13 - Anterior Lateral Leg and Foot and LL Joints Flashcards
bones of the foot
7 tarsal bones, 5 metatarsal bones and 14 phalanges.
hindfoot
calcaneus and talus
midfoot
cuboid, navicular and 3 cuneiforms
forefoot
5 metatarsals and 14 phalanges
muscles of the lateral compartment of the leg
fibularis brevis and longus
actions of the lateral compartment of the leg
evert and plantarflex
innervation of the lateral compartment of the leg
superficial fibular nerve
blood supply of the lateral compartment of the leg
perforating branches of the fibular a
extensor expansions
The extensor tendons pass onto the dorsal aspects of the digits and expand over the phalanges to form complex dorsal digital expansions.
Each extensor expansion has a proximal extensor hood
extensor hood
part of extensor expansion
proximal part
triangular in shape and wraps around the MP joints to attach to ligaments in the sole of the foot
Apex expands into 3 bands: central (attaches to middle phalanges) and two lateral (insert on distal phalanges
where do many intrinsic muscles of the sole of the foot insert
lateral bands of the extensor expansion
allows forces to be distributed over the dorsum of the entire digit
where does anterior tibial artery change its name and to what
changes to dorsalis pedis artery after it passes between malleoli and enters the dorsum of the foot
where is the pulse of the dorsalis pedis felt
dorsum of the foot as the artery passes over the tarsal bones between the tendon of extensor hallucis longus and the 1st tendon of extensor digitorum longus
OVEN FELT TO TEST FOR PERIPHERAL VASCULAR DISEASE
what does dorsalis pedis artery split into and therefore end
divides into deep plantar and 1st dorsal metatarsal arteries
common fibular nerve
L4-S2
terminates by dividing into the superficial and deep fibular nerves just after it wraps around the neck of the fibula. Due to it’s superficial location and proximity to the fibular neck, it is easily injured. Fractures of the proximal fibula may sever this nerve resulting in paralysis of all the muscles in the anterior and lateral compartments of the leg (foot drop) and loss of cutaneous innervation to the lateral aspect of the leg and dorsum of the foot.
superficial fascia of the foot
- has fibrous septa that act to
- divide it into fat-filled compartments creating shock-absorbing pads o’ fat.
- Anchor the skin to the underlying deep fascia in order to improve the ‘grip’ of the sole
plantar fascia
deep fascia on the sole of the foot which helps hold the foot together, protects the plantar surface of the foot and helps support the longitudinal arches of the foot.
plantar aponeurosis
- central thickening of the plantar fascia
- longitudinally arranged bands go from the calcaneal tuberosity to the digital sheaths and proximal phalanges
- converts foot into solid lever for gait cycle
intermuscular septa of mid and forefoot
- two of them
- extend into the mid- and fore-foot from the plantar aponeurosis
- divide foot into medial, central and lateral compartments
- interosseous compartment is located between metatarsals
intrinsic muscle layers in the sole of the foot and function
- 4 groups
- resist forces that flatten longitudinal arch
- stabilise foot for propulsion by maintaining the transverse arches
- produce minor movements of inversion/ eversion to maneuver on unstable ground
- maintain balance
blood supply of the sole of the foot
branches of the posterior tibial and dorsalis pedis arteries.
bifurcation of posterior tibial a.
- medial and lateral plantar aa. as it passes through the tarsal tunnel
- travel between 1st and 2nd muscle layers of the foot
lateral plantar artery anastomoses
- anastamoses with deep plantar artery (branch of dorsalis pedis a.
- this anastomosis forms deep plantar arterial arch which traverses sole of the foot between 3rd and 4th muscle layers at level of matatarsal bases
innervation of sole of the foot
-tibial nerve, medial and lateral plantar
nerves, as well as the sural & saphenous nerves.
-medial plantar nerve innervates four intrinsic muscles of the foot
-remaining intrinsic muscles of the foot are all innervated by the lateral plantar nerve.
between which muscle layers do the lateral plantar artery and nerve run
- 1st and 2nd
- joins with deep plantar a. to form plantar arch
between which muscle layers does plantar arch run
-3rd and 4th
between which muscle layers do medial plantar a and n run
1st and 2nd
hip joint classification
multi-axial ball and socket type of synovial joint
articular surfaces of hip joint
- head of femur with the lunate surface of the acetabulum.
- the acetabular notch is bridged by the transverse acetabular ligament
- the acetabular labrum is a
- fovea capitis in the head of the femur, attached to acetabulum by the round ligament of the head of the femur (ligamentum teres femoris capitis).
lunate surface
C-shaped with an inferior deficiency
called the acetabular notch (bridged by transverse acetabular ligament which also articulates with head of femur)
acetabular labrum
fibrocartilaginous ring that increases the depth of the acetabulum and the area of contact between the articulating surfaces
capsular ligaments
The fibrous joint capsule is reinforced externally by three ligaments, all of which have fibres that spiral around the joint: iliofemoral ligament, pubofemoral ligament, ischiofemoral ligament
iliofemoral ligament
extremely strong Y-shaped ligament that lies anterior to the hip. The ‘stem’ of the Y attaches to the anterior inferior iliac spine, the fibres run anteroinferiorly across the hip joint to insert on the intertrochanteric line. It primarily limits extension of the hip joint
pubofemoral ligament
lies anteroinferior to the hip. It originates on the iliopubic eminence, spirals inferolaterally around the femoral neck to blend with the iliofemoral ligament and fibres of the joint capsule. It primarily limits extension and abduction of the hip joint.
ischiofemoral ligament
lies posterior to the hip. It arises from the ischium, posterior to the hip joint, and extends superolaterally to blend with the fibres of the joint capsule. It primarily limits extension of the hip joint.
blood supply to hip joint
primarily from the medial and lateral circumflex femoral arteries (off the profunda femoris). **In the adult, the medial circumflex femoral artery is the most important source of blood to the femoral head and adjacent neck. Retinacular arteries branch off the medial (and lateral) circumflex femoral arteries and travel up the femoral neck to reach the femoral head. Fractures of the femoral neck may lacerate the retinacular arteries and the femoral head may become necrotic and die.
knee joint classification
Hinge-type of synovial joint, allowing for flexion and extension (with some anterior and posterior rolling & gliding)
articular surfaces of knee
- patellofemoral joint is included in the knee joint capsule, the proximal tibiofibular joint IS NOT.
- main articulation occurs between the articular surfaces of the medial and lateral femoral condyles and the articular surfaces of the medial and lateral tibial condyles on the tibial plateau.
medial and lateral menisci
- crescent-shaped fibrocartilaginous disks with thick peripheries that intervene between the distal femur and proximal tibia.
- increase the area of contact between the femur and tibia, reducing the stresses at the joint
- shock absorbers, dissipate the forces.
which meniscus is more frequently injured and why
-The medial meniscus has an attachment to the medial collateral ligament, it is less mobile than the lateral meniscus, and therefore more frequently injured.
what determines stability of the knee joint
depends on the strength of the muscles crossing it and on the following ligaments: fibular/lateral collateral ligament, tibial/medial collateral ligament, anterior cruciate ligament, posterior cruciate ligament
fibular/lateral collateral ligament
-extracapsular - a very strong ligament extending from the lateral epicondyle of femur to the fibular head. It is separated from the lateral meniscus by both the tendon of popliteus and the fibrous joint capsule. It prevents adduction of the knee joint and works with the tibial collateral ligament to limit rotation of the tibia on the femur. It is also tense in knee extension.
tibial/medial collateral ligament
-extracapsular - from the medial epicondyle of the femur to the proximal and medial aspect of the tibia. Its deep fibres blend with the joint capsule and are firmly attached to the medial meniscus. It limits abduction of the knee and works with the fibular collateral ligament to limit rotation of the tibia on the femur. It is also tense in knee extension.
anterior cruiciate ligament
(ACL) –intracapsular/ extrasynovial - attaches anteriorly on the tibia and runs supero-postero-laterally through the intercondylar notch of the femur to insert on the inside of the lateral femoral condyle. It limits extension of the knee and anterior gliding of the tibia (anterior drawer sign) and works with the posterior cruciate ligament to limit medial rotation of the tibia on the femur.
posterior cruciate ligament
(PCL) – intracapsular/ extrasynovial - attaches posteriorly on the tibia and runs supero-antero-medially through the intercondylar notch of the femur to insert on inside of the medial femoral condyle. It is mostly tense in flexion (although some fibres are tense in extension), it prevents posterior gliding of the tibia (posterior drawer sign) and works with the anterior cruciate ligament to limit medial rotation of the tibia on the femur.
blood supply of the knee
genicular anastomosis
superior tibiofubular joint type
- plane synovial
- minimal movement
tibiofibular syndesmosis
interosseous membrane
inferior tibiofibular joint
- plane synovial
- minimal movement
- reinforced by the : anterior tibiogibular ligament, posterior tibiofibular ligament
interosseous membrane
- holds tibia and fibula tightly together
- syndesmosis
talocrural joint
ankle joint
-synovial hinge joint
malleolar mortise
- lateral malleolus of the fibula with the inferior surface and medial malleolus of the tibia
- pulley shaped trochlea of the talus fits here
talar trochlea
wider anteriorly such that the ‘grip’ of the malleoli is stronger in dorsiflexion as the anterior portion of the talus becomes wedged between the distal ends of the leg bones.
why is the ankle unstable in plantarflexion
because the trochlea is narrower posteriorly and, therefore lies loosely within the mortise
in which position do most injuries of the ankle occur
plantarflexion
medial collateral (deltoid) ligament of the ankle
strong compound ligament consisting of four parts that fan out from the medial malleolus of the tibia.
-limits eversion/abduction of the ankle
lateral collateral ligament of the ankle
compound ligament consisting of three parts that fan out from the lateral malleolus of the fibula. It limits inversion/adduction of the ankle joint.
-The anterior talofibular is most commonly injured ligament of the ankle – this results from an ‘inversion’ injury causing an ankle sprain
4 major joints of the foot
- subtalar joint (inversion and eversion of foot)
- transverse tarsal joint (inversion and eversion of foot)
- metatarsophalangeal joint (flexion/extension and abduction/adduction)
- interphalangeal joints (proximal and distal: all are hinge joints allowing for flexion and extension)
2 functions of the foot
1, support body weight; 2, act as a lever to propel body forward during locomotion
purpose of arches of the feet
the ground reaction forces that act on the foot when standing have a tendency to ‘deform’ the foot in such a way as to force dorsiflexion of the anterior aspect of the foot. The foot must resist this tendency by remaining rigid, which is best achieved by maintaining an arched structure.
integrity of arches is maintained by:
- Shape of the foot bones
- Muscles
- plantar ligaments
- plantar aponeurosis
foot bones that maintain integrity of arches
- Medial arch – the head of the talus forms the keystone
- Lateral arch – cuboid is the keystone
muscles that maintain integrity of arches
- Medial arch – tibialis anterior suspends the arch from above (assisted by flexor hallucis longus and the intrinsic mm.)
- Lateral arch – fibularis longus and brevis suspend the arch from above (assisted by the intrinsic muscles of the foot)
plantar ligaments that maintain integrity of arches
- Medial arch –plantar calcaneonavicular = spring ligament (under the head of the talus), assisted by plantar ligaments
- Lateral arch – long and short plantar ligaments (especially the long plantar ligament)
plantar aponeurosis that maintain integrity of arches
-Medial and Lateral longitudinal arches – fibres of the plantar aponeurosis run between the calcaneal tuberosity and proximal phalanges. Therefore, whenever the MP joints are extended, the aponeurosis is taut. This is most relevant when a person is walking (at toe-off) or when standing on their toes. In these cases the plantar aponeurosis converts the foot into a solid lever and forms the major support of the longitudinal arches of the foot.
