In this video, Dr. Suzanna Stensaas, Ph.D., gives us an excellent overview of some very clinically relevant neuroanatomy. There are three membranes that envelop our naked brain and the entire spinal cord: the pia mater, arachnoid mater and the tough outermost membrane – the dura mater. The pia and arachnoid layers are also called the ‘leptomeninges,’ between which circulates our cerebrospinal fluid (CSF). Our CSF acts as a cushion or buffer for the brain, providing basic mechanical and immunological protection to the brain inside the skull. Swelling of these leptomeningeal membranes – which can be caused by a bacterial or viral infection in the CSF surrounding the brain and spinal cord – gives rise to the condition called ‘meningitis!’ This swelling can occupy the space between the leptomeninges and the inelastic dura mater, which inherently presses on the brain and causes the pressure inside the head to rise! Elevated intracranial pressure in patients with meningitis is a significant source of morbidity and mortality. The use of lumbar drainage and selective placement of lumbar-peritoneal shunts in the management of elevated ICP can ameliorate this sequelae.
Now, we are going to be integrating our knowledge of the meninges with another condition that occurs when a patient suffers from cranial fractures as a result of a severe head injury, which include those caused by motorcycle or automobile accidents. At the beginning of the video, we get an excellent look at the lateral surface of the dura mater and the middle meningeal artery, which provides blood-flow to the dura. An epidural hematoma is caused by blunt trauma or an accident that leads to a skull fracture, typically found in the temporal bone, that tears or ruptures these middle meningeal arteries. This is a huge reason why every healthcare professional urges motorcyclists to wear helmets! The rupture can result in rapid bleeding that causes a collection of blood between the inner skull and the dura mater leading to compression of the brain, which can be seen in the gruesome video of a real-life epidural hematoma. Therefore, an epidural hematoma can cause the pressure inside the head to rise to the point where the brain can actually herniate downward. In this case, a transtentorial herniation. This herniation is commonly associated with a cranial nerve III palsy which is indicative of cranial nerve damage due to a bleed in the skull! How scary is that?!
Written by Student Doctor: Navpreet Singh Badesha ©07/08/2017 All Rights Reserved.
Video Credit: The Department of Neurobiology and Anatomy, and Spencer S. Eccles Health Sciences Library University of Utah, Salt Lake City.
Inspired by our Director of Education: Alexander Amir
To see more videos on this topic, visit these links below!
https://www.facebook.com/MEDspiration/videos/1892211101019708/
https://www.facebook.com/MEDspiration/videos/1892781877629297/
https://www.facebook.com/MEDspiration/videos/1892781894295962/
