Lecture 18: Anterior and Latera compartments of the leg Flashcards
boundaries of the anterior compartment
Anterior
Deep (crural) fascia and skin
Posterior
Interosseus membrane
Medial
Lateral surface of tibia
Lateral
Anterior intermuscular septum
which compartment of the leg is the most susceptible to getting compartment syndrome?
anterior compartment
Closed space with little room for
expansion
anterior compartment: muscles,
nerves, arteries and veins, and action
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
interosseous membrane structure
- Interosseus membrane connects
the tibia and fibular the entire
lengths of the bones - Small hole at superior part of
membrane for a vessel
bones of leg
bones of ankle and foot
1-calcaneous
2-talus
3-cuboid bone
4-navicular bone
5-lateral cuneiform bone
6-intermediate cuneiform bone
7-medial cuneiform bone
what bones make up the ankle joint proper?
tibia( and ~fibula) and talus
at this joint: dorsi and plantafexion
calcaneus
at what joint does eversion/ inversion occur?
subtalar joint between talus and calcaneus
tibialis anterior: O, I, Action, Nerve
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
Extensor Halucis longus:O, I, Action, Nerve
Origin:
Middle anterior fibular
Interosseous membrane
Insertion:
Base of distal phalanx of great toe
Action:
Extends great toe
Dorsiflexion ankle
Nerve:
Deep Peroneal
Extensor digitorum longus: O, I, Action, Nerve
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
Peroneus tertius: O, I, Action, Nerve
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
what nerve innervates muscles of the anterior compartment?
Deep Peroneal
Lateral compartment: muscles,
nerves, arteries and veins, and action
2 muscles: peroneus longus, peroneus brevis
One nerve: superficial peroneal
No artery
Peroneus longus: O, I, Action, Nerve
Origin:
Sup 2/3 lateral fibula
Insertion:
plantar surface of Medial cuneiform &
base of 1st metatarsal
Action:
Plantarflexion ankle
Everts foot
Nerve:
Superficial Peroneal
Peroneus brevis: O, I, Action, Nerve
Origin:
Inf 2/3 anterior fibula
Insertion:
Base 5th metatarsal
Action:
Plantaflexion ankle
Everts foot
Nerve:
Superficial Peroneal
superior extensor retinaculum: tendons, position
- 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.
Inferior Extensor Retinaculum: attachments, tendons
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).
what retinacula holds down the peroneus longus and brevis?
The fibers of the superior and inferior
peroneal retinaculum contain the tendons of the Peronus longus and brevis laterally
what nerve is at risk of being damaged with a proximal fibula fracture?
the common peroneal nerve
very superficial
The course of the sciatic nerve?
- 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
what compartments of the leg are supplied by what nerves?
posterior: tibial nerve
anterior: deep peroneal
Lateral: superficial peroneal
(common peroneal nerve branches)
deep peroneal nerve pathway
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.
superficial peroneal nerve pathway:
- 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.
what spinal segments do the cutaneous nerves of the leg arise from?
The cutaneous nerves of the leg
arise from segments L4-S2 of the
spinal cord, and are terminal
branches of the Lumbosacral Plexus.
arterial branches to the knee
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
describe the pathway of the anterior tibial artery
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
describe the pathway of the posterior tibial artery
- 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.
another term for the peroneal artery
fibular artery
peroneal/fibular artery pathway:
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.
what artery supplies the posterior compartment of the leg?
posterior tibial a( branches off into peroneal/fibular artery)
what artery supplies the anterior compartment of the leg?
anterior tibial a
what artery supplies the lateral compartment of the leg?
anterior tibial and fibular arteries
dorsum of the foot?
The dorsum of foot is the area facing upwards while standing.
dorsum of the foot : contents
- 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
extensor digitorum brevis: O, I, Nerve, Action
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
extensor hallucis brevis: O, I, Nerve, Action
O: calcaneus and inferior extensor retinaculum
I: base of proximal phalanx of great toe
Nerve: deep peroneal
Action: extends great toe at MTPJ
what is the other name for peroneal( artery, nerve, peroneus muscles etc)
fibular artery and nerve
and fibularis muscles
Compartment syndrome: what is it, signs
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
foot drop: what is it , what causes it
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
