Knee Joint Flashcards
Posterior Cruciate Ligament
- arises from posterior intracondyle area of tibia and inserts laterl surface of medial femoral condyle
- shorter, straighter and stronfer than ACL
Action of PCL
prevents backward sliding of tibia on femur (anterior displacement of femur on tibia)
When is the PCL taut?
taut during flexion of knee and lax during extension
Anterior Cruciate Ligament
Arises from anterior intracondylar area of tibia and inserts into medial surface of lateral femoral condyle
ACL prevents:
Prevents forward sliding of tibia on femur (or posterior displacement of femur on tibia)
When is ACL taut/lax?
Taut during extension of knee and lax during flexion of knee
When can the ACL be torn?
when knee is hyperextended
Lateral (Fibular) collateral ligament:
separated from lateral meniscus by tendon of popliteus tenon
Function of Lateral (fibular) collateral ligament:
limits adduction of leg at knee
Medial (tibial) collateral ligament
firmly attached to medial mensicus
Function of medial (tibial) collateral ligment
prevents abduction of the leg at the knee
MCL supports knee against:
valgus force and offers resistance to both internal and external rotation
LCL limits:
varus force not affected by rotation
Shape of medial menicus
C-shaped
Shape of lateral meniscus
almost circular
Purpose of menisci:
Act as cushion or shock absorber and facilitates lubrication of articular surfaces
What binds the anterior horns of mensici:
transverse ligament
Patellar Ligament:
continuation of quadriceps tendon
Function of fibrocartilage menisci:
cushion/shock absorption
What is in popliteal fossa?
popliteal vein
popliteal artery
tibial nerve
Where does the sciatic nerve bifurcate?
popliteal fossa
Tibialis anterior origin
Lateral condyle of tibia, proximal 1/2 - 2/3 or lateral surface of tibial shaft, interosseous membrane, and the deep surface of the fascia cruris
Tibialis anterior insertion
Medial and plantar surfaces of 1st cuneiform and on base of first metatarsal
Tibialis anterior action
Dorsiflexor of ankle and invertor of foot
Tibialis anterior innervation
deep peroneal nerve (L4,L5,S1)
Extensor Digitorum Longus origin
Lateral condyle of fibula, upper 2/3 - 3/4 of medial fibular shaft surface, upper part of interosseous membrane, fascia cruris, and anterior intermuscular septum
Extensor Digitorum Longus insertion:
Splits into 4 tendon slips after inferior extensor retinaculum, each of which insert on dorsum of middle and distal phalanges as part of extensor expansion complex
Extensor Digitorum Longus action
extend toes 2-5 and dorsiflexes ankle
Extensor Hallucis Longus origin
Anterior surface of the fibula and the adjacent interosseous membrane
Extensor Hallucis Longus insertion
Base and dorsal center of distal phalanx of great toe
Extensor Hallucis Longus action
Extends great toe and dorsiflexes ankle
Extensor Hallucis Longus innervation
Deep peroneal nerve (L4,L5,S1)
Gastronemius origin
Medial head from posterior nonarticular surface of medial femoral condyle; Lateral head from lateral surface of femoral lateral condyle
Gastronemius insertion
calcaneal tuberosity
Gastronemius action
Powerful plantar flexor of ankle and flexion of the knee, concentric contraction; extension of knee
Gastronemius innervation
Tibial nerve (S1,S2)
Soleus origin
Posterior aspect of fibular head, upper 1/4 - 1/3 of posterior surface of fibula, middle 1/3 of medial border of tibial shaft, and from posterior surface of a tendinous arch spanning the two sites of bone origin
Soleus insertion
calcaneal tuberosity
Soleus action
Powerful plantar flexor of ankle
Soleus innervation
tibial nerve (S1,S2)
Plantaris origin
Inferior aspect of lateral supracondylar line of distal femur
Plantaris insertion
Middle 1/3 of the posterior calcaneal surface, just medial to Achilles tendon
Plantaris action
Plantar flexor of ankle; also flexes knee
Plantaris innervation
tibial nerve (L5,S1,S2)
Tibialis Posterior origin
Posterior aspect of interosseous membrane, superior 2/3 of medial posterior surface of fibula, superior aspect of posterior surface of tibia, and from intermuscular septum between muscles of posterior compartment and deep transverse septum
Tibialis Posterior insertion
Splits into two slips after passing inferior to plantar calcaneonavicular ligament; superficial slip inserts on the tuberosity of the navicular bone and sometimes medial cuneiform; deeper slip divides again into slips inserting on plantar surfaces of metatarsals 2 - 4 and second cuneiform
Tibialis posterior action
Principal invertor of foot; also adducts foot, plantar flexes ankle, and helps to supinate the foot
Tibialis posterior innervation
tibial nerve (L4,L5)
Flexor Digitorum Longus origin
Posterior surface of tibia distal to popliteal line
Flexor Digitorum Longus insertion
Splits into four slips after passing through medial intermuscular septum of plantar surface of foot; these slips then insert on plantar surface of bases of 2nd - 5th distal phalanges
Flexor Digitorum Longus action
Flexes toes 2 - 5; also helps in plantar flexion of ankle
Flexor Digitorum Longus innervation
Tibial nerve (S2, S3)
Flexor Hallucis Longus origin
Inferior 2/3 of posterior surface of fibula, lower part of interosseous membrane
Flexor Hallucis Longus insertion
Plantar surface of base of distal phalanx of great toe
Flexor Hallucis Longus action
Flexes great toe, helps to supinate ankle, and is a very weak plantar flexor of ankle
Flexor Hallucis Longus innervation
Tibial nerve (S2, S3)
Popliteus origin
Anterior part of the popliteal groove on lateral surface of lateral femoral condyle
Popliteus insertion
Posterior surface of tibia in a fan-like fashion, just superior to the popliteal line
Popliteus action
Rotates knee medially and flexes the leg on the thigh
Popliteus innervation
Tibial nerve (L4, L5, S1)
Peroneus Tertius origin
Arises with the extensor digitorum longus from the medial fibular shaft surface and the anterior intermuscular septum (between the extensor digitorum longus and the tibialis anterior)
Peroneus Tertius insertion
Dorsal surface of the base of the fifth metatarsal
Peroneus Tertius action
Works with the extensor digitorum longus to dorsiflex, evert and abduct the foot
Peroneus Tertius innervation
Deep peroneal nerve (L5, S1)
Peroneus Brevis origin
Inferior 2/3 of lateral fibular surface; also anterior and posterior intermuscular septa of leg
Peroneus Brevis insertion
Lateral surface of styloid process of 5th metatarsal base
Peroneus Brevis action
Everts foot and plantar flexes ankle
Peroneus Brevis innervation
Superficial peroneal nerve (L5, S1, S2)
Peroneus Longus origin
Head of fibula, upper 1/2 - 2/3 of lateral fibular shaft surface; also anterior and posterior intermuscular septa of leg
Peroneus Longus insertion
Plantar posterolateral aspect of medial cuneiform and lateral side of 1st metatarsal base
Peroneus Longus action
Everts foot and plantar flexes ankle; also helps to support the transverse arch of the foot
Peroneus Longus innervation
Superficial peroneal nerve (L5, S1, S2); may also receive additional innervation from common or deep peroneal nerves (L5, S1, S2)
Small or negative Q angle
genu varum
Q angle greater than 17 degrees
genu valgum
Movement of tibiofibular joint:
moves anterior-posterior, up and down and rotates
Bow legs:
genu vara position, lateral weight shift, supination
Knock knee:
genu valga: obese, longitudinal
arch weakness, pronation
Hyperextended knee:
knee pulled backward
Tibial torsion
medial weight shift
knock-knee, flat feet, and pronation
Anterior compartment of leg
dorsiflexors, innervated by deep peroneal, blood supply from ant. tibial aa.
Lateral compartment of leg
evertors of foot, innervated by superficial peroneal nerve, blood supply from peroneal aa.
Posterior compartment of leg
plantar flexors, innervated by tibial nerve, blood supply from posterior tibial aa.