Clinical Leg Flashcards
Common fibular nerve (L4-S2) pathway
- From sciatic nerve
- Passes around fibular neck
- Enters lateral compartment by passing through posterior intermuscular septum
- Bifurcates into terminal branches
Bifurcation of someone fibular nerve (L4-S2) terminal branches
- Deep fibular nerve
- Superficial fibular nerve
Deep fibular nerve pathway
- Terminal branch of common fibular nerve
- passes through anterior intermuscular septum
- Enters anterior compartment
Common fibular nerve (L4-S2) injury
- Susceptible to injury as it passes around fibula
- Prolonged compression
- Trauma
Prolonged compression of common fibular may result from
- Tight casts
- Excessive sitting/sleeping position
Injury to common fibular nerve (L4-S2) associated with
- Footdrop (increased tripping with gait)
- Weak dorsifelxion, to extension, and eversion
- Steppage gait
- Loss of sensation of distal anterolateral leg, dorsum of foot, 1st web space
Transmalleolar angle
- Line between center of medial/lateral malleoli
- In relation to line passing through knee joint axis
- Measures tibial torsion
Normal range of tibial torsion
- Childhood: -10-0 degrees
- Adults: 10-15 degrees external rotation
Obtaining tibial torsion angle
- Measure transmalleolar angle
- Can also use thigh foot angle
Measuring transmalleolar angle
- Patient prone
- Line through the longitudinal axis of the thigh
- Line perpendicular to the most prominent point of the malleloli
Measuring thigh foot angle
- Patient prone
- Line bisecting foot and line bisecting thigh
Kager angle
- Radiolucent triangle seen one lateral radiographs
- Kager fat pad (pre-calcaneal fat pad/pre-Achilles fat pad)
Kager triangle may be obliterated by pathologies
- Achilles pathology (tearing, inflammation)
- Calcaneal fracture
- FHL tendon pathology
- Accessory soleus muscle
Tarsal tunnel syndrome
- Compressive neuropathy of tibial nerve or it’s branches within the tarsal tunnel
- Porta pedis is also entrapment site
Symptoms of tarsal tunnel syndrome
- Altered sensation of medial/plantar foot and medial ankle (tibial nerve distribution)
- Atrophy of intrinsic foot muscles (prolonged compression)
- Tinel sign
Tinel sign
- Pain with tapping
- Percussing the nerve in tunnel
Symptoms of tarsal tunnel syndrome may be reproduced by
- Sustained dorsiflexion of ankle and MTPJs
- Sustained plantarflexion and inversion
Tarsal tunnel syndrome may be treated
- Surgically
- Conservatively
Boundaries of tarsal tunnel
- Medial: flexor retinaculum (laciniate ligament) and abductor hallucis
- Lateral: calcaneus, posterior talotibial and calcaneotibial ligaments
- Distal margin: porta pedis
Tarsal tunnel MEDIAL boundary
- Flexor retinaculum (laciniate ligament)
- Abductor hallucis
Tarsal tunnel LATERAL boundary
- Calcaneus
- Posterior tibial and calcaneotibial ligaments
- Tibia, talus, calcaneus (body and sustentaculum tail)
Tarsal tunnel DISTAL MARGIN
- Porta pedis
Ankle nerve blocks used for
- Procedures fo the foot
- Pain relief
- When more local is not possible, etc.
Ankle blocks avoid general anesthesia, avoiding
- Motor block of the leg muscles
- Sensory of the leg
Ankle blocks avoid releasing
- Anesthesia into vessels and puncturing nerves
- Anesthesia is released around the nerve
Most of the foot is innervated by nerves derived from
- Sciatic nerve (except 1)
- 5 nerves located at ankle (sensory innervation foot)
- (3 superficial, 2 deep)
3 superficial ankle nerves
- Saphenous
- Sural
- Superficial fibular
2 deep ankle nerves
- Posterior tibial
- Deep fibular
Posterior tibial nerve is blocked via
- Medial calcaneal branches
- Medial/lateral plantar nerves
Sural nerve blocks
- Lateral ankle
- Lateral heel
- Lateral foot
- Lateral 5th digit
Deep fibular nerve blocks
- 1st web space
- Superficial fibular
- Most of the dorsum of the foot and toes
Saphenous nerve blocks
- Medial foot
Subcutaneous nerve blocks at level of malleoli
- Saphenous
- Superficial fibular
- Sural
- Where they are blocked depends on procedure
Deep fibular nerve block landmarks
- EHL and TA tendons
- Medial malleolus
Perimalleolar (deep fibular nerve block)
- Lateral to EHL
- Level of the superior aspect of medial malleolus
Midtarsal (deep fibular nerve block)
- Lateral to EHL
- Medial to dorsalis pedis artery pulse
Superficial fibular nerve block
- Subcutaneous between lateral malleolus and EHL tendon (landmarks)
- Perimalleolar
- Anesthesia is administered in the area between the 2 landmarks
Perimalleolar (superficial fibular nerve block)
- Between superior aspect of lateral malleolus and EHL
Sural nerve block
- Perimalleolar
- Anesthesia is administered between the 2 landmarks
Perimalleolar (sural nerve block)
- Subcutaneous
- Between Achilles tendon and superior aspect of lateral malleolus
Posterior tibial nerve block
- Perimalleolar
- Posterior to posterior tibial pulse
- (Midway between superior aspect of medial malleolus and Achilles tendon)
Perimalleolar (posterior tibial nerve block)
- Deep to the deep fascia
- Posterior to medial malleolus
Saphenous nerve block
- Perimalleolar
- Saphenous vein is nearby and can be punctured easily
Perimalleolar (saphenous nerve block)
- Subcutaneous between TA tendon and medial malleolus
Posterior tibial nerve blocks
- Plantar foot
- Medial heel
- Toe tips
Deep fibular nerve block location
- Deeply located at ankle
- Deep to deep fascia
Types of deep fibular nerve blocks
- Perimalleolar
- Midtarsal
Deep nerve blocks at level of malleoli
- Deep fibular
- Posterior tibial
- Located deep to retinacula
- More superficial distally
- Where they are blocked depends on procedure
