Sem 2 RA week 4 Flashcards
Relations of the knee joint?
Supriorly = quadriceps tendon - blends with patella, then continues below knee as patellar tendon
lateral side = tendon of biceps femoris
medial side = sartorius muscle, gracilis and semitendinosus + semimembranosus
Knee joint type?
Articulations? Note?
Modified hinge joint
3 separate articulations:
- femoropatellar
- femorotibial (x2)
NOTE: fibula does NOT articulate at the knee joint
Articular surfaces of knee joint?
Top = inferior view of femur, anteriorly is patellar surface (concave) + posteriorly is lateral and medial condyles - between these is intercondylar notch
Middle = superior view of tibia, medial + lateral condyle, separated by intercondylar eminence (non-articular)
Bottom = posterior surface of patella (upside down), apex would point inferiorly in anatomical position, larger lateral facet + smaller medial facet (this matches on patellar surface of femur)
(in image patella has been pulled upside down)
why is lateral patellar surface larger (protudes more)?
To prevent patellar dislocation
quadriceps tendon pulls patella laterally so tendency to dislocate in lateral direction
Capsule attachments knee joint?
Anteriorly capsule fuses with quadriceps tendon (sup.), patella and ligamentum patellae (inf.)
Posteriorly encloses intercondylar fossa (blue line) of femur, on posterior surface of tibia at lateral condyle there is a gap for popliteus muscle (broken blue line)
Synovial membrane attachments knee?
Consequence?
Attaches around margin of articular surface
Bit more complex on tibia - mostly follows margins of articular surface but deviates slightly
- Follows margin of medial epicondyle → travels anteriorly along intercondylar eminence → will cut across to medial side of lateral condyle → follows margins of lat. condyle → posterior to ligamentum patellae will cut across
This creates folds
- Alar folds = fat-filled, deep to ligamentum petallae
- Infrapatellar synovial fold - deep indent where intercondylar eminence is excluded from synovial cavity
(image = superior view of tibia, red line = synovial membrane)
Infrapatellar fold - extending from intercondylar notch of femur towards intercondylar eminence of tibial plateau
note - knee has largest joint cavity in the body
Bursae of knee joint?
Function?
Expansions of synovial membrane
- Suprapatellar bursa - held in place by fibres of vastus medialis of quadriceps
- Gastrocnemius, popliteus + semimebranosus bursae = associated with tendons of muscles
- Subcutaneous prepatellar (directly in front of patella) + infrapatellar (ant. to ligamentum patellae) bursa = associated with knee but not in communication with joint capsule, also have deep infrapetallar bursa between tibia and patallar ligament
- Anserine bursa = associated with gracillis, sartorius + semitendinosus muscles as they head towards distal attachment on upper medial part of tibia
Function = lubricates movement of tendons
Ligaments of knee joint?
Extracapsular:
oblique popliteal
arcuate popliteal
medial + lateral collateral (also called tibial and fibular collateral ligamets)
Intracapsular = anterior + posterior cruciate
Popliteal ligaments?
Functions?
Oblique popliteal ligament = expansion of semimembranosus tendon, reinforces posterior capsule
Arcuate popliteal ligament = thickening og capsule over popliteus, strengthens posterolateral joint capsule
(Oblique = red)
(Arcuate = blue)
(called arcuate because it forms an arch)
Medial (tibial) collateral ligament?
Attachments?
Strong, flat thickening of capsule
Medial epicondyle of femur → medial condyle + superior medial surface of tibia (deep fibres attach to medial meniscus)
Lateral (fibular) collateral ligament?
Attachments?
Passes?
Strong and cord-like (does not blend with capsule)
Lateral epicondyle of femur → lateral head of fibula
Will pass superficial to tendon of popliteus
Attaches between 2 heads of biceps femoris tendon
(in image black arrow is pointing towards ligamentum patellae)
Cruciate ligaments?
Function?
Movement?
Specific functions?
Attachments?
They are taut in every joint position!
Function = maintain contact between femoral and tibial articular surfaces when knee flexed
Wind around each other during medial rotation of tibia → limited to 10*, greater degree of movement in lateral rotation because ligaments are unwinding
PCL = prevents femur from sliding anteriorly on tibia, particularly when knee is flexed
ACL = prevents femur from sliding posteriorly on tibia, prevents hyperextension, limits medial rotation of femur when foot is planted (knee flexed)
Attach to intercondylar eminence of tibia (anterior attaches more anteriorly on tibia but will attach more posteriorly on femur and vice versa)
ACL attachments?
Fibre arrangement?
Function?
Anterior intercondylar area of tibia → medial side of lateral condyle of femur
Fibres will spiral 110* between tibia and femur
Anteromedial band = limits flexion
Posterolateral band = limits extension
(image = left is ant.)
…
PCL attachments?
Fibre arrangement?
Function?
Posterior intercondylar area of tibia → lateral side of medial condyle of femur
Fibres closely aligned to centre of rotation of knee (important in weight transmission when knee is flexed)
Anterolateral band = limits flexion
Posteromedial band = limits extension
…
Menisci of knee?
Functions?
Types? Features?
Wedges of fibrocartilage
Functions = deepen articular surface, shock absorption
Medial meniscus = C-shaped, broad posteriorly, firmly attached to TCL
Lateral meniscus = circular, free moveable, attachment for popliteus (when contracts moves lateral meniscus)
…
Blood supply to knee?
why is it important?
Vessels?
periarticular genicular anastamosis
femoral artery passes through adductor hiatus (posterior aspect) to become popliteal artery, will terminate as anterior + posterior tibial arteries that supply leg
When bend knee will kink popliteal artery so anastomosis important to maintain blood supply
Genicular branches (4 of 5) → from popliteal artery (middle will supply cruciate ligament, medial, sup, inf. + lat. will contribute to anastamosis, anterior aspect)
Descending genicular artery → from femoral artery
Descending branch → from lateral circumflex femoral artery (profunda femoris)
Branches from anterior tibial recurrent artery
Compartments of leg?
Anterior
posterior
lateral
Larger tibia located medially
What joins the tibia and fibula?
what surrounds the muscles of the leg?
Compartments?
Posterior?
interosseous membrane
deep fascia of the leg (crural fascia)
Intermuscular septae extend from crural fascia and divide muscles of leg into ant., post. (very large) and lat. compartments
In posterior compartment there is transverse intermuscular septum that divides posterior compartment into superficial + deep
what is contained in subcutaneous fat in the leg?
Medial = great saphenous vein
Posterior = small saphenous vein
interosseous membrane?
Function?
fibres pass inferolaterally from tibia to fibula
functions: provides surface for muscle attachment + helps resist downward pull of muscles attached to fibula (i.e. prevents downwards dislocation)
superior tibiofibular joint type?
articular surfaces?
movement?
Ligaments?
plane synovial joint
head of fibula + facet on lateral tibial condyle
slight movement during dorsiflexion of ankle
anterior + posterior ligament of head of fibula
Anterior compartment of leg muscles?
Function?
Tendons?
4 muscles = tibialis anterior, extensor digitorum longus, peroneus tertius, extensor hallicus longus
Extensors of ankle joint (dorsiflexion) + digits
tendons anterior to ankle joint
Lateral compartment of leg muscles?
Function?
Tendons?
2 muscles = peroneus longus + peroneus brevis
Evertors of the foot
tendons posterior to lateral malleolus
muscles of lateral compartment attachments?
innervation?
Peroneus longus (most superficial)
attach = from head + upper ⅔rds lateral fibula → passes posterior to lat. malleolus → base of 1st metatarsal + medial cuneiform (crosses over)
Innervation = superficial peroneal nerve (L5, S1, S2) - from common peroneal nerve of sciatic
Peroneus brevis
attach = from inf. 2.3rds lat fibula → posterior to lat. malleolus → tuberosity on lat side of base of 5th metatarsal
innervation = superficial peroneal nerve (L5, S1, S2)
ridge that separates peroneus longus tendon + peroneus brevis tendon?
peroneal trochlea of calcaeneus
can see indentation on inferior surface of cuboid bone created by peroneus longus tendon
muscles of anterior compartment of leg?
innervation?
tibialis anterior
extensor digitorum longus
peroneus tertius
extensor hallicus longus
all supplied by deep peroneal nerve (L4, L5)
tibialis anterior?
attachments?
function?
most superficial + medial muscle in anterior compartment
from lateral condyle of tibia, superior ½ of lateral tibial surface + interosseous membrane → anterior to ankle joint → medial and inferior surfaces of medial cuneiform + base of 1st metatarsal
function = dorsiflexes ankle + inverts foot
extensor digitorum longus attachments?
function?
from lateral condyle of tibia, superior ¾ of medial surface of tibia + interosseous membrane → middle and distal phalanges of lateral 4 digits
extends lateral 4 digits + dorsiflexes ankle
peroneus tertius attachments?
Function?
from inf. ⅓ anterior fibula + interosseous membrane → dorsum of base of 5th metatarsal
function = dorsiflexes ankle + assists in eversion of the foot
extensor hallicus longus attachments?
function?
from middle anterior surface of fibula + interoesseous membrane → dorsal aspect of distal phalynx of hallux
Function = extends hallux + dorsiflexes ankle
extensor retinacula of the leg?
superior extensor retinaculum
ant. border of tibia → lower end of fibula
inferior extensor retinaculum = y-shaped
stem attached to calcaneus laterally
upper limb attached to medial malleolus
lower limb passes round medial border of foot to blend with dense fascia over abductor hallicus
Muscles on dorsum of foot?
Attachments?
Innervation?
common proximal attachment = superior surface calcaneus, inferior extensor retinaculum
extensor hallicus brevis (black)
→ base of proximal phalynx of hallux
Extensor digitorum brevis
→ long extensor tendons of toes 2-4
Innervation = deep peroneal nerve (L5/S1)
…
posterior
Sciatic nerve dividing into tibial (L4-S3) + common peroneal (L4-S2)
common peroneal will enter anterior and lateral parts of the leg by wrapping round neck of fibula - gives superficial (laterl compartment) + deep peroneal nerve (anterior compartment)
superficial peroneal will also give off cutaenous branch (dorsum of foot + anterolateral leg)
Deep peroneal nerve enters into anterior compartment, runs along interoesseous membrane supplying muscles → will continue anterior to ankle joint to supply foot muscles → ends as cutaneous nerve supplying 1st webspace
superficial peroneal nerve?
function?
Branch of common peroneal between peroneus longus + neck of fibula (lateral)
function = supplies muscles of lat compartment of leg, cutaneous innervation to distal anterior surface of leg + dorsum of foot
Deep peroneal nerve?
function?
branch of common pernoeal between peroneus longus + neck of fibula
passes through extensor digitorum longus + travels with anterior tibial artery supplying all anterior compartment muscles
crosses ankle joint to supply ext. digitorum brevis + ext. hallicus brevis
cutaneous innervation to 1st webspace
…
black arrows = branches of superficial peroneal nerve
Arteries of the leg?
popliteal artery gives anterior and posterior tibial arteries
anterior tibial artery = through interosseous membrane + descends in anterior compartment
Posterior tibial artery = gives fibular artery which provides perforating branches to muscles of lateral compartment (not located in lat compartment but gives perforating branches)
Arteries of dosrum of foot?
Bracnhes?
pathway? + branches
Dorsalis pedis (medial) is a continuation of anterior tibial artery
branches:
Lateral tarsal artery
deep plantar artery (sole of foot)
Arcuate artery
Arcuate artery runs across metatarsals to anastamose with lateral tarsal artery
Arcuate artery branches to give metatarsal + digital arteries
red markers = anterior tibial artery
dorsal venous arch (superficial) → drains to great saphenous vein medially
Tibia
superior posterior tibia = soleal line (attachment for soleus muscle)
above this = popliteal area (triangular - distal attachment for popliteus muscle)
distally tibia has medial malleolus
Fibula
apex - upwards projection
lateral malleolus
pronounced groove on medial side of lateral malleolus = peroneus longus + brevis tendons
Muscles of posterior compartment?
insertions?
7 muscles
3 superficial = gastrocnemius, plantaris + soleus
4 deep = popliteus, flexor digitorum longus, flexor hallucis longus + tibialis posterior
superficial muscles all insert on posterior surface of calcaneous via tendocalcaneous
tendons of deep muscles pass behind medial malleolus to plantar surface of foot (except popliteus)
gastrocnemius?
attachments?
innervation?
function?
most superficial muscle of posterior compartment
medial head = popliteal surface of femur (superior to medial condyle)
lateral head = lateral aspect of lateral condyle of femur
superficial muscles all insert on posterior surface of calcaneous via tendocalcaneous
innervation = tibial nerve (S1, 2)
Function = plantarflexes ankle, flexes knee
plantaris attachments?
Innervation?
Function?
lateral supracondylar line of femur (proximal to lateral head of gastrocnemius)
superficial muscles all insert on posterior surface of calcaneous via tendocalcaneous
innervation = tibial nerve (S1, 2)
Function = assists plantarflexion of ankle
soleus attachments?
innervation?
Function?
from soleal line of tibia, upper ⅓ of posterior fibula + tendinous arch (yellow in pic)
superficial muscles all insert on posterior surface of calcaneous via tendocalcaneous
tibial nerve (S1, 2)
Plantarflexes ankle joint
popliteus?
Attachments?
Innervation?
Function?
only muscle in deep posterior compartment that does not cross ankle joint
from lateral condyle of femur (pit for popliteus) + lateral meniscus → popliteal area of tibia (above soleal line)
tibial nerve (L4, L5, S1)
unlocks knee joint by laterally rotating femur on fixed tibia
flexor digitorum longus attachments?
innervation?
Function?
(most medial)
from posterior surface of tibia → base of distal phalanx of digits 2-5
(tendons of deep muscles pass behind medial malleolus to plantar surface of foot (except popliteus)
tibial nerve (L5, S1, S2)
flexes lateral 4 digits, weak plantarflexor of ankle
flexor hallucis longus attachments?
innervation?
Function?
from posterior surface of fibula (weird because big toe is medial but proximal attachment is lat) → base of distal phalanx of hallux
(tendons of deep muscles pass behind medial malleolus to plantar surface of foot (except popliteus))
tibial nerve (L5, S1, S2)
Flexes hallux + weak plantorflexor of ankle
tibialis posterior attachments?
innervation?
Function?
found between FDL and FHL
from post surface of tibia + fibula + interoesseous membrane → tuberosity of navicular, cuneiforms, cuboid, sustentaculum tali of calcaneous, base of 2nd, 3rd + 4th metatarsals
(tendons of deep muscles pass behind medial malleolus to plantar surface of foot (except popliteus)
tibial nerve (L4, L5)
plantarflexes ankle, inverts foot
tendons of deep muscles of posterior compartment?
medial to lat?
tibialis posterior tendon passes deep to flexor digitorum longus
groove posterior to medial malleolus
FHL grooves the posterior surface of distal tibia and posterior surface of talus
medial to lat arrangement of tendons at ankle joint = Tibialis posterior, flexor Digitorum longus, flexor Hallicus longus (Tom, Dick and Harry)
note - arrangement of tendons does not match arrangement of muscle bellies
flexor retinaculum attachment?
Contents?
from medial malleolus → calcaneous
contents = tibialis posterior, posterior tibial vessels (vein, artery nerve) + tibial nerve found between FDL and FHL tendons
(tom, dick And Very Naughty harry) - artery, vein, nerve
Arteries of posterior leg?
found?
Branches?
Posterior tibial artery = terminal branch of popliteal artery
between heads of gastrocnemuis + deep to soleus to run on surface of TP and FDL
gives fibular artery as branch
terminates as medial + lateral plantar arteries in foot
Fibular artery
runs medial to fibula, usually within FHL
tibial nerve
runs close to midline, gives numerous muscular branches that supply muscles of post compartment
like posterior tibial artery, tibial nerve will pass between heads of gastrocnemius + deep to soleus
Will continue into sole of foot, posterior to medial malleolus → medial + lateral plantar nerves
Tibial nerve pathway?
Found?
Branches?
Passes between heads of gastrocnemius and deeo to tendinous arch of soleus with posterior tibial artery
found between FHL and FDL at ankle joint
Branches = medial + lateral plantar nerves that supply the sole of the foot
lateral sural from common peroneal
medial sural from tibial nerve
landmarks dorsum of foot
L4 = big toe
L5 = middle 3 digits
S1 = pinky toe
S2 = heel
inferior tibiofibular joint type?
ligaments?
Movement?
syndesmosis
anterior + posterior tibiofibular ligament and interosseous tibiofibular ligament
interosseous ligament continuous with interosseous membrane
slight movement to accommodate wedging og trochlea of talus during dorsiflexion
ankle joint?
don’t think we have to learn this
ROM ankle joint
hinge joint
capsule and ligaments ankle joint?
why is it stronger laterally + medially?
capsule attaches around articular margins - anteriorly extends onto neck of talus
weak anteriorly + posteriorly
supported laterally + medially by strong collateral ligaments
lateral collateral ligaments of ankle joint?
from lateral malleolus of fibula
anterior talofibular → neck of talus
posterior talofibular → latral tubercle of talus
calcaneofibular → lateral surface of calcaneous
medial collateral ligament of ankle joint?
also called deltoid ligament
3 attaches to shelf of talus (sustentaculum tali)
…
relations of ankle joint
anteriorly = tendons from ant. compartment
anterior tibial artery + veins + deep peroneal nerve
medially = tendons of posterior compartment, posterior tibial artery + veins (most laterally is FHL) - remember FHL creates groove on talus
laterally = peroneus longus + brevis, also can see short saphenous vein + sural nerve
can also see vein next to medial malleolus = great saphenous vein
Photograph A shows the external surface of the knee joint. The joint is surrounded by connective tissue and a synovial capsule that has a fibrous outer layer. Extensions of the tendons of vastus medialis and lateralis support the capsule of the knee joint.
Photograph B shows the lateral side of the knee and the tendon of biceps femoris. Photograph C shows the medial side of the knee and tendons of muscles from the anterior, medial and posterior compartments of the thigh attaching to the tibia. An expansion of semimembranosus forms the oblique popliteal ligament that supports the posterior surface of the capsule of the knee joint.
Once the tendons of the medial side of the knee are reflected, the medial (tibial) collateral ligament can be seen (photograph A). It forms a thin sheet to support the medial side of the knee and also connects to the medial meniscus.
Photograph B shows the lateral side of the knee which is supported by the cord-like lateral (fibular) collateral ligament. Both ligaments are taut when the knee is fully extended.
Photograph A shows the inner surface of the knee joint. The quadriceps tendon has been sectioned and the patella reflected distally to expose the posterior surface of the patella and the femoral condyles. A healthy knee should have smooth joint surfaces. If the cartilage is damaged then pitting or grooving of the surface may be observed. A small quantity of sticky fluid will be released form the joint – this is the remains of the synovial fluid that lubricated the knee.
Photograph B shows the smooth synovial lining of the capsule and a small connective tissue structure that may initially be mistaken for the anterior cruciate ligament – the alar fold. This fold is the fringed edge of the synovial membrane.
The cruciate ligaments are best observed when the knee is flexed. Photograph A shows the anterior cruciate ligament (ACL). It attaches to the anterior intercondylar area of the tibia and passes posterolaterallyto attach to the posteromedial aspect of the lateral femoral condyle. The ACL acts to limit the forward gliding movement of the tibia on the femur.
Photograph B shows the posterior cruciate ligament (PCL). It attaches to the posterior intercondylar area of the tibia and ascends anteromedially to attach to the lateral surface of the medial femoral condyle. The PCL acts to limit the backward gliding movement of the tibia on the femur.
The medial and lateral menisci are cartilaginous structures that increase the congruency of the knee joint surfaces. The medial meniscus attaches to the anterior and posterior intercondylar areas of the tibia, the fibrous capsule and the medial collateral ligament. The lateral meniscus attaches to the tibial intercondylar eminence, the posterior intercondylar area of the tibia, the tendon of popliteus and the posterior meniscofemoral ligament.
Photograph A shows the anterior and lateral compartments of the leg. The anterior compartment contains muscle that extend (dorsiflex) the ankle and the digits. Tibialis anterior also inverts the foot. The anterior compartment is supplied by the deep peroneal nerve – this is also called the deep fibular nerve. Either name is acceptable, they both refer to the shape of the lateral bone of the leg – the fibula.
The lateral compartment contains evertors of the foot, these muscles are innervated by the superficial peroneal (fibular) nerve.
Photograph B shows the great saphenous vein – this runs along the medial surface of the thigh and knee to cross anterior to the medial malleolus. This is not truly in the anterior compartment but may be damaged when skin is removed from the tibia as part of an investigation of the anterior or posterior compartments. The saphenous branch of the femoral nerve runs alongside the great saphenous vein.
Photograph A shows another superficial structure – the superficial peroneal nerve. This nerve supplies motor innervation to the lateral compartment of the leg but sensory innervation to the skin of part of the anterior compartment and also the skin on the dorsum of the foot. Care must be taken not to damage this nerve when skin is removed from the anterior compartment.
Photograph B shows tibialis anterior. Tibialis anterior runs along the lateral surface of the shaft of the tibia. It crosses the anterior surface of the ankle joint and inserts into the medial cuneiform bone and the base of the 1stmetatarsal. It acts to dorsiflex the ankle and invert the foot.
Photograph A shows the muscle that lies lateral to tibialis anterior – extensor digitorum longus. It attaches to the medial side of the fibula and the interosseous membrane. It crosses the anterior surface of the ankle joint and inserts into the dorsal digital expansion of digits 2 to 5. It acts to extend all of the joints of those toes.
Photograph B shows extensor hallucis longus, it also attaches to the medial side of the fibula and the interosseous membrane. It crosses the anterior surface of the ankle joint and inserts into the base of the distal phalanx of the 1stdigit (the big toe or hallux). It acts to extend the joints of the 1stdigit.
The fact that these muscles are called ‘longus’ alerts you to the fact there are smaller ‘brevis’ equivalent muscles elsewhere in the lower limb. In this case they are on the dorsum of the foot. You may also have noted that ‘hallucis’ refers to a structure that passes to/moves the big toe.
Photograph A shows a common variation between individuals. Some individuals possess a peroneus tertius muscle (also called fibularis tertius) either unilaterally or bilaterally. This small muscle passes from the tendon of extensor digitorum longus and forms a small tendon that crosses the anterior surface of the ankle joint to insert into the base of the 5thmetatarsal. If present, it assists in eversion of the foot. The other muscles that evert the foot are found in the lateral compartment – there are two of them which is why this muscle is called peroneus tertius.
Photograph B shows the tendons crossing the anterior surface of the ankle. 1 is tibialis anterior, 2 is extensor hallucis longus, 3 is extensor digitorum longus and 4 is peroneus tertius.
Photograph A shows a deep dissection of the anterior compartment. The anterior tibial artery is a branch of the popliteal artery. It pierces the interosseous membrane to reach the anterior compartment of the leg. It supplies the anterior compartment and becomes dorsalis pedis to supply the dorsum of the foot.
Photograph B shows the deep peroneal nerve that runs alongside the anterior tibial artery. It originates from the common peroneal nerve near the neck of the fibula and supplies the muscles of the anterior compartment of the leg and the dorsum of the foot. It supplies cutaneous innervation to the skin of the cleft between the hallux and the second digit.
Photograph A shows the lateral compartment of the leg. The most superficial muscle is peroneus longus (also called fibularis longus).It attaches to the fibula and sends a tendon around the posterior surface of the lateral malleolus of the ankle. Peroneus longus inserts into the 1stmetatarsal and medial cuneiform.
Photograph B shows peroneus brevis (also called fibularis brevis) which also attaches to the fibula and forms a tendon that passes posterior to the lateral malleolus. It inserts into the base of the 5thmetatarsal. Both muscles evert the foot.
Photograph C shows the tendons proximal to the ankle joint. Note that the tendon of peroneus longus will come to lie behind the tendon of peroneus brevis as it passes posterior to the lateral malleolus. The sural nerve and short saphenous vein also lie posterior to the lateral malleolus.
The posterior compartment of the leg contains muscles that flex (plantarflex) the ankle and the digits. Gastrocnemius flexes the knee in addition to the ankle and tibilalisposterior can invert the foot. The muscles of the posterior compartment are innervated by the tibial nerve.
The short saphenous vein and the sural nerve lie in the superficial fascia covering the posterior compartment of the leg (photograph A). The short saphenous vein arises from the lateral side of the dorsal venous arch of the foot and passes posterior to the lateral malleolus of the ankle; it then ascends the posterior compartment to drain into the popliteal vein. The sural nerve may be a branch of the tibial or common peroneal nerves or both nerves. It supplies cutaneous innervation to the skin on the posterior compartment and around the lateral side of the foot.
The most superficial muscle in the posterior compartment is gastrocnemius (photograph B). You have already seen the medial and lateral heads forming the medial and lateral boundaries of the popliteal fossa. The two heads unite to form a tendon that passes to the calcaneus. Gastrocnemius acts to flex the knee and plantarflex the ankle.
Photograph A shows the medial head of gastrocnemius reflected to reveal soleus muscle. Soleus attaches to the tibia and the fibula, it joins with the tendon of gastrocnemius to form the tendocalcaneustendon that attaches to the calcaneus. Soleus acts to plantarflex the ankle and forms an arch above the popliteal vessels and tibial nerve (white dotted line).
Photograph B shows plantaris muscle. The small head of this muscle attaches to the lateral supracondylar line of the femur and it forms a long tendon that inserts into the calcaneus. It is a very small muscle but is said to assist in the flexion of the knee and the ankle. This muscle is not present in every individual, and when present may be unilateral or bilateral.
Photograph A shows a deeper dissection of the posterior compartment. Flexor digitorum longus lies on the medial side of the posterior compartment. It attaches to the tibia and forms a tendon that passes posterior to the medial malleolus, it inserts into the distal phalanx of the lateral 4 digits (digits 2-5). It flexes all of the joints of digits 2-5 and as it crosses the posterior surface of the ankle will also assist in plantarflexion.
Photograph B shows flexor hallucis longus which lies on the lateral side of the posterior compartment. It attaches to the fibula, interosseous membrane and the fascia over tibialis posterior. It passes its tendon posterior to the medial malleolus and it inserts into the base of the distal phalanx of the hallux. It flexes all of the joints of the big toe and assists in plantar flexion.
Photograph A shows tibialis posterior. It attaches to the tibia, fibula and interosseous membrane. The tendon of tibialis posterior passes posterior to the medial malleolus to insert into navicular, medial and intermediate cuneiforms and the bases of the 2ndto 4thmetatarsal bones. It acts to plantarflex the ankle and invert the foot.
Photograph B shows the Tom, Dick and Harry arrangement of tendons at the medial malleolus. The most medial tendon (closest to the medial malleolus) is Tom (tibialis posterior), then Dick (flexor digitorum longus) then Harry (flexor hallucis longus). In this photograph the tibial nerve and posterior tibial artery have been reflected but usually lie between the tendons of flexor digitorum longus and flexor hallucis longus.
Photograph A shows the posterior tibial artery. It arises from the popliteal artery and supplies the muscles of the posterior compartment before passing behind the medial malleolus. It then branches to form the medial and lateral plantar arteries to supply the foot. In the posterior compartment of the leg it forms a peroneal (fibular) artery.
Photograph B shows the tibial nerve that descends the posterior compartment with the posterior tibial artery. It supplies the muscles of the posterior compartment then passes with the artery posterior to the medial malleolus to form medial and lateral plantar nerves to supply muscles in the plantar surface of the foot.
Photograph A shows the dorsal venous arch that lies in the superficial fascia on the dorsum of the foot. It drains the superficial tissues of the foot and communicates with the great saphenous vein medially and the short saphenous vein laterally.
Photograph B shows branches of the superficial peroneal nerve. This nerve supplies sensory innervation to most of the dorsum of the foot.
Photograph C shows the deep peroneal nerve on the dorsum of the foot. It supplies sensory innervation to the cleft between the hallux and the 2ndtoe.
The rest of the cutaneous innervation of the foot is supplied by the saphenous nerve (medially), the sural nerve (laterally) and the medial and lateral plantar nerves (on the plantar surface).
Unlike the dorsum of the hand, the dorsum of the foot contains intrinsic muscles - short extensors of the digits. Photograph A shows extensor hallucis brevis. This muscle passes from the calcaneus to the proximal phalanx of the big toe and acts to extend the hallux.
Photograph B shows extensor digitorum brevis. This muscle passes from the calcaneus to form 3 or 4 small tendons which join the extensor expansion of the lateral digits. Digits 2-4 if there are 3 tendons or digits 2-5 if there are 4 tendons formed. Extensor digitorum brevis acts to extend the lateral digits.
Both of the short extensor muscles are supplied with motor innervation by the deep peroneal nerve.
Photograph C shows the final part of the anterior tibial artery. It crosses the anterior surface of the ankle joint to become the dorsalis pedis artery on the dorsum of the foot. Dorsalis pedis usually lies on the surface of the metatarsals between the tendons of extensor hallucis longus and the tendon of extensor digitorum longus that passes to the 2ndtoe. Dorsalis pedis supplies the dorsum of the foot and anastomoses with the medial and lateral plantar arteries.
