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What are the 3 types of Articulations?
- - Fibrous (3)
- - Cartilaginous (2)
- - Synovial (Majority)
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What does Synarthroses mean?
No Movement within a joint
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What does Amphiarthroses mean?
Slight movement within a joint
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What does Diarthroses mean?
Huge range of movement within a joint (All synovial joints are diarthroses)
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Name the 3 types of Fibrous articulations.
- - Suture- ex. skull bones (Synarthroses)
- - Syndesmosis- ex. fibula/tibia (Amphiarthroses)
- - Gomphosis- ex. tooth (Synarthroses)
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Name the 2 types of Cartilaginous articulations.
- - Synchondrosis- ex. Hyalin Cartilage; becomes Synostosis by the fusion of two centers of occification to form solid bone (Synarthroses)
- -Symphysis- ex. vertebral column (Amphiarthroses)
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What are Synovial joints?
- Majority (Diarthroses)- contain synovial fluid which
- - lubricates
- - feeds chondrocytes
- - absorbs shock
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What are the different types of joint movement?
- 1. Linear Motion (Gliding)
- 2. Rotation
- 3. Angular Motion (Tilting)
- 4. Circumduction
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What are the different types of Angular Movements?
- Abduction- take away from the body
- Adduction- take in towards the body
- Flexion- take from anatomical position adn place into the fetal position
- Extension- Bring back to anatomical position
- Pronation/Supination- take your soup and "pro" it on the floor
- Medial- rotate inward (internal)
- Lateral- rotate outward (external)
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What limits movement at synovial joints?
- Articular discs (menisci)- ex. knee or jaw
- Ligaments- Intracapsular: inside joint cavity; Extracapsular: outside joint cavity
- Tendons & Muscles- muscles contract and tendons prevent movement
- Articular Surface Contour- shape of atricular surface
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Which type of joint in the body allows the greatest range of motion?
Diarthroses
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The joint of the body tend to follow a pattern of increased strength causing less motion at the joint. Which of the following joints are the strongest:
-The pubis symphysis
-The shoulder
-The articulation between the frontal bone and a parietal bone
-The knee
The articulation between a frontal and a parietal bone
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What is an Ellipsoidal joint?
(Condylar Joint)An oval articular surface nestles within a depression on the opposing surface. ex.connect the fingers/toes to meta-carpal/tarsals
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What are Plane Joints?
(Gliding) the relatively flat articular surfaces slide across one another, but the amount of movement is very slight. ex. between carpal/tarsal bones
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What are Hinge Joints?
Permit angular movement in a single plane; like opening/closing a door. (monaxial) ex. elbow
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What is a Pivot Joint?
(monaxial) permit only rotation. ex. between the atlas/axis
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What is a Saddle Joint?
Resembles a saddle because it's concave on one end and convex on the other. Extremely Mobile.(biaxial) ex. twiddling your thumbs
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What is a Ball-and-socket joint?
The round head of a bone rests in the cup-shaped depression in another. (Triaxial) ex. Shoulder/Hip
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What does a Glenoid Labrum do?
Enlarges the joint cavity
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Which of the following ligaments is partially or completely dislocated during a shoulder separation?
Acromiaclavicular ligament
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What statement correctly describes the shoulder joint?
Articular cartilage covers the head of the humerus and the glenoid cavity.
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What contributes the most to the stabilization of a shoulder joint?
- Rotator Cuff muscles
- Ligaments & muscles that move the humerus
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The function of a bursa is to
- Reduce friction between a bone & tendon
- Smooth the surface outline of a joint
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What are the 3 main functions of the Muscular System?
- 1. Produce Macroscopic movements
- 2. Produce Forces that Prevent movement
- 3. Produce Heat
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What are the 3 types of Muscle Tissue?
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What are common properties associated with the Muscular System?
- Cells are elongated into "fibers"
- Plasma membranes are electrically 'excited'
- Muscle fibers produce Contractile Force
- Muscle fibers are extensible & elastic
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How are muscles and connective tissues "blended" in skeletal muscles?
- Skeletal Muscle (Organ)
- Muscle Fascicle (Bundle of cells)
- Muscle Fiber (Cell)
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How to Muscle Fibers develope?
- 1.Through the fusion of Myoblasts
- 2. Myosatellite cells bind to the immature muscle fiber which is surrounded my numerous nuclei
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What is the function of the Myosin head?
it acts as a motor that pulls the Z line in to shorten the sarcomere by 'sliding' between thick and thin filaments
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What is the Z line made of?
Actinin
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What is the H band?
The area of non-overlap between thick and thin filaments
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What happens as the Z line gets closer to the the A band?
The overlap shrinks
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What keeps the Z line centered?
Titin
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what is the role of Titin filamants?
Titin anchors thick filaments to the Z line (Stretch the sarcomere- strectch titin = Resistance)
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What happens when the zone of overlap is reduced to zero?
- Thick/thin filaments cannot interact at all
- Muscle fibers cannot produce any active tension
- Contraction cannot occur
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What happens if you increase the sarcomere length?
- Reduces tension
- Reduces the size of the zone of overlap
- Reduces the number of potential cross-bridge interactions
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What happens in the Optimal Resting range?
- Produce Greatest tension/force
- Maximum number of cross-bridges can form
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What happens in a decrease in sarcomere length?
- Reduces tension
- Sarcomeres cannot shorten much more
- Thin filaments meet at the M line and overlap the thin filaments on the other side
- Still produce 100% force
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What happens when the resting sarcomere is as short as it can be?
- Tension production falls to zero
- Thick filaments are jammed against the Z line (they overlap too much)
- Sarcomere cannot shorten anymore
- Interferance with cross-bridges
- Don't want to be here (Delta State)-disruptive & breaks down
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What is the cross-bridge cycle?
A series of molecular events that occur after the excitation of the sarcolemma.
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What is a Cross-bridge?
A Myosin head bound to Actin
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What structure is the functional unit of contraction in skeletal muscle fiber?
The Sarcomere
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Calcium ions couple excitation of a skeletal muscle fiber to contraction of the fiber. Where are calcium ions stored within the fiber?
The Sarcoplasmic Reticulum
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After a power stroke, the myosin head must detach from actin before another power stroke can occur. What causes cross bridge detachment?
ATP binds to the myosin head
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How does the myosin head obtain the energy required for activation?
Hydrolysis of ATP
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What specific event triggers the uncovering of the myosin binding site on actin?
Calcium ions bind to troponin and change its shape
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When does cross bridge cycling end?
Cross bridge cycling ends when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin.
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How is Contraction regulated?
- Binding sites are covered by Tropomyosin to keep from contracting
- To turn ON-Put Calcium ions in and bind to Troponin (this causes a change in the shape and rolls Tropomyosin out of the way to make it capable of turning ON)
- To turn OFF- Take away the Calcium ions and Tropomyosin rolls back in and keeps from forming cross-bridges
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Explain Excitation-Contraction Coupling.
- Excitation- A signal from the nervous system travels to every sarcomere simultaniously
- Starts the signal at the Sarcolemma and spread rapidily
- Signal comes from the Sarcolemma to the inside of the cell by Transverse tubules (T tubules)
- then travels through the Terminal cisternae to the triad and transmits an action potential to the rest of the cell and gets transduced into another signal
- The Sarcoplasmic reticulum is jammed full of calcium and the signal flows out creating a "Twitch"
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How do you initiate muscle contraction "Twitch"?
- 1. Action Potential reaches T tubule
- 2. SR releases Calcium
- 3. Active-site exposure, cross-bridge formation
- 4. Contraction begins
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How do you achieve muscle relaxation?
- 1. SR recaptures Calcium ions
- 2. Active sites covered, No cross-bridge interactions
- 3. Contraction Ends
- 4. Relaxation occurs, Passive return to resting length
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True or False?
All skeletal muscle fibers produce "twitches"?
True; But the amount of time it takes to produce "twitches" varies.
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What are Slow fibers?
- Smaller in diameter
- Darker color due to Myoglobin
- Fatigue Resistant
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What are Fast fibers?
- Larger in diameter
- Paler in color
- Easily Fatigued (Shorten more rapid and contract faster)
*Larger Diameter = More Force Produced*
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What are Parallel Muscles?
- Fascicles are parallel to longitudinal axis. (ex. Biceps)
- Parallel muscles w/ Tendinous bands (ex. Rectus abdominus)
- Wrapping (ex. Supinator)
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What are Convergent Muscles?
Fibers are based over broad area but come together at a common attachment site (ex. Pectoralis)
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What are Pennate Muscles?
- 1+ tendons run through the body of the muscle, & fascicles form oblique angles
- Unipennate-all muscles found on same side of the tendon (ex. Extensor digitorum)
- Bipennate- muscles on both sides of the tendon (ex. Rectus femoris)
- Multipennate- The tendon branches in all directions within the muscle (ex. Deltoid)
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What are Circular Muscles?
(Sphincter) fibers concentrically arranged around and opening (ex. Orbicularis Oris-Mouth)
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What are the three Classes of Levers?
- First-class: The applied force and resistance are on opposite sides of the fulcrum (ex. muscles that extend the neck)
- Second-class: resistance lies between the applied force and fulcrum (ex. plantar flexion)
- Third-class: force is applied between the resistance and fulcrum (ex. biceps brachii-flexes the elbow)
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What is the Central Nervous System (CNS)?
- Consists of the brain and spinal chord
- Integrating, Processing, & Coordinating: Sensory input & Motor output
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What is the Peripheral Nervous System (PNC)?
- Consists of all of the neural tissue outside the CNS.
- Provides Sensory info. to the CNS and carries Motor commands from the CNS to peripheral tissues/systems
- Subdivided into two divisions: Afferent- brings sensory info to the CNS; Efferent- carries motor commands to muscles/glands
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Where does the Afferent division begin in the PNS?
- Receptors: dendrites, speciallized cell/cluster of cells, complex sense organ
- Provide info. to be carried to the CNS
- Have both Somatic and Visceral components
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Where does the Efferent division begin?
- Begins inside of the CNS
- Ends in the effector: a muscle cell, gland cell, etc.
- Includes both Somatic Nervous System (SNS) and Autonomis Nervous System (ANS)
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What are Neurons? What do they consist of?
- Neurons are responsible for the transfer/processing of info. in the nervous system
- They are composed of: a cell body, dendrited, axon, and synaptic terminals
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What are Neuroglia?
(Glial cells) which are supporting cells in the nervous system
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When looking at a cross sectional view of the Central Canal, what is present?
- Ependymal cells- participate in the movement and production of cerebrospinal fluid (CSF)
- Glial cells surround the Ependymal cells
- The central canal has basal cell processes that go out in the gray matter (The surface of the Ependymal of the canal is Cilliated)
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Do do you tell the difference in an axon and a dendrite when staining a cell body of a neuron?
- Granular staining in cell body (Nissl bodies) project into dendrites a little bit. However, It Does NOT project into the axon hillock or axon itself.
- Nissl bodies-(stain dark) Rough ER; Ribosomes!
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In a neuron, where does DNA Transcription happen? Where does Translation happen?
- DNA transcription-Nucleus
- Translation into proteins- cell body
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In what direction can an Action Potential travel in a nuron?
In One Direction
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What happens if you have a site of injury on an axon?
- 1. Degeneration on the distal part (Proximal part is OK)
- 2. Invaded by phagocytes and clear they clear the way
- 3. Proximal stump spreads/grows; If one contacts the original site, it recognizes it and all of the other go away
- 4. Schwann cells go in and line the stumps. The sprout finds the Schwann cells and crawls along it. If it recognizes it, it starts Regeneration
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Neurons can be classified on the basis of the number of processes that project from their cell body.
- Anaxonic- No distinguishable axon
- Bipolar- 1 dendrite & 1 axon
- Pseudounipolar- dendrite and axon are continuous at one side of the cell body
- Multipolar- several dendrites and 1 axon (Most common)
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What is the function of Myelinated axons?
Increase Action Potential transmissions
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Neurotranmitters can either be Excitatory or Inhibitory.
- The fusion of secretory vessicles and the presynaptic membrane secrete Neurotransmitters that diffuse rapidly and bind to receptors either:
- Excitatory- open and allow depolarization of the membrane to fire off its action potential;OR
- Inhibitory- Increase polarization so it is less likely to fire off an action potential
(Whether or not a postsynaptic cell fires its own action potential is the sum of the both excitatory and inhibitory inputs)
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Neuron Organization and Processing
- Divergence- spread of information over a wide target (multiple) neurons on one postsynaptic neuron
- Convergence- A single postsynaptic neuron receives input from multiple presynaptic neurons
- Serial Processing- (simplest) a pattern of stepwise info. processing from neuorn to the next (single neurons in a line)
- Parallel Processing- Processes info. by several neurons at one time (Many different responses occur at the same time)
- Reverberation- When neural circuits use Positive feedback to continue activity of the circuit by means of Collateral Axons stimulating presynaptic neurons
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Which neuronal tissue cell type is likely to be mafunctioning if the blood-brain barrier is no longer adequately protecting the brain?
Astrocytes
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In what location would you find a somatic sensory receptor?
A skeletal muscle
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What does the Myelin Sheath do?
Increases the speed of an impulse
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Which cells produce the myelin sheath?
- Oligodendrocytes produce the myelin sheath in the CNS
- Schwann cells produce it in the PNS
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Myelinated tissue is known as white matter. Why do Myelinated Axons appear white?
The abundance of phospholipids
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What makes up the Cervical Enlargement? What does it do?
- It is made of both Gray matter and White matter
- It supplies nerves to the upper extremity
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Where does the spinal chord end?
Conus Medullaris
(There is No more CNS at this pt., only spinal nerves)
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How many spinal nerves does the Cervical region have?
eight (8)
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How many spinal nerves does the Thoracic region have?
twelve (12)
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How many spinal nerves does the Lumbar region have?
five (5)
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How many spinal nerves does the Sacral region have?
five (5)
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To avoid damaging the spinal cord during a spinal tap, the needle should be inserted _____.
Below L1– L2
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Where would you be likely to find the motor nuclei that control the extensors of the forearm?
Lateral side of the Anterior gray horn
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The ulnar nerve, which we refer to as our "funny bone" when we strike it, comes from what structure?
Brachial plexus, Medial Cord
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The specific regions of enlargment on the spinal cord are due from
- Limbs*
- increased number of neurons
- increased amount of gray/white matter
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Where do the spinal nerves start? where do they exit?
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What forms the spinal nerve?
The dorsal/ventral roots
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What are the 3 Protective Membranes surrounding the spinal cord?
- (Meninges) Protect, support, absorb shock
- Dura Mater- outermost covering (dense irregular connective tissue) "Tough Mother"
- Arachnoid Mater- (middle meningeal layer) thin layer of epith. cells that adhear to the inside surface of the Dura Mater; is separated from the Pia mater from a gap called the Subaracnoid space
- Pia Mater- inner most meningeal layer taht is in direct contact with the neural tissue (carries the blood supply)
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The Dorsal roots contain? the Ventral roots?
- Dorsal- Sensory neurons in the ganglia
- Ventral- Motor neurons only
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What is Somatotopy?
The mapping of somatic functions in different regions
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What are the Connective Tissue Layers of the Peripheral Nerve?
- Epineurium- covering peripheral nerve (outtermost layer)
- Perineurium- (around one fascicle) Carries the blood supply
- Endoneurium- individual axon covering all of the way down to Schwann cells that act as a basal lamina
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Look at Page 376 in textbook and study the chart
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What is a Dermatome?
Somatic sensory nerve distribution to the body surface
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Name the different Nerve Plexuses
- Cervical: (C1-C5)
- Brachial: (C5-T1) split into Superior Trunk, Middle Trunk, & Inferior Trunk. Which then branch into the Lateral, Posterior, and Medial cords.
- Lumbar: (T12-L4)
- Sacral: (L4-S4)
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