Board Review: Potpourri
A 27-year-old male comes to the ED after a motorcycle collision. He has extreme right leg pain and is found to have a mid-shaft tibia fracture on X-ray. You place a splint and admit patient to the trauma service. You get a call from the nurse stating that the patient has gotten a total of 5mg of IV hydromorphone, is still writing in pain, and endorsing numbness on the foot. On exam, you note the numbness to be on the dorsum of his foot. He is found to have a compartment pressure of 35mmhg. What compartment are you most worried about to have compartment syndrome?
C. Superficial posterior
D. Deep posterior
Answer: B- Lateral
Compartment syndrome is an orthopedic emergency where there is an increase in compartment pressures that compromises circulation and function of the tissues in that space. This ultimately can lead to muscle death and nerve damage. In the lower leg, there are few compartments where each can occur, and an associated “syndrome.” For our patient, the superficial fibular nerve runs through the lateral compartment and innervates the dorsum of the foot.
Anterior – deep peroneal nerve with first dorsal web space sensation
Superficial posterior – sural nerve with lateral aspect of foot and distal calf sensation
Deep posterior – posterior tibial nerve with sole of foot sensation
Image from Dr. Katy Hanson at Hanson's Anatomy
Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. Chapters 275 and 278.