Neuroanatomy Flashcards

Flashcards for Neuroanatomy Exam 2

Spinal Cord Length

Typically 40-45 cm (16-18 in) long.

Spinal Cord Neurons

Contains up to 100 million neurons.

Maximum Diameter of Spinal Cord

1.3 cm

Spinal Cord Superior Boundary

Foramen Magnum

Bell-Magendie Law

Dorsal roots contain sensory (afferent) fibers & ventral rootlets contain motor (efferent) fibers.

Conus Medullaris

Tapering end of the spinal cord.

Cauda Equina

The extended distance of the cord through the lumbar cistern, resembles a horse’s tail

Dorsal Horn Function

Synapses sensory information.

Ventral Horn Function

Contains motor neurons.

Lateral Horn Function

Has an autonomic function, is not located at every cord level.

Substantia Grisea

Another name for the gross structure of gray matter.

Funiculus

Term for a longitudinal bundle of white matter fibers.

Lamina I

Forms a thin cap of gray over the posterior horn, home of marginal nucleus.

Lamina II

Contains an important pain reception center called Substantia Gelatinosa, Dorsolateral tract synapses here.

Lamina III, IV

Contains the Nucleus Proprius, sense touch & pressure, anterior spinothalamic tract synapses here.

Lamina V

Contains the reticular formation of the cord - cervical area only, but lamina itself is found at all cord levels.

Lamina VI

Missing at some cord levels & is the most anterior aspect of the dorsal horn.

Lamina VII

Located in the intermediate gray area, descending tract fibers synapse here, home of Nucleus Dorsalis (Clarke's Nucleus) & Intermediolateral Nucleus.

Nucleus Dorsalis (Clarke’s Nucleus)

Extends like a column from cord levels C8 - L3, famous ascending fasciculus called posterior spinocerebellar tract.

Lamina IX

Innervates most of the body’s skeletal muscle & gives the ventral horn its name “Somatic Motor Horn”, carries class S alpha motor neurons & looks like a series of disconnected neurons.

Fasciculi (tracts)

Term for bundles of functionally related axons within a funiculus.

Gracilis Tract

Slender, present at all cord levels, & synapses in nucleus gracilis of the MO.

Cuneatus Tract

Wedge shaped, T5/6 up, & synapses in the nucleus cutaneous of the MO.

Anterolateral system

Combination name of the lateral & anterior spinothalamic tracts

Anterior Corticospinal tract

Located in the anterior funiculus, cross in the spinal cord & terminate in the mid thoracics.

Lower Motor Neurons

Neurons that originate in the CNS & extend fibers into the PNS to innervates somatic musculature

Pyramidal Neuron

UMN are involved with the initiation of skilled voluntary movement, in the cord they are considered corticospinal

Extrapyramidal

UMN originates in the brainstem; influence posture, muscle tone, reflexes & allows voluntary movements to be smooth & effective

Tectospinal Tract

Spinal tract originates in the superior colliculus of midbrain’s tectum, fibers cross as they descend & it is responsible for postural reflex enhancement, sight, auditory

Medial Reticulospinal Tract

Spinal tract originates in the pons tegmentum, mostly uncrossed, terminates at all cord levels in ventral horn, influences heart, blood pressure & respiratory

Fasciculus Proprius

System that contains Spinospinal fibers that extend short distances up or down, may or may not cross, located next to gray horns, very important for coordination for spinal reflexes

Dorsolateral Tract of Lissauer

Located between RL I & the posterior lateral sulcus of the cord, small diameter collateral fibers of posterior root axons (mainly in RL II)

Multiple Sclerosis

Clinical aspect results in the destruction of the CNS (not PNS) myelin, more common in females (2:1) between ages 20-40, symptoms can remit & relapse

Amyotrophic Lateral Sclerosis

Clinical aspect results in the destruction of UMN & LMN in the lateral corticospinal tract, males are twice as affected (45yo), characterized by localized weakness/clumsiness & condition will progress until diaphragm is affected resulting in death (lack of breathing)

Medulla Oblongata

Most inferior part of the rhombencephalon & brainstem

Accessory Oculomotor Nucleus (Edinger-Westphal)

Nucleus with parasympathetic control of ciliary & pupillary constrictor muscles of the eye

Lateral Medullary Stroke Syndrome aka Wallenberg’s Stroke Syndrome

A clinical aspect that results in a stroke that can come through the vertebrobasilar arteries or their branches, symptoms include loss of pain, temp sensation on side of the face or opposite side of the body

Rhomboid Fossa

A feature located at the dorsal part of the pons & forms part of the floor of the 4th ventricle

Pontine Nuclei

Relay input from the cerebral cortex back to the cerebellum via the Middle Cerebellar Peduncle of the Pons

Arbor Vitae

Extension of the cerebral white matter toward the cortex appear as a branching tree

Medulloblastomas

20% of all childhood brain tumors are & arise in the superior medullary velum, very invasive, mostly in males (2:1) ages 4-8

Ataxia

Clinical aspect involving lesions of the neocerebellum, abnormal performance, stagger to side, inability to rapidly supinate/probate hands - a lack of coordination

Dysmetria

Clinical aspect when measured movements are difficult, over or undershoot target

Nystagmus

Clinical aspect involving repetitive jerking movements of the eyeballs

Somatic Motor Horn

Ventral Horn called bc of RL9. Where largest and fastest conducting motor neurons exist

Rhombencephalon

Hindbrain (M.O., Pons, Cerebellum)