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Flashcards in Joints of the Lower Limb Deck (29)
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1
Q

Joints can be classified based on two criteria. What are they?

A

Structure (what unites the bones in a joint) and mobility

2
Q

What are the Joint Classifications based on structure?

A
  • Fibrous joints: are united by fibrous connective tissue (e.g., suture, superior tibiofibular joint) and the degree of mobility varies
  • Cartilaginous joints: are united by hyaline cartilage (e.g., 1st sternocostal joint) or fibrocartilage (e.g., pubic symphysis) and the degree of mobility is limited
  • Synovial joints: united by a complex joint capsule; this is the most common type of joint in the human body and they are highly mobile
3
Q

What components do all synovial joints have?

A
  • Synovial cartilage
  • Joint capsule
  • Joint cavity
4
Q

What are the variable structures found in synovial joints?

A
  • Bursae
  • Tendon sheaths
  • Fibrocartilage structures (i.e. Articular disc, Meniscus, Labrum)
  • Ligaments (Extracapsular, Capsular, Intracapsular)
5
Q

Describe Synovial cartilage

A

-A thin layer of hyaline cartilage covering each bone in the joint; unlike a cartilaginous joint, each bone in a synovial joint has a separate piece of cartilage covering it; in a normally functioning synovial joint, cartilage moves past cartilage; there is no direct bone to bone contact; synovial cartilage reduces friction between bones

6
Q

Describe a Joint capsule

A
  • Surrounds the articulating bones and consists of two layers
    1) Fibrous layer: superficial layer; tough and fibrous; protects remainder of joint
    2) Synovium: inner layer facing joint cavity; secretes synovial fluid
7
Q

Describe a Joint cavity

A

-Potential space defined by joint capsule; filled with a small amount of fluid called synovial fluid, which provides lubrication and nutrition to the contents of the joint capsule

8
Q

Describe Bursae

A

-Synovial structures with fibrous layer, synovium, and synovial fluid filled cavity cavity; may or may not be in communication with the main joint capsule; facilitate movements of structures that cross a joint

9
Q

Describe Tendon sheaths

A

-Specialized bursae that wrap around tendons crossing the writs and ankle to facilitate tendon movements

10
Q

What are the Fibrocartilage structures?

A
  • Articular disc: fibrocartilage pad between bones in a joint
  • Meniscus: C-shaped disc between bones in a joint
  • Labrum: rim of cartilage surrounding the articular margin of one bone in a joint
11
Q

Describe Ligaments

A

-Bands of connective tissue crossing a joint; classified based on their relationships to the joint capsule

12
Q

What are the types of ligaments?

A
  • Extracapsular: outside the joint capsule
  • Capsular: thickening of the joint capsule
  • Intracapsular: inside the joint capsule
13
Q

What are the Joints of the Lower Extremities?

A
Sacroiliac Joint
Hip Joint
Knee Joint
Tibiofibular joints
Talocrural and Subtalar joints
Arches and Ligaments of the Foot
Metatarsaophalangeal joints
Interphalangeal joints
14
Q

Describe the Sacroiliac Joint

A
  • Compound joint: partly fibrous and partly synovial; becomes more fibrous with age
  • Strengthened by ligaments (almost all of body weight is transmitted from the sacrum to the ilium, so it needs to be strong):

1) Intrinsic ligaments (restricted to the area around the joint)
- Anterior sacroiliac ligament
- Posterior sacroiliac ligament

2) Extrinsic ligaments: counteract turning moment produced by the fact that the body’s center of mass is anterior to the SI joint
- Sacrotuberous ligament
- Sacrospinous ligament

15
Q

Describe the Hip joint and what ligaments are associated with it

A
  • Ball and socket joint: potentially very mobile and unstable
  • Strengthened by a cuff of capsular ligaments
  • Iliofemoral and ischiofemoral ligaments become tight in extension to prevent hyperextension
  • Pubofemoral ligament becomes tight in abduction to prevent hyperabduction
16
Q

Describe how the acetabulum and the femoral head interact at the Hip Joint

A

1) Acetabulum
- Articular surface is C-shaped lunate surface, open ventromedially by acetabular notch
- Margin of acetabulum is extended by a fibrocartilage labrum

2) Femoral head
- Ball shaped surface with a small depression, the fovea capitis, which serves as a point of attachment of the round ligament, which weakly holds the femoral head against the acetabulum

17
Q

Describe blood supply to the hip

A
  • Lateral circumflex femoral a. femoral shaft
  • Medial circumflex femoral a.: primary blood supply to the femoral head and neck
  • Acetabular branch of the obturator a.: runs in round ligament, supplies head and neck, but not always sufficient on its own

-Hip fracture (fracture of femoral neck) can disrupt the blood supply to the femoral head/neck; if acetabular branch is insufficient, this can result in avascular necrosis of the head and neck

18
Q

Describe the knee joint

A
  • Relatively unstable hinge joint between convex femoral and flat tibial condyles
  • Patellofemoral joint: between patella and femur; patella slides back and forth in patellar groove
19
Q

What are the menisci of the knee joint?

A

-Medial and lateral menisci improve the contact between femur and tibia, making joint more stable

20
Q

What are the ligament of the Knee joint?

A
  • Lateral collateral ligament (LCL): extracapsular ligament; prevents lateral bowing of knee
  • Medial collateral ligament (MCL): capsular ligament; attached to medial meniscus; prevents medial bowing of knee
  • Anterior cruciate ligament (ACL): origin anterior on tibia; inserts posteriorly on femur; intracapsular ligament; prevents hyperextension
  • Posterior cruciate ligament (PCL): origin posterior on tibia; inserts anteriorly on femur; intracapsular ligament; prevents hyperflexion

-“Unhappy triad injury”: lateral force applied to the knee with the foot planted and the knee extended can produce hyperextension and medial bowing, tearing the 1) ACL, 2) MCL, 3) medial meniscus where it is attached to the MCL

21
Q

Describe the Tibiofibular joints

A
  • Two joints between tibia and fibula
    1) Proximal joint is synovial (superior tibiofibular joint)
    2) Distal joint is fibrous (inferior tibiofibular joint)
  • Little movement possible
22
Q

Describe the Talocrucal joint

A
  • A hinge synovial joint between distal tibia and lateral malleolus of distal fibula proximally, talus distally
  • Range of motion: dorsiflexion/plantarflexion
23
Q

Describe the Subtalar joint

A
  • A synovial joint between the talus and calcaneus

- Range of motion: inversion/eversion

24
Q

What are the Associate ligaments of the Talocrural and Subtalar joints

A
  • Medial collateral (deltoid) ligament: 4 parts; prevents hypereversion
    1) Tibionavicular ligament
    2) Tibiocalcaneal ligament
    3) Anterior tibiotalar
    4) Posterior tibiotalar
  • Lateral collateral ligament: 3 parts; prevents hyperinversion
    1) Anterior talofibular
    2) Posterior talofibular
    3) Calcaneofibular
25
Q

Describe the Arches and Ligaments of the Foot

A
  • The weight of the body is transferred from the tibia –> talus –> calcaneus –> lateral border of the foot –> metatarsal heads –> hallux (last part of the foot to leave the ground)
  • The arches of the foot are located between these weight bearing points and act as shock absorbers and assist in propelling the body forward
26
Q

What are the different arches of the foot?

A

1) Medial longitudinal arch is formed by the calcaneus, talus, navicular, three cuneiforms, 1st through 3rd metatarsals; the talus forms the keystone of the medial longitudinal arch
2) Lateral longitudinal arch is formed by the calcaneus, cuboid, and 4th and 5th metatarsals; rests on the ground while standing
3) Transverse arch is formed by the three cuneiforms, cuboid, and bases of all five metatarsals

27
Q

What maintains the foot of the arch?

A
  • Interlocking configuration of the bones of the foot
  • Plantar aponeurosis
  • Muscles/Tendons
  • Tibialis posterior and fibularis longus
  • Flexor hallucis longus, flexor digitorum longus, intrinsic muscles of the foot
  • Long plantar ligament with attachments on the calcaneus, cuboid and bases of the metatarsals
  • Short plantar ligament (plantar calcaneocuboid ligament) with attachments on the calcaneus and cuboid
  • Spring ligament (plantar calcaneonavicular ligament) with attachments on the calcaneus and navicular; supports the talus
28
Q

Describe the Metatarsaophalangeal joints and what ligaments strengthen it.

A
  • Allow flexion/extension and adduction/abduction
  • Strengthened by ligaments
    1) Collateral ligaments
    2) Plantar ligaments
    3) Deep transverse metatarsal ligaments: between adjacent metatarsals
29
Q

Describe the Interphalangeal joints

A
  • PIP and DIP on digits 2-5
  • IP only on hallux
  • Flexion and extension only
  • No deep transverse ligaments