Question | Answer |
What is the Spinal Cord? | Part of the Central Nervous System that extends from the brain |
What does the Spinal Cord contain? | Bundles of sensory and motor tracts going to and from the brain |
Sensory input to the brain is what? | Afferent |
Motor output to the skeletal muscles and glands is what? | Efferent (exit) |
Motor output to smooth and cardiac muscles (autonomic) is what? | Efferent (exit) |
What is attached to the Spinal Cord? | Spinal nerves and cranial nerves |
What do the spinal nerves and cranial nerves do? | They carry the sensory and motor messages to the body |
What does the Spinal Cord react to? | Environmental changes |
What are the 3 cord protective structures? | Vertebral column, Cerebrospinal Fluid, and Meninges |
Vertebral Column | Vertebral foramina stacked on top of one another that forms a vertebral canal for protecting the spinal cord |
Cerebrospinal Fluid | Buoyant liquid that suspends Central Nervous System tissue in weightless environment and acts as a shock absorber |
Meninges | Protective tissue coverings around spinal cord and brain |
The 3 Meninges | Dura Mater, Arachnoid Mater, and Pia Mater |
Dura Mater | "Tough Mother", Superficial, Epidural given here |
Epidural Space | Cushion of fat and connective tissue between the dura mater and wall of bony vertebral canal |
Arachnoid Mater | "Spider Mother", Middle layer, Subarachnoid Space |
Subarachnoid Space | Holds cerebrospinal fluid |
Pia Mater | "Delicate Mother", Innermost layer, Directly on the Spinal Cord and Brain, Denticulate Ligaments |
Denticulate Ligaments | Lateral, tooth-like projections that tether Spinal Cord to the Dura Mater |
Spinal Cord External Anatomy | Extends from the Medulla Oblongata of the brain to the superior border of the Second Lumbar Vertebra (L2) |
How long is the Second Lumbar Vertebra? | 18 inches long |
Cervical Enlargment | Upper limb nerve exits |
Lumbar Enlargement | Lower limb nerve exits |
Conus Medullaris | Tapered end of cord at the L2 |
Filum Terminale | Anchors the spinal cord to the coccyx |
The Filum Terminale is an extension of what? | Pia Mater |
Cauda Equina | "Horse Tail" of lower extremity nerves that begin at the Lumbar Enlargement |
Spinal Tap/Lumbar Puncture | Long Needle thats inserted into the Subarachnoid Space |
Purpose of the Spinal Tap/Lumbar Puncture | Withdraw Cerebrospinal Fluid, Contrast medium for Imaging, Adminstration site for Anesthetic |
Where do you insert the needle for a Spinal Tap/Lumbar Puncture on an Adult? | L3/L4 or L4/L5 |
What do Spinal Nerves do? | Communicate between body and spinal cord |
How many pairs of Spinal Nerves are there? | 31 Pairs |
How many pairs of Cervical Nerves are there? | 1-8 pairs |
How many pairs of Thoracic Nervesn are there? | 1-12 pairs |
How many pairs of Lumbar Nerves are there? | 1-5 pairs |
How many pairs of Coccyx Nerves are there? | 1 pair |
The Cauda Equina has? | Free floating nerve roots of lumbar, sacral, and coccygeal nerves that extend to the lower extremities |
Where does the Cauda Equina start? | The Lumbar Enlargement and hangs downward |
Where does the Cauda Equina float? | In the Cerebrospinal Fluid |
What are Rootlets? | Small bundles of Axons that make up Roots |
What do the Spinal Nerve Roots connect? | Nerve to Cord |
What are the 2 different kind of Roots? | Doral and Ventral |
Dorsal Roots | Sensory Axons from skin, muscles, and internal organs |
Dorsal Roots contain what? | Cell bodies of the Sensory Neurons |
Where do Dorsal Roots start and end? | Start at the Periphery (PNS) and end at the Cord |
Ventral Roots | Motor Axons to Effectors (muscles and glands) |
Where do Ventral Roots start and end? | Start at the Cord (CNS) and end in the Periphery |
The Interal Anatomy of the Spinal Cord | Central Canal, Anterior Median Fissure and Posterior Median Sulcus, Horns of Gray Matter, Columns and Tracts of White Matter |
Central Canal | Holds Cerebrospinal Fluid |
Anterior Median Fissure and Posterior Median Sulcus | Divides the cord into left and right halves |
Horns of Gray Matter | Dorsal, Lateral and Ventral horn |
Dorsal Horn | Sensory In |
Lateral Horn | Motor to Organs (autonomic) |
Ventral Horn | Motor Out |
Columns and Tracts of White Matter contain | Myelinated Axons in bundles called tracts that travel up and down the cord carrying information to and from the brain |
What information travels in the Spinal Cord? | Sensory and Motor Information |
Sensory Information travels where and how? | To the brain inside Ascending Tracts of Axons GOING UP & IN |
Motor Information travels where and how? | From the brain or spinal cord in Descending Tracts of Axons GOING DOWN & OUT |
Sensory Receptors in the skin detect | Stimulus |
Where do the nerve impulse travel to? | Dorsal Branch of Spinal Nerve |
Where do the nerve impulses enter? | The Dorsal Horn of Gray Matter |
What do the Interneurons connect to? | Sensory to Motor |
What is an example of a voluntary response? | When either message will ascend to the brain along the white matter tract |
What is an example of a reflexive response? | When either message will skip the brain and go directly back out if required |
Spinal Nerves are named according to what? | Where they emerge from cord, cervical plexus, or lumbar plexus |
Spinal Nerves enter with what? | Sensory information at Dorsal Horn of cord |
Spinal Nerves exit with what? | Motor information at Ventral Horn of cord |
All Spinal Nerves are what? | Mixed |
What do all Spinal Nerves contain? | Sensory and motor axons (mixed nerves) after they merge roots |
What are the 3 enlargements at the cervical and lumbar exits for the arms and legs? | Cervical Plexus, Brachial Plexus, and Lumbosacral Plexus |
Nerves that do not form a plexus | Thoracic |
What nerves run individually between each rib (intercostal)? | Intercostal Thoracic Nerves |
Roots between T2-T12 that do not form plexuses | Ventral Roots |
Why are they called Intercostal Thoracic Nerves? | Each spinal nerve between T2 and T12 travels between the ribs |
Where is the Cervical Plexus located? | In the Head and Neck |
Where do the Cervical Plexus supply to? | The skin and muscles of head, neck and upper shoulders |
The Cervical Plexus innervates the what? | Diaphragm |
C3, C4, C5 has what nerve? | The Phernic Nerve |
What Cervical Plexuses keep the diaphragm alive? | C3, C4, and C5 |
Where is the Brachial Plexus located? | In the Arms and Hands |
Where do the Brachial Plexus supply to? | The upper limbs and several neck and shoulder muscles |
MARMU nerves | Musculocutaneous, Axillary, Radial, Median and Ulnar Nerves |
What are the 3 terminal branches of the Brachial Plexus? | Radial Nerve, Median Nerve and Ulnar Nerve |
Where is the Radial Nerve? | Innervates the back of the arm (triceps and forearm extensors) and the back of the hand |
Where is the Median Nerve? | Forearm flexors and thumb to middle finger |
Where is the Ulnar Nerve? | Ring finger and little finger plus the hand muscles |
Where is the Lumbar Plexus located? | Front of Thigh |
Where do the Lumbar Plexus supply to? | The abdominal wall, external genitals and part of lower limb |
What the main nerve in the Lumbar Plexus? | Femoral Nerve |
Where is the Fermoral Nerve? | In the front of the thigh |
What is the largest nerve of the Lumbar Plexus? | The Fermoral Nerve |
Where is the Sacral Plexus located? | The Buttocks and most of the leg |
What nerve is in the Sacral Plexus? | The Sciatic Nerve |
Sciatic Nerve in the back | Pain through the lower back and down the leg, to the foot |
Cervical Nerves | C1-C2 |
Thoracic Nerves | T1-T12 |
Lumbar Nerves | L1-L6 |
Sacral Nerves | S1-S5 |
Coccygeal Nerve | C0 |