4/12 Lower Extremity Injuries - Corbett

Question 1

lower extremity

muscles, nerves, fx

Answer 1

Question 2

lumbosacral plexus

Answer 2

Question 3

femoral nerve

Answer 3

rare injury

• direct penetrating trauma
• spontaneous retroperitoneal hematoma in psoas

see quadriceps gait during heel strike

• using hand to push lower thigh/knee back bc cant flex hip/extend at knee effectively while walking (midstance)

Question 4

femoral sensory

Answer 4

Question 5

obturator nerve

Answer 5

most of it from L3, but considered L2-L4 (like femoral n)

innervates all adductor muscles (longus, befix, magnus/minimus), gracilis, obturator externus

injury?

• hard to tell bc of overlap of mm causing adduction
  
  • difficulty w ambulation bc externally rotated foot
  • groin pain worse with activity
  • loss of hip adduction, hip internal rot
  • wasting of adductor thigh muscles

Question 6

femoral and obturator nerve

anterior and medial thigh

review

Answer 6

Question 7

sacral plexus

Answer 7

Question 8

superior gluteal n

Answer 8

hip abduction: gluteus medius, gluteus minimus

• in case of injury, test by standing on one leg
  
  • strong gluteus medius/minimus → will pull pelvis down to that side
  • weak gluteus medius/minimus → cant keep pelvis level, so see dipping to opposite side when standing on the weak side = TRENDELENBERG

Question 9

inferior gluteal nerve

Answer 9

major extensor of hip: gluteus maximus

• upper and middle thirds also involved in abduction

gluteus maximus typically works against inertia of the trunk

• injury? gluteus maximus gait with trunk lurching back to compensate for the lack of strength that would usually counter the trunk’s inertia

Question 10

sciatic nerve

Answer 10

two nerves, separate proximal to popliteal fossa:

1. tibial n
2. common peroneal n

Question 11

sciatic nerve injury

Answer 11

iatrogenic (hip surgery) or hip dislocation are common causes

recall: main blood supply to hip = medial circumflex femoral artery

most common manifestation: foot drop due to common fibular n injury

Question 12

graphic: branches of sciatic n

Answer 12

Question 13

anterior vs medial vs posterior muscles of thigh

Answer 13

Question 14

common peroneal nerve

Answer 14

comes around head of fibula

Question 15

common peroneal nerve injury

Answer 15

(ignore 3rd slide - knee disloc)

Question 16

tibial nerve

tibial nerve injury

Answer 16

Question 17

peroneal nerve vs tibial nerve

motor and sensory fx

Answer 17

Question 18

doslocation of knee joint

Answer 18

anatomical complication:

• injury of popliteal artery → functionally an end artery
• injury of common peroneal nerve!

Question 19

Question 20

Question 21

knee injury ddx

• noncontact & pop
• contact & pop
• acute swelling
• lateral impact
• medial impact
• knee buckled/gave out
• fall onto flexed knee

Answer 21

ACL passes posteriorly attaches to lateral condyle (medial surface of it)

PCL passes anteriorly