Section 4, Part 1 Flashcards
What is the role of descending nerve tracts?
They carry information from the brain to influence motor neurons either directly or indirectly (though interneurons)
What are mixed spinal nerves?
Axons from sensory and motor roots that fuse to form a single unit
How many spinal nerves are there?
31 pairs
What are mixed spinal nerves made of?
Motor axons (innervate particular skeletal muscles concerned with movements of the neck, trunk, back, and limbs) and sensory axons(innervate a corresponding region of skin and muscle)
What are nerve plexuses?
Spinal nervs that use together and intermingle
What is a dermatome?
The sensory region of skin innervated by an individual nerve root
What is a myotome?
The muscles that receive their motor innervation from a given spinal nerve
Does a particular skeletal muscle receive its innervation from multiple peripheral nerves or a single peripheral nerve?
A single peripheral nerve
What comprises the peripheral spinal nerves that innervate skeletal muscles?
Axons from more than 1 spinal segment and its corresponding spinal nerve
Are the ventral rami of the thoracic spinal nerves part of a plexus?
No, they remain as individual nerves
EXCEPTION: T1 and T2
What do the intercostal nerves innervate?
They innervate the skin and muscles of the thoracic and abdominal walls
What are the 4 plexi?
Cervical, brachial, lumbar, sacral
What are the spinal nerves of the cervical plexus?
C1-C4
What is the role of the cervical plexus?
Innervation of the skin (sensation) and muscles associate with the neck
What are the spinal nerves of the brachial plexus?
C5-T1
What is the role of the brachial plexus?
Innervation of the skin and muscles acting on the upper limb
What are the spinal nerves of the lumbar plexus?
L1-L4
What is the role of the lumbar plexus?
Innervation of the skin and muscles of the lower abdominal wall in the inguinal region and the anterior and medial compartments of the thigh
What are the spinal nerves of the sacral plexus?
L4-S4
What is the role of the sacral plexus?
Innervation of the skin and muscles of the gluteal region, posterior compartment of the thigh and all of the leg and foot
What is a spinal segment?
The region of the spinal cord from which a specific spinal nerve projecs
How many spinal segments are there?
31
Is a spinal segment the same thing as the vertebral level?
No, it is not…the vertebral level is a physical landmark used to describe the location of structures
For which spinal levels does the spinal level correspond with the vertebral level?
Cervical
Where are the spinal segments of the lumbar and sacral segments located (which vertebral level)?
10th-12th thoracic vertebral level
What is the term of the dorsal and ventral roots below the level of the spinal cord?
Cauda equina
True or False:
The extent of muscle damage and/ or loss of function cannot determine the site of damage
FALSE:
The extent of muscle damage and/ or loss of function CAN determine the site of damage
These loss of functions are associated with which nerve?
Extend arm, wrist, finger joints, supinate forearm, abduct thumb in the plane of the palm
Radial nerve
These loss of functions are associated with which nerve?
Flex and oppose thumb, flex digits 2 and 3, flex or abduct wrist (“ape hand”), pronate forearm
Median
These loss of functions are associated with which nerve?
Adduct and abduct fingers other than thumb, adduct thumb, flex digits 4 and 5(“Claw hand”), flex and adduct wrist
Ulnar
These loss of functions are associated with which nerve?
Abduct arm at shoulder beyond 15 degrees
Axillary
These loss of functions are associated with which nerve?
Flex arm at elbow, supinate forearm
Musculocutaneous
These loss of sensations are associated with which nerve?
Posterior lateral arm, posterior strip on the forearm, dorsal surface of the thumb,lateral surface (thumb side) of the hand, and dorsum of the first 3 digits?
Radial
These loss of sensations are associated with which nerve?
Lateral palm, ventral thumb and digits 2 and 3, dorsal tip of the thumb and digits 2 and 3
Median
These loss of sensations are associated with which nerve?
Medial palm, all of the 5th digit and the medial side of the 4th digit
Ulnar
These loss of sensations are associated with which nerve?
Spot of the lateral arm over the deltoid
Axillary
These loss of sensations are associated with which nerve?
Lateral Forearm
Musculocutaneous
These loss of sensations are associated with which nerve?
Portion of anterior thigh, knee, and medial leg
Femoral
These loss of sensations are associated with which nerve?
Spot on medial thigh
Obturator
These loss of sensations are associated with which nerve?
Lateral leg and most of foot
Sciatic
These loss of sensations are associated with which nerve?
Bottom of foot and toes, lateral edge dorsum foot and top of toes 2-5
Tibial
These loss of sensations are associated with which nerve?
Dorso-lateral leg, most of dorsal foot
Superior fibular
These loss of sensations are associated with which nerve?
Spot between big and 2nd toe
Deep fibular
These loss of functions are associated with which nerve?
Flex leg at hip, extend knee
Femoral
These loss of functions are associated with which nerve?
Adduct thigh
Obturator
These loss of functions are associated with which nerve?
Flex knee/ extend hip
Sciatic
These loss of functions are associated with which nerve?
Plantar flex or invert foot, flex toes
Tibial
These loss of functions are associated with which nerve?
Evert foot
Superficial fibular
These loss of functions are associated with which nerve?
Dorsiflex foot, extend toes (dorsiflexion)
Deep fibular
What are the two major branches of the sciatic nerve?
Tibial and common fibular nerve
What are peripheral mononeuropathies?
Injuries to an individual peripheral nerve arising directly from the plexus
What are plexopathies?
Plexus lesions that produce more extensive but still restricted distribution of symptoms related to the innervation of the components of the plexus that are damaged
