III. Joints Where Bones Join

General information Functions 1. gives skeleton mobility and holds it together still is “weakest link” in skeleton. B. When joints are classified according to structure, they are named for material binding bones together

C.Stuctural types of Joints 1. Fibrous 2. Cartilagenous 3. Synovial

1. Fibrous Joints a.are immovable (synarthrotic) joined by fibrous connective with no joint cavity. Ex: sutures b.Gomphoses in Gum c.Distal tibiofibular joint

2. Cartilageonus Joints 1. Articulating bones joined by bar or plate of hyaline cartilage; no joint cavity. Two types: a. Synchrondroses b. Symphyses 1. Synchrondrosis a bar or plate of hyaline cartilage joins bones. May be synarthrotic or amphiarthrotic. 2. Symphyses are fibrocartilage pad joined to the articular cartilage at the end of a bone. They are amphiarthrotic and built for flexibility and strength. Examples the two Symphisus pubis of pelvis, Intervertebral joints, and manubruim of breast bone where it joins the body of the breast bone.

Synchrondroses- bar or plate of hyaline cartilage joins bones Synchrondroses- bar or plate of hyaline cartilage joins bones. Joint is immoveable (synarthrotic). Ex. epiphyseal plate

2. Symphyses- hyaline cartilage of articulating bone end is fused to pad or plate of fibrocartilage Ex. Pubic symphysis, intervertebral discs. Slightly moveable

a. definition: articulating bones are joined by fluid - filled joint capsule. They are diarthrotic, or freely moveable, include most joints of body, i.e., hinge, ball and socket, plane, condyloid, pivot and saddle joints. 3. Synovial Joints

b. General structure of synovial joint (1) Articular cartilage (2) Joint cavity (3) Articular capsule (4). Synovial fluid (5) Reinforcing ligaments

(6) Other parts associated with synovial joints (a)fatty pads (b)bursae (c)menisci (d)tendon sheath

c. Types of joints(1) Knee is hinge joint

d. Type of movement - Angular movement at hinge joints, elbow shown Flexion (decreases angle) Extension (increases angle)

Angular movement at ball and socket joints Adduction movement toward the body center Abduction movement away from body center

(2) Shoulder is ball and socket

Rotational movement around an axis at hip, shoulder and C1 and C2. Circumduction, movement in a small circle at ball and socket (shoulder & hip) and saddle joint Metacarpal/thumb

e. Origin and insertions of muscles the origin is the end of muscle attached to immoveable end insertion end of the muscle that is attached to moveable end

g. Movements at synovial joints d. More Movement at synovial joints Gliding movement at Plane joints (intercarpal & intertarsal joints) flat surfaces glide across each other @ Js g. Movements at synovial joints

flexion/extension at condyloid joint, interphalangeal joint

Rotational movement at Pivot joint, radioulnar joint one bone pivots around another stationary bone,

Joints to know

The Bones Stop Here