Joints Flashcards
What does it mean to have hypermobility?
Double-jointed; when someone’s joints has more range of motion
What are causes of hypermobility?
- abnormally shaped ends of one or more bones in a joint
- weak ligaments (due to differences in protein structures, genetics, and/or hormone levels)
- stretched ligaments due to training
- muscle tone can influence ROM of joins (yoga exercise vs body building)
How manty joints are in the human body?
230
What is an articulation/joint?
Where 2 bones interconnect
What is the function of joints?
To hold bones together and allow movement
- each joint has a compromise between the need for strength and the need for mobility
What are the two ways to classify joints?
Structural and Functional
What are the structural classifications of joints?
Based on the structure holding bones together
- Bony fusion
- Fibrous joint
- Cartilaginous
- Synovial joints
What are the functional classifications of joints?
Based on the range of motion of joints
- synarthroses (immovable; fibrous or cartilaginous and may eventually fuse)
- amphiarthrosis (slightly/limited movable; fibrous or cartilaginous)
- diarthroses (freely movable; synovial; contains synovial fluid)
Summary of types of joints; Synarthroses
Immovable
a) sutures: dense fibrous connective tissue between the skull bones
b) gomphoses: fibrous connective tissue periodontal ligament that binds teeth to the jaw
c) synchondroses: cartilaginous rigid bridge between two bones (epiphyseal cartilage of long bones)
d) synostosis: bony fusion, two completely rigid bones fused together so that the boundary disappears (e.g. epiphyseal lines)
Summary of types of joints; Amphiarthroses
Slightly movable; collagen fibres or cartilage
a) syndesmoses: fibrous ligament between tibia and fibula
b) symphysis: fibrous cartilaginous pad between vertebrae
c) interosseous membrane: fibrous
Summary of types of joints; Diarthroses
Freely movable; fibrous articular capsule containing synovial fluid
a) synovial: ends of long bones
What are gomphoses?
Synarthroses:
Fibrous connective tissue: periodontal ligament that binds teeth to the jaw
What are synchondroses?
Synarthroses:
Rigid bridge of cartilage between two bones
What are synostoses?
Synarthroses:
Totally rigid, two bones fused together so that boundary disappears
What are syndesmoses?
Amphiarthroses:
bones connected by a ligament (made of collagen); fibrous joint
What is symphysis?
Amphiarthroses:
Bones separated by a fibrous cartilage pad
What is interosseous membrane?
Amphiarthroses:
Between diaphysis of the tibia and fibula, lots of collagen, very fibrous
What is articular cartilage?
Resembles hyaline cartilage but no perichondrium, higher water content than normal, and synovial fluid produced by synovial membranes
function: to prevent bone-to-bone contact and reduce friction
What is the joint cavity?
A synovial cavity
What lines the joint cavity?
a) Articular capsule; fibrous layer continuous with periostea of the articulating bones
b) Synovial membrane; outer layer of loose areolar connective tissue plus incomplete inner layer of synoviocytes and macrophages that do not extend over the articulating parts of the articular cartilage and menisci
What is synovial fluid?
Fluid that fills cavity and is secreted by synoviocytes of the inner layer ‘epithelium’ chemical makeup
- similar to interstitial fluid with high levels of proteoglycans
- clear and viscous
functions: lubrication to reduce friction, nutrient distribution from vessels in synovial membrane areolar tissue, shock absorption; distributing shock evenly across articular surfaces
What are the accessory structures of some synovial joints?
articular discs/menisci, fatty pads, ligaments, bursae, tendon sheath
What are articular discs/menisci?
Articular discs or menisci: wedges of fibrocartilage separating the articular surfaces
functions: channel the flow of synovial fluid
What are fatty pads?
Fatty pads: between fibrous capsule and synovial membrane or bone, covered with layer of synovial membrane
functions: protect articulating surfaces, packing material: filling in spaces as joint cavity changes shape
What are ligaments?
Connective tissues that stabilize joints and connect bones
strengthen and support the joint; reinforcement
What are the additional lubricating structures of synovial joints?
Bursae: small, fluid-filled pockets
Tendon sheath: similar structure, wraps around joint to limit and support the joint’s range of motion
What are the (4) factors that stabilize synovial joints?
- Articular surfaces shapes
- Collagen fibres of the joint capsule and any ligaments present
- Presence of other bones, skeletal muscle, fat pads, or cartilage
- Tension in tendons and muscle contraction muscle tone; moves bone in a specific direction
What is luxation?
Dislocation; when bones come out of alignment
result: can tear the capsule wall, making the shoulder more prone to future dislocations
sensory neurons in joint capsule, ligaments, tendons (but not in joint cavity) to sense paint
What are the forms of dynamic motion?
Initial position
Gliding movement
Angular motion
Circumduction
Rotation
What are the types of synovial joints? (7)
- Ball and socket (hip, shoulder)
- Ellipsoidal/Condyloid (metacarpals to phalanges, mandible to temporal
- Saddle (thumb)
- Hinge (elbow, phalanges)
- Pivot (radius to ulna, atlas to axis)
- Gliding (wrist, ankle, vertebra)
- Plane/Gliding (intervertebral discs)
What are ball and socket joints?
Motion allowed: triaxial
- angular, circumduction, rotation
Examples: hips, shoulder
What are ellipsoidal/condyloid joints?
Oval end of one bone fits into depression of another
Motion allowed: biaxial
- angular
Examples: radiocarpal joint, metacarpophalangeal 2-5 (where fingers meet palm)
What are saddle joints?
Similar to ellipsoid joint, with more range
Motional allowed: biaxial
- angular?
Examples: base of thumb
What are hinge joints?
Rounded end of one bone fits in groove of another
Motion allowed: monaxial
Examples: elbow, knee, between phalanges
What are pivot joints?
Rounded end of one bone fits through the ligament attached to the other
Motion allowed: monaxial (rotation)
Examples: joint between first two vertebrae, proximal radioulnar joint
What are gliding joints?
Planar joints
Motion allowed: monoaxial/multia
Examples: between clavicle and sternum, intercarpal and intertarsal
What is flexion?
Motion in atero-posterior plane, reduces angle between articulating bones
What is extension?
Oppose of flexion, returns bones to anatomical position
What is hyperextension?
Extension beyond anatomical position
What is abduction?
Swing away from the long axis of the body; movement of a limb laterally away from the midpoint of the body
What is adduction?
Opposite of abduction, returning to anatomical position; movement of a limb medially towards the body
What is circumduction?
Movement of a body region in a circular motion
What is supination?
Palm faces forwards; aligned with the anterior of the body; radius and ulna are parallel
What is pronation?
Palm turns backwards; aligned with the posterior of the body; radius crosses over ulna
What is lateral rotation?
External rotation, anterior surfaces moves away from long axis
What is medial rotation?
Internal rotation, anterior surfaces moves towards long axis
What is lateral flexion?
The movement of the body laterally; side-bending
What is elevation?
Movement in the superior direction
What is depression?
Movement in the inferior direction
What is dorsiflexion?
Backward bending and contraction of the hand or foot (ankle flexion)
What is plantar flexion?
Ankle bends in the direction that points the feet forward
What is dislocation?
Bones forced out of alignment
- can damage the articular
- can tear ligaments
- can distort the joint capsule
What is bursitis?
Inflammation of bursa
- wearing tight, pointy shoes
What is tendonitis?
Inflammation of the tendon sheath
What is arthritis?
Inflammatory or degenerative disease in joint
What is osteroarthritis?
Result of normal wear and tear, usually affects older people
- articular cartilage becomes damaged/roughened, breaks down (poor collagen formation)
- bones may rub together, form spurs and inflammation
- slow and progressive
What is rheumatoid arthritis?
An autoimmune disease triggered by bacteria or viral infection or other causes (genetics) that can occur at any age
- massive inflammation of synovial membrane, swelling
- scar tissue forms on articular surfaces, synovial membranes may ossify, forming spurs
