Term
| What is a joint AKA articulation? |
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Definition
| Junction where two or more bones meet |
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Term
| What is the function of a joint? |
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Definition
| To hold bones together and control the amount of skeletal movement |
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Term
| What are the functionality classifications of joints (in order of least to most mobile)? |
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Definition
- Synarthrosis(es): immovable joint (e.g. adult cranial bones)
- Amphiarthrosis(es): slightly movable joint (e.g. intervetebral joints)
- Diarthrosis(es): freely movable joint (e.g. hip, wrist)
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Term
| Name and describe the structural classifications of joints |
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Definition
- Bony joints AKA synostosis: synarthrotic joints following ossification between two bones (e.g.s upper jaw which is R + L Maxilla)
- Fibrous joints: band or sheet of fibrous CT binding bones together
- Suture: found only int he cranium, slightly amphiarthrotic, sutural ligament is lter replaced by bone to become synarthrotic synostosis
- Syndesmosis(es): bones joined by an interosseous ligament that might exhibit some degree of amphiarthrosis. (e.g.s distal tibia-fibula joint)
- Gomphosis(es) peg-and-socket joint with a short ligament. Slightly amphiarthrotic. Tooth-to-jawbone is only gomphosis in the body, held by periodontal ligament.
- Cartilaginous joints: bones connected via cartilage
- Synchondrosis(es): hyaline cartilage connects bones; amphiarthrotic; e.g. epiphyseal plate, 1st rib-to-sternum (NOTE that both of these become synostoses with age)
- Symphysis(es): a fibrocartilaginous plate or disk connecting bones; amphiarthrotic; e.g. intervertebral disk, pubic symphysis
- Synovial joints: diarthrotic; bones are joined together via a joint capsule and separated via joint cavity containing synovial fluid. Most of the skeletal joints are these
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Term
| Describe the structure of a synovial joint |
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Definition
- Joint capsule AKA Articular capsule spans across the joint holding the opposing bones together; this is double-layered
- Outer fibrous capsule: dense irregular CT
- inner synovial membrane (with areolar CT)
- This layer secretes synovial fluid (thick/viscous fluid) composed of three things:
- Interstitial Fluid (Food): rich with albumin
- Hyaluronic acid (Lube): lubricates joint to reduce friction
- Macrophages (Cleaners): cleans up the joint cavity
- Joint cavity: space/cavity between the ends of the opposing bones, filled with synovial fluid
- Hyaline cartilage: covers the opposing epiphyseal ends that face the joint cavity; absorbs some compression and decreases friction within the joint
- Ligaments: Dense regular CT, reinforces joint capsule, can have intracapsular and/or extracapsular ligaments
- Meniscus/i: found in some synovial joints (e.g. knee); a fibrocartilaginous pad/disk to help shock absorbption
- Brusa/ae: fluid-filled sac between the skin and bone that reduces friction and acts as a cushion
- Tendon sheath: a special, elongated bursa that wraps around a tendon subjected to friction
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Term
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Definition
| A place where, during joint movement, one bone moves/one bone is stationary |
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Term
| What are the axes of rotation? |
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Definition
- Uniaxial: movement of bone around one axis of rotation
- Biaxial: movement of bone around 2 axes of rotation
- Multiaxial: movement of bone around 3 or more axes of rotation
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Term
| What are the synovial joint classifications based on axes of rotation? |
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Definition
- Uniaxial: hinge and pivot joints
- Biaxial: plane AKA gliding joints, condylar joints, saddle joints
- Multiaxial: ball-and-socket joints (only shoulder and hip)
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Term
| What are flexion, extension, and hyperextension? |
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Definition
- Flexion: Bending motion in which the angle between two bones is decreased
- Extension: Bending motion in which the angle between two bones is increased
- Hyperextension: extension beyond the normal anatomical position
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Term
| What are plantarflexion and dorsiflexion? |
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Definition
- Plantarflexion: Extension of the foot at the ankle (toes point distally)
- Dorsiflexion: Flexion of the foot at the ankle (toes point superiorly)
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Term
| What are abduction and adduction? |
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Definition
- Abduction: movement away from the midline (for limbs) or away from the longitudinal axis of the hand or foot (for phalanges)
- Adduction: movement toward the midline (for limbs) or movement towards the longitudinal axis of the hand or foot (for phalanges)
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Term
| What are rotation and circumduction? |
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Definition
- Rotation: movement of abone around its own longitudinal axis
- Circumduction: the distal end of the bone moves in a circular motion while the proximal end of the bone remains stable
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Term
| What are supination and pronation? |
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Definition
- Supination: external rotation of the palms, making the radius and ulna parallel (hand looks like it's ready to hold a cup of soup)
- Pronation: internal rotation of the palms, making the radius and ulna cross over
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Term
| What are inversion and eversion? |
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Definition
- Inversion: with the 5th toe on the ground the soles face internally
- Eversion: with the 1st toe on the ground the sole faces externally
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Term
| What are protraction and retraction? |
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Definition
- Head, jaws, or shoulders move in a forward motion (anteriorly)
- Retraction: head, jaws, or shoulders move in a backward motion (posteriorly)
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Term
| What are elevation and depression? |
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Definition
- Elevation: raising a body part (superiorly)
- Depression: lowering a body part (inferiorly)
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Term
| What are the affects of aging on joints? |
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Definition
- Increased viscosity and decreased amounts of joint fluid
- Atrophy and thining of the joint articular cartilage
- Decreased amount of capsule and ligament flexibility
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Term
| What is a sprain and what are its classifications? |
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Definition
- Overstretching or tearing of a ligament
- Type I (<50% torn), Type II(>50% but <100% torn), Type III(100% torn)
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Term
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Definition
| Overstretching or tearing of a muscle |
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Term
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Definition
| Inflammation and/or swelling of a bursa, typically caused by trauma or friction |
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Term
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Definition
| Inflammation of tendon sheathes; usually caused by overuse |
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Term
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Definition
| Complete loss of bone-to-bone contact at a joint |
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Term
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Definition
| Partial dislocation of a joint |
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Term
| What are arthritis and its subtypes? |
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Definition
- Arthritis: inflammation of a joint
- Rheumatoid arthritis: chronic, systemic disease of autoimmune origin; inflammation of CT, primarily the synovial membranes, leads to destruction and instability of synovial joints
- Osteoarthritis: aging disease, wear-and-tear makes joint cartilage disintegrate, creating rough articular surfaces, resulting in pain and decreased joint movements. Eventually results in ankylosis (joint fusion)
- Gout: inflammatory response to hyperuricemia, uric acid crystals are deposited in joints and periarticular CT, activates complement system, resulting in pain and inflammation
- Infectious AKA spetic arthritis: results from hematogneous spread of pathogens or from direct inoculation of pathogens (via trauma, surgery)
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