Chapter 8: Joints

Synarthroses

Immovable joints; largly restricted to the axial skeleton

What are examples of some synarthrosis joints?

Sutures of the skull and the articulations between the teeth

Amphiarthroses

Slightly movable joints; largely restricted to the axial skeleton

What are examples of some amphiarthrosis joints?

The pubic symphysis and the intervertebral discs

Diarthroses

Freely movable joints; predominates in the appendicular skeleton

What are example(s) of some diarthroses joints?

The finger joints

Joint capsule

The two layered capsule that encloses the joint cavity; consists of fibrous layer and the synovial membrane

Synovial membrane

The inner layer of the joint capsule that is composed of loose connective tissue

What is the function of the synovial membrane?

To cover all internal joint surfaces that are not hyaline cartilage and to make/secrete synovial fluid

Synovial fluid

Slippery fluid that occupies all the free spaces within the joint capsule

What is the function of the synovial fluid?

To reduce friction between the cartilages

Articular cartilage

The glassy-smooth hyaline cartilage that covers the joints surfaces

What is the function of the articular cartilage?

To absorb compression placed on the joints

Meniscus

The C-shaped fibrocartilage that separates the articular surfaces

What is the function of the meniscus?

To modify the shape of bone ends to stabilize the joint and minimize wear and tear on the joints surfaces

Ligament

Bands made of flexible fibrous connective tissue; connecs bone to bone

What is the function of the ligaments?

To reinforce and strengthen the synovial joints & connect the bones

Tendon

Cord(s) made of dense regular connective tissue; connects muscle to bone

What is the function of the tendons?

To connect muscle to bone

Bursae

Flattened fibrous sacs lined with synovial membrane

What is the function of the bursae?

To act as “ball bearings” and reduce friction between adjascent structures during joint activity by taking pressure off the actual synovial membrane

Joint structure determines.. 

Direction and distance of movement (range of motion)

How are joints classified?

Based on their structure or degree of movement

What are the 3 different kinds of joint structures?

Fibrous, cartilaginous, and synovial

What are the 3 different types of joint degrees of movement?

synarthrosis, amphiarthrosis, and dairthrosis

Fibrous joints

Joints that are jointed by collagen fibers; permits little or no movement

What are the 3 types of fibrous joints?

Suture, syndesmosis, and gomphosis

Suture

Joints held together with very short, interconnecting collagen fibers, and bone edges interlock; found only in the skull

Syndesmosis

Joints held together by a ligament; fibrous tissue can vary in length, but is longer than in sutures

Gomphosis

"Peg in socket' fibrous joint that binds the teeth to its bony sockets

Gliding

Flat bone surface glides or slips over another without appreciable angulation or rotation

Example(s) of a gliding joint

intercarpal/intertarsal joints and flat articular process of vertebrae

Hinge 

Movement that allows movement in only one plane/direction

Example(s) of a hinge joint

elbow joints and interphalangeal joints

Ball and socket

Allows joints to move in many directions

Saddle

Two concave, straddle joints that allows for medial/lateral and anterior/posterior movement

Example(s) of saddle joints

Carpometacarpal joints of the thumbs

Ellipsoid

Ovoid joint that allows joint to move medial/lateral and anterior/posterior

Example(s) of ellipsoid joints

Knuckle and wrist joints

Pivot

Uniaxial movement; allows rotary movement around a single axis

Example(s) of a pivot joint

Proximal radioulnar joints

What are the articulating bones of the skull?

Cranial and facial bones

What are the articulating bones of the elbow?

Ulna, radius, & the humerus

What are the articulating bones of the coxal?

Hip bone and femur

What are the articulating bones of the knee?

Femur and tibia

The _____ ____ is the only bone that does not articulate with any other bones.

Hyoid bone

Flexion

The bending movement along the sagittal plane that decreases the angle of the joint andd brings the articulating bones closer together

Extension

Opposite of flexion — movement along the sagittal plane increases the angle between the articulating bones and typically straightens a flexed limb or body part

Hyperextension

The movement of a joint beyond its normal range of motion

Dorsiflexion

Lifting the foot so its superior surface approaches the shin

Plantar flexion

depressing the foot (pointing the toes)

Abduction

moving a limb away from the body midline in the frontal plane

Opposition

Movement used to touch your thumb to the tips of the other fingers on the same hand

Adduction

Moving a limb towards the body midline in the frontal plane

Rotation

Turning a bone around its longitudinal axis

Circumduction

Moving a limb or finger so that it describes a cone in space

Supination

Rotating the forearm laterally so that the palm faces anteriorly or superiorly

Pronation

Forearm rotates medially and the palm faces posteriorly or inferiorly (Radius crosses over)

Inversion

The soles of the foot turn medially

Eversion

The sole of the foot faces laterally

Describe the structure of cartilaginous joints

Joined together via cartilage, no joint cavity present, and not very movable (ex: epiphyseal plate, pubic symphysis, intervertebral joint)

What are the two kinds of cartilaginous joints?

Synchondrosis and symphyses

Synchondrosis

A bar/plate of hyaline cartilage unites the bones — virtually all of these are synarthrotic (no movement)

What is an example of a synchondrosis cartilaginous joint?

Epiphyseal plate

Symphyses

A type of cartilagineous joint in which the bones are united via fibrocartilage

What is an example of symphysis cartilaginous joints?

Intervertebral joints and the pubic symphysis

Describe the synovial joint structure

Bones are covered with articular cartilage, separated by a joint cavity and enclosed in articular capsule lined with the synovial membrane

Name the 6 kinds of diarthrotic joints

Gliding, hinge, ball and socket, saddle, ellipsoid, and pivot

What is labeled “A”?

Periosteum

What is labeled “B”?

Fibrous membrane

What is labeled “C”?

Synovial membrane

What is labeled “E”?

Synovial joint cavity

What is labeled “F”?

Articular cartilage

What is labeled “A”?

Ligament

What is labeled “B”?

Joint cavity

What is labeled “C”?

Articular cartilage

What is labeled “D”?

Fibrous layer

What is labeled “E”?

Synovial membrane

What is labeled “G”?

Articular/joint capsule

What component of the synovial joint is tagged with blue tape?

Ligament

What component of the synovial joint is tagged with blue tape?

Meniscus

What is labeled “A”?

Bursa

What is labeled “B”?

Tendon sheath

What is labeled “C”?

Tendon

Synchondrosis

A type of cartilaginous joint where hyaline cartilage unites two bones

Cartilaginous joints

Joints that are joined via cartilage, contain no joint cavity, and are not very movable; two types

Cartilage discs

Modifies the shape of the joint to allow two bones of different shapes to fit together