LIGAMENTS (COLLATERALS)
ACTIONS THEY RESTRICT
LOCATION
Tidbits
LCL -Lateral Collateral Ligament
-restricts varus deviation
-attaches lateral epicondyle of the femur –fibular head
pencil-like (make it easier to palpate)
MCL - Medial Collateral Ligament
(tibial collateral ligament)
-restricts valgus deviation
-attaches medial epicondyle of the femur -medial condyle of the tibia
-deep fibers of the ligament are attached to the medial meniscus
-when the outside of the knee is hit, causes valgus deviation
-flat thickening of the joint capsule
ACL-Anterior Cruciate Ligament
-restricts tibia from sliding forward
-restricts femur from sliding back
-whether tibia or femur goes fwd or back -it’s the same result
-attaches anterior on the tibia – posterior on the femur
-slack when knee is flexed and taut when the knee is in full extension
-presents as pain walking up stairs
PCL- Posterior Cruciate Ligament
-restricts tibia on the femur from sliding back
-restricts tibia on the femur from sliding fwd
-opposite to ACL
-attaches posterior on tibia – anterior on femur
-slack when knee is extended and taut when knee is in full flexion
-presents as pain walking downstairs
Medial and Lateral Coronary Ligaments
-attach the medial and lateral menisci to their respective tibial plateaus
Valgus: means “go out”; lateral deviation of the distal bones of a joint
* When the knee is fixed and the tibia (specially the distal end) has deviated laterally (relative to the knee)
* Ie. Knock-knee
Varus: means “return”; medial deviation of the distal bone of a joint
* When the knee is fixed and the tibia (specifically the distal end) has deviated medially (relative to the knee)
* Ie. Bow-leg
Valgus vs. varus diagram slide176
Patella: the knee – triangle-shaped sesamoid (a bone embedded in a tendon-usually shaped like a sesame seed) bone in the tendon of the quadriceps (most specifically the rectus femoris muscle)
Anterior View: base – the flat superior edge; apex – the more pointed inferior edge
Posterior View: vertical ridge; medial and lateral articular facet -flat surface; facets articulate with the patellar surface of the femur and the medial and lateral condyles of the femur (depending on where in the range it is)
Menisci of the knee (sing.meniscus) Greek: crescents
-C-shaped plates of fibrocartilage attached to the articular surfaces of the tibia
-the center is thinner than the outer edges
-they are slightly more mobile and aid in the spreading of synovial fluid during knee movement
-PRIME: function as shock absorbers
-function to deepen the articulation (provide a more stable articulation between the tibia and femur)
-the ends of the C-shape are called horns
-the medial meniscus is attached to the medial collateral ligament (MCL)
-weight – bearing/ twisting motion which causes meniscus tear – pop/crack sounds
-meniscal injuries – you’ll know by the sound/swelling that inform the person of injury
Ligaments of the knee (transverse) draw diagram on slide 187
-the 2 meniscii are connected anteriorly by the transverse ligament of the knee
Knee Joints
Movements
Attachments
Tidbits
Tibiofemoral
-flexion
-extension (straighten knee)
-internal rotation (limited) only when knee is flexed at 90 angle
-external rotation (limited)
-rotation occurs ONLY when the knee is flexed
-modified hinge (bc it allows for some rotation)
-biaxial (some say uniaxial)
-medial and lateral condyles of the tibia articulate with the medial and lateral femoral condyles
-closed pack position for tibiofemoral joint is full extension
-loose pack position is 25-30 angle of knee flexion; this allows maximal space for swelling
Patellofemoral
-plane-small relatively flat surfaces gliding on top
-medial and lateral facets of the patella articulate with the patellar surface of the femur
-patella moves down (inferiorly) during flexion and (superiorly/up and laterally/out) during extension
-most patellar dislocation happen laterally
-lateral femoral condyle projects farther (anteriorly) than the medial femoral condyle
-this more anterior prominence of the lateral femoral condyle prevents the patella from tracking too far laterally
The knee has 3 articulations:
1. Lateral condyle of the tibia articulates with the lateral femoral condyle
2. Medial condyle of the tibia articulates with the medial femoral condyle
3. Patella articulates with the femur
Windlass Mechanism of the Foot:
-as the toes extend, the plantar fascia tightens (bc it crosses the MTPs)
*as it tightens, it pulls the calcaneus anteriorly (fwd) and elevates the arches putting the foot into a position of supination (supination: plantar flexion, inversion, forefoot adduction)
-this occurs whether the action is active, passive, weight-bearing or non-weight bearing
(draw picture)
Popliteus Muscle:
Attaches: superior/proximal attachment to the lateral condyle of the femur
-inferior/distal attachment: posterior proximal surface of the tibia, superior to the soleal line
-action: flexion of the knee (very weak)
-action: medial (or internal) rotation of the knee (key)
Screw Home Mechanism of the knee:
Why is it impt to know popliteus can turn inwards from shin? Tibia is slightly longer on the medial side
-when the knee is fully extended, the tibia rotates laterally (due to the medial condyle being longer) which locks the knee into a more stable position – this is the screw home mechanism
-to flex the knee, the popliteus medially rotates the tibia to ‘unlock’ the knee and allow it to flex
-therefore popliteus is referred to as the “key to the knee” bc it “unlocks” the screw home mechanism
(if you feel your knee grinding or not smooth it’s bc the popliteus is not unlocking)
Muscle
Attachments
Function
Popliteus
Posterior proximal surface of the tibia, superior to the soleal line
Flexion of the knee (very weak)
Primary function: Medial/internal rotation of the knee (key)
Anterior leg
Tibialis Anterior
based of the 1st MT, 1st cuneiform (plantar surface)
Dorsiflex
inversion
Extensor Hallucis Longus (EHL)
base of the distal phalanx of the 1st toe
Extension of MTP-metatarsal phalangeal, IP-interphalangeal of 1st digit
-assists in dorsiflexion, inversion
Extensor digitorum longus (EDL)
middle and distal phalanges of lateral 4 toes
-dorsiflex
-eversion
-extension of Metatarsal phalangeals (MTPs), PIPs, DIPs 2nd-5th digits
Peroneous Tertius
Only Andrew has it
Base of the 5th MT
-dorsiflex (weak)
-eversion (weak)
Lateral leg
Peroneous Longus
Base of the 1st MT, 1st cuneiform
Passes through the tunnel formed by the extensions of the long plantar ligament
-plantar flexion
-eversion (prime mover)
Peroneous brevis
Tuberosity of the 5th MT
Plantar flexion
Eversion (prime mover)
Both tendons pass BEHIND the lateral malleolus, note the peroneal retinacula and the associated tendon sheets
Superficial Posterior leg
Gastrocnemius
Calcaneus (via achilles tendon)
-Plantar flexion
-knee flexion (weak)
Soleus
Calcaneus (via achilles tendon)
Plantar flexion
Gastrocnemius and soleus together are often called the triceps surae
Plantaris
Calcaneus
Plantar flexion (weak)
Knee flexion (weak)
A weak muscle but if it ruptures there can be a LOT of pain
Deep Posterior leg
Tibialis Posterior
Navicular tuberosity and surrounding bones: cuneiforms, cuboid, bases of 2nd-4th MTs
Plantar flexion
inversion
Flexor Hallucis Longus
Plantar surface of 1st distal phalanx
1st MTP, 1st IP flexion
Plantar flexion
Flexor digitorum longus
Plantar surface of distal phalanges of lateral 4 toes
PIP/DIP
MTP flexion of 2nd-5th digits
Plantar flexion
There is only1 foot muscle- in the dorsum of the foot: extensor digitorum brevis
Medial distal 4 phalanges
Extension of medial 4 toes
5th is extended by EDL ONLY
Extensor hallucis brevis and extensor digitorum brevis are essentially the same muscle
*the muscles in a compartment (leg) share the same general function, the same nerve supply, and the same blood supply
General Rule:
All muscles in anterior compartment can dorsiflex, every other muscle in the leg will contribute to plantar flexion
It’s about where the muscle is crossing over in the medial malleolus
If the muscle is located in front – dorsiflex; behind the medial malleolus/ lateral axis – it will plantar flex
-gastrocnemius & soleus, share a common distal tendon called the Achilles tendon which attaches to the calcaneus
-note: the fascia of the calf is continuous with the plantar aponeurosis (achilles tendon fans out into plantar aponeurosis)
NOTE: all tendons that pass BEHIND the medial malleolus will plantar flex
-note the flexor retinaculum – this forms a tunnel called the tarsal tunnel (clinically relevant) (possible causes of tarsal tunnel syndrome: prolonged eversion/pronation, chronic tendonitis, direct trauma, RA)
-note the order of the tendons from anterior to posterior (T, D, H or T,D, an H)
Tendon palpation, tendon sheaths & the retinacula
-note the tendons: from medial to lateral, you will palpate TA, EHL, EDL
-note the superior extensor retinaculum and the inferior extensor retinaculum
-the retinacula prevent the tendons from bowing as the muscles contract
-retinacula: is latin for hold back (to retain) Zigzag sheath
-where there is the possibility of friction between the tendons and the retinacula, there is a tendon sheath which surrounds the tendon
-connective tissue outer layer for structure and protection with a synovial inner layer for lubrication (as the tendon moves)
Stuff on quiz
Muscles Chart- distal attachments (insertions), function-what can it do in this plane/axis?
Look at wording
How to stretch gastrocnemius-dorsiflexion on ankle, full extension on knee; soleus-flexion of knee
tibialis anterior
extensor hallucis longus
extensor digitorum longus
peroneus tertius (Andrew has one)
tibialis posterior
flexor hallucis longus
flexor digitorum longus
extensor digitorum brevis (only 1 intrinsic foot muscle in the dorsum of the foot)