Neuroanatomy Flashcards
Central Nervous System (CNS)
Brain and Spinal Cord
Peripheral Nervous System (PNS)
The parts of the nervous system outside of the brain and spinal cord
Meninges
Protective covering of the nervous system composed of three layers: Dura Mater, Arachnoid, Pia Mater
Dura Mater
Tough outer layer of the meninges
Arachnoid
Middle web-like layer of the meninges
Pia Mater
Delicate inner layer of the meninges
Lobes of the Brain
Frontal Lobe, Parietal Lobe, Temporal Lobe, Occipital Lobe
Frontal Lobe Function
Voluntary movement (motor cortex), expressive language (broca’s area), higher level executive functions
Temporal Lobe Function
Hearing, memory, emotion, and some aspects of language (wernicke’s area)
Parietal Lobe Function
Somatosensory Cortex
Occipital Lobe Function
Visual Cortex
Central Sulcus
Separates the Motor (frontal lobe) and Sensory (parietal lobe) Cortices
Precentral Gyrus
Precentral gyrus is on the lateral surface of each frontal lobe, anterior to the central sulcus. It runs parallel to the central sulcus and extends to the precentral sulcus. The primary motor cortex is located within the precentral gyrus and is responsible for the control of voluntary motor movement
Postcentral Gyrus
Primary somatosensory cortex and receives the majority of the somatic sensory relay information from the thalamus
Homunculus
Latin for “little man”
A distorted representation of the human body, based on a neurological “map” of the areas and proportions of the human brain dedicated to processing motor functions, or sensory functions, for different parts of the body
Grey Matter
Grey matter (or gray matter) makes up the outermost layer of the brain and is pinkish grey in tone, hence the name grey matter. It gets its grey tone from the high concentration of neuronal cell bodies in contains. Grey matter also contains unmyelinated axons.
White Matter
White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons).
Cerebellum
Latin for “little brain”
A major structure of the hindbrain that is located near the brainstem. This part of the brain is responsible for coordinating voluntary movements. It is also responsible for a number of functions including motor skills such as balance, coordination, and posture
Thalamus
The thalamus is a small structure within the brain located just above the brainstem between the cerebral cortex and the midbrain and has extensive nerve connections to both. The primary function of the thalamus is to relay motor and sensory signals to the cerebral cortex
Brainstem
The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata.
Brainstem + Cranial Nerves
Midbrain (Upper Brainstem): CN III-IV
Pons (Middle Brainstem): CN V-VIII
Medulla (Lower Brainstem): CN IX-XII
Cranial Nerve I
Olfactory Nerve
Modality: Sensory
Function: Smell
Monitored: NA
Cranial Nerve II
Optic Nerve
Modality: Sensory
Function: Vision
Monitored: VEP
Cranial Nerve III
Oculomotor Nerve
Modality: Motor
Function: Eye movement, pupillary constriction
Monitored: EMG from extraocular muscles (inferior rectus)
Cranial Nerve IV
Trochlear Nerve
Modality: Motor
Function: Eye movement
Monitored: EMG from superior oblique
Cranial Nerve V
Trigeminal Nerve
Modality: Both
Function: Facial sensation, mastication
Monitored: EMG from masseter and/or temporalis
Cranial Nerve VI
Abducens Nerve
Modality: Motor
Function: Eye movement
Monitored: EMG from lateral rectus
Cranial Nerve VII
Facial Nerve
Modality: Both
Function: Facial expression, autonomic input to salivary glands, taste to anterior 2/3 of tongue
Monitored: EMG from frontalis, orbicularis oculi, orbicularis oris, mentalis
Cranial Nerve VIII
Vestibulocochlear Nerve
Modality: Sensory
Function: Hearing and balance
Monitored: BAER
Cranial Nerve IX
Glossopharyngeal Nerve
Modality: Both
Function: Motor to stylopharyngeus, sensation to tonsils and pharynx, taste to posterior 2/3 of tongue, input to parotid gland
Monitored: EMG from soft palate
Cranial Nerve X
Vagus Nerve
Modality: Both
Function: Motor to vocal cords, parasympathetic to thoracic and abdominal viscera
Monitored: EMG from vocal cords (RLN)
Cranial Nerve XI
Spinal Accessory Nerve
Modality: Motor
Function: Motor to trapezius and sternocleidomastoid
Monitored: EMG from trapezius and/or sternocleidomastoid
Cranial Nerve XII
Hypoglossal Nerve
Modality: Motor
Function: Motor to tongue
Monitored: EMG from tongue
Circle of Willis
Interconnecting blood vessels that supply blood to the brain. Contains communicating arteries to cover for other arteries if they are blocked.
Internal Carotid Arteries (ICA)
Supplies blood from the common carotid artery to the anterior portion of the brain via the middle and anterior cerebral arteries
Middle Cerebral Arteries (MCA)
Supplies blood from the Internal Carotid Arteries to the lateral cortex of the brain (includes upper extremity SSEPs)
Anterior Cerebral Arteries (ACA)
Supplies blood from the Internal Carotid Arteries to the medial cortex and frontal lobe (includes lower extremity SSEPs)
Vertebral Arteries (VA)
Travel up the transverse foramina of the cervical vertebrae, enter the foramen magnum, head anteriorly, and join together to form the Basilar Artery (BA)
Basilar Artery (BA)
Formed by the Vertebral Arteries (VA). Travels up the ventral surface of the pons and branches off to the cerebellum, pons, midbrain, and thalamus. Terminates into the Posterior Cerebral Arteries (PCA).
Posterior Cerebral Arteries (PCA)
Arise from the terminal tip of the Basilar Artery (BA). Perfuse the posterior cortex (occipital lobe)
Cerebellar Arteries (CA)
Perfuse the cerebellum and parts of the brainstem
Superior Cerebellar Arteries (SCA)
Arise from the superior portion of the Basilar Artery (BA). Perfuse the superior portion of the cerebellum.
Anterior Inferior Cerebellar Arteries (AICA)
Arise from the lower part of the Basilar Artery (BA). Perfuse the inferior portion of the cerebellum and feeds into the internal auditory artery of the inner ear.
Posterior Inferior Cerebellar Arteries (PICA)
Arise from the Vertebral Arteries (VA) near the vertebrobasilar junction. Perfuses inferior portion of the cerebellum and parts of the medulla oblongata
Communicating Arteries
Serve to connect the vasculature of the Circle of Willis. Provide a means of collateral circulation.
Anterior Communicating Artery (A Com)
Posterior Communicating Arteries (P Com)
Spinal Cord
Extends from the skull down to L2. Carries all information from the body to the brain (afferent, sensory) and from the brain to the body (efferent, motor). Terminates into the Cauda Equina.
Conus Medullaris
The tapering of the spinal cord at the base, usually occurring from T11 through L2
Cauda Equina
The nerve roots of the lumbar and sacral spine. Since the nerve roots of this region begin in the conus medullaris, they must travel down for a distance before exiting at their vertebral levels, thus forming the free standing nerve roots of the “horse’s tail”
White Matter of the Spinal Cord
Surround the spinal cord. Myelinated axons that carry ascending or descending signals to or from the brain.
Grey Matter of the Spinal Cord
Form the grey butterfly shape when viewing a cross-section of the spinal cord. Unmyelinated interneurons. Spinal cord processes incoming/outgoing signals from the grey matter. Anterior and posterior protrusions of the butterfly pattern are called the anterior and posterior horns.
Dorsal Root
Mediates all incoming sensory impulses into the spinal cord. The dorsal root ganglion (the “bulge”) contains the sensory cell bodies.
Ventral Root
Mediates the outgoing motor impulses from the spinal cord. Cell bodies contained in the ventral horn of the grey matter in the spinal cord.
Anterior Spinal Artery
Runs the entire length of the midline of the spinal cord. Perfuses the anterior 2/3 of the spinal column.
Posterior Spinal Arteries
Runs the entire length of the spinal cord. Located immediately lateral to the posterior columns. Perfuses the posterior 1/3 of the spinal column.
Radicular (Segmental) Arteries
Located at the each segment of the spinal cord, supplying blood to the anterior and posterior spinal arteries. Most are underdeveloped and don’t contribute much to perfusion. A few are exceptions, the most important being the Artery of Adamkiewicz, which is usually located around T10
Brachial Plexus
C5-T1
A network of nerves in the shoulder supplying the upper extremities
Median Nerve
C5-T1
Innervates the abductor pollicis brevis and several muscles of the forearm.
Ulnar Nerve
C8-T1
Innervates the abductor digiti minimi as well as other hand and forearm muscles.
Radial Nerve
Innervates the triceps, brachioradialis, and other wrist flexors in the forearm
Axillary Nerve
Supplies three muscles in the arm: deltoid (a muscle of the shoulder), triceps (long head) and teres minor (one of the rotator cuff muscles).
This nerve also carries sensory information from the shoulder joint.
Musculocutaneous Nerve
Innervates the Biceps
Lumbosacral Plexus
Branching of nerves from the lumbar and sacral spine
Sciatic Nerve
Large nerve in the upper leg, formed by the joining of the peroneal and posterior tibial nerves.
Posterior Tibial Nerve
L4-S3
Branch of the sciatic nerve. Descends through the midline of the popliteal fossa and wraps around the medial malleolus. Innervates the gastrocnemius and foot flexors.
PTN gives us largest amplitude cortical response which is why it’s the preferred nerve for monitoring lower extremity SSEPs
Peroneal Nerve
L4-S2
Branch of the sciatic nerve. Descends lateral to the fibular head. Innervates the tibialis anterior among other foot dorsiflexors.
Femoral Nerve
L2-L4
Innervates the quadriceps and femoris muscles
Saphenous Nerve
Sensory branch of the femoral nerve. Transmits sensory information from the medial portion of the leg and foot.
(Best to use this nerve when monitoring the lumbar plexus) during
Vertebrae
Individual segments making up the spinal column. The human body usually contains 33 vertebrae Cervical: 7 Thoracic: 12 Lumbar: 5 Sacral: 5 (fused) Coccygeal: 4 (fused)
Vertebral Body
Main cylinder of bone that stacks on top of other vertebral bodies.
Pedicles
Two columns of bone on either side of the vertebral body, connecting it to the lamina
Lamina
The posterior wall of bone that covers and protects the spinal cord
Transverse Process
Protrusions of bone that stick out laterally from the pedicles
Spinous Process
The protrusions of bone that stick out from the posterior portion of each vertebrae
Foramen
A hole between the anterior and posterior portions of the vertebra through which nerve roots exit the spinal cord
Examples of IPSPs
Gamma aminobutyric acid (GABA) and glycine
Examples of EPSPs
Glutamate and acetylcholine
Which artery supplies blood to the medial portion of the Somatosensory Cortex?
Anterior Cerebral Artery (ACA)
Which artery supplies blood to the lateral portion of the Somatosensory Cortex?
Middle Cerebral Artery (MCA)