SHPEP A&P - joints (lecture 5)

Joints (articulations)

Where two or more bones meet

Function of joints

give skeleton mobility and hold skeleton together

fibrous joints (synarthroses)

consists of inflexible layers of dense connective tissue, holds the bones tightly together (IMMOVABLE)

Where are fibrous joints located?

sutures of skull, between teeth and jaw

cartilaginous joints (amphiarthroses)

allow only SLIGHT movement and consist of bones connected entirely by CARTILAGE

Where are cartilaginous joints located?

Epiphyseal plates, rib & sternum, pubic symphysis

synovial (diarthroses)

freely movable joints of the body, bones separated by FLUID-CONTAINING joint cavity

synovial fluid

joint-lubricating fluid secreted by the synovial membrane, REDUCES FRICTION BETWEEN CARTILAGES

Menisci

Fibrocartilage that partially divides a joint cavity at knee, reduces friction

Bursa

Flattened sacs containing fluid. Occur where bones, ligaments, tendons, muscles, skin rub together

lateral meniscus

cartilage in the knee between the lateral femoral condyle and the lateral tibial plateau

medial meniscus

Cartilage in the knee between the femoral condyle and the medial tibial plateau

plane joint

short slipping or gliding movements (carpals/wrist)

Hinge joint

Joint between bones that permits motion in only one plane (elbow, ankle, fingers)

pivot joint

rotating bone turns around an axis; (connection between radius/ulna and humerus)

Condyloid (ellipsoidal) joint

Oval-shaped projection fits into an oval-shaped depression (wrist, knuckle)

saddle joint

type of joint found at the base of each THUMB; allows grasping and rotation

ball and socket joint

shoulder and hip

every skeletal muscle attached to bone/connective tissue at 2+ points known as…

Origin & insertion

Origin

attached to the immovable or less movable bone

Insertion

attachment to movable bone

Gliding

flat bone surfaces slide or glide over each other (back and forth, side to side)

angular movements

increase or decrease the angle between two bones

Flexion

Decreases the angle of a joint (bending a knee)

Extension

increases the angle of a joint along sagittal plane (straighten limbs, unbend knee)

Abduction

Moving away from midline along frontal plane (spread apart fingers)

Adduction

Move toward the midline (arm moving in)

Circumduction

circular movement of a limb at the far end (pitcher winding up to throw ball)

Supination

movement that turns the palm up (try to hold a soup bowl)

Pronation

turning the palm downward (bones form an X, relaxed position) (pro = pro basketball player dribbles)

Elevation

raising a body part (shrug up)

Depression

lowering a body part (shrug down)

Inversion

Turning the sole of the foot inward (medially)

Eversion

turning the sole of the foot outward (laterally)

Dorsiflexion

bending of the foot or the toes upward

Plantar flexion

bending of the sole of the foot by curling the toes toward the ground (plant your feet to the ground)

Protraction

Moving a part forward (jut out)

Retraction

moving a part backward (bring it back in)

Opposition

Movement of the thumb to touch the fingertips