L20 - Nerve Plexus and Branches

Question 1

Dorsal and ventral rami supply…

Answer 1

Dorsal: Intrinsic back muscles and skin, zygopophyseal joints

Ventral: Supplies everything else

So, dorsal rami is SMALLER than ventral

Question 2

Plexus

Answer 2

Intricate network/web

Question 3

Different in horn size

Answer 3

Thoracic (T1-11) = ventral horn smaller, less to innovate.

Cervical (C1-4) and lumbar = ventral horn bigger, innovate limbs

Question 4

Phrenic nerve

Answer 4

MNEMONIC = C3, 4, 5 ALIVE!

• Nerve from C3-5, helps keep diaphragm alive
• Multiple nerves contribute to it, if one dies, diaphragms okay

Question 5

Thoracic plexus (T1-11)

Answer 5

T1-6 = innovates chest
T7-11 = abdominal, overlying skin, etc

Question 6

Cervical plexus (C1-4)

Answer 6

Motor: Innovates anterior neck
Sensory: Innovates skin of neck, parts of head/shoulders

Question 7

Ventral rami plexuses of limbs (Think SUBWHALE?)

Answer 7

Brachial (C5-T1)
- Innovates pectoral girdle, upper limb

Lumbar plexus (L1-L4)
- Innovates thigh

Sacral Plexus (L4-S4)
- Glutes, pelvis, leg, foot

Question 8

Brachial plexus

Answer 8

The M shape =
1. Musculocutaneous
2. Median
3. Ulnar

Underneath =
1. Axillary
2. Radial

emerges between anterior and middle scalenes, 1st rib and clavicle

Question 9

Musculocutaneous innovation

Answer 9

Motor: Anterior arm
sensory = forearm

Question 10

Median innovation (center of cubital fossa, carpal tunnel)

Answer 10

motor = anterior forearm + thenar (thumb side) muscles
sensory = hand, tips of lateral 3 and a 1/2 digits

Question 11

Ulnar innovation

Answer 11

motor = flexor carpi ulnaris, flexor digit profundus
sensory = Lateral 1 1/2 digits

Question 12

Axillary

Answer 12

motor = Deltoid, teres minor
sensory = patch over deltoid

Question 13

radial

Answer 13

motor = posterior arm and forearm
Sensory = dorsal aspect of lateral 3 1/2 hand (not tips)

Question 14

Ventral rami in area of limbs form

Answer 14

Plexuses:
1) Brachial (C5-T1)
2) Lumbar (L1-4)
3) Sacral (L4-S4)

Question 15

Lumbar plexus

Answer 15

L1-4
1. Femoral nerve
2. Obturator nerve

Question 16

Femoral nerve

Answer 16

• anterior thigh, medial leg, medial foot

Question 17

Obturator nerve

Answer 17

Medial patch

Question 18

Sacral plexus

Answer 18

L4-S4
SCIATIC NERVE
1. Tibial nerve
2. Common fibular nerve (deep, superficial)

Question 19

Tibial nerve

Answer 19

Posterior thigh and leg and foot (plantar)

Question 20

Common fibular

Answer 20

ONLY SHORT HEAD OF BICEPS FEMORIS

Question 21

Deep fibular

Answer 21

Anterior leg, extend toes

Question 22

Superficial fibular nerve

Answer 22

Lateral leg, evertors and plantar