Lecture 25:Posterior Leg compartment and popliteal fossa

Question 1

margins of popliteal fossa

Answer 1

The superior margins are
* Biceps Femoris (laterally) and
Semimembranosus and Semitendinosus
(medially)
* The inferior borders
* Medial and lateral heads of Gastrocnemius

Question 2

contens of popliteal fossa

Answer 2

• Popliteal artery and vein
• Tibial and Common Peroneal nerves

Question 3

structures in the popliteal fossa from deep to superficial( starting from the knee joint)

Answer 3

• From deep to superficial:
• Knee joint capsule
• Popliteus (not examinable)
• Popliteal artery (most medial)
• Popliteal vein
• Tibial nerve (from sciatic N)
• The artery is the deepest structure in the
  fossa (closest to the knee joint/ tibia and
  femur).

Question 4

what structure is likely to be affected 1st in knee dislocation?

Answer 4

popliteal a

Question 5

sural nerve

Answer 5

• Tibial nerve has superficial branch that exits the popliteal fossa and travels down posterior aspect of leg on gastrocnemeus and becomes = sural nerve (also gets a branch from common peroneal nerve)

sural nerve is derived from 2 branches of common peroneal and tibial nerve

Small saphenous vein runs with sural nerve

Question 6

great saphenous vein runs with…

Answer 6

saphenous nerve

Question 7

leg compartments

Answer 7

Three compartments
Anterior, lateral and posterior
Two sub-compartments in posterior leg:
Superficial
Deep

Question 8

Posterior Compartment
Muscles- Superficial

Answer 8

-gastrocnemius
-soleus
-plantaris

3 muscles, all innervated by tibial nerve

Question 9

Gastrocnemius: O, I, Action, Nerve

Answer 9

O: 2 heads: medial and lateral femoral condyles.
I: calcaneus via Achilles tendon/calcaneal tendon
Action: Plantarflex ankle, flexes knee
Essential for Jumping and walking
Nerve: Tibial

Question 10

Soleus: O, I, Action, Nerve

Answer 10

O: superior 1/3 post fibula also tibia
I: calcaneus via Achilles tendon/calcaneal tendon
Action: Plantarflex ankle. Walking
Nerve: Tibial

Question 11

Plantaris: O, I, Action, Nerve

Answer 11

O: Superior to lateral head gastrocnemius on femur
I: medial side of tendon achilles( seperate from achilles tendon)
Action: Plantarflex ankle
Nerve: Tibial

Good as a tendon for tendon grafts
(70)% have one

Question 12

Tibialis posterior: O, I, Action, Nerve

Answer 12

O: post tibia & fibula and interosseous membrane
I: Complex insertion into Navicula, medial cuneform + all bones of
mid and hind foot
Action: Plantarflexes ankle
Inverts foot
medial to axis of foot
Reinforces arches of foot
Nerve: tibial n

Question 13

Flexor digitorum longus: O, I, Action, Nerve

Answer 13

O: middle half of tibia
I: distal phalanges of lateral 4 toes
Action: Flexes toes, plantarflexes ankle,
Reinforces the arches of the foot
Nerve: tibial

Question 14

Flexor hallucis longus: O, I, Action, Nerve

Answer 14

O: inferior 2/3 of fibula and interosseous membrane
I:distal phalanx great toe
Action: Flexes great toe, plantarflexes ankle,
Reinforces the arches of the foot
Nerve: tibial

Question 15

Popliteus: O, I, Action, Nerve

Answer 15

O: posterior tibia
I: lateral condyle femur, lateral meniscus
Action: Medially rotates tibia
Nerve: tibial

Question 16

Triceps surae

Answer 16

gastrocnemius + soleus

Question 17

posterior compartment muscles- deep

Answer 17

-tibialis posterior
-flexor digitorum longus
-flexor hallucis longus
-popliteus

Question 18

Answer 18

Question 19

arteries of the posterior leg compartments

Answer 19

• The Posterior Tibial artery travels through the deep posterior compartment,
• Accompanied by the tibial nerve and veins
• Runs posterior to the medial malleolus.
• Posterior tibial Artery divides into its two terminal branches, the Medial and Lateral Plantar arteries to the sole of the foot.
• Travels with vein and sits between superficial and deep compartments

Question 20

bleeding from posterior tibial artery or politeal fossa: what do we also need to consider?

Answer 20

possible damage to the nerves
as arteries and nerves travel together in the posterior leg

Question 21

tarsal tunnel structures

Answer 21

T. Tibialis posterior
D Flexor digitorum longus
A Posterior tibial artery
V Vein
N. Tibial nerve

H. Flexor Hallucis longus
Tom Dick And Very Naughty Harry
Harry is naughty as tendon crossed
everyone in foot

Question 22

clinical presentation of achilles tendon rupture

Answer 22

The clinical presentation is the inability to push off (due to loss of plantarflexion)

Question 23

most commonly ruptured tendon

Answer 23

The Achilles tendon is the most commonly injured tendon in the body
* Injuries can occur at the musculotendinous junction, within the tendon itself, or where it attaches to the calcaneus

• “Like kicked in back if leg”
• Audible snap

Question 24

fabella

Answer 24

• The fabella (little bean) is a sesamoid bone located in the tendon of the lateral head of
  gastrocnemius in some people.
• It is often mistakenly interpreted as a fracture or loose body on a lateral xray

Question 25

venous thrombosis

Answer 25

* Formation of blood clot in leg veins. * Usually deep veins -> can travel to the lungs * Occurs when: * Slow blood flow * Increased coagulability * Damage to epithelium * Eg surgery, childbirth, trauma, OC pill, * 1/3 patients >40 yrs having major surgery or MI develop venous thrombosis

Question 26

femoral nerve: motor & cutaneous innervation

Answer 26

* Originate from L2, L3, L4 * Enter thigh under inguinal ligament splits into multiple muscular branches to **anterior thigh muscles** * Also innervates **skin on anterior aspect of thigh** via anterior cutaneous nerve of thigh * And **medial leg and foot via saphenous nerve **(runs with saphenous vein) * Supplies hip joint (in part)

Question 27

obturator nerve: motor & cutaneous innervation

Answer 27

* Originate from L2, L3, L4 * Enter thigh under through the obturator foramen * Supplies muscular branches to medial compartment thigh muscles * Also innervates small area of skin on medial thigh via cutaneous branch

Question 28

sciatic nerve(tibial nerve): motor & cutaneous innervation

Answer 28

* L4-S4 LS plexus * Sciatic nerve has 2 branches: * Tibial nerve * Common Peroneal nerve * The Tibial nerve supplies all the muscles of the posterior compartments (thigh and leg) before passing posterior to the medial malleolus. * In the sole of the foot Medial and Lateral Plantar nerves (Cutaneous to sole of foot and motor) * A branch of the Tibial nerve and Common Peroneal nerve form the Sural nerve. * The Sural nerve supplies the skin to the lateral and posterior sides of the inferior leg and heel.

Question 29

sciatic nerve( common peroneal nerve): motor & cutaneous innervation

Answer 29

* The Common Peroneal Nerve divides into: * Deep Peroneal nerve * Superficial Peroneal nerve * The Deep Peroneal nerve supplies anterior compartment, the muscles of the dorsum of the foot, and then becomes cutaneous to the first webspace * The Superficial Peroneal nerve enters the lateral compartment and supplies both the muscles. * This nerve then continues as a cutaneous nerve, supplying the skin of the anterior leg and most of the dorsum of the foot.