Popliteal Fossa & Lower leg Flashcards
Popliteal Abscess and Tumor
Pain from abscess or tumor is typically severe in this area due to fascia being strong and limiting expansion. Abscesses spread superiorly and inferiorly due to the lack of expansion in this area.
Popliteal Pulse
Prone position with knee flexed to relax the fascia and hamstrings. Pulse is felt in inferior part of fossa wehre artery is related to tibia. Weak or loss of pulse is sign of femoral artery occulsion.
Popliteal Aneurysm
Aneurysm usually causes edema and pain in the fossa and can be distinguished from other masses by feeling pulsation and hearing arterial sounds. The artery is deep to the nerve and this can stretch the nerve or compress its blood supply and pain would be referred to the medial aspect of calf ankle or foot.
Popliteal Hemorrhage
Popliteal artery is close to the surface of the femur and joint capsule, if the distal femur is fractured or dislocated it can rupture the artery resulting in hemorrhage. Can result in arterioivenous fistula. Can lose leg if not taken care of.
If femoral artery has to be ligated blood can bypass the occulusion by the genicular anastomosios and reach pop artery distal to the ligation.
Injury to tibial nerve:
How it occurs and result
Uncommon bc it is located deep in the poplital fossa, but a deep laceration to the fossa can injure it. Posterior dislocation can also injure it. This will result in loss of function in the posterior leg muscles and and intrinsic muscles of the foot, lack of plantar flexion and flexion of toes. Also loss of sensation on sole of foot.
Containment and spread of compartmental infections in the leg
The boundaries of each leg compartment are strong and increasing their volume due to a suppuration infection increases intracompartmental pressure. Inflammation in the anterior and posterior compartments of the leg spread distally, but a purulent infection in lateral compartment can ascend proximally into popliteal fossa along the fibular nerve. Fasciotomy is necessary to relieve pressure and debride infection.
Shin Splints (Tibialis Anterior Strain)
Edema and pain in area of distal 2/3 of tibia from repetitive microtrauma of tibialis anterior causing small tears in the periosteum of the tibia or attachments to deep fascia of leg.
Mild form of compartment syndrome and occur during traumatic injury or athletic overexertion of muscles.
Fibularis muscle and evolution of the foot
Anthropods feet are inverted so they walk on outer borders, but our feet are everted (pronated) so our soles are on the ground. Pronation is due to medial migration of distal attachment of fibularis longus across the sole of the foot and fib tertius attached to 5th metatarsal base.
Foot drop:
what nerve
Common fibular nerve is superficial and most injured in the lower limb as it winds subcutaneously around fibular neck. Nerve can also be severed if fib neck fractures or severely stretched with knee joint dislocation/injury.
Results in flaccid paralysis of all muscles in anterior and lateral compartments of the leg, which lead to dorsiflexion and eversion of foot and ankle. Loss of dorsiflexion leads to footdrop and it is exacerbated by inversion of the foot making the limb too long so the toes don’t clear ground when in swing phase. {See what are the three ways to compensate.}
What are the three ways to compensate for foot drop, pelvic tilt, spastic paralysis or contraction of soleus?
Each of these results in the limb being too long. In foot drop the foot flops on the ground during heel strike
1. Waddling gait in which the person leans to the opposite side and hikes the hip.
- Swing out gait in which the long limb is swung out laterally (abducted) to allow toes to clear ground
- High stepping steppage gait where extra flexion is given at the hip and knee to raise foot high to keep toes from hitting
Deep fibular nerve Entrapment:
what compartment, common name for this, where does deep fib nerve bass
Excessive use of muscles supplied by deep fibular nerve (ant. compartment) can result in muscle injury and edema in this compartment. Entrapment causes compression of deep nerve and pain in ant compartment. Compression of deep fib nerve by tight fitting ski boots can occur where nerve passes deep to inferior extensor retinaculum and EHB. Pain occurs in dorsum of foot and radiates to web space btw 1st and 2nd toe, thong flip flops.
Ski boots are common cause of this nerve entrapment so it is called ski boot syndrome, but it can also occur in soccer players and runners from tight shoes.
Superficial fibular nerve entrapment
Chronic ankle sprains can produce recurrent stretching of superficial fib nerve causing pain along lateral side of leg and dorsum of foot an ankle. numbness and paresthesia present.
Fabella
Located in lateral head of gastrocnemius. Knee replacements can injure this bone.
Calcaneal tendinitis
9-18% of runnning injuries. Microscopic teares of collagen fibers in the tendon superior to its attachment on calcaneus result in tendinitis. Pain occurs during walking especially with rigid soled shoes. It is due to orepetitive activities such as running or increasing training suddenly, or poor footwear
Ruptured Calcaneal tendon:
What muscles are affected, how does it occur, how does walking occur
Usually occurs in poorly conditioned people with a history of calcaneal tendinitis. Hear a snap during plantarflexion with extended knee followed by immediate calf pain and dorsiflexion of plantarflexed foot. In a completely ruptured tendon you can feel the gap. Affects gastrocnemius, plantaris, soleus.
Most severe acute muscular problem of the leg, these people can’t plantarflex and passive dorsiflexion is excessive.
Walking is only possible if limb is laterallly rotated rolling over transversely placed foot during stance phase without pushing off. Bruising in malleolar region occurs and a lumb appears in calf due to shortening of triceps surae.
