Extremity Injuries Principle #2: Assessment of Neurovascular Status

00:01 So the second principle I really wanna emphasize is the importance of assessing and documenting a neurovascular exam.

00:09 Now, based on your history and physical, you should have some hypotheses about what parts of the body are injured.

00:16 So if you think the patient has a fracture in the wrist or in the ankle.

00:19 You can use that information to figure out what neurovascular structures are in that region and what specific neurovascular injuries you might be concerned about.

00:30 I do wanna emphasize that vascular injuries in particular are always an emergency.

00:34 So anytime you have a patient with a pulseless or cold extremity, you need to take that very seriously and treat the patient properly.

00:42 If they have a vascular injury in association with the fracture, you wanna reduce the fracture.

00:47 By which I mean straighten the bones back out to try to restore perfusion.

00:52 That way you're gonna avoid ischemic damage and ultimately limb loss.

00:56 If you're not able to get pulses back by reducing the fracture, you wanna involve a surgeon because that's a sign that potentially there is a blood vessels that's transected or occluded and you need to address that properly again to avoid limb loss.

01:11 So our neurovascular assessment is always gonna include three components.

01:16 Obviously, vascular and neuro, so we're gonna do a vascular exam, a sensory exam and a motor exam for every single patient.

01:25 Let's go back to our case.

01:27 So on the neurovascular front, our patient has intact pulses in both the hand and the foot.

01:33 So radial, ulnar, dorsalis pedis and posterior tibial pulses are all good.

01:39 The extremities are warm, pink and well perfused.

01:42 On the neurologic front, remember I said she had a paresthesias over the dorsum of her hand.

01:48 Now, if you look at this image, this depicts the peripheral innervation of the hand.

01:54 So the areas that are shaded in blue are areas that are innervated by the median nerve.

02:00 So that's gonna be basically the palm of the hand from the forth finger over, as well as the tips of the dorsal fingers.

02:09 The radial nerve is gonna innervate the majority of the dorsum of the hand and the fingers up to the distal interphalangeal joint and then the ulnar nerve innervates the lateral aspect of the hand, so the entire pinky and the section of the ring finger.

02:27 Our patient has numbness in this area over the dorsum of the hand raising concern for radial nerve injury.

02:34 What's missing from this exam that I just reported to you? Remember, I told you there are three pieces that you need to include in every neurovascular assessment.

02:44 Vascular, sensory and motor.

02:46 So we cover the first two but we didn't cover the motor exam.

02:50 I just wanted to take a minute to demonstrate the motor assessment of the hand.

02:53 So the radial nerve provides wrist extension, meaning the ability to pull the wrist up.

03:00 And thumb abduction, the ability to give a thumbs up sign and keep the thumb up away from the rest of the hand.

03:08 Those are radial nerve functions.

03:10 The median nerve provides flexion of the first through third digits.

03:15 So the ability to bring the fingers down against resistance.

03:19 Also, thumb up position.

03:21 So the ability to bring in the thumb in against the fingers and you can assess that by giving the okay sign and seeing whether or not the patient can prevent you from pulling through.

03:32 Lastly, the ulnar nerve handles finger abduction and adduction.

03:37 So the ability to pull the fingers apart against resistance and the ability to pull the fingers together against resistance.

03:45 These are simple exam maneuvers that you can do to assess the integrity of each of the three nerves that innervate the hand.

03:52 Now, our patient, our primary concern is radial nerve.

03:57 We know that she has tenderness over the distal radius, the radial aspect of the wrist and that's clearly the area where the radial nerve runs right through.

04:05 She has also numbness in the hand dorsum which is innervated by the radial nerve.

04:09 So we wanna specifically focus on motor assessment of radial nerve function.

04:15 So again, we're gonna be looking for wrist extension and thumb abduction.

04:21 Now, these maneuvers are painful for patients when they have fractures.

04:25 So we really need to make sure that we're providing adequate analgesia so the patient is capable of giving us good effort and we get an accurate assessment of their motor function.

04:35 So back to our case.

04:37 We were able to assess the patient's wrist extension and thumb abduction.

04:41 It's 5 out of 5.

04:43 So normal strength although she does of course indicate that it's painful.

04:47 And we decided at this point to get x-ray.

04:49 So we do basically the entire arm from the forearm down to the hand and we also do the entire lower leg on the right.

04:58 Now, x-ray result should never be a surprise.

05:01 So before we even order these films we should have a hypothesis about what's gonna be wrong with the patient.

05:06 In this case what radiographic results do we expect? Probably, she's gonna have a fracture in the right wrist.

05:13 We're specifically concerned about the radius.

05:15 And we're also concerned about the ankle and the tib-fib based on her tenderness on exam.

05:22 And indeed here are x-ray results.

05:25 So the patient is found on x-ray to have a Maisonneuve fracture which is basically a combination fracture involving the distal tibia and the proximal fibula.

05:36 This is associated with rotational force.

05:39 Now remember, our patient trip over the cat and when she fell she had a planted foot.

05:43 So her foot's firmly on the ground and she sort of twisted around it causing a rotational force which disrupts the syndesmotic ligament that connects the tibia to the fibula.

05:56 This results in a grossly unstable ankle and always require surgical fixation.

06:02 So this is actually a pretty bad fracture to have.

06:05 Shouldn't be that much of a surprise though, again based on our physical exam results where the patient was tender over the medial ankle and lateral leg just distal to the knee basically exactly where her fractures are.

06:21 Here's our upper extremity x-ray.

06:22 It's read by the radiologist as normal.

06:25 However, we go back and re-examine the patient and she has significant tenderness right here in the region that is outline on the picture.