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Neuroantanomy
Count Bobula Spinal Cord Lecture
| Question | Answer |
|---|---|
| Where does the spinal cord begin and end? | superiorly at foramen magnum Ends at L1/L2 invertebral disc |
| The spinal cord is continuous with what structure | medulla oblongata |
| What is the length of the cervical enlargement? | C5 to T1 |
| Cervical enlargement gives rise to what? | brachial plexus |
| What does the brachial plexus do? | innervate upper limb |
| What segment of spinal cord extends from L1 to S3 | Lumbosacral or Lumbar enlargement |
| What rises from the lumbosacral enlargement? | lumbar and sacral plexuses which innervate lower limb |
| The three terminating structures of the spinal cord are what? | Conus Medullaris, Filum Terminale, Cauda Equina |
| What is a connective tissue filament extending from the conus medullaris to attach at the coccyx? | Filum Terminale |
| Which spinal nerves are part of the Cauda Equina? | roots that extend below the conus medullaris |
| Until what week of development does the spinal cord run the length of the vertebal canal? | 8th |
| What is the alignment of spinal cord segments and verterbrae prior to the 8th week | The are aligned with corresponding segments |
| When does the vertebral column begin growing faster than the spinal cord? Result | 3rd month. inferior end lies at progressively higher vertebral levels |
| What are the levels of the spinal cord and verterbra at 6 months, birth, adult? | 6 months = S1 birth = L3 Adult = L1/L2 |
| How do the spinal roots elongate to maintain innervation? | descend obliquely to intervertebral foramina |
| What are the three meninges of the spinal cord? | Dura Mater Arachnoid (mater) Pia Mater |
| The loose sac, _____, around spinal cord and cauda equina that is continuous with _______ of the brain. | dura mater, dura |
| The inferior termination of the dura? | blindly at S2 |
| Where is the Filum terminale internum? | Upper part that is within dural sac |
| Where is filum terminale externum? What covers it? | passes out of dural sac and picks up investment of dura mater |
| Where is the coccygeal ligament? | same thing as filum terminale externum - continuation of filum terminale after dural sac |
| What is between dura mater and vertebrae? | epidural space |
| What is in the epidural space? | fat, loose connective tissue, internal vertebral venous plexus |
| Where is the internal vertebral venous plexus? | epidural space |
| What is the epineurium? | connective tissue covering of a nerve |
| where to the dura mater and epineurium meet? | dura mater forms a sleeve around the roots of each spinal nerve. It fuses with the epineurium at the intervertebral foramen |
| Who da arachnoid? | delicate membrane that lines the internal surface of the dura mater |
| What is the beginning and ending of the arachnoid? | continuous with cranial arachnoid; extends full length of dural sac; lines dural sleeves around spinal nerves |
| Where is the subdural space? | potential space between dura mater and arachnoid |
| Where is the subarachnoid space? beginning? ending? | real space between arachnoid and pia mater Continous with sub of brain and extend to S2, also go in spinal nerve root sleeves |
| What is in the subarachnoid space? | cerebrospinal fluid |
| What is filled with CSF and contains anterior and posterior nerve roots of the cauda equina and filium terminale internum? | Lumbar cistern |
| What are the boundaries of the lumbar cistern? | subarachnoid space inferior to conus medullaris |
| Where should you stick the ho for a lumbar puncture? | between L3/L4 or L4/l5 verterbral arches |
| What is the vascular membrane the intimately follows the surface of the spinal cord and nerve roots within arachnoid? | Pia Mater |
| What is the superior boundary of the Pia Mater? | continuous with pia mater of medulla oblongata |
| What other structure in the spinal cord rises from pia mater? | part of the filum terminale |
| What stabilizes the spinal cord in the coronal plane? | Denticulate ligament |
| Where can denticulate ligament be found? | lateral edges between anterior and posterior roots |
| What is the denticulate projections relationship with the arachnoid? | penetrate it |
| What is the name of the deep groove along the anterior midline of the spinal cord? | Anterior Median Fissure |
| What is the shallow groove along the posterior midline? | posterior median sulcus |
| Where do the rootlets of the anterior roots of the spinal nerves attach? | anterolateral sulcus |
| Where do the rootlets of the posterior roots of the spinal nerves attach? | posterolateral sulcus |
| what spinal cord surface feature is located between the posterior median sulcus and posterolateral sulcus | Posterior intermediate sulcus |
| What spinal cord surface feature is only present in the cervical and upper thoracic regions of the spinal cord | posterior intermediate sulcus |
| Spinal nerves are formed by what? | Anterior (ventral) and Posterior (dorsal) roots |
| Efferent fibers are what type? Which direction? | ventral, motor fibers carrying information away from spinal cord, |
| Afferent fibers are what type, which direction? | dorsal, sensory fibers carrying information to the spinal cord |
| What does the dorsal root contain that the anterior root does not? Name? | a ganglion that contains the cell bodies of the sensory neurons - posterior root ganglion |
| Why are spinal nerves called mixed? | contain both motor and sensory fibers |
| Which spinal nerve ramus is smaller? What does it innervate? | Posterior ramus innvervates skin and deep muscles of back |
| Which spinal nerve ramus is larger? what does it innervate? | anterior ramus innervates skin and muscles of limbs and anterolateral trunk and superficial back muscles |
| How many pairs of spinal nerves exist? Break them down: | 31 pair:P 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal |
| Nerves leave the vertebral canal where? C1-C7, C8, T1 down | C1-C7: superior to the vertebra C8: between C7 and T1 T1 down: inferior to the vertebra |
| Where is the central cavity of the spinal cord? What does it do? | narrow cavity in center of cord that communicates with the ventricular system of brain |
| With what specific ventricle does the central cavity communicate? What lines it? | lined by ependymal cells, it communicates with the fourth ventricle |
| Where is the gray mater and white matter? | gray matter centrally located, white mater on periphery |
| Which matter has a butterfly or H shape? | Gray matter |
| What are the four regions of the gray matter? | posterior horn, anterior horn, intermediate zone, lateral horn |
| What are the two segments of the lateral horn? | thoracic and upper lumbar |
| How is the gray matter constructed? What is the formal name? | divided into layers based on cytoarchitecture, called the laminae of Rexed |
| What layers fit posterior horn? | laminae I to VI |
| What layers fit intermediate zone? | lamina VII |
| What layers fit Anterior zone? | part of VII plus VIII and IX |
| What layer fit Around central canal? | Lamina X |
| How does sensory information reach higher neuraxis in the brain? | carried by sensory fibers through the dorsal roots to the neurons in the posterior horn then axons ascend to white matter in neuraxis |
| Where is the marginal nucleus? What lamina is it? | marginal or posteromarginal nucleus is at apex of posterior horn, lamina I |
| Lamina II makes up what? | Substantia Gelatinosa of the posterior horn nuclei |
| Laminae III and IV form what? | nucleus proprius or proper/principal sensory nucleus of posterior horn nuclei |
| In what special regions or segments are the posterior horn nuclei found? | All are present along the whole length of the spinal cord? |
| The anterior horn is mostly involved with what? | voluntary movements |
| Where do the axons travel from neurons located in the anterior horn? | leave through anterior roots to supply skeletal muscle fibers |
| What is the name of neurons in anterior horn? | somatic motor neurons |
| What supply extrafusal muscle fibers | alpha motor neurons |
| What supply intrafusal muscle fibers (where)? | Gamma motor neurons in muscle spindles |
| What is an extrafusal muscle fiber? | standard muscle fiber that generates tension by contraction allowing for skeletal movement |
| What makes up a motor unit? | The alpha motor neuron and the extrafusal muscle fibers it innervates make up the motor unit. The connection between the alpha motor neuron and the extrafusal muscle fiber is a neuromuscular junction. |
| What are intrafusal muscle fibers | These fibers are a proprioceptor that detect the amount and rate of change of length in a muscle. |
| What are the two parts of the anterior horn? | medial motor column and lateral motor column |
| Which column has motor neurons that innervate limb muscles? Where are the neurons found? | lateral column in cervical and lumbosacral enlargements |
| What does the medial motor neurons innervate? where is it found? | neck and truck, or axial musculature...found at all levels |
| What is the phrenic nucleus? What segments does it exit? | leaves via C3-C5, innervates diaphragm via phrenic nerve |
| What motor nucleus sends axons out C1-C5 to form the spinal root of the accessory nerve? | Accessory nucleus |
| What area of gray matter is continuous medially with gray matter around the central canal | Intermediate zone |
| What is the purpose of the intermediate zone | interneurons for segmental and intersegmental intergration of spinal functions |
| What nuclei are found in the medial part of the intermediate zone? | Nucleus of Clarke/nucleus dorsalis/thoracic nucleus |
| What segments are nucleus of Clarke | C8-L3 |
| Where do the axons of thoracic nucleus go? | ascend in white matter to cerebellum in posterior spinocerebellar tract |
| What forms the lateral horn? Segments? | preganglionic sympathetic neurons of the intermediolateral nucleus, segments T1-L2 |
| What are the sacral parasympathetic nucleus? | S2-S4 preganglionic parasympathetic neurons |
| What are the three regions in which white matter is found in the spinal cord? | Posterior (dorsal)Funiculus lateral funiculus anterior (ventral) funiculus |
| What are the boundaries of the dorsal funiculus? | between posterior median sulcus and posterolateral sulcus |
| what are the boundaries of the ventral funiculus? | between anterolateral suclus and anterior median fissure |
| what are the boundaries of the lateral funiculus? | between posterolateral and anterolateral sulci |
| Which direction do the fibers of the white matter of spinal cord travel? Pupose? | long ascending and descending tracts that interconnect the spinal cord to the brain |
| What interconnects the white matter spinal cord segments? | propriospinal (intersegmental) fibers |
| Where are propriospinal (intersegmental) fibers found? | fasciculus proprius: narrow band adjacent to gray matter |
| Why are propriospinal fibers important? | coordinate complicated messages from other body parts |
| Name of super important area of white matter anterior to gray matter and deep to median fissure? | Anterior White commissure |
| Why is the anterior white commissure important? | contains fibers that cross from one side of the cord to the other - ALL pain and temperature sensation must travel through it |
| What part of white matter do all pain and temperature signals travel through? | anterior white commissure |
| Where Lissauer's tract? What are it's other names? | posterolateral tract, dorsolateral fasciculus lies between apex of posterior horn and spinal cord surface |
| What is the area of white matter that lies at the top of the butterfly or posterior horn | dorsal fasciculus of Lissauer |
| How does the dorsal fasciculus of Lissauer disseminate information? | propriospinal fibers and fibers from posterior root. These bifurcate and ascend or descend to travel 1 or 2 segments to collaterals in posterior horn |
| What sensory modalities are carried by the ascending tracts of spinal cord? | all signals from receptors: pain, thermal, tactile, muscle and joint |
| The posterior column has two parts. What are they? | fasciculus gracilus (medialy) fasciculus cuneatus (laterally from T6 up) |
| What does fasciculus gracilus commnicate? From where? | info from lower half of body: discriminative touch, vibration, limp position and motion |
| How far does f. gracilus info go up? | to cerebral cortex (consciousness) |
| What is transmitted by fasciulus cuneatus? | info. from upper half of body - T6 and up - also discriminative touch, vibration, limb position |
| Where and what is the tract that transmits pain, temparture and non-discriminative information? | spinothalmic tract lies lateral and anterior to anterior horn |
| What is the very thin, skin like layer around the spinal cord that carries proprioceptive and tactile information to cerebellum | anterior and posterior spinocerebellar tracts |
| Where at the anterior and posterior spinocerebellar tracts located? | at periphery of lateral funiculus |
| How are lateral and anterior corticospinal tracts different than ant/lat spinocerebellar tracts | Look at name. They go from cortex to spine...thus descending tracts |
| Where is the most important descending tract that carries 90% of the information | lateral corticospinal - located in lateral funiculus, deep to posterior spinocerebellar tract |
| Where is the anterior corticospinal tract? | anterior funiculus, just lateral to anterior median fissure |
| What tract starts at the red nucleus in the brain then enters the spinal cord | rubrospinal tract |
| Where does the rubrospinal tract travel | lateral funiculus, just anterior to lateral corticospinal tract |
| What information does the rubrospinal tract carry? | control of muscle tone, especially limb flexor muscles (excitatory) |
| What tract carries excitatory influence to increase the tone of extensor muscles? | Lateral vestibulospinal tract |
| Where does the lateral vestibulospinal tract start and run? | starts in lateral vestibular nucleus, runs in anterior funiculus close to surface |
| where does the medial vestibulospinal tract start and run? | starts in medial and inferior vestibular nuclei, runs in medial part of anterior funiculus as part of medial longitudinal fasciculus |
| What is unique about vestibulospinal tract? | 1. only in cervical region 2. controls head and neck position 3. travels as part of bidirectional path, the medial longitudinal fasciculus |
| What tract starts at the pons? path? | medial (pontine) reticulospinal tract begins at reticular formation of pons, descends in anterior funiculus |
| where does lateral reticulospinal tract begin and run? | start in reticular formation of medulla, descend in anterior part of lateral funiculus |
| what do the reticulospinal fibers control? How do we differentiate the two tracts? | muscle tone; pontine (excitatory);medullary (inhibitory) |
Created by:
El Diablo
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