Anatomy: Popliteal Fossa and Posterior Leg Flashcards
Bones of leg, functions
Tibia bears the weight of the body. Fibula functions as an attachment for muscles primarily and also for stability of the ankle joint.
Type of joints:
femur/tibia -
femur/patella -
ankle -
femur/tibia - hinge
femur/patella - sliding, gliding
ankle - hinge at medial malleolus of tibia, lateral malleolus of fibula and talus, other movements associated w/ ankle include tarsal bones
a sesamoid bone embedded in the quadriceps tendon.
patella
The ____ does not participate in the knee joint.
fibula
originates on the lateral side of the dorsal venous network of the foot; passes behind the lateral malleolus up the back of the leg usually to empty into the popliteal vein.
Small Saphenous Vein
______ accompanies small saphenous vein
sural nerve
union of branches from tibial and common fibular nerve
sural nerve
Varicose veins
bulging, tortuous superficial veins.
Causative factors include carrying extra weight, long hours of sitting or standing, smoking. Blood can pool in the veins, expanding them and making the one-way valves incompetent. Blood is forced to flow in the reverse direction, into the superficial veins (pressure gradient determines direction of blood flow) where there is less external support. There is also a hereditary component.
Popliteal fossa boundaries
superolaterally-biceps femoris
superomedially-semitendinosus and semimembranosus
inferiorly-both heads of the gastrocnemius
Floor is popliteal surface of the femur
Roof-skin and popliteal fascia
Contents of popliteal fossa (Deep to superficial)
- Popliteal artery and vein (having traversed the adductor magnus muscle)
- Common Fibular and Tibial nerves (divisions of sciatic nerve)
- Fat and lymph nodes
Popliteal artery damage
The Popliteal artery lies closest to the femur it is prone to entrapment injury in distal femoral fractures or dislocations (tibial nerve also at risk)
Popliteal artery is a continuation of _______
femoral artery (name change at adductor hiatus)
___________ arteries provide collateral circulation around the knee
Medial/lateral inferior/superior genicular arteries
Divisions of sciatic nerve
common fibular and tibial nerves
Pathway of common fibular nerve
winds around head of fibula subQly (vulnerable) - under cover of fibularis longus, divides into superficial and deep fibular nerves
The Femoral artery passes through the _________ and becomes the popliteal artery
adductor hiatus
Baker’s Cyst
A Baker cyst is swelling caused by fluid from the knee joint protruding to the back of the knee. When an excess of knee joint fluid is compressed by the body weight between the bones of the knee joint, it can become trapped and separate from the joint to form the fluid-filled sac of a Baker cyst.
Baker’s Cyst causative agent
Baker cysts are common and can be caused by virtually anything causing joint swelling (arthritis). The excess joint fluid (synovial fluid) bulges to the back of the knee to form the Baker cyst. The most common type of arthritis associated with Baker cysts is osteoarthritis, also called degenerative arthritis. Baker cysts can occur in children with juvenile arthritis of the knee. Baker cysts also can result from cartilage tears (such as a torn meniscus), rheumatoid arthritis, and other knee problems.
Popliteal aneurysm
rarely have symptoms. They are often discovered during routine examination. They are more likely to occur in the older population, and in men > women. These types of aneurysms do not rupture frequently but a blood clot can reduce blood flow to the foot, potentially cutting blood completely from the foot and necessitating amputation. Surgical repair is usually straightforward, successful and durable. Rupture is rare but requires immediate surgery to preserve the limb.
Compartments of leg formed by ________
and what are they
anterior and posterior crural intermuscular septa (extensions of deep crural fascia) attaching to fibula
Anterior
Lateral
Posterior
Posterior compartment further divided into _______ and _______ posterior compartments by _________
superficial and deep posterior compartments by transverse crural intermuscular septum
hinge joint movements of ankle
plantarflexion (heel up), dorsiflexion (toes up)
Muscles in the posterior compartment _________ the foot at the ankle
plantarflex
Gastrocnemius O/I, innervation, functions
Originates from lateral and medial condyles and inserts on the posterior surface of the calcaneus via the calcaneal tendon (Achilles).
Tibial nerve – S1, S2
Flexes knee joint and plantarflexes ankle
Tibial nerve spinal cord derivation
S1, S2
Tennis leg
strain of the medial head of the gastrocnemius occurring in individuals who are poorly conditioned and over the age of 40 - caused by sudden and abrupt changes of direction to bring about a tear in the calf muscle (overstretch muscle by full extension of knee and dorsiflexion of ankle at same time)
Plantaris O/I, innervation, function (special feature)
Lateral condyle of femur –> calcaneus
Analogous to palmaris longus (missing in 5-10% people)
Plantarflex ankle, weakly flex knee joint
Tibial nerve
Soleus O/I, innervation, function
Soleal line of tibia/fibula/interosseous membrane –> calcaneus
Tibial nerve
Plantarflexor (powerful but slow) of ankle, antigravity muscle that contracts alternately w/ extensor muscles to maintain balance
tendinitis
inflammation of a tendon; most common is Achilles tendon (debilitating). Occurs as a result of repetitive activities, especially in individuals who take up running after inactivity or suddenly increase training. Tendon rupture is often sustained by poorly conditioned people who have had a history of tendinitis. Most severe, acute muscular problem of the leg!
Calcaneal Tendon Reflex (ankle jerk) tests _______
S1,2 nerve roots
tendon reflex elicited while a person’s feet are dangling over side of examining table. The result of the reflex hammer striking the calcaneal tendon proximal to the calcaneus is plantarflexion of the ankle joint - If S1 is compressed or injured, as in a herniation of the L5-S1 disc, the reflex is absent.
Popliteus O/I, innervation, function
lateral femoral condyle –> tibia
Tibial nerve
Flexes knee, unlocks knee by lateral rotation of femur on tibia
Flexor digitorum longus I, innervation, function
base of distal phalanges of lateral four digits
Tibial nerve
Flexes distal phalanges of lateral 4 toes and plantarflexes ankle joint
Tibialis posterior I, innervation, funciton
Tarsal bones and base of metatarsals, runs along interosseous membrane
Tibial nerve
Plantarflexes foot at ankle, major inverter of foot
Flexor Hallucis Longus
Distal phalanx of great toe
Tibial nerve
Flexes distal phalanx of big toe and plantarflexes ankle joint
Order of deep muscles (2)
DTH –> TDH
The ___ nerve supplies all of the muscles in the posterior leg compartment
tibial
The Tibial nerve enters the _________ of the leg between the heads of the gastrocnemius. It passes through a hiatus in the ______ to gain access to the deep group of muscles deep to the __________. The tibial nerve divides into ____ and ______ ______ nerves as it enters the sole of the foot.
The Tibial nerve enters the posterior compartment of the leg between the heads of the gastrocnemius. It passes through a hiatus in the soleus to gain access to the deep group of muscles deep to the transverse crural intermuscular septum. The tibial nerve divides into medial and lateral plantar nerves as it enters the sole of the foot.
Injury to Tibial Nerve
uncommon because of its deep location in the popliteal fossa and posterior compartment. Ways that the nerve could be injured include deep lacerations and posterior dislocation of the knee joint. Paralysis of the muscles in the posterior compartment of the leg and intrinsic muscles of the sole of the foot will occur.
branches of the Popliteal artery
Anterior tibial artery (pierces IO membrane and lies on anterior side)
Posterior tibial artery (runs with tibial nerve)
a branch of the posterior tibial that supplies the lateral compartment
Fibular artery
Plantar Reflex
L4, L5, S1, S2
Lateral aspect of sole of foot strokes beginning at heel and crossing to base of great toe
Normal - flex great toe
Infants - fan toes and dorsiflex (Babinski sign) (abnormal older than 2)
extends from the medial malleolus to the calcaneus; the tendons of the deep flexor muscles (Tom, Dick and Harry) surrounded by their synovial sheaths, tibial nerve and posterior tibial artery pass deep to it behind the medial malleolus
Flexor Retinaculum
Order of contents passing through flexor retinaculum
TDANH Tibialis Posterior Flexor Digitorum Longus Posterior Tibial Artery Tibial Nerve Flexor Hallucis Longus
