Lower Limb Joints Flashcards
Anterior SI joint
. Synovial joint btw interlocking auricular surfaces of sacrum and ilium
. Auricular surfaces covered by articular cartilage
Posterior SI joint
. Syndesmosis btw tuberosties of sacrum and ilium
Intrinsic ligament of SI joint
. Ant./post. SI ligament
. Interosseous ligament
Ant. SI ligament
. Ant. Portion of fibrous joint capsule
Interosseous SI ligament
. Spans btw tuberosities of sacrum and ilium
. Strongest ligament in body
. Primary weight-bearing structure
Posterior SI ligament
Post. External continuation of interosseous SI ligament
. Blends w/ sacrotuberous ligament inf.
Extrinsic ligaments of SI joint
. Iliolumbar: connects transverse process of L5 to pos. Iliac crest, blends w/ ant. SI ligament, stabilizes SI joint, sometimes connected to L4
. Sacrospinous: prevent excessive ant. rotation
. Sacrotuberous (same as above)
Movement permitted by SI joint
. Small amount of gliding and rotation (pelvic tilt)
. Relatively immobile
Interosseous SI ligaments function
. Transmit weight of upper body to pelvic bones
Sacrospinous and sacrotuberous ligament function
. Resist ant. Rotation of sacrum in response to vertical loading of sacral base ant. To SI joint’s transverse axis
What percentage of femur head resides w/in the acetabulum?
More than 50%
Congenital hip dysphasia
. Development anomaly
. Causes intermittent dislocation of femur head from acetabulum
. Risks: family history, female, breech presentation
. Infants screened for this
Hip Joint surfaces that have articular cartilage
. Femoral head including its fovea
. Lunate surface of acetabulum
Hip joint surfaces not covered by articular cartilage
. Acetabulum fossa
. Has synovium covered acetabulum fat pad instead
Transverse acetabular ligament
. Spans acetabular notch
. Connects free ends of labrum
. Forms foramen for passage of nerves and vessels
Femoroacetabular impingement syndrome
. Bone spurs on femoral head and/or acetabular margin create friction and restrict movement
. Contact can erode articular cartilage or tear the labrum
Acetabular labrum
. Incomplete fibrocartilage ring
. Attaches to acetabular rim
. Deepens acetabulum
Joint capsule of hip joint
. fibrous capsule attaches to acetabular rim external to the labrum and to transverse acetabular ligament
. Encircles femoral neck
. Ant. Attaches to intertrochanteric line and base of greater trochanter
. Post. Cross neck sup. To intertrochanteric crest but is free margin
. Fibers have spiral course from pelvis to femur
Traumatic hip dislocation
. Caused by car accidents or falls
. 90% are post.
. Complications: acetabular fracture, sciatic n. Injury, interruption of femoral head blood supply
. Presents as shortened limb in fixed adducted med. rotated position
Intrinsic ligaments of hip joint
. Iliofemoral
. Pubofemoral
. Ischiofemoral
Iliofemoral ligament
. Strongest intrinsic ligament
. From AIIS and acetabular rim to intertrochanteric line
. Makes inverted Y
. Convers. Sup. And ant. Surfaces of joint
. Prevents hyperextension, limits rotation in standing, limits adduction
Pubofemoral ligament
. Second strongest
. Arises from pubic portion of acetabular rim
. Attaches distally to inf. End of intertrochanteric line
. Covers inf. Aspect of hip
. Limits extension, abduction, and lat. rotation
Ischiofemoral ligament
. Weakest
. From ischial portion of acetabular rim
. Attaches distally to base of greater trochanter
. Covers post. Aspect hip joint
. Limits extension, abduction, and med. rotation
Ligament of femoral head
. Also called round ligament of femur, ligamentum teres Femoris
. Weak extrinsic ligament w/in hip joint capsule
. From borders of acetabular notch and transverse acetabular ligament
. Attaches to fovea of femoral head
. Enclosed in synovial fold that transmits acetabular branch of obturator a.
. Tightens during hip adduction, it not significant support
How capsular ligaments stabilize hip
. In standing or extension, winding of spiral fibers tightens hip capsule (esp. iliofemoral)
. Windings pulls femoral head into acetabulum and stabilizes joint w/ minimal muscular effort
. Flexion unwinds fibers for greater ROM
. Tonic contraction of med. and lat. rotators provide dynamic support
Range of hip flexion when knee is flexed is limited by ____
. Soft tissue contact
Straight leg flexion is limited by ____
Muscular tension
Hip extension is limited by _____
. Capsular ligaments to 10-20 degrees
. Esp. Iliofemoral
What ligament needs to be lax in gymnasts?
Iliofemoral
Hip joint blood supply
. Branches of med. and lat. femoral circumflex aa.
. A. To head of femur is small branch of obturator a. That courses w/in ligament of femoral head
What nn. Supply hip joint?
. Femoral
. Obturator
. Sup. Gluteal
. N. To quadratus femoris
Leg-calve-perthes
. Femoral head collapse from fracture that disrupts blood supply
. Disease is pediatric condition
. Risk factor: male, family history
Articulations in knee joint
. Medial and lateral tibiofemoral
. Patellofemoral
What structures in knee joint are covered w/ articular cartilage?
. Condyles and patellar surface of femur
. Condyles of tibia
What surfaces in knee joint do not have articular cartilage?
. Intercondylar area of tibial plateau
. Provides attachments for ligaments and menisci
What femoral condyle is larger?
Medial
. Larger w/ longer articular surface
Q-angle
. Due to difference in condylar size
. Btw tibia and femur
. Males: 10-15 degrees
. Female: 15-18 degrees
Lat. lip do femur’s patellar surface function
. Resists lat. displacement of patella
. Guides movement during fl/extension
Fibrous capsule of knee joint
. Attached to margins of femoral articular surfaces and tibial plateau
. Thin post., strengthened med. and lat. by collateral ligaments
. Post. Capsule has arcuate popliteal ligament that is a gap that admits popliteus tendon
. Ant. Capsule replaced by quad tendon, patella, and patellar ligament
Synovial membrane of knee joint
. Lines majority of capsule
. Post. Forms infrapatellar synovial fold that excludes intercondylar area
. Extends sup. Deep to quad tendon forming suprapatellar bursa continuous w/ joint cavity
Infrapatellar synovial fold
. Encloses cruciate ligaments
. Subdivides synovial cavity into med. and lat. compartments
Menisci attachments
. Peripheral margins attach to tibial condyles via coronary ligaments
. Horns attach to intercondylar area
. Med. meniscus attached to med. collateral ligament
Menisci shape
. Thick peripherally and thinner centrally (wedge-shaped)
. Med. meniscus is crescent-shaped
. Lat. meniscus is circular shaped
Med. Meniscus characteristics
. Attached to med. collateral ligament
. Less mobile
. More susceptible to injury
Lat. meniscus characteristics
. Horns more closely spaced
. Less susceptible to injury
. Does NOT attach to lat. collateral ligament
Zones of meniscus
. Peripheral red zone: better blood supply, heads more readily
. Central white zone: avascular
What connects menisci?
Transverse ligament
. Coordinates movements during fl/extension
Discoid meniscus
. Meniscus covers all or most of tibial condyle
. Prone to injury due to poor blood supply and altered joint mechanics
. 3% population has lat. one, 0.1% population has med. one
Medial collateral ligament (MCL) and functions
. Broad, flat intrinsic ligament covering med. aspect of knee
. From med. epicondyle of femur to med. tibial condyle and shaft
. Deep fibers attach to med. meniscus
. Ligament gets tight during extension
. Resists lat. rotation and abduction
Fibular (lat.) ligament (LCL)
. Strong, cord-like extrinsic ligament
. From lat. epicondyle of femur to head of fibula
. Tight in extension
. Resists lat. rotation and adduction of leg
. Superficial to tendon of popliteus m. Separating it from lat. menisci
. Anterolateral ligament (ALL)
. Thickening of capsule btw lat. epicondyle and lat. tibial condyle post. To gerdy’s tubercle
. Deep fibers attach to lat. meniscus
. Resists adduction and med. rotation of leg
Barn-door sign
. Identifies excessive opening of joint caused by damage to collateral ligaments
Cruciate ligaments
. PCL and ACL
. Cord-like extrinsic ligaments w/in joint capsule but outside synovial cavity
. Enclosed by infrapatellar synovial fold
. Tight in extension
. Resist med. rotation of tibia and ab/dduction of knee
ACL
. Attached to ant. Intercondylar area of tibia and posterolateral intercondylar notch of femur
. Resists ant. Displacement of tibia or post. Displacement of femur
PCL
. Attaches to post. Intercondylar area of tibia and anteromedial intercondylar notch of femur
. Resist post. Displacement of tibia or ant. Displacement of femur
Segond fracture
. Avulsion of ALL’s tibial attachment
. Occurs in 10% ACL rupture
. High incidence in ACL injuries in female athletes
Sequence of knee extension
. Lat. femoral condyle reaches limit of articular surface sooner than med. one and ACL becomes taut
. Femur rotates med. using ACL as pivot
. Med. condyle glides post. And rotates to achieve max congruence w. Tibia and full extension
Sequence of knee flexion
. Initiated by popliteus m. Which rotates femur lat.
. Moves med. condyle forward to unlock knee
. Movement completed by principal knee flexor muscles
Why is fully extended knee so stable?
. Collateral ligaments taut
. Cruciate ligaments are tightly wound (screw-home position)
What provides dynamic support of the knee?
. Quads
. Hamstrings
. Tensor fasciae latae and IT band provide lad. Stabilization
Unhappy triad
. Blow to lat. knee when foot is planted when knee is extended
. Damage to med. collateral ligament, med. meniscus, and ACL
Blood supply of knee joint
. Genicular aa. (Direct and indirect branches of femoral, popliteal, and ant. Tibial aa.)
. Form genicular anastomosis
Innervation of knee joint
. Articular branches of femoral, tibial, common fibular, obturator, and saphenous nn.
Superior tibiofibular joints
. Plane-type synovial joint btw lat. condyle of tibia and fibular head
. Supported by ant. And post. Ligaments of fibular head
. Joint permits sup. Translation of fibula during dorsiflexion of ankle
Middle tibiofibular joint
. Syndesmosis formed by interosseous membrane of leg and shafts of tibia and fibulas
Inferior tibiofibular joint
. Syndesmosis btw distal ends of tibia and fibula supported by ant., post., and interosseous tibiofibular ligaments
Interosseous membrane of tibiofibular joint resists ____
Inf. Pull of leg muscles originating from fibula
Talocrural (ankle) joint structure
. Hinge synovial joint btw distal surface and med. malleolus of tibia, lat. malleolus of fibula, and trochlea of talus
. Distal tibia and malleoli form mortise (deep socket) w/ 3 articulations for sup., med., and lat. trochlea
. Thin fibrous capsule reinforced med. and lat. by ligaments
Ankle ligaments
. Med. collateral ligament (deltoid): fan-shaped attaching med. malleolus to talus, navicular, and sustentaculum tali, fibers blend w/ plantar calcaneonavicular ligament, resists eversion and supports med. longitudinal arch
. Lat. collateral ligament: ant. Talofibular, calcaneofibular, and post. Talofibular ligaments arising from lat. malleolus, resists inversion
Ankle sprain
. Most frequent injury in body
. Caused by inversion on planted foot typically
. ATF first, followed by calcaneofibular and post. Talofibular
Ankle joint function
. Permits dorsi/plantar flexion and small amount of inversion/eversion in plantarflexed position
. During dorsiflexion, joint surfaces are tight-packed and stabilized by interosseous talofibular ligament making it stable
Ankle joint blood supply
. Malleolus branches of ant. Tibial, post. Tibial, and fibular aa.
Ankle joint innervation
. Articular branches of tibial and deep fibular nn.
Subtalar joint
. Plane-type btw post. Articular surfaces of talus and calcaneus
. Fibrous capsule attaches to margins of articular surfaces
. Reinforced by intrinsic ligaments and interosseous talocalcaneal ligament
. Permits movement of inversion and eversion
Talocalcaneonavicular joint
. 3 articulations: 2 plane type btw middle and ant. Articular surfaces of talus and calcaneus and talonavicular joint (ball and socket btw head of talus and prox. Navicular)
. Fibrous capsule reinforced on plantar surface by spring ligament that attaches to sustentaculum tali and navicular tuberosity
. Allows gliding and rotary movements in coordination w/ inversion/eversion of foot
Sinus tarsi syndrome
. Tenderness, ankle instability, and pain on inversion and plantarflexion
. Due to issues w/ tarsal sinus and interosseous talocalcaneal ligament
Transverse tarsal joint
. Compound joint formed by 2 transversely aligned joints (talonavicular and calcaneocuboid)
. Calcaneocuboid is plane-type joint btw ant. Calcaneus and post. Cuboid
Ligaments in transverse tarsal joint
. Plantar calcaneocuboid (short plantar): attaches calcaneus to inf. (Plantar) surface of cuboid
. Long plantar ligament: from calcaneal tuberosity and attached to cuboid bone and bases of metatarsals II-V forming tunnel for fibularis longus tendon, superficial to short ligament
3 major ligaments of mid foot
. Long and short plantar ligaments
. Plantar calcaneonavicular ligament
. Support foot’s longitudinal arches
Intertarsal and tarsometatarsal joints
. Plant joints btw distal tarsals ( cuneiforms and cuboid) and metatarsals
. Allow limited gliding
. Strengthen transverse arch
MP joints of foot
. Condyloid joints btw metatarsals and bases of prox. Phalanges
. Allow fl/extension and ab/dduction
. Fibrous joint capsule deficient dorsal where it is replaced by extensor tendons
MP joint of foot ligaments
. Med. and lat. collateral ligaments (intrinsic) unite metatarsal head w/ prox. Phalangeal base and plantar plate, reinforce med. and lat. parts of fibrous capsule, tighten w/ flexion, limit ab/dduction of flexed joint
. Plantar plate ligament: fibrocartilage attaching metatarsal head to phalangeal base, reinforces ant. Capsule and creates socket for metatarsal head
. Deep transverse metatarsal ligaments: connect plantar plates
IP joints of foot
. Hinge joints btw phalanges
. Have plantar plates should and joint capsules w/ med. and lat. collateral ligaments
. Only allow fl/extension
Blood supply and innervationof foot joints
. Articular branches of med. and lat. planter nn. And aa.
