Exam 2 material: spinal roots Flashcards
Major arm dermatome: C5
overlying lateral upper arm
Major arm dermatome: C6
Lower arm, thumb, lateral index finger (6-shooter)
Major arm dermatome: C7
middle hand, finger
Major arm dermatome: C8
medial hand, ring/pinky fingers
Major arm dermatome: T1
medial side of arm
Major trunk dermatome: T4
runs across nipple
Major trunk dermatome: T10
runs across umbilicus (belly button)
Major trunk dermatome: T12
inguinal ligament (bottom of thorax at groin)
Major leg dermatome: L1/2/3
-anterior upper leg
“candycane” down leg (higher laterally and goes lower medially)
Major leg dermatome: L3/4
crosses patella
Major leg dermatome: L4
anterior, medial lower leg
Major leg dermatome: L5
anterior, lateral lower leg and medial foot (big toe)
Major leg dermatome: S1
lateral foot, posterior lower leg
Major leg dermatome: S2
Posterior upper leg
Major leg dermatome: S3/4
Buttocks/perianal
Myotomes: C5
elbow flexion, arm abduction (deltoid/biceps)
Myotomes: C6
wrist extension
Myotomes: C7
elbow extension (triceps)
Myotomes: C8
finger flexors
Myotomes: T1
finger abduction
Myotomes: L1/2
hip flexion (iliopsoas)
Myotomes: L3/4
knee extension (quads)
Myotomes: L4
ankle dorsiflexion
Myotomes: L5
big toe dorsiflexion… extension? (extensor hallucis longus)
Myotomes: S1
ankle plantarflexion
what nerve root does this reflex: biceps
C5/6
what nerve root does this reflex: brachioradialis
C6
what nerve root does this reflex: triceps
C7
what nerve root does this reflex: patellar
L3/4
what nerve root does this reflex: Achilles
S1
Brachial plexus
- Segments
- roots
- trunks
- divisions
- cords
- branches
Erb-Duchenne palsy (injury to what and presented as what?)
- injury to upper trunk
- combined C5/6 injury
- usually due to downward traction on shoulder/arm relative to head
- commonly seen after births complicated by a stuck shoulder (shoulder dystocia)
- Presented as “Waiter’s tip”
- adducted shoulder
- extended elbow
- arm IR
- wrist in flexion
Klumpke’s palsy (injury to what and presented as what?)
- injury to lower trunk
- combined C8/T1 injury
- usually due to upward traction on arm relative to head
- commonly seen in children being pulled up by arms, or people breaking their fall by catching onto something (and subsequently jerking their arm/shoulder upwards)
- presented as “Claw hand”
- similar to combined median/ulnar palsy
- loss of intrinsic hand function
- all fingers over extended from long extensors
- (just FYI - distal joints actually flex because of long flexors making the claw-like appearance)
Lumbosacral plexus (injury and nerves)
- less commonly injuried
- can be injured in trauma, or as part of abdominal/pelvic pathologies
- nerves
- femoral
- from roots L2-L4
- involved in cutaneous sensation to leg and upper leg function
- obturator
- from roots L2-L4
- primarily controls proximal leg muscles
- Sciatic
- from roots L4-S4
- controls posterior leg, lower leg, and lower leg sensation
- femoral
Radial nerve (major sensory and motor areas)
- majory sensory
- posterior hand
- lesions around axilla will also affect posterior/lateral upper arm
- major motor
- triceps (C7)
- Brachioradialis (C6)
- Wrist extensors (C6)
- supinator (C6/7)
- abductor pollicis longus (C7)
Median nerve (major sensory and motor areas)
- major sensory
- lateral fingers, palm
- ***with lesions in carpal tunnel, only fingers
- Major motor
- Pronator teres (C6/7)
- Flexor digitorum superficialis/profundus (digits I and II) (C8)
- opponens pollicis (T1)
Ulnar nerve (major sensory and motor areas)
- Major sensory
- medial hand/fingers
- injury distal to branches can spare regions
- distal to dorsal cutaneous branch: dorsal hand spared
- distal to palmar cutaneous branch: palm of hand spared
- Major motor
- flexor digitorum profundus (digits III and IV) (C8)
- abductor digiti minimi (C8/T1)
- adductor pollicis (T1)
Thumb motor control
- RUM!
- Radial nerve: abduction
- Ulnar nerve: adduction
- Medial nerve: opposition
Wrist drop
- radial palsy
Preacher’s hand
- median nerve palsy
- (try to close hand and first 3 fingers dont close)
Ulnar claw
- ulnar palsy
*
“simian hand”
- Median and ulnar palsy
Common peroneal nerve (major sensory and motor areas)
- Major sensory
- Lateral leg
- dorsal foot
- Major motor
- peroneus longus/brevis (L5/S1; foot eversion)
- tibialis anterior (L4; foot dorsiflexion)
- Extensor digitorum/hallucis longus (L5; toe extension)
Tibial nerve (major sensory and motor areas)
- Major sensory:
- bottom of foot
- major motor
- gastroc/soleus (S1/2)
- Tibialis posterior (L4/5; foot inversion)
- Flexor digitorum/hallucis longus (S1/2)
