Exam #5: Joints Flashcards
What covers the head of the femur?
Articular cartilage
What is the only part of the head of the femur that is NOT covered by articular cartilage?
Fovea capitis femoris
Where is the articular cartilage the strongest?
Superior portion of the head; it has to support the most weight
What is the articular surface of the acetabulum called?
Lunate surface of the acetabulum
Does the head of the femur extend into the acetabular fossa?
No
Describe the composition of the floor of the acetabulum.
The acetabulum does NOT forma complete circle, the floor is composed of a fibroelastic mass
What are the three main ligaments of the hip?
1) Iliofemoral ligament
2) Pubofemoral ligament
3) Ischiofemoral ligament
What is the main function of the ligaments of the hip?
Prevention of hyperextension
What is the strongest & widest ligament of the hip?
Iliofemoral ligament
What are the attachments of the iliofemoral ligament?
AIIS and intertrochanteric line
What are the specific functions of the iliofemoral ligament ?
Prevents hyperextension & external rotation
Where does the pubofemoral ligament attach?
Superior ramus of the pubis & obturator crest to iliofemoral ligament
What are the specific functions of the pubofemoral ligament?
Prevents hyperextension, external rotation, and ABduction
Describe the arrangement of the ischiofemoral ligament.
Spirals from the ischial body to the femoral neck
What is the functional outcome of the spiral arrangement of the ischiofemoral ligament?
Extension winds the spiraling ligaments & fibers more tightly, constricting the capsule & drawing the femoral head tightly into the acetabulum–>stability
What are the specific functions of the ischiofemoral ligament?
Prevents hyperextension & internal rotation
What is the Ligament Capitis Femoris?
Ligament of the head of the femur that attaches to the fovea of the femur & transverse acetabular ligament
What is the function of the Ligament Capitis Femoris?
Becomes tense when the FLEXED thigh is ADducted
*Also, note that it contains a small artery that is an important blood supply to the head of the femur (for growth) in children
What is the Acetabular Labrum?
“Lip of the Acetabulum”
- The Acetabular Labrum narrows the acetabulum to add stability
What is the Transverse Acetabular Ligament?
Continuation of the Acetabular Labrum across the Acetabular Notch
What are the two major sources of blood supply to the head of the femur?
1) Obturator a.
2) Medial & Lateral Circumflex Femoral a.
Describe the blood supply to the head of the femur from the Obturator a.
The Acetabular Branch comes off the Obturator a. & then gives rise to the Artery to the head of the femur, which passes through the Ligament Femoris Capitis
Describe the blood supply to the femur from the Femoral a.
The Femoral a. gives off the Profunda femoris a. Typically, the Medial & Lateral Circumflex Femoral a. branch from the Profunda & go to the femur, giving off Retinacular a.
What is the difference between a Basal & Subcapital fracture of the femur?
Basal= occurs at the base of the femoral neck–does not interrupt blood supply
Subcapital= occurs just under the head of the femur–blood supply to the head of the femur can be impaired, leading to avascular necrosis
What is the largest joint in the body?
Knee
*Note that despite being the largest, it is also the most unstable
What three bones make up the knee joint?
1) Femur
2) Patella
3) Tibia
What bones in the knee joint does the patella articulate with?
Femur ONLY
*The patella does NOT articulate with the tibia
What type of joint is between the tibia and femur?
This is a synovial hinge joint but it does allow some degree of rotation, so it is better called a CONDYLOID joint
What type of joint is between the patella and femur?
Gliding joint
What is the difference between the quadriceps tendon and the patellar ligament?
Quadriceps tendon= quadriceps muscles–>patella
Patellar ligament= patella–>tibial tuberosity
What is the Fibular Collateral Ligament?
Lateral Collateral Ligament
Where does the Fibular (Lateral) Collateral Ligament attach?
Lateral epidcondyle of the femur to the head of the fibula
What is the Tibial Collateral Ligament?
Medial Collateral Ligament
Where does the Tibial Collateral Ligament attach?
Medial epicondyle of the femur to the medial tibia
How do the Fibular Collateral Ligament & Tibial Collateral Ligament differ?
Lateral= rounded/ rope-like and NOT attached to the lateral menisci
Medial= flat & ribbon-like & ATTACHED to the medial meniscus
If the Medical Collateral Ligament is injured, what else is likely to be injured?
Medial Meniscus
What is the Oblique Popliteal Ligament?
A posterior ligament of the knee that forms as an expansion of the semimembranosus tendon–it forms the floor of the popliteal fossa
Where does the Oblique Popliteal Ligament attach?
Medial condyle of the tibia to lateral condyle of the femur
What is the Arcuate Popliteal Ligament?
A posterior-lateral ligament of the knee that arches over the tendon of the popliteal muscle
Where does the Arcuate Popliteal Ligament attach?
Intercondylar area of the tibia to the fibular head
What is the Coronary Ligament?
The ligament that attaches the menisci to the joint capsule
How many intra-articular ligaments are there of the knee? Which are the most important?
There are 5 intra-articular ligaments of the knee; two of them are important:
1) ACL
2) PCL
How are the cruciate ligaments named?
By their tibial attachments
What is the function of the ACL?
Prevention of posterior displacement of the femur on the tibia i.e. it stops “HYPEREXTENSION” of the knee
What is the function of the PCL?
Prevention of anterior displacement of the femur on the tibia i.e. it stops HYPERFLEXION of the knee
What are the structural differences between the ACL & PCL?
ACL is longer & weaker, PCL is shorter and stronger
Describe the structure of the menisci.
C-chaped fibrocartilage that is thicker on the outside and thinner on the inside
What artery penetrates the capsule of the knee & supplies the intercondylar structures?
Middle genicular artery
What is the unhappy triad of the knee?
This is an injury pattern to the knee seen with a lateral blow to the knee when the foot is fixed, or with twisting forces. The outcome is involves three tears:
1) MCL
2) Medial menisci
3) ACL
What is an anterior drawer sign? What causes an anterior drawer sign?
An anterior drawer sign is when the tibia is able to slide forward under the femur upon testing by an examiner
- Caused by skiing accidents
- Indicates ACL rupture
What is a posterior drawer sign? What causes a posterior drawer sign?
A posterior drawer sign is when the free tibia slides posterior under the femur
- Caused by car accidents when the tibial tuberosity strikes the dashboard with the knee flexed
- Indicates PCL rupture
What are the colloquial terms for genu varum & genu valgum?
Genu varum= bowleg
Genu valgum= knock knee
What three bones form the ankle joint?
1) Trochlea of the talus
2) Tibia
3) Fibula
When is the ankle joint most stable? When is it most unstable? Why?
Most stable= dorsiflexion
Least stable= plantar flexion
The anterior part of the trochlea is wider than the posterior part. Dorsiflexion forces the anterior part backward; thus, the malleoli exert more pressure & make the joint more stable.
What ligament is on the medial side of the ankle?
Deltoid ligament
What ligament is on the lateral side of the ankle?
Lateral ligament
Which ligament of the ankle is stronger? What is the clinical outcome?
The medial “Deltoid” ligament is the stronger of the two ankle ligaments; thus, the lateral ligament more frequently is sprained by inversion injury
What is a Pott’s Fracture?
A Pott’s Fracture is a severe injury to the ankle caused by forced eversion; there are three hallmark’s of a Pott’s fracture:
1) Deltoid ligament pulls the medial malleolus apart, fracturing it
2) Lateral malleoli fracture
3) Fibula fracture
I.e. Pott’s fracture= fracture of medial & lateral malleoli + fibula
What is the Subtalar Joint?
Joint between the talus & calcaneus
What is the function of the Subtalar Joint?
Permits inversion & eversion
What are the functions of the arches of the foot?
Add to weight bearing, resilience, shock absorption, & propelling of the lower limb during walking
What bones form the medial longitudinal arch?
Calcaneus Talus Navicular 3x Cuneiforms 3x medial metatarsals
What supports the medial longitudinal arch?
Spring ligament
Plantar aponeurosis
What bones form the lateral longitudinal arch?
Calcaneus
Cuboid
Lateral 2x metatarsals
What supports the lateral longitudinal arch?
Long plantar ligament
Short plantar ligament
Plantar aponeurosis
What is the major difference between the medial & lateral longitudinal arch?
Medial longitudinal arch does NOT rest on the ground
What bones form the Transverse arch?
Cuboid
3x Cuneiforms
Bases of all the metatarsals