Brain Injury Terms

Key Brain Injury Terms

We published a full brain injury glossary at http://www.waiting.com/glossary.html courtesy of HDI Publishers, 1992. However, as we are using certain technical terms on braininjuryhelp.com, we have included certain of those terms here.

Acceleration/Deceleration Injury: If a person is moving at a high rate of speed and suddenly comes to an unexpected stop the head movement can cause injury to the brain.  The skull goes from being a protective shield to an obstacle of the brain.

Axon:   Neuron process that carries impulses away from the nerve cell body. The axon is the conduction part of the cell.

Axonal bulb (axonal terminals): The bulbous distal endings of the terminal branches of an axon.

Cerebral Cortex :  The outer gray matter region of the  cerebral hemispheres.

Brain Flap:   This is the part of the skull that is cut away by a neurosurgeon during a craniotomy to relieve the pressure caused by brain swelling.

Cortical Contusion: A cortical contusion is a bruise to the brain sometimes called a hematoma.  Cortical referring to the cortex or surface of the brain.

Cranial Nerve V (trigeminal nerve):   Three branches spring from this nerve.  It is the largest of the cranial nerves and supplies sensory fibers to the face and motor fibers to the chewing muscles.

Cranial Nerve VI (abducens nerve): – This nerve controls the extrinsic eye muscle makes the eyeball turn laterally.

Craniotomy (craniectomy): This is the name for the surgery that a neurosurgeon perform to remove part of the skull (brain flap) to relieve pressure.

Cribriform Plates: A plate like bone structure that forms the roof of the nasal cavatiy and the floor of the anterior cranial fossa.  It has holes in it for the nerves to travel from the brain to their corresponding counterparts.

Dendrite:  A branching neuron process that serves as a receptive, or input, region.  The dendrite is a neuron that transmits an electrical signal toward the cell body.

Epidural hematoma: An epidural hematoma is a hematoma that occurs between the dura and the skull.

Entorhinal Cortex: This is an area of the brain the works as a hub for memory and navigation.  It is located in the medial temporal lobe.  ***

Fissures:  The deeper valleys of the brain.  This valley is deeper than the sulci. **

Herniation of the Cerebral Cortex:  The bigger concern in acute treatment of severe brain injury is the risk of herniation of the cerebral cortex into the brainstem area. (A herniation means the bulging of some type of organ into an area where it is not intended, as in a hernia in the groin area is the herniation of the intestines through the wall of the abdomen.)

Hippocampus: Limbic System structure that plays a role in converting new information into long term memories. ***

Hippocampal Complex:  This region is the hippocampus, dendrate gyrus  and the subiculum combined.  All needed for memory function.

Gyri (Gyrus): The hills are called gyri.  This is the outward  fold of the cerebral cortex. **

Lateral Cerebral Fissure: The temporal lobes are separated from the lobes above it by the lateral cerebral fissure. This is also known as the Sylvan fissure.

Medulla Oblongata:  This is the part of the brain that is located on the lower half of the brainstem.  Sensory and motor neurons travel through the medulla oblongata which helps in sending messages to the spinal cord.

Midbrain (mesencephalon) :  The midbrain is located in the front part of the brain stem.  It is responsible for relaying information to the auditiory, visual and motor systems.

Midline Shift: If the brain is swelling on one side, it pushes one hemisphere across this center line.   This is called a “midline shift.”  A midline shift is one of the most obvious evidences of brain swelling that can be seen on a CT scan.

Neuron:  Cell of the nervous system specialized to generate and transmit electrical signals.

Parahippocampal Gyrus:  This is part of the brain’s limbic system and is the part that creates memories and visual scenes.  It also serves for recognition of certain verbal cues.

Parasagittal Contusions:  The gliding contusions that occur from the sliding of the brain across the inside of the skull.  Greenfield’s p842, so called because they occur primarily to the parasaggital white matter.

Perirhinal Cortex:  This part of the brain that receives high sensory information and is accepted to be an important region for memory. ***

Severe Diffuse Axonal Injury:   This is one of the most dangerous pathological conditions that can occur. It is the cause of death in most cases where the patient never makes it to the hospital. Diffuse axonal injury Thus, diffuse axonal injury is also called a “shearing injury.

Soma (somatic nervous system)  Part of the sensory dealing with reception in the body wall and limbs that receives input from exteroceptors, proprioceptor and interoceptors.

Subdural hematoma: Subdural hematoma is a hematoma that occurs between the dura  and the brain. The dura is a thick outer membrane to protect the brain.

Sulci (sulcus): The valleys of the brain.  A furrow on the brain not as deep than a fissure. ** 

Synapse (the “synaptic junction”):  Functional junction or point of close contact between two neurons or between a neuron and an effector cell.

Whiplash:  This describes injury to the neck cause by motion such in acceleration/deceleration.  It is not a medical term and is most often used referring to motor vehicle accidents.

** To the degree you want to understand the geography of the brain, these terms can be helpful because it is specific gyri and fissure. It has important connections with the cerebellum, basal ganglia and motor divisions of the thalamus.

*** Many of the regions of the temporal lobes are critical for learning and memory. The middle portion of these lobes are important for the learning of new information. The medial portion of the temporal lobes contain the hippocampus, the critical brain structure for short term memory, the brain’s save button. The hippocampus combines with the entrohinal, perirhinal cortices and parahippocampal gyrus, to form the hippocampal complex. The hippocampal complex has direct connections to the entire brain.

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Gordon Johnson

Attorney Gordon Johnson is one of the nations leading brain injury advocates. He is Past-Chair of the TBILG, a national group of more than 150 brain injury advocates. He has spoken at numerous brain injury seminars and is the author of some of the most read brain injury web pages on the internet.

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