Musculoskeletal Injuries — Lesson 6

Overview

Learning Objectives

Understand skeletal anatomy and classify fracture and dislocation types
Perform proper neurovascular assessment (the 6 Ps and CSM)
Apply splinting principles and identify specific splinting techniques
Manage dislocations by splinting in the position of comfort, monitoring CSM, and evacuating
Manage open fractures, dislocations, and special scenarios (amputations, compartment syndrome)
Understand Ottawa Rules for ankle and knee injuries

Musculoskeletal injuries are among the most common injuries encountered in wilderness settings. A twisted ankle on a hiking trail, a fall onto an outstretched hand, or a climbing accident can all result in fractures or dislocations. In remote settings, proper field management is critical because evacuation may take hours or days.

This lesson covers the assessment and management of fractures and dislocations using wilderness-appropriate techniques. Your priorities are: assess neurovascular status, prevent further injury, immobilize/splint, reassess, and evacuate appropriately.

Critical Principle: Neurovascular compromise (absent pulse, loss of sensation, or paralysis distal to the injury) is an emergency requiring rapid evacuation. Pain by itself is not neurovascular compromise — but pain with passive stretch suggests compartment syndrome, covered later in this lesson. Do not delay if blood flow is compromised.

Anatomy & Injury Types

Skeletal Anatomy Basics

The skeletal system consists of:

Long Bones: Femur, tibia, humerus, radius, ulna. Composed of a shaft (diaphysis) and ends (epiphysis) with a growth plate in children.
Joints: Where two or more bones meet. Held together by ligaments. Cartilage covers bone ends to reduce friction.
Tendons: Connect muscles to bone.
Ligaments: Connect bone to bone, stabilizing joints.

Fracture Classification: Open vs. Closed

Closed Fracture: Bone is broken but skin is intact. No direct communication between fracture and environment.

Open (Compound) Fracture: Bone is broken AND skin is broken, allowing direct contamination. Risk of infection and greater blood loss. More serious than closed fractures.

Fracture Types by Pattern

Type	Description	Typical Mechanism
Transverse	Fracture line perpendicular to bone shaft	Direct blow or bending force
Oblique	Fracture line at an angle (45°) to bone shaft	Twisting or combined bending/axial load
Spiral	Fracture line wraps around bone shaft	Twisting force (common in skiing injuries)
Comminuted	Bone broken into 3+ pieces	High-energy trauma (e.g., car crash, fall from height)
Greenstick	Incomplete break; bone bends but doesn't completely fracture (common in children)	Bending force in flexible pediatric bone

Dislocation

A dislocation (luxation) is displacement of a bone from its normal position at a joint. Often accompanied by tearing of ligaments and supporting structures. Common sites: shoulder, patella (kneecap), elbow, fingers. Note: a true knee (tibiofemoral) dislocation is a rare, limb-threatening emergency — do not confuse it with a kneecap (patella) dislocation.

Sprain vs. Strain

Sprain: Tear of ligament (bone-to-bone) from excessive joint motion. Usually swelling, bruising, pain with movement.
Strain: Tear of muscle or tendon. May be acute or chronic. Pain and weakness.

Mechanism of Injury Patterns

Understanding the mechanism helps predict which structures are injured:

Fall on outstretched hand (FOOSH): Often causes wrist fractures (Colles' fracture) or shoulder dislocation
Axial load (impact from above): Vertebral compression fractures or femur fractures
Twisting: Ankle sprains, spiral fractures of tibia
Hyperextension: Knee ligament injuries, elbow dislocations

Assessment of Musculoskeletal Injuries

Secondary Survey Tool: DCAP-BTLS

During the secondary survey (after life threats are addressed), assess the injury site for:

Deformity: Is the limb angulated or shortened compared to the opposite side?
Contusions: Bruising indicating trauma
Abrasions: Scraping suggesting mechanism
Punctures/Penetrations: Holes in the skin; if over a fracture site = open fracture
Burns: Check for thermal injury
Tenderness: Palpate gently; point tenderness over bone suggests fracture
Lacerations: Cuts in the skin; if over a fracture site = open fracture
Swelling: Edema from bleeding into tissues

Neurovascular Assessment: The 6 Ps

Critical: Perform neurovascular checks BEFORE and AFTER splinting. If neurovascular status worsens after splinting, loosen the splint immediately.

The 6 Ps of Neurovascular Assessment:

P	Assessment	Concerning Finding
Pain	Ask about pain severity and character. Severe pain disproportionate to injury suggests compartment syndrome.	Severe pain with passive stretch; pain out of proportion
Pallor	Check skin color distal to injury. Compare to opposite limb.	Pale, white, or cyanotic (blue) skin distal to injury
Pulse	Palpate distal pulse (e.g., dorsalis pedis for ankle, radial for wrist).	Absent or very weak pulse distally
Paresthesia	Ask about tingling or "pins and needles" sensation.	Numbness, tingling, or burning distal to injury
Paralysis	Test motor function distal to injury (move fingers/toes on command).	Weakness or inability to move distal structures
Pressure	Palpate the limb. Look for tense, swollen compartments.	Tight, swollen compartments; tenseness with passive stretch pain

CSM Assessment

CSM = Circulation, Sensation, Motion — a simpler version of the 6 Ps:

C - Circulation: Distal pulse, skin color/temperature, capillary refill
S - Sensation: Can patient feel touch/pain distal to injury?
M - Motion: Can patient move fingers/toes on command?

Ottawa Ankle and Knee Rules

Ottawa Ankle Rules: Imaging (X-ray) is recommended if there is bony tenderness over ANY of the following:

Posterior edge or tip of the lateral malleolus (outer ankle bone) — the distal 6 cm
Posterior edge or tip of the medial malleolus (inner ankle bone) — the distal 6 cm
Navicular bone (midfoot)
Base of the 5th metatarsal (bony bump on the outer edge of the midfoot)

OR inability to bear weight (take 4 steps) both immediately after injury and at the time of assessment. These are OR criteria — any ONE positive finding suggests the need for imaging/evacuation.

Ottawa Knee Rules: Imaging is recommended if ANY of the following is present:

Age 55 or older
Isolated tenderness of the patella (no other bony tenderness)
Tenderness at the head of the fibula
Inability to flex the knee to 90°
Inability to bear weight (take 4 steps) both immediately after injury and at the time of assessment

In wilderness settings, use these rules to guide evacuation priority.

Splinting Principles & Techniques

General Splinting Principles

Golden Rules of Splinting:

Immobilize joints ABOVE and BELOW the fracture site
Pad bony prominences to prevent pressure ulcers
Reassess neurovascular status (6 Ps or CSM) after splinting
Splint in position of comfort; if circulation below the injury is absent, the evacuation becomes EMERGENT
Apply ice/cold if available to reduce swelling
Elevate if possible to reduce swelling

Common Splinting Techniques

SAM Splint (Soft Aluminum Malleable): Versatile, compact, reusable. Molds to any shape. Excellent for forearm, wrist, ankle, knee. Pad with extra material and secure with elastic bandages.

Improvised Splints: In wilderness, use materials at hand:

Sticks/branches padded with clothing
Rolled-up sleeping bag or pad alongside the limb
Buddy taping (taping injured finger to adjacent healthy finger)
Sling and swathe for upper extremity

Suspected Femur (Thighbone) Fracture: Apply a well-padded rigid splint or an anatomic splint (padding between the legs, then securing the injured leg to the uninjured leg). A femur fracture can bleed 1-1.5 liters internally — treat for shock (supine flat, prevent heat loss) and evacuate urgently. For reference: EMS providers may apply a commercial traction splint (e.g., Kendrick, Thomas) for mid-shaft femur fractures — this is an EMS device, not a WFA skill.

Angulated Limbs & Reduction

Reduction is NOT a WFA skill. Reduction (realigning a fractured or dislocated bone) is performed by medical professionals. 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 regularly
If there is no pulse or sensation below the injury, the evacuation becomes EMERGENT

Dislocations

Anterior Shoulder Dislocation (Most Common)

The humeral head dislocates anteriorly out of the glenoid cavity. Classic presentation:

Arm held in slight abduction and external rotation ("arm held away from body")
Arm cannot be internally rotated
Severe pain
Palpable bulge anteriorly
Loss of normal rounded shoulder contour

Field Management: Immobilize in position of comfort with sling and swathe. Check pulse, sensation, and motor function (CSM) before and after applying the sling, and recheck regularly during evacuation. Do not attempt reduction — that is performed by medical professionals. Evacuate.

Patella (Kneecap) Dislocation

Usually dislocates laterally (outward). Presents with:

Severe pain and quadriceps muscle spasm
Visible lateral displacement of patella
Inability to straighten knee

Field Management: Splint the knee in the position of comfort with generous padding (a rolled sleeping bag or pad works well). Check CSM before and after splinting. Do not attempt to straighten the leg or push the kneecap back into place. Some patella dislocations reduce spontaneously as the patient moves — if this happens, still splint and evacuate for medical evaluation.

Finger/Toe Dislocations

Usually obvious deformity. Splint in the position found — buddy tape the injured digit to its healthy neighbor, or use a padded splint, in the position of comfort. Check CSM before and after. Do not attempt reduction; evacuate for evaluation and reduction by medical professionals.

Hip Dislocation

Rare but serious. Most commonly posterior dislocations. Presents with:

Severe pain in hip/groin
Leg internally rotated and adducted ("fetal position")
Unable to move leg
Potential sciatic nerve injury (foot drop, sensory loss)

Field Management: Immobilize in the position found, padding generously with clothing or sleeping bags. This is a neurovascular emergency — the femoral head is at risk of avascular necrosis if hospital reduction is delayed. EMERGENT evacuation required.

Dislocation Management at the WFA Level

For ALL dislocations:

Splint or sling in the position of comfort
Check CSM before and after splinting, and recheck regularly during evacuation
Evacuate — reduction is performed by medical professionals
Absent pulse or sensation below the joint = EMERGENT evacuation

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

Open Fractures & Special Considerations

Open Fractures: Immediate Management

Open fractures are surgical emergencies due to high infection and complication risk.

Immediate Steps:

Splint 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 remove dirt. Gentle irrigation is protective against infection.
Cover with clean (preferably sterile) dressing. May need to dress around exposed bone.
Splint and elevate to reduce swelling
If bone was exposed at any point — even if it has slipped back beneath the skin — document it and report it at hospital handoff.
EMERGENT evacuation to hospital for surgical management (cleaning, internal fixation)

Amputated Parts

If a limb or digit is amputated:

Control bleeding on the amputated stump with direct pressure
Retrieve the amputated part if possible
Wrap it in clean cloth or gauze moistened with saline or clean water ONLY — never use antiseptics or bleach, which damage tissue and can make the part non-replantable
Seal the wrapped part in a plastic bag, then place the bag on ice or in cold water — NEVER place the part directly on ice
Label with time of amputation
Transport with patient to hospital — digits may remain viable up to about 12 hours warm or 24 hours cooled; larger parts tolerate much less. Cool the part and evacuate emergently.
EMERGENT evacuation

Compartment Syndrome

Definition: Increased pressure within a closed muscle compartment (group of muscles enclosed by fascia), compromising blood flow and causing tissue death if not relieved.

Classic Presentation:

Pain DISPROPORTIONATE to injury (hallmark finding)
Pain with passive stretch of muscles in the compartment (e.g., passive extension of fingers if forearm compartment involved)
Tight, swollen compartment on palpation
Paresthesia and weakness (late)

Common Sites: Anterior compartment of leg (tibia/fibula fracture), forearm, thigh.

Field Management:

Recognize the clinical suspicion based on disproportionate pain
Remove any tight dressings or splints (may worsen compartment pressure)
Elevate limb only to heart level (elevation beyond this reduces compartment perfusion)
EMERGENT evacuation to hospital for fasciotomy (surgical incision to relieve pressure)

Remember: Compartment syndrome is not obvious on X-ray or clinical exam initially. Suspicion is based on clinical findings (pain out of proportion, pain with passive stretch). Do not miss it — it requires emergency surgical decompression.

Clinical Scenarios

Scenario 1: Ankle Fracture with Intact Distal Pulses

A 26-year-old backpacker twisted her ankle stepping off a rock. She reports immediate severe pain and swelling. Exam shows obvious swelling and deformity (foot in inverted position). You assess: Dorsalis pedis pulse present and strong, foot is pink and warm, she can move her toes and feels touch. By Ottawa Ankle Rules, she has tenderness over the lateral malleolus.

Analysis: This is likely an ankle fracture with intact neurovascular status. Ottawa Ankle Rules indicate imaging (X-ray) is appropriate, but this is wilderness medicine — you may not have X-ray capability.

Field Management:

Treat as a fracture (assume positive until proven otherwise)
SAM splint the ankle, immobilizing the ankle joint. Pad bony prominences.
Recheck distal pulses, sensation, and motor function after splinting
Elevate and apply cold (snow/cold water) to reduce swelling
Pain control: acetaminophen or ibuprofen if available
Evacuation: URGENT (same day if possible) for imaging and evaluation
If neurovascular compromise develops (pulse disappears, foot becomes pale or cold), adjust splint immediately and prepare for emergency descent

Expected Outcome: With proper splinting and evacuation, good prognosis for recovery.

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, obvious deformity (shortened, angulated leg), and significant swelling. Distal exam shows: foot is pale and cool, dorsalis pedis pulse is absent, he cannot move toes (paralysis), severe pain. He's in shock (HR 124, RR 24, BP 96/62).

Analysis: This is a femur fracture with neurovascular compromise (absent pulse, paralysis, pale cool foot). This is an EMERGENCY. A femur fracture can bleed 1-1.5 liters internally — treat this patient as a serious shock risk in addition to the limb threat.

Immediate Actions:

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 leg). Do not attempt realignment or traction — that is higher-level care.
Treat for shock: position supine and flat, insulate from the ground, and prevent heat loss.
Document CSM (circulation, sensation, motion) serially — recheck and record every 15 minutes, noting times.
EMERGENT evacuation by helicopter if available. This patient requires hospital surgery urgently.
Monitor vitals and neurovascular status continuously.

Key Point: An absent distal pulse means the limb is at risk. At the WFA level, the response is splint in position, shock care (supine flat, prevent heat loss), serial CSM documentation, and the fastest possible evacuation — not field realignment.

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

Key Concepts to Remember:

Always assess neurovascular status BEFORE and AFTER splinting
Splint immobilizing joints above and below the fracture
Open fractures: irrigate gently, cover, splint in position, EMERGENT evacuation
Compartment syndrome: suspect if pain is out of proportion — requires emergency fasciotomy
Neurovascular compromise (absent pulse, sensation, or motor function below the injury) = EMERGENT evacuation; splint in position — realignment and reduction are performed by medical professionals
Ottawa Rules guide imaging decisions (ankle, knee) — any ONE positive criterion counts
Suspected femur fracture: well-padded rigid or anatomic splint, shock care, urgent evacuation (traction splints are an EMS device)

Glossary of Terms

Angulation

Abnormal bending or deviation of a bone from its normal axis; indicates fracture or dislocation.

Avascular Necrosis

Death of bone tissue due to loss of blood supply; can occur with hip dislocations if not reduced promptly.

Closed Fracture

A fracture where the bone is broken but the skin is intact; no communication with external environment.

Compartment Syndrome

Increased pressure within a closed muscle compartment leading to tissue hypoperfusion and necrosis; requires emergency surgical decompression.

CSM

Circulation, Sensation, Motion — simplified neurovascular assessment to evaluate distal limb status.

Dislocation (Luxation)

Complete displacement of a bone from its normal position at a joint.

FOOSH

Fall On Outstretched Hand — common mechanism causing wrist and shoulder injuries.

Fracture

A break in the continuity of bone due to trauma or pathology.

Open Fracture

A fracture where the bone is broken AND there is a break in the overlying skin; high risk for infection and blood loss.

Ottawa Ankle/Knee Rules

Evidence-based clinical decision tools to determine which patients require X-ray imaging for ankle and knee injuries.

Pulse

The regular beating of the arteries; assessed distal to injury to ensure adequate blood flow. Absent distal pulse = neurovascular emergency.

Reduction

Restoration of a dislocated bone or joint to its normal position; performed by medical professionals — not a WFA skill.

Splint

A device or technique used to immobilize a fracture or dislocation, preventing motion and further injury.

Sprain

Tear of a ligament (bone-to-bone connection) from excessive joint motion.

Strain

Tear of a muscle or tendon from overuse or trauma; less serious than sprain typically.

Traction Splint

An EMS device that applies gentle longitudinal traction to stabilize mid-shaft femur fractures, reducing pain and internal bleeding; not applied at the WFA level.

The 6 Ps

Pain, Pallor, Pulse, Paresthesia, Paralysis, Pressure — a systematic approach to assessing neurovascular status distal to injury.