Anatomy: Popliteal Fossa and Posterior Leg

Question 1

Bones of leg, functions

Answer 1

Tibia bears the weight of the body. Fibula functions as an attachment for muscles primarily and also for stability of the ankle joint.

Question 2

Type of joints:
femur/tibia -
femur/patella -
ankle -

Answer 2

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

Question 3

a sesamoid bone embedded in the quadriceps tendon.

Answer 3

patella

Question 4

The ____ does not participate in the knee joint.

Answer 4

fibula

Question 5

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.

Answer 5

Small Saphenous Vein

Question 6

______ accompanies small saphenous vein

Answer 6

sural nerve

Question 7

union of branches from tibial and common fibular nerve

Answer 7

sural nerve

Question 8

Varicose veins

Answer 8

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.

Question 9

Popliteal fossa boundaries

Answer 9

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

Question 10

Contents of popliteal fossa (Deep to superficial)

Answer 10

1. Popliteal artery and vein (having traversed the adductor magnus muscle)
2. Common Fibular and Tibial nerves (divisions of sciatic nerve)
3. Fat and lymph nodes

Question 11

Popliteal artery damage

Answer 11

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)

Question 12

Popliteal artery is a continuation of _______

Answer 12

femoral artery (name change at adductor hiatus)

Question 13

___________ arteries provide collateral circulation around the knee

Answer 13

Medial/lateral inferior/superior genicular arteries

Question 14

Divisions of sciatic nerve

Answer 14

common fibular and tibial nerves

Question 15

Pathway of common fibular nerve

Answer 15

winds around head of fibula subQly (vulnerable) - under cover of fibularis longus, divides into superficial and deep fibular nerves

Question 16

The Femoral artery passes through the _________ and becomes the popliteal artery

Answer 16

adductor hiatus

Question 17

Baker’s Cyst

Answer 17

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.

Question 18

Baker’s Cyst causative agent

Answer 18

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.

Question 19

Popliteal aneurysm

Answer 19

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.

Question 20

Compartments of leg formed by ________

and what are they

Answer 20

anterior and posterior crural intermuscular septa (extensions of deep crural fascia) attaching to fibula
Anterior
Lateral
Posterior

Question 21

Posterior compartment further divided into _______ and _______ posterior compartments by _________

Answer 21

superficial and deep posterior compartments by transverse crural intermuscular septum

Question 22

hinge joint movements of ankle

Answer 22

plantarflexion (heel up), dorsiflexion (toes up)

Question 23

Muscles in the posterior compartment _________ the foot at the ankle

Answer 23

plantarflex

Question 24

Gastrocnemius O/I, innervation, functions

Answer 24

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

Question 25

Tibial nerve spinal cord derivation

Answer 25

S1, S2

Question 26

Tennis leg

Answer 26

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)

Question 27

Plantaris O/I, innervation, function (special feature)

Answer 27

Lateral condyle of femur --> calcaneus Analogous to palmaris longus (missing in 5-10% people) Plantarflex ankle, weakly flex knee joint Tibial nerve

Question 28

Soleus O/I, innervation, function

Answer 28

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

Question 29

tendinitis

Answer 29

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!

Question 30

Calcaneal Tendon Reflex (ankle jerk) tests _______

Answer 30

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.

Question 31

Popliteus O/I, innervation, function

Answer 31

lateral femoral condyle --> tibia Tibial nerve Flexes knee, unlocks knee by lateral rotation of femur on tibia

Question 32

Flexor digitorum longus I, innervation, function

Answer 32

base of distal phalanges of lateral four digits Tibial nerve Flexes distal phalanges of lateral 4 toes and plantarflexes ankle joint

Question 33

Tibialis posterior I, innervation, funciton

Answer 33

Tarsal bones and base of metatarsals, runs along interosseous membrane Tibial nerve Plantarflexes foot at ankle, major inverter of foot

Question 34

Flexor Hallucis Longus

Answer 34

Distal phalanx of great toe Tibial nerve Flexes distal phalanx of big toe and plantarflexes ankle joint

Question 35

Order of deep muscles (2)

Answer 35

DTH --> TDH

Question 36

The ___ nerve supplies all of the muscles in the posterior leg compartment

Answer 36

tibial

Question 37

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.

Answer 37

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.

Question 38

Injury to Tibial Nerve

Answer 38

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.

Question 39

branches of the Popliteal artery

Answer 39

Anterior tibial artery (pierces IO membrane and lies on anterior side) Posterior tibial artery (runs with tibial nerve)

Question 40

a branch of the posterior tibial that supplies the lateral compartment

Answer 40

Fibular artery

Question 41

Plantar Reflex

Answer 41

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)

Question 42

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

Answer 42

Flexor Retinaculum

Question 43

Order of contents passing through flexor retinaculum

Answer 43

``` TDANH Tibialis Posterior Flexor Digitorum Longus Posterior Tibial Artery Tibial Nerve Flexor Hallucis Longus ```