Chapter 21 Flashcards
How are nerves named?
- named according to the level of the vertebral column at which they emerge
- the vertebra
Where do the nerves exit in relation to the associated vertebra?
- the cervical nerves exit above the vertebra they are named after
- the rest of the nerves exit underneath the vertebra they are named after
How many of each nerve are there?
- Cervical: 8 pairs
- Thoracic: 12 pairs
- Lumbar: 5 pairs
- Sacral: 5 pairs
- Coccygeal: 1 pair
How is a spinal nerve formed?
-the anterior root and posterior root join together
Is the anterior root motor or sensory?
-motor
Is the posterior root motor or sensory? What is something special that it contains?
- sensory
- dorsal root ganglion
What are the branches that come off the spinal nerve?
- anterior ramus
- posterior ramus
- meningeal ramus
- rami communicante
Where does the anterior ramus innervate?
- muscles and glands in the upper and lower limbs
- lateral and anterior portions of the neck and trunk
Where does the posterior ramus innervate?
-the skin and some deep muscles of the posterior head, neck, and trunk
What does the rami communicante do?
-joins the nerve to the sympathetic chain
What is a plexus?
-the braiding of the nerves which causes multiple nerves to go to one location
What are the pros of the plexuses?
-if damage happens to one nerve then the others can still allow the location to function
What are the plexuses made of?
-anterior rami
What are the different plexuses?
- cervical plexus
- brachial plexus
- lumbar plexus
- sacral plexus
What is the progression of the brachial plexus?
-roots-> trunks-> divisions-> cords-> nerves
What anterior rami make up each plexus?
- Cervical: C1-C5
- Brachial: C5-T1
- Lumbar: L1-L4
- Sacral: L4-S4
What important nerves come off the cervical plexus? Function?
- Phrenic nerve
- C3,4,5 keep the diaphragm alive
What important nerves come off the bracial plexus? Function?
- axillary nerve: shoulder
- radial nerve: posterior arm and forearm
- musculocutaneous nerve: anterior arm
- median nerve: anterior forearm, part of hand
- ulnar nerve: anterior forearm and part of hand
What important nerves come off the lumbar plexus? Function?
- femoral nerve: motor: muscles of anterior thigh; sensory: anterior thigh and medial side of leg
- obturator nerve: motor: adductors of thigh
What important nerves come off the sacral plexus? Function?
- sciatic nerve: motor: posterior thigh, entire leg, and entire food; sensory: everything that the femoral doesn’t cover
- pudendal nerve: anus
What is erb-duchenne palsy?
- waiter’s tip
- loss of sensation along the lateral side of the arm
- injury to the C5-C6
What is wrist drop?
- the inability to extend the wrist and fingers
- injury to radial nerve
What is a dermatome? How does it relate to shingles?
- the skin surface area supplied by sensory fibers of a given spinal nerve
- shingles affects one dermatome
What is a myotome?
-skeletal muscle or group of muscles that receives motor axons from a given spinal nerve
How many cranial nerves are there?
-12 pairs
What are the cranial nerves?
- Olfactory
- Optic
- Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Vestibulocochlear
- Glossopharyngeal
- Vagus
- Accessory
- Hypoglossal
What do the names of the cranial nerves represent?
-the names represent their function/what they effect
What do the numbers of the cranial nerves represent?
-the numbers represent the order that the nerves come off the brain from anterior to posterior
Which nerves are sensory?
- Olfactory
- Optic
- vestibulocochlear
Which nerves are motor?
- Oculomotor
- Trochlear
- Abducens
- Accessory
- Hypoglossal
Which nerves are mixed?
- Trigeminal
- Facial
- Glosspharyngeal
- Vagus
What is the optic chiasm?
-some of the fibers of each nerve cross to the oppostire and continue via the optic tract
What is Bell’s palsy?
- paralysis of CN VII (facial)
- inability to close eyes
- impairment of taste and salivation
What nerve is damaged with vertigo?
-CN VIII (vestibulocochlear)
What neurotransmitter causes contraction of skeletal muscle?
-acetylcholine
What is a reflex?
-a predicable response to a stimulus
Describe each reflex:
- Cranial reflex:
- Spinal reflex:
- Somatic reflex:
- Autonomic reflex:
- Flexor reflex:
- Crossed extensor reflex:
- Withdrawal reflex:
- Kneejerk reflex:
- Ankle jerk reflex:
- Plantar reflex:
- Corneal reflex:
- Abdominal reflex:
- Segmental reflex:
- Monosynaptic reflex:
- Polysynaptic reflex:
- Ipsilateral reflex:
- Contralateral reflex:
- Stretch reflex:
- Cranial reflex: if the center of a reflex arc is in the brain
- Spinal reflex:if the center of a reflex is in the spine
- Somatic reflex: contraction of skeletal muscles
- Autonomic reflex: contraction of smooth or cardiac muscles; secretion by glands
- Flexor reflex: when a flexor muscle responds
- Crossed extensor reflex: impulses move across the spinal cord to trigger contralateral extension
- Withdrawal reflex: when you pull back from pain
- Kneejerk reflex: response to tapping patellar ligament
- Ankle jerk reflex: abnormal response indicating disease
- Plantar reflex: an object running along the bottom of the foot causing the toes to fan or curl
- Corneal reflex: blinking when cornea has been touched
- Abdominal reflex: when the umbilicus moves in response to stroking the side of the abdomen
- Segmental reflex: impulse enters and leaves at the same segment of the spinal cord
- Monosynaptic reflex: impulses travel through only one synapse
- Polysynaptic reflex:
- Ipsilateral reflex: impulses enter and leave on the same side
- Contralateral reflex: impulsed enter and leave on opposite sides
- Stretch reflex: caused the stretching of a muscle
What is the result of a somatic reflex?
- Skeletal muscle contraction:
- Smooth muscle contraction:
- Cardiac muscle contraction:
- Glandular excretion:
What is the result of an autonomic reflex?
- Skeletal muscle contraction:
- Smooth muscle contraction:
- Cardiac muscle contraction:
- Glandular excretion:
What is the pathway of a reflex?
-know the pathway from sensory stimulation all the way to the action of the effector
What is the Babinski sign? What does it indicate? When is it normal?
- toes fan out when testing plantar reflex
- indicates destruction of pyramidal tracts
- normal in infants
