Lower extremity nerves

Question 1

What lower extremity nerves are at risk in abdominal surgery?

Answer 1

• Iliohypogastric (T12-L1) (open)
• Genitofemoral (L1-2) (laproscopic)

Question 2

Iliohypogastric nerve supplies sensory innervation to where?

Answer 2

Suprapubic region

Question 3

The iliohypogastric nerve supplies motor sensation to what muscles?

Answer 3

• Transverse abdominis
• Internal oblique

Question 4

Burning or tingling sensation in surgical incision site radiating to inguinal and suprapubic region indicates injury to what nerve?

Answer 4

Iliohypogastric nerve (T12-L1)

Question 5

The Genitofemoral nerve (L1-2) supplies sensory innervation to where?

Answer 5

• scrotum/labia majora
• Medial thigh

Question 6

The genitofemoral nerve is involved in what reflex?

Answer 6

Cremastor reflex
(if damaged sensation to medial thigh beneath inguinal ligament will be impaired)

Question 7

The lateral femoral cutaneous nerve (L2-3) supplies sensation to where?

Answer 7

Anterior and lateral thigh
- Injury will decrease sensation

Question 8

How may the lateral cutaneous nerve (L2-3) be damaged?

Answer 8

• Tight clothing
• Obesity
• Pregnancy
• Pelvic procedures

Question 9

What nerve supplies sensation to the medial thigh?

Answer 9

Obturator (decreased sensation to this area if damaged)

Question 10

How may the obturator nerve be damaged?

Answer 10

Pelvic surgery

Question 11

Obturator nerve supplies motor innervation to what muscles?

Answer 11

• Obturator externus
• Adductor longus
• Adductor brevis
• Gracilis
• Pectineus
• Adductor magnus

Question 12

How may the femoral nerve (L2-4) be damaged?

Answer 12

Pelvic fracture

Question 13

What muscles does the femoral nerve innervate?

Answer 13

• Quadraceps
• Iliacus
• Pectineus
• Sartorius

Question 14

What will injury to the femoral nerve (eg pelvic surgery) result in?

Answer 14

• Decreased leg extension
• Decreased patellar reflex

Question 15

What muscles does the sciatic nerve innervate?

Answer 15

• Semitendinosus
• Semimembranosus
• Biceps femoris
• Adductor magnus

Question 16

What does the sciatic nerve (L4 - S3) divide into?

Answer 16

• Common peroneal (fibular) nerve
• Tibial nerve

Question 17

What can cause injury to the sciatic nerve?

Answer 17

• Herniated disc
• Posterior hip dislocation

Question 18

How may the common peroneal (fibular) nerve be injured?

Answer 18

• Trauma or compression of lateral aspect of leg
• Fibular neck fracture

Question 19

What does the common peroneal (fibular) nerve supply sensation to?
Superifical and deep peroneal nerve

Answer 19

Superficial peroneal nerve:
- Dorsum of foot (except webspace between hallux and 2nd digit)

Deep peroneal nerve:
- Webspace between hallux and 2nd digit

Question 20

What muscle does the superificial peroneal nerve innervate?

Answer 20

Peroneus longus and brevis

Question 21

What muscle does the deep peroneal nerve innervate?

Answer 21

Tibialis anterior

Question 22

Injury to the common peroneal nerve will result in what?

Answer 22

• Loss of sensation to dorsum of foot
• Foot drop - cannot dorsiflex

Question 23

The tibial nerve supplies sensory innervation to where?

Answer 23

Sole of foot

Question 24

How can the tibial nerve be injured?

Answer 24

• Knee trauma
• Baker cyst (proximal lesion)
• Tarsal tunnel syndrome (distal lesion)

Question 25

The tibial nerve innervates what muscles?

Answer 25

- Flexor muscles of foot (plantarflexion) - Biceps femoris (long head) - Triceps surae - Plantaris - Popliteus

Question 26

What will injury to the tibial nerve (L4- S3) result in?

Answer 26

- Loss of plantarflexion, inversion - Foot everted at rest - Inability to curl toes - Loss of sensation to sole of foot

Question 27

What muscles does the superior gluteal muscle innervate?

Answer 27

- Gluteus medius - Gluteus minimus - Tensor fascia latae

Question 28

Trandelenburg sign is a result of an injury to what nerve?

Answer 28

Superior gluteal

Question 29

What can cause injury to the superior gluteal nerve?

Answer 29

IM injection to superomedial gluteal region

Question 30

Describe Trandelenburg sign

Answer 30

Pelvis tilts becuase wight-bearing leg cannot maintain alignment of pelvis through hip abduction - Lesion is to contralateral side of hip that drops - Ipsilateral to leg which patient stands on

Question 31

The inferior gluteal nerve innervates what muscle?

Answer 31

Gluteus maximus

Question 32

What can injury to the inf gluteal nerve (gluteus maximus) result in?

Answer 32

Difficulty climbing stairs, rising from seated position; loss of hip extension

Question 33

Injury to the inferior gluteal nerve (L5-S2) can be caused by whaat?

Answer 33

Posterior hip dislocation

Question 34

Sensory innervation to the perineum is supplied by what nerve?

Answer 34

Pudendal (S2-4)

Question 35

What does the pudendal nerve innervate (motor)?

Answer 35

External urethral and anal sphincters

Question 36

How can injury to the pudendal nerve occur?

Answer 36

- Stretch injury during childbirth - Cycling, horesriding

Question 37

What may injury to the pudendal nerve result in?

Answer 37

- Decreased sensation to the perineum and genital area - Fecal and urinary incontinance

Question 38

Where is used as a landmark for injection to target the pudendal nerve during childbirth?

Answer 38

Ischial spine