Spinal Nerves Flashcards
Identify these features of a spinal nerve
List what each pair of spinal nerves supplies to a dermatome
Somatic general sensory innervation
Motor functions
Reflex functions
What is a dermatome?
An area of skin innervated by one spinal nerve
Dorsal roots contain sensory axons only while ventral roots contain motor axons. True/false?
True
The C5 dermatome covers which area of the arm?
Badge patch
C6, C7 and C8 are the dermatomes of which fingers?
C6 - thumb
C7 - middle
C8 - little
Where are the dermatomes for T1 and T2 located?
T1 - medial forearm
T2 - medial arm
T4 is the dermatome that covers what part of the body?
Male nipple
What dermatome is the umbilicus contained within?
T10
Identify the dermatomes of the lower limb
What is the difference between a spinal nerve and a named nerve?
A spinal nerve contains axons from one spinal cord level while a named nerve contains axons from one or more spinal cord level supplying a particular area
What are the spinal nerve roots of the femoral nerve?
L2-L4
Name the nerves supplying each part of the neck
Little
Goats
Tread
Softly
Identify the named nerve cutaneous innervation of the upper limb
Identify the named nerve cutaneous innervation of the anterior aspect of the lower limb
Identify the named nerve cutaneous innervation of the posterior aspect of the lower limb
Stimulating the area innervated by the femoral nerve causes an action potential in which part of the spinal cord?
Posterior horn
Which two plexi are generally tested in myotome testing?
Brachial
Lumbosacral
How can the C5 myotome be tested? Which muscle is mainly tested?
Shoulder abduction
Deltoid
Which myotomes are tested in elbow flexion and extension?
C6 (flexion)
C7 (extension)
A patient is unable to hold your finger in their clenched fingers when you pull it out. What myotome is affected?
C8
What myotome is responsible for finger abduction?
T1
The L3 myotome is responsible for what movement? What is the main muscle involved?
Knee extension
Quadriceps femoris
What myotomes are responsible for ankle dorsiflexion and plantarflexion?
L4 (dorsiflexion)
L5 (plantarflexion)
A patient is unable to stick their big toe in the air. Which myotome is affected?
L5
What myotome is tested when asking a patient to flex their knee? What muscle enables this?
S2
Biceps femoris
Outline what occurs in the patellar reflex
Quadriceps fibres are stretched causing APs in the anterior rami axons within the femoral nerve. These sensory APs are conducted to the posterior horn of L3 before synapsing on lower motor neurons that supply quadriceps
What are the main spinal reflexes that can be tested? What are their nerve roots?
Biceps brachii (C5/6)
Brachioradialis (C6)
Triceps brachii (C7)
Knee jerk (L3)
Ankle jerk (S1)
