Limbs Flashcards
Describe when vasculature of the upper limb is likely to be damaged
Subclavian - clavicle fractures
Anterior humeral circumflex - proximal humerus fracture
Brachial - posterior elbow dislocation
Profunda brachii - humeral shaft fracture
Radial - PCI
Describe any important anatomical features and therefore common injury points of the musculocutaneous nerve
Travels beneath biceps therefore is well protected
Stab wounds
Describe any important anatomical features and therefore common injury points of the Axillary nerve
Through the quadrangular space with posterior circumflex humeral artery then wraps around the surgical neck
- surgical neck of humerus fractures
- anterior shoulder dislocation
Describe any important anatomical features and therefore common injury points of the radial nerve
Enters the posterior compartment and winds around the spiral groove before passing infront of the lateral epicondyle
- humeral shaft fracture
- proximal radius fracture
- stabs wounds to anticubital fossa or wrist
- Saturday night palsy
Describe any important anatomical features and therefore common injury points of the median nerve
Travels lateral to the brachial artery then crosses over to sit medially to it in the antecubital fossa
- supracondylar humerus fractures
- stab wounds
- carpal tunnel syndrome
Describe any important anatomical features and therefore common injury points of the ulnar nerve
Behind the medial epicondyl Through guyon’s canal - supracondylar humerus fractures - medial epicondyl fracture - elbow dislocation - stab wounds
What happens in a “pulled elbow”
There is subluxation of the radial head out of the annular ligament due to a direct pull on an extended pronated arm
How is a pulled elbow reduced
Flex and fully supinate
OR
Pronate and fully extend
What is a green stick fracture
One cortical surface of the bone breaks whilst the other bends
What is a torus/buckle fracture
The cortex of the bone buckles
Describe the MOI and signs on imaging of a supracondylar humeral fracture
FOOSH
Joint effusion causing fat pad sign
What are the complications of a supracondylar fracture
Brachial artery, median nerve, radial nerve damage
Malunion
Compartment syndrome
What are the elbow ossification centres (CRITOL)
Capitulum - 1 Radial head - 3 Internal (medial) epicondyle - 5 Trochlea - 7 Olecranon - 9 Lateral epicondyle - 11
What is the salter Harris classification
Classification of fractures across growth plates in children
1 - straight through (epiphysis separates from metaphysis)
2 - above (piece of metaphysis separates with the epiphysis)
3 - lower than
4 - through everything (articular surface, epiphysis, plate, metaphysis)
5 - rammed (epiphyseal plate is crushed)
When using interosseous devices where is the fluid/drugs going
Into medullary cavity venous sinusoids or long bones
What are the locations for interosseous device insertion
Proximal tibia (below and medial to tuberosity) Distal tibia (above medial malleolus) Distal femur Proximal humerus (greater tubercle) Sternum
What are the contraindications for interosseous device use
Infection or fracture proximal to insertion sight
Ipsilateral vascular injury
Unsuccessful first attempt
Osteoporosis
What are the complications of interosseous devices
Osteomyelitis
Iatrogenic fracture
Fat or bone microemboli
Fluid extravasation = compartment syndrome
Femoral nerve - what are the important anatomical pathway relations and common injury sites
Under psoas major appearing laterally Under inguinal ligament Femoral triangle Adductor canal - anterior hip dislocation and IVDU
Obturator nerve - what are the important anatomical pathway relations and common injury sites
Under psoas major and appears medially
Sits along pelvic wall
Through obturator canal
- anterior hip dislocations, pelvic surgery
Sciatic nerve - what are the important anatomical pathway relations and common injury sites
Greater sciatic foramen below piriformis
Descends inferolaterally deep to biceps femoris
- posterior hip dislocations (especially tibial part!), IM injections, disc prolapse
Tibial nerve - what are the important anatomical pathway relations and common injury sites
Arises in popliteal fossa travelling in posterior compartment
Posterior to medial malleolus
- very rare, tarsal tunnel syndrome
Common fibular nerve - what are the important anatomical pathway relations and common injury sites
Wraps around the neck of fibula and gives off superficial and deep
- fibular neck fractures, tight casts
- superficial fibular can get stretched in ankle sprains
Which way does the femur most commonly dislocate an how does this present
Posteriorly
Shortened and interiorly rotated
What are the complications of hip dislocations
Posterior - sciatic nerve damage, AVN
Anterior - femoral and obturator nerve, artery and vein damage
What is the appearance of a posterior hip dislocation on x-ray
Loss of Shentons line
Femoral head appears smaller
Loss of lesser trochanter
Head superimposes roof of acetabulum
How does a NOF fracture present and what is the major complication
Shortened and externally rotated lower limb (unopposed iliopsoas)
Groin, medial thigh and knee pain
Compication: AVN due to medial circumflex damage
Describe the MOI and structures than can be damaged in a posterior knee dislocation
Posteriorly directed forces against proximal tibia (dashboard injuries)
Popliteal artery!!
Common fibular nerve
Cruciates and collaterals
What investigations need doing following a knee dislocation
Vascular assessment feeling for dorsalis pedis and posterior tibial
ABI and CTA
Assess common fibular nerve
MOI for patellar dislocation
Fixed foot and flexed knee with the femur rotating internally leading to lateral dislocation
What is the patella apprehension test and what is it used for
Diagnose patella dislocations
With the leg extended press the medial side of the patella pushing it laterally and observe the patients face
What is a LisFranc injury
Disruption of the medial cuneiform and 2nd metatarsal
This can range from a sprain to a fracture-dislocation
How do LisFranc injuries occur and what is the resulting deformity
Axial load on a hyperplantarflexed forefoot (RTC or fall from height)
Metatarsal moves dorsally on the tarsal
How do LisFranc injuries present
Tenderness along LisFranc joint
Medial plantar bruising
Diminished dorsalis pedis
Imaging: widened space between 1/2 metatarsal with dorsal displacement of proximal base of 2nd metatarsal
When do you get calcaneous fractures
Axial loading eg fall from height
What are the palpable leg/foot pulses
Posterior tibial- behind medial malleolus
Dorsalis pedis - lateral to extensor hallucis longus
What are the prehospital indications for amputation
Limb is trapping patient at an unsafe scene
Limb is trapping a patient who will die in the time taken to extract them
Mutilated non survivable limb
Dead patient whos limb is delaying access to potentially live patients
What is compartment syndrome
Rise in osseofacial compartment to the point at which perfusion decreases
Describe the pathophysiology of compartment syndrome
Fracture, crush injury, tight dressing or extravasation leads to bleeding and oedema = increased interstitial pressure = reduced venous outflow relative to arterial inflow = compartment pressure rises further. When compartment pressure > arterial pressure there is reduced arterial inflow = ischaemia to muscle and nerve
How does compartment syndrome present and what needs to be done
Pain out of proportion, parasthesia, pal, pulseless, perishingly cold, paralysis
Fasciotomy
Where does compartment syndrome commonly occur and why
Anterior leg and anterior/volar forearm
Interosseous membrane is tight, small compartment, vessels located here
What are the 2 factors that leads to tissue damage in reperfusion injury
ROS leading to oxidative cell damage
Inflammatory response with cytokine activation
What is the relation of stabbings to Langers lines
Perpendicular to = gape
Parallel to = slit like
List the methods available for haemorrhage control
Direct pressure Packing with sterile gauze and bandages Haemostatic agents Tourniquet REBOA TXA
What are the types of haemostatic agents
Mucoadhesive agents eg Celox - adheres to tissue physically blocking bleeding + promotes clot formation and RBC bonding by absorption and dehydration
Factor concentrators eg QuickClot - absorbs water content of blood leavin concentrated protein and cellular components
How should a torniquet be applied
Directly to the skin and as distal as possible
A second tourniquet may be applied proximally
Where is the clavicle most likely to fracture and what is the resulting position of the medial and lateral segments of clavicle
Within the middle 3rd as it’s the thinnest with no support from muscles or ligaments
Medial - pulled superiorly by SCM
Lateral - drops by weight of arm and pectoralis pull
What structures can be damaged in a clavicle fracture
Subclavian artery and vein
Brachial plexus
Apex of lung
What can be damaged in a proximal humerus fracture
Axillary nerve
Anterior humeral circumflex artery = AVN
What is a complication of humeral shaft fractures
Radial nerve and profunda brachii damage as they sit in radial groove of the humerus
Which way does the shoulder most commonly dislocate and why
Anteriorly - rotator cuff provides posterior support + anteriorly there is a weak point of the joint capsule
What are the forces involved in a anterior shoulder dislocation
Excessive extension and external rotation of the humerus
How does a anterior shoulder dislocation present (signs and imaging)
Step off deformity at acromion
Imaging shows the humeral head displaced medially, inferiorly and overlying the glenoid
What structures can be damaged in a shoulder dislocation
Axillary nerve
Rotator cuff
Biceps tendon
Which way is the humerus rotated in a posterior shoulder dislocation and what is seen on imaging
Internally rotated humerus giving the “lightbulb” sign on x-ray
Which way does the elbow most commonly dislocate
Posterolateral (the humerus is driven through the anterior joint capsule)
What structures can be damaged with an elbow dislocation
Ulnar nerve
Brachial artery and radial nerve can be damaged but this is rare
Ulnar collateral ligament
What structure can be damaged in a distal radial fracture
Median nerve
Compare a Colles and Smiths distal radial fracture
Colles - land on extended wrist. Dorsal angulation and displacement of the distal fragment
Smiths - land on flexed wrist. Volar angulation ad displacement of the distal fragment
