Articulations (Joints) Lecture Practice Flashcards

Comprehensive practice flashcards covering structural and functional joint classifications, synovial joint anatomy, biomechanical levers, joint movements, and pathologies from the Articulations (Joints) lecture.

What is an articulation (joint)?

An articulation, or joint, is the place of contact between bones, between bone and cartilage, or between bones and teeth.

What are the two general ways that joints can be classified?

Joints are classified structurally (based on the type of connective tissue binding the bones and the presence or absence of a joint cavity) and functionally (based on the degree of movement permitted).

What are the three structural classifications of joints, and how are they defined?

1. Fibrous joints: joined by dense regular connective tissue with no joint cavity. 2. Cartilaginous joints: joined by cartilage with no joint cavity. 3. Synovial joints: bones separated by a fluid-filled joint cavity enclosed by an articular capsule.

What are the three functional classifications of joints, and how are they defined?

1. Synarthrosis: an immobile joint. 2. Amphiarthrosis: a slightly mobile joint. 3. Diarthrosis: a freely mobile joint.

What is the definition of a synarthrosis?

A synarthrosis is an immobile joint.

What is the definition of an amphiarthrosis?

An amphiarthrosis is a slightly mobile joint.

What is the definition of a diarthrosis?

A diarthrosis is a freely mobile joint.

What is the relationship or tradeoff between the mobility and stability of a joint?

There is an inverse relationship: as the mobility of a joint increases, its stability decreases; conversely, greater joint stability results in decreased mobility.

What is the main function of fibrous joints?

The main function of fibrous joints is to hold articulating bones firmly together, providing stability with little to no movement.

What are the three types of fibrous joints?

The three types of fibrous joints are gomphoses, sutures, and syndesmoses.

What are the characteristics and functional classification of a gomphosis?

A gomphosis resembles a 'peg-in-a-socket', consisting of the roots of teeth held in the dental alveoli of the mandible and maxillae by periodontal membranes; it is functionally classified as a synarthrosis (immobile).

What are the characteristics and functional classification of a suture?

A suture is an immobile fibrous joint (synarthrosis) found only between certain bones of the skull, characterized by interlocking, wavy edges united by dense regular connective tissue.

What is a synostosis?

A synostosis is an obliterated, completely ossified joint formed when the fibrous tissue between bones (such as a suture) ossifies, fusing the bones into a single solid bone.

What is an example of a synostosis?

An example of a synostosis is the fused frontal (metopic) suture of the frontal bone or fused epiphyseal lines in adult long bones.

What are the characteristics, functional classification, and an example of a syndesmosis?

A syndesmosis is a fibrous joint where articulating bones are joined by long strands of dense regular connective tissue (such as an interosseous membrane); it is functionally classified as an amphiarthrosis; an example is the interosseous membrane between the radius and ulna.

In what very basic way do cartilaginous joints differ in structure from fibrous joints?

Cartilaginous joints have cartilage (hyaline cartilage or fibrocartilage) connecting the articulating bones, whereas fibrous joints are held together by dense regular connective tissue (both lack a joint cavity).

What are the main functions of cartilaginous joints?

The main functions of cartilaginous joints are to resist compression and tension, absorb shock, and provide structural stability with slight to no movement.

What are the two types of cartilaginous joints?

The two types of cartilaginous joints are synchondroses and symphyses.

What are the characteristics of a symphysis, and what are two examples?

A symphysis is a cartilaginous joint where bones are connected by a pad or wedge of fibrocartilage, acting as a shock absorber; it is functionally an amphiarthrosis; two examples are the pubic symphysis and intervertebral discs.

What are the characteristics of a synchondrosis, and what are two examples?

A synchondrosis is a cartilaginous joint where articulating bones are joined by hyaline cartilage; it is functionally classified as a synarthrosis; two examples are epiphyseal plates in growing long bones and costochondral joints.

Nearly all the joints of the limbs and most joints of the body belong to which structural class?

Synovial joints.

In synovial joints, articulating bones are separated by a fluid-filled space called what?

A joint cavity (or synovial cavity).

What are the essential anatomical structures to identify and label in a synovial joint?

The articular capsule (outer fibrous layer and inner synovial membrane), joint cavity, synovial fluid, articular cartilage covering bone ends, and reinforcing ligaments.

What are the basic anatomical features common to all synovial joints?

An articular capsule, a joint cavity, synovial fluid, articular cartilage, ligaments, nerves, and blood vessels.

What are the two layers of the articular capsule, and how is each described?

1. Outer fibrous layer: composed of dense connective tissue that strengthens the joint to prevent bones from being pulled apart. 2. Inner synovial membrane: composed of areolar connective tissue that lines internal joint surfaces (except over articular cartilage) and secretes synovial fluid.

What is the primary function of the synovial membrane?

The synovial membrane secretes viscous synovial fluid, which lubricates the joint cavity and nourishes the chondrocytes of articular cartilage.

What are the functions of articular cartilage in a synovial joint?

Articular cartilage reduces friction during movement, cushions articulating bone ends, and acts as a shock absorber to protect underlying bone.

Where is articular cartilage located in a synovial joint?

Articular cartilage covers the articulating epiphyses (ends) of opposing bones within the joint cavity.

What are the characteristics of synovial fluid?

Synovial fluid is a viscous, oily fluid composed of secretions from the synovial membrane and a filtrate from blood plasma.

What are the primary functions of synovial fluid?

Synovial fluid lubricates articular cartilage to reduce friction, nourishes and removes metabolic wastes from chondrocytes, and acts as a shock absorber during joint compression.

How does synovial fluid nourish the chondrocytes located in articular cartilage?

Because articular cartilage is avascular, joint compression and decompression during movement pump synovial fluid into and out of the cartilage matrix, circulating nutrients and removing wastes (weeping lubrication).

What is the function of ligaments in a joint?

Ligaments connect bone to bone, reinforce and strengthen the joint capsule, and prevent excessive or undesirable movements.

Where are ligaments located with regard to the joint capsule?

Ligaments can be extrinsic (separate from and located outside the capsule) or intrinsic (thickenings of the articular capsule itself, which may be extracapsular or intracapsular).

What type of sensory information do nerves carry from the joint capsule and ligaments?

Nerves carry sensory information regarding proprioception (joint position, movement, and stretch) and nociception (pain perception).

Why does a joint have an extensive blood supply supplying the joint capsule and ligaments?

Blood vessels deliver oxygen and nutrients to the living tissues of the joint capsule and ligaments, remove waste products, and produce the plasma filtrate required to form synovial fluid.

How does a ligament differ from a tendon?

A ligament connects a bone to another bone, whereas a tendon attaches a skeletal muscle to a bone.

How is a ligament similar to a tendon regarding its tissue type?

Both ligaments and tendons are composed of dense regular connective tissue containing abundant, parallel collagen fibers.

What is the function of fat pads found in some synovial joints?

Fat pads act as cushions and packing material, filling spaces created during joint movement and protecting the joint structures.

What is the structural composition of bursae?

A bursa is a closed, saclike fibrous structure lined internally by a synovial membrane and filled with synovial fluid.

What is the function of bursae in and around joints?

Bursae alleviate and reduce friction where muscles, tendons, ligaments, bones, or skin rub against one another during movement.

What is a tendon sheath, and why is it needed?

A tendon sheath is an elongated, cylindrical bursa wrapped around a tendon; it is needed to minimize friction where tendons pass through tight, confined spaces (such as the wrist and ankle).

What is the purpose of a wedge of fibrocartilage (articular disc) within a joint?

A wedge of fibrocartilage improves the fit between irregularly shaped articulating bone ends, cushions impact, and enhances joint stability.

What is the name of the wedges of fibrocartilage located in the knee joint?

The menisci (specifically, the medial meniscus and the lateral meniscus).

How are synovial joints classified?

Synovial joints are classified by the shapes of their articulating surfaces and the types and axes of movement they permit (uniaxial, biaxial, or multiaxial).

In terms of planes/axes of movement, how are uniaxial, biaxial, and multiaxial movements defined?

A uniaxial movement occurs in $1$ plane/axis; a biaxial movement occurs in $2$ planes/axes; a multiaxial movement occurs in $3$ planes/axes.

What are the six structural types of synovial joints?

The six types are plane joints, hinge joints, pivot joints, condylar joints, saddle joints, and ball-and-socket joints.

For each of the six types of synovial joints, what are the articulating surfaces, permitted movements, and an example?

1. Plane: flat surfaces; gliding; intercarpal joints. 2. Hinge: convex surface into concave depression; uniaxial (flexion/extension); elbow joint. 3. Pivot: rounded surface into a ring; uniaxial (rotation); atlantoaxial joint. 4. Condylar: oval convex into concave; biaxial; metacarpophalangeal joints. 5. Saddle: reciprocal saddle surfaces; biaxial; 1st carpometacarpal joint. 6. Ball-and-socket: spherical head into cup; multiaxial; glenohumeral (shoulder) joint.

What is biomechanics?

Biomechanics is the study and application of mechanical principles and the physics of forces to the structure and movement of living organisms and the human body.

In the human body's musculoskeletal lever systems, what corresponds to the lever, the fulcrum, and the effort?

In the body, a lever is a bone, the fulcrum is the joint, and the effort is muscular contraction (force applied by muscle).

What are the three types of lever systems, and what does the mnemonic 'FRE' stand for?

The three types are 1st class, 2nd class, and 3rd class levers. The mnemonic 'FRE' indicates which component is located in the middle: 1st class has the Fulcrum in the middle (R-F-E); 2nd class has Resistance in the middle (F-R-E); 3rd class has Effort in the middle (F-E-R).

What is a 'real world' example and a joint example of a 1st class lever?

A real-world example is a seesaw (or pair of scissors); a joint example is the atlanto-occipital joint of the neck (extending the head).

What is a 'real world' example and a joint example of a 2nd class lever?

A real-world example is a wheelbarrow; a joint example is standing on tiptoes (plantar flexion at the metatarsophalangeal joints).

What is a 'real world' example and a joint example of a 3rd class lever?

A real-world example is a pair of tweezers (or forceps); a joint example is elbow flexion (biceps brachii flexing the forearm).

Which class of lever is the most common in the human body?

The 3rd class lever is the most common class of lever in the human body.

In a 2nd class lever, what is the mechanical relationship between force and load?

In a 2nd class lever, a small force balances a large resistance (or load).

What are the four general categories of movement at synovial joints as discussed in lecture?

1. Gliding motion: flat bone surfaces slide past each other. 2. Angular motion: increases or decreases the angle between articulating bones. 3. Rotational motion: a bone turns around its own longitudinal axis. 4. Special movements: unique actions occurring at specific joints (e.g., elevation, depression, inversion, eversion).

What are the specific actions of key synovial joint movements (such as flexion, extension, abduction, and adduction)?

Flexion: decreased angle between articulating bones; Extension: increased angle between articulating bones; Hyperextension: extension beyond anatomical position; Abduction: movement away from midline; Adduction: movement toward midline; Circumduction: distal end traces a cone; Supination: palm turns anteriorly; Pronation: palm turns posteriorly.

How are movements such as flexion, gliding, and rotation categorized into movement categories?

Flexion, extension, abduction, adduction, and circumduction are angular movements; sliding between carpal bones is a gliding movement; turning of the head or forearm is a rotational movement; movements like elevation, depression, inversion, and eversion are special movements.

What are distinguishing characteristics of common joint injuries such as sprains, dislocations, and cartilage tears?

A sprain involves stretching or tearing of joint ligaments; a dislocation (luxation) occurs when articulating bones are forced completely out of alignment; a cartilage (meniscal) tear involves damage to fibrocartilage pads under compression/shear; bursitis is inflammation of a bursa.

What are distinguishing characteristics of osteoarthritis, rheumatoid arthritis, and gouty arthritis?

Osteoarthritis is a degenerative 'wear-and-tear' condition resulting in loss of articular cartilage and bone spurs; Rheumatoid arthritis is an autoimmune inflammatory disorder causing synovial membrane thickening (pannus) and joint destruction; Gouty arthritis is caused by the accumulation and crystallization of uric acid in synovial fluid and joints (often the great toe).