how many pairs of spinal nerves that serve defined segments of the human body.
31 pairs of spinal nerves
8 pairs of cervical spinal nerves
This is possible because the first pair (C1 spinal nerves) exits the spinal column between the occipital bone and the atlas (C1). The remaining 7 pairs (C2-C8 spinal nerves) exit below each of the 7 cervical vertebrae via the intervertebral foramina. All the spinal nerves are mixed nerves.
The spinal cord is surrounded by
the dura, arachnoid, and pia maters (the meninges)
is a real space filled with CSF
site of needle insertion for lumbar puncture
extends along the entire length of the vertebral canal and surrounds the spinal cord. It also extends along the initial portion of the radiating spinal nerves
location of white and grey matter
directly adheres to the spinal cord
contains ascending and descending tracts of nerves traveling to and from the brain
peripheral white matter
serves as a center for spinal reflexes.
central gray matter
conducts signals from dilating blood vessels in the palate to the brain, which interprets the pain as coming from the forehead.
runs the entire length of the spinal cord, is contiguous with the brain and contains cerebrospinal fluid (CSF)
The central canal
each of which gives rise to a pair of spinal nerves that emerge from the cord through the intervertebral foramina
The spinal cord develops as 31 segments
can be sensory, motor, or mixed (sensory and motor)
________________carry both types of information and some axons are transmitting impulses in one direction,
while other axons are transmitting impulses in the opposite direction
All spinal nerves are mixed nerves.
Most of the spinal nerves are associated with specific ____________(an area of skin innervated by all the cutaneous neurons of a certain spinal or cranial nerve).
Dermatomes of the ______________ are seen on the face
trigeminal nerve (cranial nerve V)
is acquired by the respiratory route and causes a head-to-toe rash in children.
Chickenpox (varicella) virus
Numerous cutaneous and visceral sensory neurons share the same ascending tracts.
Explanation of referred pain.
is the muscle(s) served by a single nerve root (spinal nerve or cranial nerve). It is the motor equivalent of a dermatome
The majority of the spinal nerves combine and then split again as networks of nerves referred to as
The exceptions are T2-T12 and S5-Co1, which do NOT form plexuses
formed primarily by spinal nerves C1-C4 (C5 is not considered to part of this plexus, even though it contributes some axons)
The cervical plexus, and particularly spinal nerves C3, C4, and part of C5, give rise to the
which innervates the diaphragm. Injury above C3 would lead to death by suffocation.
is formed primarily by spinal nerves C5-C8, and T1. This plexus gives rise to five nerves that serve the arm or hand.
The brachial plexus
innervates the teres minor muscle and the deltoid muscle
The axillary nerve
innervates muscles in the antebrachium and manus.
The median nerve
It receives sensory information from the palmar side of fingers #1, #2, #3, and the lateral one-half of finger #4 and from the dorsal tips of these same fingers.
innervates the biceps brachii muscle and several other muscles.
The musculocutaneous nerve
It receives sensory input from the lateral surface of the forearm
innervates the triceps brachii and numerous muscles of the antebrachium
The radial nerve
It receives sensory input from the posterior arm and forearm surface and the dorsolateral side of the hand.
passes near the medial epicondyle of the humerus, is the “funny bone”. It innervates muscles in the antebrachium and manus.
the ulnar nerve
It receives sensory input from the skin of the dorsal and palmar aspects of fingers #5, and the medial half of finger #4.
formed by spinal nerves L1-L4. It gives rise to two major nerves: the femoral nerve and the obturator nerve
The lumbar plexus
area affected if quadriplegic
innervates the quadriceps femoris muscles on the anterior of the thigh to help extend the knee. It also innervates the sartorius muscle and the Iliopsoas muscle.
The femoral nerve
It receives sensory input from the anterior and inferomedial thigh as well as the medial aspect of the leg.
Compression of the lateral femoral cutaneous nerve by clothing, belts, long periods of standing, and by prolonged marching or hiking leads to
(“tingling thigh syndrome”)
innervates the gracilis and several other muscles.
The obturator nerve
It receives sensory information from the superomedial skin of the thigh
is formed by spinal nerves from L4, L5, and S1-S4. It gives rise to the sciatic nerve, which is actually composed of two nerves: the tibial nerve and the common fibular (common peroneal) nerve.
The sacral plexus
is composed of these two nerves wrapped in a common connective sheath. These two nerves separate just above the popliteal fossa.
The sciatic nerve
A tight ______________can compress the sciatic nerve
innervates the hamstrings, the gastrocnemius, the soleus, and several other muscles.
The tibial nerve
It receives sensory input from the skin on the plantar surface of the foot.
innervates the peroneus (fibularis) longus, the tibialis anterior, and several other muscles of the leg and foot. This is the branch of the sciatic nerve that caused me problems!
The common fibular nerve (common peroneal nerve)
It receives sensory input from the anterolateral part of the leg, the toes, and dorsum of the foot.
is a serious neurologic condition in which damage to the cauda equina causes loss of function of the lumbar plexus, (nerve roots) of the spinal canal below the termination (conus medullaris) of the spinal cord. CES is a lower motor neuron lesion.
Cauda equina syndrome (CES)
typically leads to death by asphyxiation because the victim cannot use the spinal nerves to contract the intercostal muscles and cannot utilize the phrenic nerve to contract the diaphragm.
Severing the spinal cord above C3
Damage below C3 also results in
quadriplegia, but the person can still utilize their diaphragm for breathing via their intact phrenic nerves.
Transtentorial Brain Herniation is one step in what process?
Rotrocausdal Brain Deterioration
What is the last reversible stage of rostrocausdal brain deterioration?
decerebrate posturing, which occurs when the cerebrum and midbrain push down on the upper pons.
The brain has two important functional systems, which work together for a common function, even though their components may be scattered throughout the brain. What are they?
Reticular Formation & Limbic System
Why does odor have such a strong effect on memory recall?
because olfaction is not processed or filtered out by the thalamus
What is the most common serious disease of the CNS?
Cerebrovascular accidents (CVAs), or strokes
local area of dying or dead tissue
decerebrate posturing looks like?
waiter reaching for check behing him
decordicate posturing looks like?
holding a cord of wood
bulge in the wall
build-up of fatty plaques in vessel wall
contralateral paralysis of the body
brief episodes of lost sensation or motor ability or "tingling" in the limbs, resulting from a temporary plug in a blood vessel that dissolves in a matter of minutes
transient ischemic attack (TIA)
singultus. irritation to phrenic nerve causes spasmodic contractions of diaphragm which causes epiglottis to close suddenly
in trigeminal neuralgia, what vessel is causing the putting pressure on the nerve?
the superior cerebellar artery
"suicide disease", "painful tic", and "tic douloureux" are all names for what disorder?