Articulations (Joints) Flashcards
Flexion
- generally a decrease in the angle between anterior surfaces of bones - exception - knee and toes.
Dorsiflexion
- Moving the dorsum of the foot toward the anterior leg
Planterflexion
- Moving the plantar surface of the foot away from the leg
Extension
- increase in angle between anterior surfaces - (same exceptions as for flexion definition) - Generally restores structure to its anatomical position.
Hyperextension
- continuation of extension beyond anatomical position. More commonly used to describe extension beyond normal range of motion. Clinically reserved for injury.
Abduction
- usually movement of bone away from the midline of the body - exceptions are the digits of extremities.
Adduction
- usually movement toward midline.
Rotation
- movement of bone around its long axis (spin)
medial rotation - anterior surface moves toward midline
lateral rotation - anterior surface moves away from midline
Circumduction
- distal end moves in circle while proximal end remains stable - may partly involve flexion, abduction, adduction, extension and rotation.
Inversion
- movement of sole of foot inward (medially)
Eversion
- movement of sole of foot outward
Protraction
- thrusting jaw anteriorly
Retraction
- returning protracted part (pulling jaw back)
Supination
- movement so palms face anteriorly
Pronation
- movement so palms face posteriorly
Elevation
- part of body moves upward (hyoid bone in swallowing)
Depression
- movement downward (depress mandible when open mouth)
Opposition
- movement of anterior surface of thumb to face anterior surface of fingers
Articulation - Joint
- point of contact between bones
* because of many different bones in body and many different functions for these bones - many different joint types
3 types of Joint by functional classification
A. synarthroses - immovable joints
B. amphiarthroses - slightly movable joints
C. diarthroses - freely movable joints
Structural Classification: Fibrous Joints (What, examples)
- no joint cavity - bones joined by fibrous connective tissue
- permit little or no movement
- examples:
a. Sutures in skull - bones are united by a very thin layer of fibrous C.T. - these are synarthroses joints
b. distal articulation of tibia and fibula. - is slightly moveable - thus amphiarthrotic.
c. articulations of the roots of the teeth with maxillae and mandible - synarthrotic joints
Structural Classification: Cartilaginous Joints (What, 2 details)
- where bones are connected by cartilage - tight - little or no movement
- 2 kinds:
1. Synchondrosis - connecting material is hyaline cartilage - synarthrotic (immovable)
- example: epiphysial plate in long bones or junction between ribs and sternum
note – ep. plate will become replaced by bone when growth ceases thus becoming a synostosis (joint all bone).
2. Symphysis - connecting material = fibrocartilage disc. - found between vertebral bodies and symphysis pubis
- amphiarthrotic (slightly moveable)
Structural Classification: Synovial Joints (8 details)
- articulations with a synovial or joint cavity.
- no tissue interconnects bones - free to move - thus diarthrotic
- have articular cartilage - covers surfaces in articulation area but does not connect bones. This is hyaline cartilage.
- surrounded by articular capsule - surrounds joint enclosing the cavity - composed of
2 layers:
a. Fibrous Capsule - outer - dense connective tissue
- flexible - allows movement of joint but prevents dislocation - fibers become arranged in parallel bundles = ligaments
b. Synovial Membrane - inner - loose connective tissue with elastic fibers
- secretes synovial fluid which lubricates and provides nourishment to articular cartilage - similar to egg white in consistency - changes viscosity becoming less so with increased activity. Amount varies from joint to joint - but is only present in amount to just cover articular surfaces.
5. Accessory Ligaments
- may be extracapsular or intracapsular depending on whether they are inside or outside of the articular capsule.
- examples: extracapsular - fibular collateral ligament (in knee) intracapsular - cruciate ligaments (in knee)
6. Some joints (i.e. knee and TMJ) may have fibrocartilage “pads” between articular surfaces these are articular discs or menisci
7. Some joints (i.e. shoulder and hip) have a fibrocartilage rim to deepen the joint socket called a labrum.
Structural Classification: Bursae (4 details)
- sac-like structures similar to synovial joint cavity
- filled with fluid similar to synovial fluid
- found between bone and skin, muscle, tendon, or ligaments and help to reduce friction
- inflammation of bursa - bursitis
example: Housemaid’s knee or carpet layer’s knee