Musculoskeletal Injuries — Lesson 6

Overview

Learning Objectives

Know basic skeletal anatomy, and sort fractures and dislocations by type
Do a proper neurovascular check (the 6 Ps and CSM)
Apply the principles of splinting and know the specific techniques
Manage a dislocation: splint it in the position of comfort, watch CSM, and evacuate
Manage open fractures, dislocations, and the special cases (amputations, compartment syndrome)
Know the Ottawa Rules for ankle and knee injuries

Bone and joint injuries are some of the most common injuries you'll see in the backcountry. A rolled ankle on the trail, a fall onto an outstretched hand, a climbing fall: any of them can break a bone or dislocate a joint. Out here the evacuation can take hours or days. A broken ankle a mile from the car is a bad afternoon, but three days in, it's a logistics problem, and you're managing it the whole way out.

Your job is to check neurovascular status, keep the injury from getting worse, immobilize it (splint), recheck, and evacuate at the right urgency.

No pulse, no feeling, or no movement below the injury is an emergency. That's neurovascular compromise, and it needs a rapid evacuation. Pain by itself isn't neurovascular compromise. Pain when you passively stretch the muscles is different, because it suggests compartment syndrome (covered later in this lesson). If blood flow is compromised, don't delay.

Anatomy & Injury Types

Skeletal anatomy basics

The parts that matter here:

Long bones: femur, tibia, humerus, radius, ulna. Each has a shaft (diaphysis) and ends (epiphyses), and in children a growth plate.
Joints: where two or more bones meet. Ligaments hold them together, and cartilage covers the bone ends to cut friction.
Tendons: connect muscle to bone.
Ligaments: connect bone to bone and stabilize the joints.

Fracture classification: open vs. closed

Closed fracture: The bone is broken but the skin is intact. The break has no direct opening to the outside.

Open (compound) fracture: The bone is broken and the skin is broken, so contamination has a direct path in. It carries a higher infection risk and more blood loss than a closed fracture, and it's more serious.

Fracture types by pattern

Type	Description	Typical Mechanism
Transverse	Break runs straight across the shaft	Direct blow or bending force
Oblique	Break runs at an angle (45°) across the shaft	Twisting, or bending combined with an axial load
Spiral	Break wraps around the shaft	Twisting force (common in ski injuries)
Comminuted	Bone broken into 3 or more pieces	High-energy trauma (a car crash, a fall from height)
Greenstick	An incomplete break. The bone bends but doesn't break all the way through (common in children)	Bending force on a child's flexible bone

Dislocation

A dislocation (luxation) is a bone pushed out of its normal position at a joint. The ligaments and other supporting structures often tear with it. Common sites are the shoulder, the kneecap (patella), the elbow, and the fingers. Don't confuse a kneecap dislocation with a true knee dislocation (tibiofemoral). A true knee dislocation is rare, and it's a limb-threatening emergency.

Sprain vs. strain

Sprain: a torn ligament (bone to bone) from the joint moving too far. Usually swelling, bruising, and pain with movement.
Strain: a torn muscle or tendon. It can be sudden (acute) or long-running (chronic). Pain and weakness.

Mechanism of injury patterns

The mechanism tells you what's likely to be hurt:

Fall on outstretched hand (FOOSH): often a wrist fracture (Colles' fracture) or a shoulder dislocation
Axial load (impact from above): vertebral compression fractures or femur fractures
Twisting: ankle sprains, spiral fractures of the tibia
Hyperextension: knee ligament injuries, elbow dislocations

Assessment of Musculoskeletal Injuries

Secondary survey tool: DCAP-BTLS

In the secondary survey, once the life threats are handled, check the injury site for:

Deformity: is the limb bent or shorter than the other side?
Contusions: bruising, a sign of trauma
Abrasions: scrapes, which hint at the mechanism
Punctures/Penetrations: holes in the skin. Over a fracture site, that's an open fracture.
Burns: look for thermal injury
Tenderness: press gently. Point tenderness over bone suggests a fracture.
Lacerations: cuts in the skin. Over a fracture site, that's an open fracture.
Swelling: fluid (edema) from bleeding into the tissues

Neurovascular assessment: the 6 Ps

Check before the splint goes on, and again after. If it's worse after splinting, loosen the splint immediately.

The 6 Ps of neurovascular assessment:

P	Assessment	Concerning Finding
Pain	Ask how bad it is and what it feels like. Severe pain out of proportion to the injury suggests compartment syndrome.	Severe pain with passive stretch; pain out of proportion
Pallor	Check skin color below the injury and compare it to the other limb.	Pale, white, or bluish (cyanotic) skin below the injury
Pulse	Feel for the pulse below the injury (dorsalis pedis, on top of the foot, for an ankle; radial, at the wrist, for a forearm or elbow).	Absent or very weak pulse below the injury
Paresthesia	Ask about tingling or "pins and needles."	Numbness, tingling, or burning below the injury
Paralysis	Test movement below the injury: have them move their fingers or toes.	Weakness, or they can't move the fingers or toes
Pressure	Feel the limb for tense, swollen compartments.	Tight, swollen compartments; tense, with pain on passive stretch

CSM assessment

CSM = Circulation, Sensation, Motion. It's the short version of the 6 Ps:

C - Circulation: pulse below the injury, skin color and temperature, capillary refill
S - Sensation: can they feel touch or pain below the injury?
M - Motion: can they move their fingers or toes when you ask?

Ottawa ankle and knee rules

Ottawa Ankle Rules. An X-ray is recommended if there's bony tenderness over any of these:

The posterior edge or tip of the lateral malleolus (the outer ankle bone), in its lowest 6 cm
The posterior edge or tip of the medial malleolus (the inner ankle bone), in its lowest 6 cm
The navicular bone (midfoot)
The base of the 5th metatarsal (the bony bump on the outer edge of the midfoot)

Or if they can't bear weight (take 4 steps) both right after the injury and when you assess them. These are OR criteria. Any one positive finding suggests they need imaging, and out here that means evacuation.

Ottawa Knee Rules. Imaging is recommended if any of these is present:

Age 55 or older
Tenderness of the kneecap only (isolated patellar tenderness, no other bony tenderness)
Tenderness at the head of the fibula
They can't bend the knee to 90°
They can't bear weight (take 4 steps) both right after the injury and when you assess them

The rules were written to decide who gets an X-ray. In the wilderness, use them to set evacuation priority.

Splinting Principles & Techniques

General splinting principles

Splinting basics:

Immobilize the joints above and below the fracture
Pad the bony prominences so the splint doesn't cause pressure sores
Don't put a strap or tie directly over the fracture site. Secure above and below it.
Leave the fingertips or toes visible (a window) so you can keep checking them
Check CSM before the splint goes on, again right after, and every so often during the evacuation
Splint before you move the patient, unless the scene forces you to move first
Splint fractures in the position found. Splint or sling dislocations in the position of comfort. If there's no circulation below the injury, the evacuation becomes emergent.
Ice or cold, if you have it, to bring down swelling
Elevate if you can, also to bring down swelling

Common splinting techniques

SAM splint (soft aluminum malleable): It's compact and reusable, and it molds to any shape. It works well on the forearm, wrist, ankle, and knee. Pad it with extra material and secure it with elastic bandages.

Improvised splints: Out here you build with what you've got:

Sticks or branches, padded with clothing
A rolled sleeping bag or pad alongside the limb
Buddy taping: tape the injured finger to the healthy finger next to it
A sling and swathe for the arm and shoulder (upper extremity)

Suspected femur (thighbone) fracture: Use a well-padded rigid splint, or an anatomic splint (padding between the legs, then the injured leg secured to the uninjured one). A femur fracture can bleed 1 to 1.5 liters internally. Treat for shock (flat on the back, insulated from the ground, prevent heat loss) and evacuate urgently. For reference: EMS may apply a commercial traction splint (Kendrick, Thomas) for a mid-shaft femur fracture. It's an EMS device, not a WFA skill.

Angulated limbs and reduction

Reduction is not a WFA skill. Reduction means realigning a broken or dislocated bone, and medical professionals do it. At this level of training:

Splint fractures in the position found. Splint or sling dislocations in the position of comfort.
Check CSM before and after splinting, and recheck it regularly.
If there's no pulse or sensation below the injury, the evacuation becomes emergent.

Dislocations

Anterior shoulder dislocation (the most common)

The ball at the top of the upper arm bone (the humeral head) comes forward out of the shoulder socket (the glenoid cavity). The classic picture:

The arm held slightly away from the body and rotated outward (slight abduction and external rotation)
They can't rotate the arm inward
Severe pain
A bulge you can feel at the front
The normal rounded contour of the shoulder is gone

Field management: Immobilize it in the position of comfort with a sling and swathe. Check circulation, sensation, and motion (CSM) before and after the sling goes on, and recheck regularly during the evacuation. Don't try to reduce it. Medical professionals do that. Evacuate.

Patella (kneecap) dislocation

It usually goes to the outside (laterally). You'll see:

Severe pain, and the thigh muscle (quadriceps) in spasm
The kneecap visibly shifted to the outside
They can't straighten the knee

Field management: Splint the knee in the position of comfort with plenty of padding. A rolled sleeping bag or pad works well. Check CSM before and after splinting. Don't try to straighten the leg or push the kneecap back into place. Some kneecaps slide back in on their own as the patient moves. That's good for them, but it doesn't change your plan. Splint and evacuate for a medical evaluation.

Finger and toe dislocations

The deformity is usually obvious. Splint it in the position of comfort: buddy-tape the injured digit to its healthy neighbor, or use a padded splint. Check CSM before and after. Don't try to reduce it. Evacuate so medical professionals can evaluate and reduce it.

Hip dislocation

Rare, but serious. Most are posterior. You'll see:

Severe pain in the hip or groin
The leg turned inward and drawn across the midline (internally rotated and adducted), usually with the hip bent and the leg looking shorter
They can't move the leg
Possible sciatic nerve injury (foot drop, loss of sensation)

Field management: Immobilize it in the position found, padded generously with clothing or sleeping bags. It's a neurovascular emergency. If hospital reduction is delayed, the head of the femur can lose its blood supply and die (avascular necrosis). Emergent evacuation.

Dislocation management at the WFA level

For every dislocation:

Splint or sling it in the position of comfort
Check CSM before and after splinting, and recheck regularly during the evacuation
Evacuate. Reduction is for medical professionals.
No pulse or sensation below the joint means an emergent evacuation

For reference: in remote settings, rescuers with higher-level medical training sometimes reduce certain dislocations when the evacuation will be long. That skill is beyond the scope of this course.

Open Fractures & Special Considerations

Open fractures: immediate management

An open fracture needs a hospital and a surgeon within hours. The risk of infection and other complications is high.

Right away:

Keep it still in the position found. Realigning a fracture is higher-level care, not a WFA skill. If the limb has no pulse or sensation below the injury, the evacuation becomes emergent.
Gently irrigate the wound with clean water or saline to wash out dirt. It helps protect against infection.
Cover it with a clean dressing, sterile if you have one. You may need to dress around exposed bone.
Splint it over the dressing, in the position found. Elevate it if you can, to reduce swelling.
If bone was exposed at any point, even if it's slipped back under the skin, write it down and report it at the hospital handoff.
Urgent evacuation to a hospital for surgery (cleaning and internal fixation). No pulse or sensation below it, or signs of shock, makes it emergent.

Amputated parts

If a limb or digit is amputated:

Control the bleeding first. A limb amputation gets a tourniquet right away, high and tight, with the time noted. A finger or toe usually stops with direct pressure.
Get the amputated part if you can
Wrap it in clean cloth or gauze moistened with saline or clean water only. Never use antiseptics or bleach. They damage the tissue and can make the part impossible to reattach.
Seal the wrapped part in a plastic bag, then put the bag on ice or in cold water. Never put the part directly on ice.
Label it with the time of amputation
Send it to the hospital with the patient. Digits can stay viable up to about 12 hours warm or 24 hours cooled; larger parts tolerate much less.
Emergent evacuation

Compartment syndrome

Definition: Pressure rises inside a closed muscle compartment (a group of muscles wrapped in a sheath of fascia). It chokes off blood flow, and the tissue dies if the pressure isn't relieved. Picture a dry bag cinched shut while someone keeps stuffing it. The bag won't give, so everything inside gets crushed, blood vessels included.

Classic presentation:

Pain out of proportion to the injury. This is the hallmark.
Pain when the muscles in the compartment are passively stretched (for the forearm, you straighten their fingers for them)
A tight, swollen compartment when you feel it
Tingling (paresthesia) and weakness, which come late

Common sites: the front (anterior) compartment of the lower leg with a tibia or fibula fracture, the forearm, and the thigh.

Field management:

Suspect it from the findings, starting with the out-of-proportion pain
Loosen anything tight: dressings, bandages, splint straps. They can raise the pressure in the compartment. Keep the limb splinted, just not squeezed.
Raise the limb only to heart level. Any higher cuts blood flow to the compartment.
Emergent evacuation to a hospital for a fasciotomy (a surgical incision to relieve the pressure)

It's easy to miss early. Compartment syndrome isn't obvious at first, on X-ray or on exam. You suspect it from what you find: pain out of proportion and pain on passive stretch. It needs emergency surgery to release the pressure (surgical decompression).

Clinical Scenarios

Scenario 1: Ankle Fracture with Intact Distal Pulses

A 26-year-old backpacker twists her ankle stepping off a rock. Severe pain and swelling start right away. On exam there's obvious swelling and deformity, with the foot turned inward (inverted). Her dorsalis pedis pulse is present and strong, the foot is pink and warm, and she can move her toes and feel your touch. By the Ottawa Ankle Rules, she has tenderness at the posterior edge of the lateral malleolus.

What's going on: Probably an ankle fracture, with intact neurovascular status. The Ottawa Ankle Rules say she should get an X-ray. Nobody packed one.

What you do:

Treat it as broken until someone proves otherwise.
SAM-splint the ankle so the ankle and foot can't move, with the splint running well up the lower leg. Pad the bony prominences, leave the toes visible, and keep straps off the break.
Recheck the pulse, sensation, and movement below the injury after splinting, and again every so often on the way out.
Elevate it and apply cold (snow or cold water) to bring the swelling down.
Pain control: acetaminophen or ibuprofen, if you have it.
Evacuation: urgent (same day if possible) for imaging and evaluation if she can't bear weight, which is likely with this much deformity. If she can walk on it splinted, it's non-urgent, but she still walks out to get it imaged.
If neurovascular compromise develops (the pulse disappears, the foot turns pale or cold), loosen the splint immediately and get ready for an emergency descent.

Where it goes: With proper splinting and evacuation, she should recover well.

Scenario 2: Femur Fracture with Neurovascular Compromise

A rock climber falls 15 feet and lands on his leg. He has severe pain in the thigh, an obvious deformity (the leg is shortened and angulated), and significant swelling. Below the injury, the foot is pale and cool, the dorsalis pedis pulse is absent, he can't move his toes (paralysis), and the pain is severe. He's in shock: HR 124, RR 24, BP 96/62.

What's going on: A femur fracture with neurovascular compromise (an absent pulse, paralysis, and a pale, cool foot). This is an emergency. A femur fracture can bleed 1 to 1.5 liters internally, so treat him as a serious shock risk on top of the threat to the limb.

What you do now:

Splint the leg in the position found with a well-padded rigid or anatomic splint (pad between the legs and secure the injured leg to the uninjured one). Don't try to realign it or pull traction. That's higher-level care.
Treat for shock: lay him flat on his back, insulate him from the ground, and prevent heat loss.
A 15-foot fall is a spine mechanism. Keep him still, ask the spine questions (Lesson 7), and move him as one unit when you have to move him.
Recheck CSM (circulation, sensation, motion) every 15 minutes and write down each result with the time.
Emergent evacuation, by helicopter if one is available. He needs surgery at a hospital as fast as you can get him there.
Keep watching his vitals and neurovascular status the whole time.

No pulse means the limb is at risk. At the WFA level, your job is to splint in position, treat for shock (flat on the back, prevent heat loss), document CSM serially, and get the fastest evacuation you can. Field realignment isn't part of it.

Knowledge Check

10 questions. Pick an answer to get immediate feedback. Answer order is shuffled each attempt, and your best score is saved on this device.

Summary & Key Takeaways

The short version:

Check neurovascular status before and after every splint.
Splint so the joints above and below the fracture can't move. Pad it, keep straps off the break, and leave the fingers or toes showing.
Open fractures: irrigate gently, cover, splint in position, urgent evacuation.
Compartment syndrome: suspect it when the pain is out of proportion. It needs an emergency fasciotomy.
No pulse, sensation, or motor function below the injury is neurovascular compromise and an emergent evacuation. Splint in position. Realignment and reduction are for medical professionals.
The Ottawa Rules (ankle, knee) guide imaging decisions. Any one positive criterion counts.
Suspected femur fracture: a well-padded rigid or anatomic splint, shock care, and an urgent evacuation. Traction splints are an EMS device.

Glossary of Terms

Angulation

A bone bent or deviated off its normal axis. It means a fracture or dislocation.

Avascular Necrosis

Bone tissue dying because it's lost its blood supply. It can happen after a hip dislocation that isn't reduced promptly.

Closed Fracture

A broken bone with the skin intact. The break has no opening to the outside.

Compartment Syndrome

Pressure building inside a closed muscle compartment until the tissue loses blood flow (hypoperfusion) and dies (necrosis). Needs emergency surgical decompression.

CSM

Circulation, Sensation, Motion. A simplified neurovascular check of the limb below an injury.

Dislocation (Luxation)

A bone pushed completely out of its normal position at a joint.

FOOSH

Fall On Outstretched Hand. A common way to injure the wrist and shoulder.

Fracture

A break in a bone, from trauma or from disease (pathology).

Open Fracture

A broken bone and a break in the skin over it. High risk of infection and blood loss.

Ottawa Ankle/Knee Rules

Evidence-based decision tools for which ankle and knee injuries need an X-ray.

Pulse

The regular beat you feel in an artery. Check it below an injury to make sure blood is getting through. No pulse below the injury is a neurovascular emergency.

Reduction

Putting a dislocated bone or joint back in its normal position. Medical professionals do it. It isn't a WFA skill.

Splint

A device or technique that immobilizes a fracture or dislocation so it can't move and get worse.

Sprain

A torn ligament (the bone-to-bone connection) from the joint moving too far.

Strain

A torn muscle or tendon, from overuse or trauma.

Traction Splint

An EMS device that applies gentle traction along the length of the leg to stabilize a mid-shaft femur fracture, easing pain and internal bleeding. Not applied at the WFA level.

The 6 Ps

Pain, Pallor, Pulse, Paresthesia, Paralysis, Pressure. A checklist for neurovascular status below an injury.