Joints and Their Classification

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Questions and Answers

What is the primary function of the articular cartilage in the knee joint?

To connect the tibia and fibula

To reduce friction and absorb shock (correct)

To provide stability to the femur

To facilitate muscle attachment

Which component of the knee joint is primarily responsible for load distribution and stability?

Head of fibula

Anterior cruciate ligament

Lateral meniscus (correct)

Lateral condyle

Which ligament is most essential in preventing anterior displacement of the tibia relative to the femur?

Medial collateral ligament

Lateral collateral ligament

Anterior cruciate ligament (correct)

Posterior cruciate ligament

What role do the menisci play in the mechanics of the knee joint?

They absorb shock and improve joint stability. Signup and view all the answers

Which muscles are primarily associated with the movements of flexion and extension at the knee joint?

Quadriceps and hamstrings Signup and view all the answers

Which statement correctly describes the structure of menisci in the knee joint?

Menisci function to distribute weight across the joint. Signup and view all the answers

Which ligaments are primarily responsible for stabilizing the knee joint?

Anterior cruciate ligament and posterior cruciate ligament Signup and view all the answers

Which muscle group is primarily involved in knee extension?

Quadriceps femoris Signup and view all the answers

How do menisci contribute to the mechanics of the knee joint?

By enhancing the congruence between femur and tibia Signup and view all the answers

What role do bursae play in knee joint mechanics?

They reduce friction between moving parts Signup and view all the answers

The patellar ligament connects which two structures?

Patella and tibia Signup and view all the answers

Which of the following statements about the joint capsule in the knee is correct?

It encloses the joint cavity and maintains the synovial fluid. Signup and view all the answers

What is the function of the articular cartilage in the hip joint?

To reduce friction during movement Signup and view all the answers

Which ligament is NOT a reinforcing ligament of the hip joint?

Medial collateral ligament Signup and view all the answers

How does the joint capsule of the hip joint contribute to its mechanics?

It restricts movements to prevent dislocation Signup and view all the answers

What characteristic differentiates the hip joint from the shoulder joint regarding movement?

The hip joint has less freedom of movement Signup and view all the answers

Which of the following structures acts as the socket in the hip joint?

Acetabulum of coxa Signup and view all the answers

What role does the synovial membrane play in the hip joint?

It produces and secretes synovial fluid Signup and view all the answers

Which muscle group is primarily responsible for stabilizing the hip joint?

Gluteal muscles Signup and view all the answers

What action is primarily facilitated by the hip joint during locomotion?

All of the above Signup and view all the answers

The ligamentum capitis serves what primary purpose in the hip joint?

It connects the head of the femur to the acetabulum Signup and view all the answers

Which of the following statements about hip joint mechanics is true?

The hip joint's structure allows for rotational movement Signup and view all the answers

Study Notes

Joints

Joints are functional junctions between bones
They bind parts of the skeletal system together
They make bone growth possible
They permit parts of the skeleton to change shape, such as during childbirth
They enable the body to move in response to skeletal muscle contraction

Classification of Joints

Structural classification, based on the material that connects the bones:
- Fibrous joints: Dense connective tissues connect bones. No synovial cavity
- Cartilaginous joints: Hyaline cartilage or fibrocartilage connects bones
- Synovial joints: Dense irregular CT allows free movement
Functional classification, based on the amount of movement allowed:
- Synarthrosis joints: Considered immovable
- Amphiarthrosis joints: Slightly movable
- Diarthrosis joints: Freely movable

Fibrous Joints

No synovial cavity
There are three types (functional synarthroses):
- Sutures: Between flat bones, teeth-like projections, thin layer of dense irregular CT between bones
- Gomphosis: Cone-shaped bony process in a socket. Only found where the periodontal ligament joins to the mandible or maxilla
- Syndesmosis: A sheet or bundle of fibrous tissue connects bones. Examples include interosseous membrane between tibia and fibula

Cartilaginous Joints

Synchondrosis: Bands of hyaline cartilage unite bones. Examples include: epiphyseal plate (temporary) between the manubrium and the first rib (this eventually ossifies during adult life, becoming synarthrosis)
Symphysis: Pad of fibrocartilage between bones. All occur in the midline of the body. This includes the pubic symphysis and joints between bodies of adjacent vertebrae

General Structure of a Synovial Joint

Synovial joints are freely movable (diarthroses).
There are three types of diarthroses:
- Uni-axial: Hinge joint (elbow) and Pivot joint (between atlas [C1] and the dens of axis [C2]).
- Bi-axial: Saddle joint and Condylar or ellipsoidal joint
- Multi-axial: Ball and socket joint (hip, shoulder) and Gliding or plane joint.

Synovial Joint

Synovial membrane lines the interior of the joint capsule and secretes synovial fluid
Synovial fluid lubricates, cushions, prevents abrasion, and supports chondrocytes of the articular cartilages through nutrient distribution
Even in a large joint like the knee, the total amount of synovial fluid is normally less than 3 mL

Types of Synovial Joints Based on Shape

Nonaxial, uniaxial, biaxial, multiaxial are classifications based on the type of movement these joints allow

Uniaxial Synovial Joints

Pivot joint: Between atlas (C1) and the dens of axis (C2), and also between radius and ulna
Hinge joint: Elbow joint (humerus and ulnar) and between phalanges (finger and toe bones)

Biaxial Synovial Joints

Saddle joint: Between carpal and metacarpal (thumb)
Condyloid joint: Between metacarpals and phalanges, and between radius and carpals.

Multiaxial Synovial Joints

Ball-and-socket joint: Hip joint and shoulder joint
Gliding joint: Sacroiliac joints, acromioclavicular, sternoclavicular joints, joints between carpals, and between tarsals, and between facets of adjacent vertebrae

Shoulder Joint

Ball-and-socket joint, head of humerus and glenoid cavity of scapula
Loose joint capsule, bursae, ligaments prevent displacement
Wide range of movement (circumduction)

Glenohumeral Joint

This type of joint includes parts of the scapula, clavicle, and humerus
Includes joint capsule, synovial membrane, bursae, and ligaments

Elbow Joint

Hinge joint
Trochlea of humerus, trochlear notch of ulna, capitulum of humerus, head of radius
Flexion and extension
Numerous reinforcing ligaments
Stable joint

Knee Joint

Largest, most complex joint
Medial and lateral condyles of distal femur and proximal tibia
Femur articulates anteriorly with the patella
Strengthened by ligaments and tendons
Menisci separate the femur and tibia
Bursae.

Hip Joint

Ball-and-socket joint
Head of femur and acetabulum of coxa
Heavy joint capsule
Numerous reinforcing ligaments
Less freedom of movement than the shoulder
Circumduction

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Description

Explore the fascinating world of joints, the functional junctions between bones that enable movement and shape changes in the skeletal system. Learn about the structural and functional classifications of joints, including fibrous, cartilaginous, and synovial types. Test your knowledge and understanding of this vital aspect of human anatomy.