Q8-1a. Anterior Compartment Conference Flashcards
list the three borders of the tibia,
which are palpable
- anterior border (palpable)
- interosseous/lateral border
- medial border (palpable)
The anterior osteofascial compartment is found between what two borders of the tibia?
Anterior & Interosseous/Lateral Borders
You make an anterior incision parallel to the anterior border of the tibia.
Which dermatome did you cut?
L4/L5 dermatome
which nerve supply the L5 dermatome?
- lateral sural cutaneous nerve;
- & superficial fibular
which nerve supply the L4 dermatome?
saphenous nerve
with an anterior incision parallel to the anterior border of the tibia (about 1 cm lateral to anterior border) –>
by widening the incision MEDIALLY, which structures will be running through the superficial fascia?
- great saphenous vein
- saphenous nerve
with an anterior incision parallel to the anterior border of the tibia (about 1 cm lateral to anterior border) –>
by widening the incision LATERALLY, which structures will be running through the superficial fascia?
crural fascia overlying tibialis anterior
anterior osteofascial compartment:
contents
- muscles
- tibialis anterior
- EHL (extensor hallucis longus)
- EDL (extensor digitorum longus)
- Fibularis tertius
- anterior tibial artery & veins
- deep fibular nerve
motor innervation to muscles of anterior compartment
deep fibular nerve
main blood supply to muscles of anterior compartment?
anterior tibial artery
common function of muscles of anterior compartment
ankle dorsiflexion
when are the anterior compartment muscles ESPECIALLY active during the gait cycle?
- HEEL CONTACT/heel strike/initial contact
- decelerate the foot so it touches down on the ground in a controlled manner
- SWING PHASE
- keeps the foot from dragging on the ground
tibialis anterior: main origins
- Crural fascia
- Interosseous membrane
- Lateral tibial condyle
- Superior half of lateral surface of tibia
tibialis anterior: insertion
•Medial-plantar surfaces of both the medial cuneiform & MT 1 base
tibialis anterior: major actions
dorsiflexes the ankle;
inverts the foot
what retinacula does the Tibialis anterior and EHL muscles pass deep to?
- superior extensor and
- inferior extensor
(both arms)
Extensor hallucis longus:
main origins and insertion
- origins
- •Middle part of anterior/medial surface of fibula
•Interosseous membrane
- insertion
- Base of Distal phalanx of the hallux
Extensor hallucis longus:
major actions
- Dorsiflexes ankle
- Dorsiflexes hallucal MTPJ and IPJ
Extensor hallucis longus contributes to the formation of what structure that covers the dorsum of the hallux?
Extensor expansion
What is the role of the extensor expansion?
It anchors the EHL tendon in place
What is the name of the medial tendinous slip originating from the EHL (or less frequently, the TA or EHB) that inserts onto the dorsomedial aspect of the first MTPJ?
Extensor hallucis capsularis
What is thought to be the function of the extensor hallucis capsularis?
retract the MTPJ capsule to prevent its impingement during MTPJ dorsiflexion
The extensor hallucis capsularis is variable in size. If it’s larger, what may it be mistaken for?
EHL
extensor digitorum longus:
main origins and insertion
Origins
- Crural fascia
- Anterior crural intermuscular septum
- Interosseous membrane
- Lateral condyle of tibia
- Head & superior 3/4s of anterior/medial surface of fibula
Insertion: Middle & distal phalanges of Digits 2-5
extensor digitorum longus:
major actions
- Dorsiflexes ankle
- Dorsiflexes MTPJS and IPJS of digits 2-5
- Everts foot (secondary)
what retinacula does the EDL and fibularis tertius pass deep to?
stem of superior extensor and inferior extensor
At the level of the ankle, the extensor digitorum longus divides into how many tendons?
4 tendons
What are the functions of the extensor expansions formed in part by the EDL tendons?
- Allows the EDL to extend the proximal phalanx to which this tendon has no attachment
- Controls actions of the interossei & lumbrical muscles
what are the 2 parts of the extensor expansion?
extensor sling
extensor wing/hood
what is the path of the EDB and EDL digital insertions
(dorsal view)
- As EDB tendon crosses PP, joined by EDL tendon
- At PP head, combined tendons trifurcate into 1 middle & 1 lateral and medial slip
- Middle Slip attaches to IP
- Medial and Lateral Slips reunite & attach at DP
fibularis tertius:
main origins and insertion
MAIN ORIGIN(S)?
- Anterior crural interosseous septum
- Interosseous membrane
- Inferior 1/3 of anterior/medial surface of fibula
- Usually fused with EDL
INSERTION?
Usually on dorsum of base/prox. shaft of MT 5
Can also attach to proximal end of MT 4 shaft
fibularis tertius:
main actions
- Dorsiflexes ankle (accessory role)
- Everts foot (accessory role)
anterior tibial artery:
origin and termination
Origin:
One of two terminal branches off popliteal artery @ soleal line
Termination:
After crossing the ankle, it continues as the Dorsalis Pedis/Dorsal Artery of the Foot
what are the superior branches of the:
anterior tibial artery?
- popliteal artery
- posterior tibial recurrent artery
- anterior tibial recurrent artery
what are the 3 inferior branches of the:
anterior tibial artery?
- dorsalis pedis
- anterior lateral malleolar artery
- anterior medial malleolar artery
deep fibular/ peroneal nerve:
origin and termination
Origin:
- One of the terminal branches of the Common Fibular/Peroneal Nerve
Termination:
- Lateral & Medial Terminal Branches
course of deep fibular/ peroneal nerve in anterior compartment
- originates in/or just before the fibular tunnel between fibularis/ peroneus longus & neck of fibula
- passes thru the anterior intermuscular septum to enter anterior compartment and as it courses medially to the EDL, it meets up w/ the anterior tibial vessels
- then it follows same course described for anteior tibial artery
After passing through the interosseous membrane, the anterior tibial artery travels deep to and between which two muscles?
- descends between the tibialis anterior & extensor digitorum longus muscles
just proximal to the talocrural joint, it is crossed by which tendon?
EHL tendon
In its final portion, the anterior tibial artery lies deep to the superior extensor retinaculum and between which two tendons?
continues as the dorsalis pedis artery onto the dorsum of the foot lateral to the tendon of the extensor hallucis longus and medial to the extensor digitorum longus and deep peroneal nerve
