The level of the lumbosacral spinal cord affected by injury can be inferred from the pattern of muscle function shown by the patient.
|
Spinal Segments |
Muscle |
Function |
|
L2, L3 |
adductor longus and brevis |
hip adductors |
|
L3, L4 |
quadriceps |
knee extensors |
|
L4, L5 |
tibialis anterior |
ankle dorsiflexors |
|
L5, S1 |
extensor hallucis longus |
great toe extensor |
|
S1, S2 |
gastrocnemius, soleus |
ankle plantarflexors |
|
S2, S3, S4 |
sphincter ani externus |
anal sphincter |
The muscles (except for the sphincter ani) are innervated by 2 segments or roots.
If both segments are functional, then the muscle strength is normal.
If one segment is functional, then muscle strength is weak.
If neither segment is functional, then the muscle is paralyzed.
|
Injury Level |
Normal Muscles |
Weak Muscles |
Nonfunctioning Muscles |
|
L1 or above |
|
|
hip adductors |
|
L2 |
|
hip adductors |
knee extensors |
|
L3 |
hip adductors |
knee extensors |
ankle dorsiflexors |
|
L4 |
knee extensors |
ankle dorsiflexors |
great toe extensor |
|
L5 |
ankle dorsiflexors |
great toe extensor |
ankle plantarflexors |
|
S1 |
great toe extensor |
ankle plantarflexors |
anal sphincter |
|
S2 |
ankle plantarflexors |
anal sphincter |
|
Specialty: Neurology
ICD-10: ,
