Lumbosacral Plexus

Question 1

Pelvis

Answer 1

1. Ilium
2. Ischium
3. Pubis

Fused together at acetabulum (hip socket)

Question 2

Muscles & Nerves

Answer 2

Glutei → gluteal nerve
Adductors → obturator
Quadriceps → femoral
Hamstrings & ankle/toe flexors → tibial
Ankle & toe extensors → peroneal (fibular)

Question 3

Posterior Divisions

Answer 3

Ventral surface elevators
Hip abductors & flexors
Knee & foot extensors

Question 4

Anterior Divisions

Answer 4

Medial & dorsal surface depressors
Hip extensors
Knee & foot flexors

Question 5

Medial

Answer 5

Adductors

Question 6

Lateral

Answer 6

Glutei

Extensors

Question 7

Anterior

Answer 7

Ilio-psoas & quadriceps

Question 8

Posterior

Answer 8

Hamstrings

Flexors

Question 9

Quadriceps (Vasti)

Answer 9

Hip flexion & knee extension
RESIST - prevent knee collapse
- Rectus femoris
- Vastus lateralis
- Vastus intermedius
- Vastus medialis
FEMORAL nerve

Question 10

Adductors

Answer 10

Hip aDduction

OBTURATOR nerve

Question 11

Gluteals

Answer 11

Hip aBduction

Superior & inferior GLUTEAL nerve

Question 12

Anterior Leg

Answer 12

Dorsiflexion & toe extension

Common PERONEAL nerve

Question 13

Posterior Thigh/Leg

Answer 13

Hip extension, knee flexion, plantar flexion, & toe flexion

TIBIAL nerve

Question 14

Sciatic Nerve

Answer 14

Common peroneal (fibular) & tibial nerves
Posterior compartment thigh, leg, & foot sole
Emerges under piriformis
Midpoint b/w greater trochanter & posterior superior iliac spine

Question 15

Peroneal Nerve

Answer 15

Lateral to fibula neck

Lateral cutaneous calf

Question 16

Obturator Nerve

Answer 16

Medial thigh compartment

Question 17

Femoral Nerve

Answer 17

Anterior thigh compartment

Question 18

Femoral Triangle

Answer 18

Superior angle - inguinal ligament
Lateral - sartorius muscle
Medial - adductor longus

Lateral → medial
Femoral nerve → femoral artery → femoral vein

Question 19

Hamstrings

Answer 19

Innervation = tibial portion sciatic nerve
Extend hip & flex knee
Prevent trunk jack-knifing
- Biceps femoris (short head receives peroneal innervation)
- Semitendinosus
- Semimembranous

Question 20

Adductors

Answer 20

Innervation = obturator nerve
Thigh (hip) aDduction
- Adductor brevis
- Adductor longus
- Adductor magnus

Question 21

Extrinsic Plantar Flexors

Answer 21

Innervation = tibial nerve
Plantar flexion
Drives toe off & able to store energy
- Gastrocnemius (medial & lateral head) → Achilles tendon
- Plantaris
- Soleus

Question 22

Ankle & Toe Extensors

Answer 22

Innervation = peroneal (fibular) nerve

• Extensor digitorum longus
• Extensor hallucis longus
• Peroneus tertius
• Tibialis anterior

Question 23

Foot Inverters

Answer 23

Tibialis post
Flexor digitorum longus
Popliteus
Flexor hallucis longus

Question 24

Foot Everters

Answer 24

Peroneus longus
Peroneus brevis
Brevis tendon
Longus tendon
Extensor hallucis longus
Peroneus tertius

Question 25

Intrinsic Foot Muscles

Answer 25

Superficial layer - abductor hallucis, flexor digitorum brevis, & abductor digiti minimi
Deeper layer - flexor hallucis brevis, flexor digiti minimi brevis, adductor hallucis, oblique head (control the big toe)

Question 26

Gluteus Maximus

Answer 26

Thigh (hip) extension
Extensor provides upright stability
Prevent trunk jack-knifing

Question 27

Gluteus Medius & Minimus

Answer 27

Thigh (hip) aBduction

Provide pelvis balance

Question 28

Iliopsoas

Answer 28

Flex thigh (hip)
Functions to initiate limb swing

Question 29

Anterior Tibial Muscles

Answer 29

Dorsiflex

Function to control foot position during swing & position foot for heel-strike

Question 30

Lateral Ankle → Plantar Foot

Answer 30

Tibialis posterior
Flexor digitorum longus
Flexor hallucis longus

Question 31

Popliteal

Answer 31

Lateral → medial

Tibial nerve → popliteal vein → popliteal artery