Flashcards in Locomotor: PBL 3 (Compartment Syndrome) Deck (43):
Describe the contents of the anterior compartment of the leg
Anterior tibial artery, common peroneal (fibular) nerve (gives off branches of superficial and deep peroneal nerves)
Describe the contents of the lateral compartment of the leg
Fibular artery, common peroneal nerve (superficial and deep peroneal nerves)
Describe the contents of the posterior compartment of the leg
Posterior tibial artery and tibial nerve
What are the branches of the common peroneal nerve?
Superficial and deep
What is the motor role of the deep peroneal nerve?
Supplies tibialis anterior, extensor digitorum longus and extensor hallucis longus involved in dorsiflexion and toe extension
What is the motor role of the superficial peroneal nerve?
Supplies fibularis longus and brevis (eversion of the foot)
What muscles does the tibial nerve supply?
Flexor digitorum longus, flexor hallucis longus and tibialis posterior (plantarflexion)
Describe the branches of the tibial nerve
Sural nerve given off (sensory to calf), in the foot branches into medial and lateral plantar branches:
What are the branches of the sciatic nerve?
Common peroneal and tibial
What is the sensory role of the superficial peroneal nerve?
Skin of anterior and lateral leg and dorsum of foot (mainly)
What is the sensory role of the deep peroneal nerve?
1st interweb space of the toes
What is the sensory role of the tibial nerve
Lateral plantar nerve - sensory to lateral 1 1/2 toes on plantar surface
Medial plantar nerve - sensory to medial 3 1/2 toes on plantar surface
Which muscles are involved in dorsiflexion (with toe extension)?
Tibialis anterior, extensor digitorum longus and extensor hallucis longus
Which muscles are involved in eversion?
Fibularis longus and brevis
Which muscles are involved in plantarflexion?
Superficial (attach to calcaneal tendon): gastrocnemius, soleus and plantaris
Deep (attach to foot bones): tibialis posterior, flexor digitorum longus and flexor hallucis longus
Describe the superficial veins of the lower limb
Great saphenous vein (starts medial anterior and drains into femoral vein)
Small saphenous vein (drains the posterior calf into the popliteal vein)
Describe the path of deep veins in the lower limb
Femoral vein --> lateral circumflex femoral and profunda (lateral bundle) AND continuation of femoral medially --> popliteal vein (as femoral enters fossa) --> posterior tibial, anterior tibial and peroneal/fibular veins
Describe the passage and divisions of arteries in the lower limb
Femoral artery --> medial circumflex and profunda.
Profunda femoris --> popliteal as it enters fossa
Popliteal artery --> common tibial --> anterior and posterior tibial arteries
Popliteal artery --> fibular artery also
What are the types of compartment syndrome?
Acute and chronic
Describe acute compartment syndrome
Occurs after traumatic injury which causes severely high pressure in a compartment leading to insufficient blood supply (ischaemia) and requires emergency surgery otherwise there will be resultant permanent nerve and muscle damage
Describe chronic compartment syndrome
Exercise-induced variety whereby pressure in the muscle increases to extremes during exercise causing a decrease in blood flow to the affected area --> ischaemia
Describe the symptoms of compartment syndrome
Extreme tightness in affected muscles, painful burning sensation if exercise is continued, foot drop
Explain the cause of compartment syndrome
Due to excessive pressure on or within the muscle compartments; if there is any swelling of tissue due to injury or exercise, this can cause the compression of venules and lymphatic vessels, preventing them from draining. Therefore, while arterial inflow is increased, outflow is diminished and this causes further pressure build-up within the compartment eventually leading to the compression of arteries in the area --> ischaemia
How may compartment syndrome be treated?
Conservative treatments (chronic) - rest, anti inflammatory drugs, manual decompression (rest affected limb in line of heart)
Surgical (acute) - fasciotomy whereby incisions are made in the affected compartment to allow decompression and relieve pressure on lymphatics and venules to allow increased blood flow through the muscle
What complications can arise with compartment syndrome?
Failure to relieve pressure can result in myonecrosis (muscle death) which can have long-lasting effects, especially if there is associated nerve damage, it could even lead to paralysis of the region
Why could compartment syndrome cause severe ankle weakness?
Due to loss of nerve supply to the muscles of the ankle
Why could compartment syndrome cause bilateral foot drop?
Damage to the deep peroneal nerve as it's involved in producing dorsiflexion, so without there is unopposed plantarflexion (OR relaxed response)
Why could compartment syndrome cause oedema?
Due to compression preventing the drainage of lymph and venous blood
Why could compartment syndrome cause loss of an Achilles reflex?
Because nervous stimulation to the Achille's tendon is impaired
Why could compartment syndrome cause elevated creatine kinase levels?
This molecule is formed in muscle death so is indicative of myonecrosis
Why could compartment syndrome cause myoglobin in the urine?
Damage to the muscle cells affects the calcium channel mechanisms, and therefore there are increased levels of free Ca2+ which affects several calcium-dependent enzymes and therefore compromises the integrity of the cell membrane and allows the release of myoglobin --> dark urine indicative of myoglobin
Why could compartment syndrome cause myonecrosis?
Ischaemia leads to muscle cell death as cells don't receive enough nutrients to respire
Why could compartment syndrome cause impaired sensation over the lateral aspect of the leg?
Due to damage to the superficial peroneal nerve
Why could compartment syndrome cause impaired dorsum sensation?
Compression of the superficial peroneal nerve
Why could compartment syndrome cause impaired sensation over the sole of the foot (plantar surface)
Due to the tibial nerve being compromised leading to the lateral and medial plantar nerves being diminished
What movements are specific for the talocrural (ankle) joints?
Dorsiflexion and plantarflexion
What movements are specific for the sub-talar joints?
Inversion and eversion
What is the role of myoglobin?
Acts as an oxygen store in muscles
What is the role of creatine kinase?
Combines creatine and an inorganic phosphate to form phosphocreatine (PCr) - a source of immediate energy
Where would you palpate for the dorsalis pedis pulse?
Lateral to the tendon of extensor hallucis longus on the dorsum of the foot
Where would you palpate for the posterior tibial pulse?
Half way between the medial malleolus and the Achilles tendon (calcaneal tendon)
What is the definition of a muscular compartment?
A group of muscles that have a common blood and nerve supply and function and are surrounded by a layer of deep fascia