Derived from femoral nerve over tibia, peroneal nerve over extensor compartment.
Gives an infrapatellar branch supplying subcut periosteum of upper tibia & skin over
- then descends just behind the GSV ¨ bifurcates above malleolus
- ¨ main anterior branch ends on medial side of foot at MTP Jt.
Branch of common peroneal, supplies deep fascia & skin over upper extensor / peroneal areas.
¨ rest of extensor / peroneal compartment skin
Directly attached to subcut fat; deep fascia blends with its periosteum.
GSV and saphenous nerve lie in fat with lymph passing up from foot to superficial inguinal nodes.
Most of its deep anastomoses are about this area ¨ deep veins of calf:
(1) 3 ankle perforators: below med malleolus, 10cm above it and just below middle of leg.
(2) 1 just below knee joint level (BoydÕs)
(3) Mid-thigh (Hunterian) ¨ femoral vein in the adductor canal.
The posterior arch vein often joins the lower perforators together, then joins GSV below knee.
Some of the perforators join the venae comitantes of the posterior tibial artery
Others join the venous plexus deep to soleus
Valves directed inwards where veins pierce deep fascia, and where they join deep veins
- hence saphenous blood passes deep via these perforators
- then pumped up via contractions of soleus and other calf muscles
- flow reverses if valves incompetent ¨ varicosity.
Upper subcutaneous surface of tibia receives 3 tendons from each of constituent parts of hip:
Sartorius (from ilium; femoral nerve)
Gracilis (from pubis; obturator nerve)
Semitendinosus (from ischium; sciatic nerve)
- the bursa anserinus separates them deep to flattened sartorius tendon.
Covers muscles only, not bone ie not subcutaneous tibia Ð attaches to periosteal borders.
- extends from anterior border of tibia around lateral leg to posterior, enclosing muscles
2 intermuscular septa pass from it to fibula ¨ enclose peroneal compartment; extensor compartment lies between anterior septum and tibia; flexor compartment lies between posterior septum and tibia.
(484)
Boundaries: Between deep fascia and interosseous membrane; prone to compartment syndrome.
- medially is the extensor surface of tibia
- laterally is the extensor surface of fibula and anterior intermuscular septum
Contains: tibialis anterior, EHL, EDL, peroneus tertius, deep peroneal nerve (which supplies all of the extensors) and anterior tibial vessels.
Deep fascia is thick inferiorly, forming sup extensor retinaculum.
- this is attached to anterior tib and fib.
- Deep to retinaculum lie: (medial ¨ lateral): tib ant, EHL, EDL and peroneus tertius.
- Only tib ant has a synovial sheath here.
- Anterior tibial bundle is deep to retinaculum, b/n EH and EDL, vessels medial to nerve.
Arises: upper 2/3 of tibia, interosseous membrane and deep fascia
- descends as a tendon in a sheath
Inserts: medial
cuneiform + 1st MT cf peroneus longus inserts into opp
side of same bones
Nerve: deep peroneal and recurrent genicular (L4)
Action: combined dorsiflexion and inversion; helps maintain medial longitudinal arch.
Test: dorsiflex against resistance.
Arises: middle 1/2 of fibula + adjacent interosseous membrane
- deep at origin, but emerges b/n tib ant and EDL in lower leg
- then crosses in front of ant tib vessels and deep peroneal nerve from lat to med side.
Inserts: base of terminal phalanx of hallux. Has its own synovial sheath in the foot.
Nerve: deep peroneal (L5)
Action: dorsiflexes great toe, secondarily the ankle.
Test: dorsiflex great toe against resistance (useful for L5 testing).
Arises: upper 3/4 of fibula, & small area of tibial condyle & interosseus membrane
- acquires sheath below superior extensor retinaculum, shares with peroneus tertius.
- insert same as hand extensors: dorsal extensor expansion over prox phalanx divides into 3 slips: central inserted into base of middle phalanx; sides reinforced by lumbricals & interossei ¨ base of distal phalanx.
Nerve: deep peroneal (L5,S1)
Action: dorsiflex lateral four toes
Test: dorsiflex toes against resistance.
Arises: lower 1/3 of fibula
Inserts: base of 5th MT, and extends along its surface a little.
Nerve: deep peroneal L5,S1
Action: dorsiflexes and everts foot.
Arises over neck of fibula by bifurcation of common peroneal
¨ spirals around it deep to EDL ¨ lies lateral to anterior tibial artery on interosseous membrane.
- ie between EDL and tib ant, then between EHL and tib ant before EHL crosses medially.
At ankle (medially ¨ laterally):
|
TA & EHL |
artery |
nerve |
EDL & PT |
It supplies the 3 muscles of extensor compartment of leg.
Arises at bifurcation of popliteal artery in calf, passes forwards through upper interosseous membrane between head of tib posterior
- companion vein on each side runs down
- ¨ anterior recurrent branch pierces tibialis anterior to anastomosis around upper end of tibia
¨ then runs down on anterior surface of interosseous membrane.
Runs down to cross tibia at ankle, midway between malleoli, to become dorsalis pedis artery.
- deep peroneal nerve lies lateral. EHL crosses in front from lateral ¨ medial.
- accessible (1) at origin and (2) anterior to ankle joint.
Superior: synovial; b/n lat tib condyle ¨ fibular head (flat surfaces)
- reinforced capsule by anterior and posterior ligaments
- may communicate with a deep bursa under popliteus tendon and then to knee joint.
- allows only passive movement in response to talar loading.
Interosseus membrane: slope steeply from tibia to fibula, continuous distally with interosseous tibiofibular ligament: bind bones, provide attachments and resist downward pull on fibula.
Inferior: fibrous; from convex medial distal fibula and concave fibular notch of distal tibia.
- strong anterior and posterior tibiofibular ligaments and interosseous tibiofibular ligament
- only slight movement occurs, with fibula rotating laterally a little during dorsiflexion.