Lecture 18: Anterior and Latera compartments of the leg

Question 1

boundaries of the anterior compartment

Answer 1

Anterior
Deep (crural) fascia and skin

Posterior
Interosseus membrane

Medial
Lateral surface of tibia

Lateral
Anterior intermuscular septum

Question 2

which compartment of the leg is the most susceptible to getting compartment syndrome?

Answer 2

anterior compartment

Closed space with little room for
expansion

Question 3

anterior compartment: muscles,
nerves, arteries and veins, and action

Answer 3

4 muscles:
Tibialis anterior
Extensor digitorum longus (EDL)
Extensor hallucis longus (EHL)
Peroneus tertius

1 artery (and vein):
Anterior tibial artery and vein

1 Nerve:
Deep peroneal nerve

action:
dorsiflexion
It is the dorsiflexor compartment

Question 4

interosseous membrane structure

Answer 4

• Interosseus membrane connects
  the tibia and fibular the entire
  lengths of the bones
• Small hole at superior part of
  membrane for a vessel

Question 5

bones of leg

Answer 5

Question 6

bones of ankle and foot

Answer 6

Question 7

Answer 7

1-calcaneous
2-talus
3-cuboid bone
4-navicular bone
5-lateral cuneiform bone
6-intermediate cuneiform bone
7-medial cuneiform bone

Question 8

what bones make up the ankle joint proper?

Answer 8

tibia( and ~fibula) and talus

at this joint: dorsi and plantafexion

Question 9

Answer 9

calcaneus

Question 10

at what joint does eversion/ inversion occur?

Answer 10

subtalar joint between talus and calcaneus

Question 11

tibialis anterior: O, I, Action, Nerve

Answer 11

Origin:
Upper half lateral tibia
Interosseous membrane

Insertion:
Medial cuneiform and base 1st
metatarsal

Action:
Dorsiflexion ankle
Inverts ankle at subtalar joint

Nerve:
Deep Peroneal

Question 12

Extensor Halucis longus:O, I, Action, Nerve

Answer 12

Origin:
Middle anterior fibular
Interosseous membrane
Insertion:
Base of distal phalanx of great toe
Action:
Extends great toe
Dorsiflexion ankle
Nerve:
Deep Peroneal

Question 13

Extensor digitorum longus: O, I, Action, Nerve

Answer 13

Origin:
Lateral condyle tibia
Superior 2/3 medial fibular
Interosseous membrane

Insertion:
Middle and distal phalanges of lateral 4 toes

Action:
Dorsiflexion ankle
Extends toes

Nerve:
Deep Peronea

Question 14

Peroneus tertius: O, I, Action, Nerve

Answer 14

Origin:
Inferior 1/3 anterior/medial surface of fibula
Interosseous membrane

Insertion:
Base (dorsal side) of 5th metatarsal

Action:
Dorsiflexion ankle
Everts foot

Nerve:
Deep Peroneal

Question 15

what nerve innervates muscles of the anterior compartment?

Answer 15

Deep Peroneal

Question 16

Lateral compartment: muscles,
nerves, arteries and veins, and action

Answer 16

2 muscles: peroneus longus, peroneus brevis

One nerve: superficial peroneal

No artery

Question 17

Peroneus longus: O, I, Action, Nerve

Answer 17

Origin:
Sup 2/3 lateral fibula

Insertion:
plantar surface of Medial cuneiform &
base of 1st metatarsal

Action:
Plantarflexion ankle
Everts foot

Nerve:
Superficial Peroneal

Question 18

Peroneus brevis: O, I, Action, Nerve

Answer 18

Origin:
Inf 2/3 anterior fibula

Insertion:
Base 5th metatarsal

Action:
Plantaflexion ankle
Everts foot

Nerve:
Superficial Peroneal

Question 19

superior extensor retinaculum: tendons, position

Answer 19

• The Superior Extensor Retinaculum is a band of deep fascia. It passes from the tibia to the fibula, above the malleoli.
• It binds down the tendons of Extensor Digitorum Longus, Extensor Hallucis Longus, Peroneus Tertius and Tibialis Anterior, preventing them from bowstringing during dorsiflexion.

Question 20

Inferior Extensor Retinaculum: attachments, tendons

Answer 20

The Inferior Extensor Retinaculum is a Y-shaped band of deep fascia. The lateral attachment is to the upper surface of the calcaneus; the medial side attaches to the medial malleolus (proximally) and the plantar
aponeurosis (distally).

Question 21

what retinacula holds down the peroneus longus and brevis?

Answer 21

The fibers of the superior and inferior
peroneal retinaculum contain the tendons of the Peronus longus and brevis laterally

Question 22

what nerve is at risk of being damaged with a proximal fibula fracture?

Answer 22

the common peroneal nerve
very superficial

Question 23

The course of the sciatic nerve?

Answer 23

• The Sciatic Nerve (L4-S3) divides in the posterior
  thigh into its two terminal branches, the Tibial
  nerve and the Common Peroneal nerve.
• 2cm in width
• Exits from pelvis via greater sciatic foramen
• Lies on posterior aspect of adductor magnus
• Divides into 2 branches : the Common Peroneal
  Nerve and the the Tibial nerve

sciatic nerve highlighted

Question 24

what compartments of the leg are supplied by what nerves?

Answer 24

posterior: tibial nerve

anterior: deep peroneal
Lateral: superficial peroneal
(common peroneal nerve branches)

Question 25

deep peroneal nerve pathway

Answer 25

The Deep Peroneal nerve is the nerve to the anterior compartment, where it travels with the Anterior Tibial artery. It crosses the ankle joint, supplies the muscles of the dorsum of the foot, and then becomes cutaneous to the first webspace.

Question 26

superficial peroneal nerve pathway:

Answer 26

* The Superficial Peroneal nerve enters the lateral compartment and supplies both the muscles in this compartment. * This nerve then continues as a cutaneous nerve, supplying the skin of the anterior leg and most of the dorsum of the foot.

Question 27

what spinal segments do the cutaneous nerves of the leg arise from?

Answer 27

The cutaneous nerves of the leg arise from segments L4-S2 of the spinal cord, and are terminal branches of the Lumbosacral Plexus.

Question 28

Answer 28

Question 29

arterial branches to the knee

Answer 29

The Femoral artery becomes the Popliteal artery as it enters the superior aspect of the Popliteal Fossa. Branches to the knee from descending branch of lateral circumflex femoral artery, femoral artery, anterior tibial artery

Question 30

describe the pathway of the anterior tibial artery

Answer 30

After the Popliteal artery exits the fossa inferiorly, it trifurcates (divides into three) – the Anterior Tibial artery, the Posterior Tibial artery and the Peroneal artery. The Anterior Tibial artery passes anteriorly through a gap in the Interosseus membrane to become the artery to the anterior compartment. At the ankle joint it crosses midway between the malleoli, between the tendons of EDL and EHL, to become the Dorsalis Pedis artery (artery to the dorsum of the foot). The Dorsalis Pedis gives off a branch called the Deep Plantar artery, which passes between the 1st and 2nd metatarsals to form part of the Deep Plantar Arch

Question 31

describe the pathway of the posterior tibial artery

Answer 31

* After giving off the Anterior Tibial artery, the Popliteal artery continues as the Posterior Tibial artery. * This bifurcates to give off the Peroneal (fibular) artery. * The Posterior Tibial artery travels through the deep posterior compartment, accompanied * by the Tibial nerve and veins, eventually running posterior to the medial malleolus. * After this point the artery divides into its two terminal branches, the Medial and Lateral Plantar arteries, to the sole of the foot.

Question 32

another term for the peroneal artery

Answer 32

fibular artery

Question 33

peroneal/fibular artery pathway:

Answer 33

The Peroneal artery runs laterally towards the fibula (still within the deep posterior compartment) giving perforating branches to the muscles of the posterior and lateral compartments and also a nutrient artery to the fibula.

Question 34

what artery supplies the posterior compartment of the leg?

Answer 34

posterior tibial a( branches off into peroneal/fibular artery)

Question 35

what artery supplies the anterior compartment of the leg?

Answer 35

anterior tibial a

Question 35

what artery supplies the lateral compartment of the leg?

Answer 35

anterior tibial and fibular arteries

Question 36

dorsum of the foot?

Answer 36

The dorsum of foot is the area facing upwards while standing.

Question 37

dorsum of the foot : contents

Answer 37

* 2 Muscles Extensor digitorum brevis (EDB) Extensor hallucis brevis (EHB) * 3 Nerves Deep peroneal Superficial peroneal Saphenous (medial from femoral nerve) * 1 artery with lots of branches

Question 38

extensor digitorum brevis: O, I, Nerve, Action

Answer 38

O: calcaneus and inferior extensor retinaculum I: middle and distal phalanges of lateral 4 toes( with EDL) Nerve: deep peroneal Action: extends toes at MTPJs and IPJs

Question 39

extensor hallucis brevis: O, I, Nerve, Action

Answer 39

O: calcaneus and inferior extensor retinaculum I: base of proximal phalanx of great toe Nerve: deep peroneal Action: extends great toe at MTPJ

Question 40

what is the other name for peroneal( artery, nerve, peroneus muscles etc)

Answer 40

fibular artery and nerve and fibularis muscles

Question 41

Compartment syndrome: what is it, signs

Answer 41

Compartment syndrome is a limb-threatening and potentially life-threatening condition. It most often occurs in the leg or forearm following trauma. It occurs when the pressure inside a compartment is raised to the point that there is no longer an arterial supply to the compartment, putting muscles and eventually nerves at risk of ischemia and necrosis. The clinical findings are pain, pallor, pulselessness, paraesthesia, paralysis **Sign!:** Pain that does not subside after immobilising the limb( in case of broken bones) and analgesia

Question 42

foot drop: what is it , what causes it

Answer 42

Weakness of anterior compartment muscles (dorsiflexion) Occurs when common peroneal, or deep peroneal nerves are injured. The passive position of the foot is plantar flexed and inverted. Results in high stepping or slapping gait as dorsiflexors of the ankle are not functioning. Causes? damage to: Deep Peroneal Nerve Sciatic Nerve L4/5