A&P 1 Chapter 8 Joints Flashcards
Functional classes of joints
Synarthroses-immovable
Amphiarthrosis- slightly movable
Diarthrosis-freely movable
Functions of joint
- Give Skeleton mobility
- hold Skeleton together
Fibrous joints
- most are immovable
- Bound together by fibers
- no joint cavity
Three types:
Sutures
Syndesmoses
Gomphoses
Suture
- has short, interconnecting fibers, where bone edges interlock
- Found only in the skull
- synostoses- skulls bones fused together in middle age
Syndesmosis
- Joint held together by a ligament
- Fibrous tissue can vary in length, but is longer than in sutures
- immovable to slightly movable
Ex: ligament connecting the distal ends of the tibia and fibula
Gomphosis
- “Peg in socket” fibrous joint
- Periodontal ligament holds tooth in socket
(Think gomma)
Cartilaginous joints
- The joints are both rigid and slightly movable
- No cavity
Synchondroses
Symphysesm
Synchondrosis
Bones united by hyaline cartilage
- Most common example of synchondrosis are the epiphyseal plates in long bones of children
- joint between the costal cartilage of the first rib and sternum
Symphyses
Bones united by fibrocartilage.
- Compressive and resilient,
- acts like shock absorber and permits limited amount of movement at the joint.
Ex: intervertebral discs at spine and pubic symphysis of pelvis
Synovial joints
Joints in which the articulating bones are separated by a fluid containing joint cavity. Most joints of the body fall into this category.
Six distinguishing features:
- Articular cartilage
- joint cavity
- articular capsule
- synovial fluid
- Reinforcing ligaments
- Nerves and blood vessels
Six Distinguishing features of Synovial joints
- Articular cartilage
- joint (articular) cavity
- articular capsule
- synovial fluid
- Reinforcing ligaments
Articular cartilage
Smooth hyaline cartilage covers the opposing bone surfaces. Absorbs compression
Joint (Articular) cavity
Unique to synovial joints, the cavity is a space that contains small amount of synovial fluid.
Articular capsule
Encloses the joint cavity with two layers.
Fibrous layer: composed of dense irregular connective tissue
Synovial membrane: composed of loose connective tissue
Synovial fluid
Provides a slippery, weight bearing film that reduces friction between the cartilages.
Reinforcing ligaments
Synovial joints are reinforced and strengthened by bandlike ligaments:
Capsular ligaments: thickened parts of the fibrous layer
Extracapsular ligaments: ligaments outside of capsule
Intracapsular ligaments: within capsule
Nerves and blood vessels
Synovial joints are richly supplied with sensory nerve fibers within the capsule.
- Can detect pain
- Monitors joint position and stretch
Bursae / Bursa
Rolling “bags” between structures of joint that lessen friction.
-flattened fibrous sacks lined with synovial membrane and containing a thin-film of synovial fluid within. They occur when ligaments, muscles, skin, tendons, and bones rub together.
Tendon Sheaths
An elongated bursa that wraps around the tendon subjected to friction where tendons are crowded together.
ex: wrist
Angular movements
Movements that increase or decrease the angle between two bones.
Include:
Flexion, extension, hyperextension, abduction, adduction, circumduction
Flexion
Bending movement that decreases the angle of the joint and brings the articulating bones closer together. Usually a long sagittal plane.
Ex: bending the head forward on chest.
Extension
- the reverse of flexion
- involves movement along the sagittal plane
- increases the angle between the articulating bones
- typically straightens a flexed limb
Gliding movements
- flat bone surface glides or slips over another
- back and forth side to side
- without angulation or rotation
Ex: Wrists and ankles… (Queen wave)
Adduction
- moving toward the midline
- the opposite of abduction
Circumduction
- Movement of the limb so that it describes a cone in space
- the distal end of the limb moves in a circle, while the point of the cone (the shoulder or the hip joint) is more or less stationary
Rotation
Turning of one bone around its own long access
-common at hip and shoulder joints
Abduction
- “Moving away” from midline
ex: raising the thigh laterally (hip abductor)
Supination & Pronation
Supination -turning backwards (see Palm of hand)
Pronation - turning forward
Dorsiflexion/ plantar flexion
Dorsiflexion: wrist/foot flexion (upward movement)
Plantar flexion: wrist/foot extension (downward movement
Synarthroses
Immovable joints
Syn= together Arthro= joint
Amphiarthroses
Slightly movable joints
Amphi= both sides
Diarthroses / diarthrotic
Freely movable joints
Dia= through, apart
Inversion /Eversion
Inversion - sole of foot turns medially
Eversion - sole of foot faces laterally
Protraction / Retraction
Protraction- mandible projects forward (anteriorly)
Retraction- mandible (jaw) moves backwards (posteriorly)
Elevation / Depression
Elevation- lifting body part superiorly
Ex: shrugging shoulders
Depression- moving the elevated part inferiorly
Ex: chewing gum jaw is elevated and depressed
Opposition
Saddle joint between metacarpal and trapezium allows thumb to move to opposite sides
Types of movements
Gliding- nonaxial (hand queen wave)
Media/Lateral axis (flexion/extension) [uniaxial movement] - hinge joint
Anterior/posterior axis (adduction/abduction) [biaxial movement] -
Vertical axis (Rotation) [uniaxial movement]
All directions [multiaxial]
Origin/insertion of muscle attachment across synovial joint
Origin – attachment to the immovable bone
Insertion – attachment to be movable bone
Hinge joints
- Motion is along a single plane
- Uniaxial joints permits flexion and extension only
Ex: elbow and interphalangeal joints
Pivot joints
- uniaxial movement
- Bone fits into sleeve/ligaments of another bone and spins within
Condyloid or ellipsoidal joints
Articular surface of one fits into complementary depression in another
Biaxial joints permit all angular motions
Ex: Radiocarpal (wrist) metacarpalphalangeal (knuckle)
Saddle joint
Each articular joint has both a concave and convex surface
Biaxial movement
Allows for oppositional movement
Ex: thumb
Ball and socket joint
round head a bone articulates within socket of another
Multiaxial joint freely moving
Ex: shoulder and hip joints
Temporomeandibular joint (TMJ)
Mandibular condyle articulate with the temporal bone
Hinge movement (depression and elevation) and side to side movement
Sprains
Torn or stretched ligaments
Cartilage injuries
- The snap and pop of overstressed cartilage
- repaired with arthroscopic surgery
Dislocations
Bones are forced out of alignment (by falls or sports injury)
Usually accompanied by sprains, inflammation, and joint mobilization
subluxation-partial dislocation of a joint
Bursitis
Inflammation of bursa caused by blow or friction
Treated with anti-inflammatory drugs
Tendinitis
Inflammation of tendon sheets typically cause by overuse
Arthritis
- types of inflammatory or degenerative diseases exist
- widespread in US
- Acute form – caused by bacteria treated with antibiotics
- chronic form- osteoarthritis rheumatoid praise and Gouty arthritis
Osteoarthritis (OA)
Often called “wear and tear” – most common form of arthritis
85% of Americans develop (OA) prevalent amongst the aged
Rheumatoid arthritis (RA)
- chronic, inflammatory, autoimmune disease
- unknown cause
- Usually appears between the ages of 40 to 50
Symptoms include joint tenderness, anemia, osteoporosis, muscle atophy
Gaudi arthritis
Deposits of uric acid crystals in joints and soft tissue
Typically affects the joint of the large toe
If untreated bones can fuse and immobilize the joint
Stability of synovial joints
- articular surfaces (shape -minor role for stability)
- ligaments (The more the stronger)
- muscle tone (most important stabilizing factor)
Articulation
Where two bones make contact
