Joints and Synovial Joint Movements

A joint or articulation

connects a bone with another bone, cartilage, or tooth.

infrapatellar fat pad

cushion between patellar ligament and synovial capsule.

Amphirarthroses

is slightly movable joints. These include: intervertebral joints, the tibiofibular joint, and the pubic symphysis.

retraction

move a body part backward or posterior. Example: bring jaw back toward face.

Fibrous capsule

outer dense fibrous connective tissue layer of the articular capsule that is continuous with the periosteum of the bone; also forms ligaments when fibrous bundles are parallel.

There are 6 types of synovial joints based on the structure of the articulating bone surfaces at the joints. The joint structure determines the movement of the joint.

planar (gliding) hinge pivot condyloid saddle ball-and-socket

plantar flexion

point your toes downward; raise your heels.

dorsiflexion

point your toes upward; stand on your heels.

bursa

reduces friction; 13 bursae in knee.

The thumb joint is the only ____ joint in the body.

saddle

Examples of fibrous joints:

skull joints (sutures), teeth sockets, and the distal joint between the tibia and fibula.

Most of the cartilaginous joints are

slightly movable joints, such as the intervertebral discs and the pubic symphysis.

Synovial cavity

small space between the two articulating bones.

hyperextension

(excessive) excessive extension movement beyond normal anatomical position. Example: moving head backwards.

flexion

(to bend) decrease in the angle between bones of a joint; usually occurs on a sagittal plane. Example: moving head forward, like to bow your head.

extension

(to stretch out) increase in the angle between bones of a joint; restore to anatomical position. Example: bringing head back to regular position, to anatomical position.

Ball-and-socket

Description: ball-shaped head articulates with cup-shaped socket. Movement: freely movable joint; flexion and extension; abduction and adduction; circumduction; rotation. Examples: shoulder and hip joints. Multiaxial

Hinge

Description: convex bone surface articulates with a concave bone surface. Movement: flexion and extension. Examples: knee, elbow, ankle, interphalangeal. Monaxial

Planar (gliding)

Description: flat or slightly curved plane. Movement: gliding motion back and forth and/or side to side. Examples: intercarpal joints, intertarsal joints, sternoclavicular joints, acromioclavicular joints, sternocostal joints, vertebrocostal joints.

Condyloid (ellipsoid)

Description: oval convex projection articulates with oval concave depression. Movement: flexion and extension, abduction and adduction, circumduction. Examples: wrist and metacarpophalangeal joints Biaxial

Pivot

Description: rounded or pointed projection articulates with ring formed by bone and ligament. Movement: rotation. Examples: atlanto-axial joint (C1 & C2), radioulnar joint: turns palm anteriorly and posteriorly. Monaxial

Saddle

Description: saddle-shaped depression articulates with projection that fits into the saddle. Movement: same as condyloid joint, except more exaggerated.. Examples: carpometacarpal joint (thumb) Biaxial

The functional classification of joints is made on the basis of the amount of movement the joints allows.

Synarthroses Amphiarthroses Diarthroses

All synovial joints are

diarthroses.

depression

downward movement lowering body part vertically. Example: to slump shoulders.

patellar ligament

extension of tendon from quadriceps muscle; connects patella to tibial tuberosity and stabilizes the joint anteriorly.

lateral (fibular) collateral ligament

extracapsular ligament; adds strength to joint laterally.

medial (tibial) collateral ligament

extracapsular ligament; adds strength to joint medially.

Synovial joints

have a small synovial cavity (space) between the two bones that permits a greater amount of movement than fibrous or cartilaginous joints.

Fibrous joints

have dense fibrous connective tissue with strong collagen fibers that hold the joints firmly together with no synovial cavity. This type of joint permits little to no movement.

Cartilaginous joints

have either hyaline cartilage or fibrocartilage connecting the bones with no synovial cavity. Usually, there is a small degree of movement with this type of joint.

The knee is classified as a ____ joint, but when flexed it also demonstrates gliding and rotation movements.

hinge

Articular cartilage

hyaline cartilage covering the ends of the bones in the synovial cavity.

Most of the fibrous joints, such as sutures and teeth sockets, are

immovable joints.

The cartilaginous epiphyseal plates of long bones, however, are

immovable joints.

Synovial membrane

inner layer of the articular capsule; composed of aerolar connective tissue containing elastic fibers and adipocytes.

lateral meniscus

inside of joint cavity; cushions knee joint.

medial meniscus

inside of joint cavity; cushions knee joint.

Examples of cartilaginous joints:

intervertebral joints, the pubic symphysis, and the joint between the manubrium and body of the sternum.

anterior cruciate ligament (ACL)

intracapsular ligament; attaches the femur and tibia anteriorly.

posterior cruciate ligament (PCL)

intracapsular ligament; stabilizes joint posteriorly.

Diarthroses

is freely movable joints. Most of the joints in the body are, about 90%.

Synarthroses

is immovable joints. These include: the sutures between the skull bones and the teeth sockets.

Several ligaments (tough, dense tissue that holds bone to bone) are found in the knee joint:

medial meniscus lateral meniscus medial collateral ligament lateral collateral ligament anterior cruciate ligament (ACL) posterior cruciate ligament (PCL) patellar ligament infrapatellar fat pad bursa

protraction

move a body part forward or anterior on a horizontal plane. Example: pushing jaw outward from face.

circumduction

move a distal part of an appendage in a circle. Example: keeping arm straight, and moving in a circle motion, and/or moving hips in a circle motion.

abduction

move appendage away from the midline. Example: Raising leg out to the side, away from the body.

adduction

move appendage toward the midline. Example: Lowering leg back to the body, to the anatomical position.

gliding

nearly flat bone surfaces slide or glide over each other.

Synovial fluid

secreted by the synovial membrane; lubricates the articular cartilages to reduce friction.

Articular capsule

structure that encloses the synovial joint and synovial cavity; has two layers: the fibrous capsule and synovial membrane.

Although synovial joints vary in structure, they have several common features:

synovial cavity articular cartilage articular capsule fibrous capsule synovial membrane synovial fluid

The majority of the joints in the human body are synovial joints. For example:

the shoulder, elbow, hip, and knee joints.

The term synovial comes from:

the synovial fluid present in the synovial cavity that resembles the albumin of an uncooked egg, only more viscous. Dense fibrous connective tissue on the exterior of the joint holds the bones together.

The knee is

the most complex and highly stressed joint. Is also the location of many joint injuries.

Types of Movement at Synovial Joints:

A. GLIDING B. ANGULAR -flexion -extension -hyperextension -abduction -adduction -circumduction C. ROTATION D. SPECIAL JOINT MOVEMENTS -elevation -depression -protraction -retraction -supination -pronation -inversion -eversion -dorsiflexion -plantar flexion

However, the fibrous tibiofibular joint is

a slightly movable joint.

The shoulder joint is a ____ joint.

ball-and-socket

rotation

turn on a pivot with a circle. Example: rotate head from side to side.

supination

turn palm of oustretched hand upward. Example: like you are asking for more soup. (soup = supination)

pronation

turn palm of outstretched hand downward.

inversion

turn the sole of the foot inward.

eversion

turn the sole of the foot outward.

elevation

upward movement raising body part vertically. Example: to bring your shoulders up.