ANATOMY - spinal nerves Flashcards
how many cervical spinal nerves are there
8
7 cervical vertebrae but one above every vertebrae AND one below C7
how many thoracic spinal nerves are there
where do they leave the spinal column
12
under each of the thoracic vertebrae (bc there are 8 cervical ones, one below c7)
how many sacral spinal nerves are there
5
how many coccygeal spinal nerves are there
1
how many spinal nerve pairs are there
31
where are roots/rootlets in relation to the spinal nerve
behind it (between spinal nerve and spinal cord)
where are the rami in relation to the spinal nerve
in front of it
spinal nerve SPLITS into anterior and posterior rami
what modality is in the anterior rami
where does it supply
mixed - motor and sensory
to most of body
what modality is in the posterior rami
where does it supply
mixed - sensory and motor
posterior body wall
what modality is in the anterior roots/rootlets
motor
bc Anterior want to get close to the Action
what modality is in the posterior roots/rootlets
sensory
what is the joining of anterior and posterior rami called
the spinal nerve
by which categorization method do spinal nerves supply muscles
myotomes
by which categorization method do spinal nerves supply skin sensation and somatic motor function
dermatomes
shoulder and clavicle dermatome
C4
badge patch dermatome
C5
lateral forearm and thumb dermatome
C6
middle finger dermatome
C7
little finger dermatome
C8
medial forearm dermatome
T1
medial arm and top of chest (sternal angle) dermatome
T2
anterior and posterior trunk dermatomes
T2-T12 (L3 on back)
nipple dermatome
T4
belly button dermatome
T10
‘hands in pockets’ dermatome
L1
lateral thigh dermatome
L2
medial thigh and knee dermatome
L3 (three = knee)
medial calf (medial malleolus) dermatome
L4
big toe and lateral calf dermatome
L5 (biggest number = 5 for the biggest toe)
little toe and heel dermatome
S1 (smallest number = 1 for smallest toe)
posterior leg dermatome
S2
saddle dermatome
S3
anal passage dermatome
S5
is there a C1 dermatome
no bc no dorsal (posterior) roots
pubic symphysis dermatome
T12
xiphoid process dermatome
T8
what are the 4 spinal nerve plexuses
cervical plexus
brachial plexus
lumbar plexus
sacral plexus
which spinal nerves is the cervical plexus made up of
C1-C4
which spinal nerves is the brachial plexus made up of
C5-T1
which spinal nerves is the lumbar plexus made up of
L1-L4
which spinal nerves is the sacral plexus made u of
L5-S4
C5 myotome
shoulder abduction
C6 myotome
elbow flexion
C7 myotome
Elbow extension
C8 myotome
finger flexion
T1 myotome
finger abduction
L3 myotome
knee extension
L4 myotome
ankle dorsiflexion
L5 myotome
big toe extension
S1 myotome
ankle plantarflexion
S2 myotome
knee flexion
biceps reflex spinal nerve
C5
supinator reflex spinal nerve
C6
triceps reflex spinal nerve
C7
knee reflex spinal nerve
L4
ankle reflex spinal nerve
S1
apart from dermatomes, what is the other skin innervation that we need to know
named nerves
what is the pneumonic for the named nerves of the head
hence what are the named nerves of the head
which spinal nerves supply these named nerves
little goats tread softly
lesser occipital
greater auricular (around the ear)
transverse cervical
supraclavicular
C1-C4
what is the named nerve that supplies the skin just outside the ear
great auricular nerve
which named nerve supplies the littlefinger
ulnar
which named nerve supplies most of the palm of the hand (not little finger) and finger nails
medial
which named nerve supplies the dorsum of the hand (not little finger)
radial
which named nerve supplies most of the anterior thigh
femoral
which named nerve supplies most of the anterior calf
saphenous nerve (from the femoral)
which named nerve supplies most of the posterior lower limb
posterior cutaneous nerve of the thigh
if there is sensory damage to a nerve but motor function from it is fine, where is the problem
posterior rootlet/root (or above) damage
if there is sensory damage in more than one dermatome, where might the problem be
named nerve!
if you have established a sensory problem in 1 dermatome, what should you check
check all other dermatomes - to exclude it being a named nerve problem
check associated myotome - to identify if its just sensory or motor problem too (whether the problem is before or after the spinal nerve and rami)
where does posterior rami of spinal nerves supply
the back
what is the lump in the posterior root (before it become spinal nerve) called
dorsal root ganglion
is dorsal anterior or posterior
posterior
is ventral anterior or posterior
anterior
which named nerve supplies first web space of foot only
deep fibular
