along the axon2. Therefore, the direction of white matter bundles can be elucidated by determining the principal diffusivity of water. The three-dimensional representation of the diffusion coefficient can be given by a tensor and its mathematical decomposition provides the direction of the tracts3; this MRI technique is known as diffusion tensor imaging (DTI). By connecting the information acquired with DTI, three-dimensional depictions of white matter fascicles are obtained4. The virtual dissection of white matter bundles is rapidly becoming a valuable tool in clinical research.

Our journey begins with a transverse section of tightly packed axons as seen through light microscopy. Although represented as a two-dimensional "slice", we see that these axons in fact resemble tubes. A simulation of water molecules diffusing randomly inside the axons demonstrates how the membranes and myelin hinder their movement across them and shows the preferred diffusion direction --along the axons. The tracts depicted through DTI slowly blend in and we ride along with them. As we zoom out even more, we realize that it is a portion of the corpus callosum connecting the two sides of the brain we were traveling on and the great difference in relative scale of the individual axons becomes evident. The surface of the brain is then shown, as well as the rest of the white matter bundles--a big, apparently chaotic tangle of wires. Finally, the skin covers the brain.

With the exception of the simulated water molecules, all the data presented in the animation is obtained through microscopy and MRI. Computer algorithms for the extraction of the cerebral structures and a custom-built graphics engine make our journey through the brain's anatomy possible in a living person.

Micrograph courtesy of Dr. Christian Beaulieu, University of Alberta.
Music by Mario Mattioli.

References:
1. Stejskal, E.O., et al., J. Chem. Phys., 1965. 42:
2. Beaulieu, C., NMR Biomed., 2002. 15:435-55.
3. Basser, P.J., et al., J. Magn. Reson. B, 1994. 103:247-54.
4. Mori, S., et al., NMR Biomed., 2002. 15:468-80.

A nephron (from Greek νεφρός (nephros) meaning "kidney") is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.

The Zika virus, first identified in Uganda in 1947, is transmitted by the same type of mosquito that carries dengue fever, yellow fever, and chikungunya virus. A mosquito bites an infected person and then passes those viruses to other people it bites. Outbreaks did not occur outside of Africa until 2007, when it spread to the South Pacific.

Medical examination of the abdomen from Loyola University, Chicago

The cell cycle or cell-division cycle is the series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells.

McMurray's maneuver is used to detect the presence of meniscal tears. To detect a medial meniscal injury, the patient is put in a supine position with the knee in maximum flexion. One hand of the examiner is placed on the posteromedial margin of the involved knee and the other hand supports the foot. The tibia is then externally rotated, and the knee is extended slowly. The test is positive if there is an audible or palpable click or popping sensation during extension of the involved knee.

Womens Issues and Blood Clotting

Bate's Visual Guide Pediatric Head-to-Toe Assessment

The abortion pill is a medicine called mifepristone that ends an early pregnancy.In general, it's used up to 70 days — 10 weeks — after the first day of a woman's last period. Patients over this mark can have an in-clinic abortion procedure.

Hemophilia B is a hereditary bleeding disorder caused by a lack of blood clotting factor IX. Without enough factor IX, the blood cannot clot properly to control bleeding.

Polyarteritis nodosa Email this page to a friend Email this page to a friend Facebook Twitter Google+ Polyarteritis nodosa is a serious blood vessel disease. The small and medium-sized arteries become swollen and damaged. Causes Arteries are the blood vessels that carry oxygen-rich blood to organs and tissues. The cause of polyarteritis nodosa is unknown. The condition occurs when certain immune cells attack the affected arteries. More adults than children get this disease. The tissues that are fed by the affected arteries do not get the oxygen and nourishment they need. Damage occurs as a result. People with active hepatitis B or hepatitis C may develop this disease.

Animation of Scarless Varicose Vein Treatment No Knife Endovenous Laser

Hemophilia A, also called factor VIII (FVIII) deficiency or classic hemophilia, is a genetic disorder caused by missing or defective factor VIII, a clotting protein. Although it is passed down from parents to children, about 1/3 of cases are caused by a spontaneous mutation, a change in a gene. According to the US Centers for Disease Control and Prevention, hemophilia occurs in approximately 1 in 5,000 live births. There are about 20,000 people with hemophilia in the US. All races and ethnic groups are affected. Hemophilia A is four times as common as hemophilia B while more than half of patients with hemophilia A have the severe form of hemophilia.

Surgical procedure of Tonsillectomy and Adenoidectomy

Simple or Total Mastectomy. The entire breast is removed, but no lymph nodes are taken in this procedure. Simple mastectomy is most frequently used for further cancer prevention or when the cancer has not spread to the lymph nodes.Oct 29, 2014

Epilepsy is a chronic disorder, the hallmark of which is recurrent, unprovoked seizures. Many people with epilepsy have more than one type of seizure and may have other symptoms of neurological problems as well. Sometimes EEG testing, clinical history, family history and outlook are similar among a group of people with epilepsy. In these situations, their condition can be defined as a specific epilepsy syndrome. The human brain is the source of human epilepsy. Although the symptoms of a seizure may affect any part of the body, the electrical events that produce the symptoms occur in the brain. The location of that event, how it spreads and how much of the brain is affected, and how long it lasts all have profound effects. These factors determine the character of a seizure and its impact on the individual. Esssentially, anything the brain can do, it can do in the form of a seizure. Having seizures and epilepsy can affect one's safety, relationships, work, driving and so much more. Public perception and treatment of people with epilepsy are often bigger problems than actual seizures.

Pulmonary edema is almost always treated in the emergency room or hospital. You may need to be in an intensive care unit (ICU). Oxygen is given through a face mask or tiny plastic tubes are placed in the nose. A breathing tube may be placed into the windpipe (trachea) so you can be connected to a breathing machine (ventilator) if you cannot breathe well on your own. The cause of edema should be identified and treated quickly. For example, if a heart attack has caused the condition, it must be treated right away. Medicines that may be used include: Diuretics that remove excess fluid from the body Medicines that strengthen the heart muscle, control the heartbeat, or relieve pressure on the heart

Full Body Centric is a video introduction to homeopathy from the perspective of patients newly using this form of treatment. Neither condemning conventional medicine or homeopathic medicine, it explores the philosophies and techniques behind homeopathy. Interviews include a range of experts and doctors from varying backgrounds and answers many of the questions that arise when starting any new path. What are the similarities and differences between the homeopathy and conventional medicine? What are in remedies and how are they made? Is this something that is useful for everyone?