CNS: Spinal Cord & Spinal Nerves 

Gross Anatomy of External Spinal Cord  

​Denticulate ligaments
(dentate ligaments):
    anchor the spinal cord to the dura mater.
    base of triangle shaped ligament attached at the
    pia mater and attached to the arachnoid/dura mater
    at the apex.

​Conus medullaris
(conus terminalis):
    lower end of the spinal cord near L1/L2

Cauda equina
(horse tail):
 bundle of spinal nerves:
      2nd - 5th lumbar nerve pairs
      1st - 5th sacral nerve pairs
      coccygeal nerve


 Filum terminale
(terminal thread):
       20cm string of fibrous tissue extending from the apex
       of the conus medullaris 

​Sympathetic chain ganglia
(paravertebral ganglia):
extend from both sides of cord at ventral and lateral positions from neck to coccyx

ganglion = a structure containing nerve cell bodies often seen as an enlarged area on a nerve)

​Cross- Sectional Anatomy of a Spinal Segment 

​   dura mater, arachnoid mater, pia mater
​   these three membranes line the skull and
   vertebral canal and cover the brain and
​   spinal cord.

​Epidural space  

​Subarachnoid space 

​Anterior median fissure  
Posterior median sulcus 
Central canal  (w.CFS)
Gray commissure (X)

​Dorsal root
    Dorsal nerve roots carry
    sensory info via afferent
    fibers to the
    CNS from the PNS. 
Dorsal root ganglion
    A ganglion is a cluster
    nerve cell bodies found
    outside the CNS. Dorsal
    root ganglia are found on
    the dorsal/posterior root 
    of nerves entering the spinal
    cord. Dorsal root ganglia
    transmit sensory info receptors
    to the CNS. 

Ventral root
​    Ventral roots carry info
    from the CNS via efferent
    fibers to a muscle/gland
    etc to initiate a response.

Spinal nerves 
    The ventral root joins
    with the dorsal root
    outside the vertebral column
    to form a spinal nerve.

Grey matter vs White matter:
    grey matter contains many cell bodies but few myelinated axons,
    white matter contains few cell bodies but myelinated axons
    the color difference is due to the white myelin)

​​White matter columns:
    White matter is subdivided
    into dorsal/posterior,
    lateral and
​    ventral/anterior columns.
    Each type of column contains
    axons with specific functions.
    Ascending tracts of column fibers
    carry sensory information up to the brain.
    Descending tracts carry motor
    info/instructions down from the brain.

​Gray matter horns:
    Gray matter forms three
    pairs of horns:
    Dorsal/posterior horns
    have neurons that receive
    sensory information from the body
    which is relayed via ascending
    pathways, to the brain.
    Ventral/anterior horns have
    motor neurons that leave
    the spinal cord to control skeletal muscle.
    Intermediate columns and lateral horns
    also contains neurons that control visceral organs.​

                                                             Week 2:
                       Spinal Nerve Plexuses & Peripheral Nerves:  
When adjacent spinal nerves combine their nerve fibers, 
                                               a Nerve Plexus (braid) is produced. 
                                              (reference pages 446 + in our text)
     *for each nerve, identify and learn the tissue that nerve innervates


1. Cervical Plexus: (nerves C1-C5) 
​(ears, neck, back of head, shoulders and diaphragm) 

lesser occipital nerve
great auricular nerve
transverse cervical nerve
supraclavicular nerve
phrenic nerve    ​

2. Brachial Plexus: (nerves C5-T1) 
      (controls muscles of the shoulder, elbow, wrist and hand) 
    Musculocutaneous nerve
​    Axillary nerve
    Radial nerve
    Median nerve
    Ulnar nerve

3. Lumbar Plexus: (nerves L1-L4) 
    Femoral nerve
    Obturator nerve
    Iliohypogastric nerve
    Ilioinguinal nerve
    Lateral femoral cutaneous nerve

​4. Sacral Plexus (nerves L4-S4) 

    Sciatic nerve (w/fibular and tibial branches)
    Inferior Gluteal nerve
​    Superior Gluteal nerve
    Pudendal nerve
    Posterior Femoral Cutaneous nerve

​5. Thoracic Nerves T2-T12

     Spinal nerves arising from the thoracic vertebrae do not form a plexus  
     for nerves T2-T12...
     each nerve runs along one rib to innervate the rib, skin and muscle in that thoracic area.

​      ​
​                                                                                Week 3:
                                                     Brain Anatomy & Cranial Nerves 

Major Regions of the Brain:

​The cerebrum has a right and left hemisphere joined by the corpus callosum.
Functions: initiate/coordinate movement, vision, hearing, touch, judgment and
reasoning along with problem solving, emotions, and learning.

The brainstem includes the pons, midbrain, and the medulla.
Functions: movement of eyes/mouth, sensory relay of heat/pain, respiration, consciousness, cardiac function, involuntary muscle movements, sneezing, coughing, vomiting/swallowing.
The pons controls eye/face movements.
The medulla is the control center for the heart/lungs.

The cerebellum's functions include:
coordinating voluntary muscle movements/maintaining posture, balance, and equilibrium.

External features of the Cerebrum:

​​Cerebral cortex (= crinkled surface of grey matter)
Longitudinal fissures
Cerebral hemispheres
Cerebral lobes: frontal, parietal, temporal, occipital
Gyrus (gyri) & sulcus (sulci)
         (= ridges & grooves on cerebral cortex)
Central sulcus
Primary sensory cortex (= post-central gyrus)
Primary motor cortex (= pre-central gyrus)
(see Sagittal and Inferior Views)


sagittal and inferior views:
​Corpus callosum
Lateral ventricles
​        (fluid-filled chamber
​        enclosed within each hemisphere)
Choroid plexus
Pineal gland
Pituitary gland
    (attaches pituitary gland
      to hypothalamus)
Optic chiasm
Olfactory bulbs
Optic tracts (nerves)
Optic nerve
Mammillary body


​Brain Stem
(identify in both sagittal and external views)
Medulla oblongata
Corpora quadrigemina:

superior colliculi & inferior colliculi
Cerebral peduncles

Arbor vitae...white matter
Cortex...grey matter

3 Layers of cranial meninges:
​Dura mater, Arachnoid mater, Pia mater
Subarachnoid space

Superior sagittal sinus
  (a vein that drains blood from brain)

Lateral ventricle
Third ventricle
Fourth ventricle
Cerebral aqueduct
​   (connects 3rd & 4th ventricle)

​Cranial Nerves (12): know names & #(roman numeral) of each cranial nerve
#                  Name of Nerve                           Fiber Type                                        Major Function(s) 

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    The Nervous System
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