Joints & Movement

Unit 2

articulations (joints)

where 2 or more bones meet; often cartilage

3 types of joints?

fibrous, cartilaginous, and synovial

Types of fibrous joints?

• sutures

• syndesmosis

• gomphosis

fibrous joints: sutures

held together with very short interconnecting fibers and interlocking bone edges

• only found in skull

fibrous joints: syndesmosis

held together by a ligament or interosseus membrane

• fibrous tissue can vary in length, but is always longer than in sutures

fibrous joints: gomphosis

“peg in socket”

• only in the tooth/jaw joint (periodontal ligament hold tooth in socket)

cartilaginous joints allow for what?

limited movement; joined by cartilage (hyaline or fibrocartilage)

2 types of cartilaginous joints?

• synchondrosis

• symphysis

cartilaginous joints: synchondrosis

bones connected by hyaline cartilage

• ex: costosternal joint of rib 1 (joint between rib & sternum)

cartilaginous joints: symphysis

bones connected by fibrocartilage

• ex: pubic symphysis & intervertebral discs

synovial joints

allow lots of movement'; contain synovial fluid to reduce friction

• also include articular cartilage and ligaments

articular capsule is composed of?

• outer fibrous membrane

• inner synovial membrane that secretes synovial fluid into the joint cavity

synovial fluid

viscous and “slippery” that comes from cells that secrete hyaluronic acid that attracts water

stability of synovial joints depends on which 3 factors?

• shape of articular surfaces (how bones physically fit together or interact w one another)

• # and position of ligaments & other supportive structures

• stabilizing muscles!

different synovial joint shapes allow for what?

different types of movements

ball & socket joint

ball/socket arrangement; movement in many places

• ex: hip

hinge joint

cylinder/trough arrangement; movement in 1 plane

• ex: elbow/ulna

pivot joint

rotational movement

• ex: radius & in C1 and C2

labrum

supportive synovial structure; forms a rim on the ‘socket’ of a ball and socket joint = deepens the socket and increases the surface area of articulation between the bones

• made of fibrocartilage

menisci

supportive synovial structure; medial and lateral menisci of knee deepens articular surface, prevents side to side rocking of femur & absorbs shock

• made of firbocartilage

what are the 2 stabilizing ligaments in the knee?

• medial & lateral collateral ligaments (MCL, LCL)

• anterior & posterior cruciate ligaments (ACL, PCL)

collateral ligaments

prevent side-to-side movement

cruciate ligaments

prevent rotation & anterior/posterior movement

bursa

sac of fluid that separates structures to prevent them from rubbing together

tendon sheath

fluid-filled sac that wraps around some muscle tendons (reduce friction during muscle contraction & movement)

sprains

ligaments stretched or torn

cartilage tears

fragments may reduce movement, cause joint to lock (not move), and/or cause pain

bursitis & tendonitis

inflammation of bursa or tendons

• often caused by repetitive use/friction or prolonged pressure on an aera

arthritis

inflammation of a joint, causing pain and often limited mobility at the affected joints

• ex: rheumatoid arthritis - autoimmune

• ex: osteoarthritis - age; repetitive use

• ex: Lyme arthritis - untreated Lyme’s disease

abduction/adduction (movement in frontal plane)

movement away from midline (lateral)/movement back to the midline (medial)

flexion/extension (movement in sagittal plane)

bending the joint/straightening the joint

lateral flexion/extension (movement in frontal plane)

movement of the vertebral column

• movement away from midline (lateral)/movement back to midline

lateral/medial rotation

rotational movement around a central axis of a body part

• rotation away from midline/rotation toward midline

circumduction

circular movement that is a sequential combination of other movements

pronation/supination (movement of forearm)

radius rotated over ulna; palm posterior/radius and ulna parallel; palm anterior

opposition (movement of the thumb & fingers)

bringing the tip/pad of thumb in contact with any finger on the same hand

• protraction/retraction

• elevation/depression

• anterior/posterior movement of shoulders & mandible

• superior/inferior movement of shoulders & mandible

inversion/eversion

rotation of bottom of foot to face medially/laterally

dorsiflexion/plantar flexion

bending foot superiorly/interiorly (pointing toes)