Learn / Level 2

Myotomes & reflexes

Match movements to the root levels that drive them, then the deep tendon reflexes. After each answer the body map lights up the same level's dermatome, so the two stay linked in your head.

Drill

Movements by level

Movement	Levels	Muscles	Nerve	How to test
Shoulder abduction	C5	Deltoid, supraspinatus	Axillary, suprascapular	Abduct arm against resistance at ~30–90°.
Shoulder external rotation	C5	Infraspinatus, teres minor	Suprascapular, axillary	Elbows at side, rotate forearms outward against resistance.
Elbow flexion	C5C6	Biceps brachii, brachialis, brachioradialis	Musculocutaneous (radial for brachioradialis)	Flex the supinated forearm against resistance.
Wrist extension	C6	Extensor carpi radialis longus & brevis	Radial	Make a fist and hold the wrist cocked back against resistance.
Elbow extension	C7	Triceps brachii	Radial	Push the forearm out from a flexed position.
Wrist flexion	C7	Flexor carpi radialis, flexor carpi ulnaris	Median, ulnar	Flex the wrist against resistance.
Finger extension	C7	Extensor digitorum	Radial (posterior interosseous)	Hold the fingers straight while you push them down.
Finger flexion	C8	Flexor digitorum superficialis & profundus	Median, ulnar	Grip strength / curl fingers against resistance.
Thumb extension	C8	Extensor pollicis longus & brevis	Radial (posterior interosseous)	Hitchhiker's thumb against resistance.
Finger abduction	T1	Dorsal interossei, abductor digiti minimi	Ulnar	Spread the fingers against resistance.
Finger adduction	T1	Palmar interossei	Ulnar	Hold a paper between the fingers.
Hip flexion	L2L3	Iliopsoas	Femoral & direct lumbar branches	Seated, lift the knee against resistance.
Hip adduction	L2L3L4	Adductor group	Obturator	Squeeze the knees together against resistance.
Knee extension	L3L4	Quadriceps femoris	Femoral	Seated, straighten the knee against resistance.
Ankle dorsiflexion	L4L5	Tibialis anterior	Deep fibular (peroneal)	Pull the foot up toward the shin against resistance; heel-walk.
Ankle inversion	L4	Tibialis anterior & posterior	Deep fibular, tibial	Turn the sole inward against resistance.
Great toe extension	L5	Extensor hallucis longus	Deep fibular (peroneal)	Pull the big toe up against resistance — the classic L5 test.
Hip abduction	L5S1	Gluteus medius & minimus, tensor fasciae latae	Superior gluteal	Side-lying, lift the leg up against resistance; Trendelenburg sign.
Ankle eversion	L5S1	Fibularis (peroneus) longus & brevis	Superficial fibular	Turn the sole outward against resistance.
Ankle plantarflexion	S1S2	Gastrocnemius, soleus	Tibial	Push the foot down against resistance; toe-walk / heel raises.
Hip extension	S1	Gluteus maximus	Inferior gluteal	Prone, lift the thigh off the table against resistance.
Knee flexion	S1S2	Hamstrings	Sciatic (tibial division)	Prone, bend the knee against resistance.
Toe plantarflexion	S2	Flexor digitorum longus, flexor hallucis longus	Tibial	Curl the toes against resistance.
Anal sphincter tone / bladder control	S2S3S4	External anal & urethral sphincters	Pudendal	'S2, 3, 4 keeps the pee off the floor.'

Teal = the level conventionally quoted for that movement on exams.

Deep tendon reflexes

Reflex	Level	Nerve	Muscle	Note
Biceps	C5	Musculocutaneous	Biceps brachii	C5–C6; C5 is the tested level.
Brachioradialis	C6	Radial	Brachioradialis	C5–C6; the C6 reflex.
Triceps	C7	Radial	Triceps brachii	C6–C8; C7 is the tested level.
Finger flexor (Hoffmann's)	C8	Median/ulnar	Finger flexors	Hoffmann's sign is an upper-motor-neuron sign, not a normal reflex.
Patellar (knee jerk)	L4	Femoral	Quadriceps	L2–L4; L4 is the tested level.
Medial hamstring	L5	Sciatic (tibial)	Semitendinosus/semimembranosus	The closest thing to an L5 reflex; often absent normally.
Achilles (ankle jerk)	S1	Tibial	Gastrocnemius/soleus	S1–S2; S1 is the tested level.
Anal wink / bulbocavernosus	S3	Pudendal	External anal sphincter	S2–S4.

Mnemonic for the big five: S1-2 buckle my shoe (ankle), L3-4 kick the door (knee), C5-6 pick up sticks (biceps), C7-8 lay them straight (triceps).