PLTW Human Body Systems 4.1

Joints

Joints

The point of contact between bones in an animal skeleton.

Range of motion

The range a joint can be moved.

Cartilage

A translucent type of connective tissue that is used throughout most of the skeleton. It is also used to create bones through ossification.

Fibrous joints

Joints connected with fibrous tissue that don’t allow for movement. The sutures in the skull are this type of joint.

Cartilaginous joint

A joint that is slightly moveable, but does not have a completely free range of movement. An example is the pubic symphysis.

Synovial joints

A type of joint that is connected by a synovial cavity with liquid that allows a large range of motion.

Saddle joint

A type of joint that allows for abduction, adduction, flexion, extension, and circumduction. It cannot do rotation, though. One example is the joint in the thumb that connects the carpals and the metacarpals (trapeziometacarpal joints or first carpometacarpal joint).

Ball and socket joint

The joint that allows the widest range of movement and permits all types of movements. Examples are the shoulders and the hip.

Condyloid joint

A type of joint that allows flexion, extension, abduction, and adduction movements. An example is the wrist, where the radius, ulna, and carpal bones meet.

Plane (or gliding) joint

Joints that only allow for a gliding movement in a sliding motion, like those depicted in the image. One example is the intercarpal joints in the wrist.

Hinge joint

A type of joint that can only do flexion and extension. One example is the knee.

Pivot joint

This joint can only do the rotation movement, and is unable to do any other movement. One example of this is the neck (specifically where the atlas and axis cervical vertebrae meet).

Hyaline cartilage

Translucent blue-ish white cartilage made of cells in a homogenous matrix.

Articular cartilage

Hyaline cartilage that is attached to articular bone surfaces.

Synovial fluid

The fluid that lubricates joints, nourishes cartilage, and helps in a joint type (with many subtypes) to promote a large range of motion and allow for many movements.

Ligament

Dense connective tissue that attaches bones, made of fibrous tissue.

Tendon

A cord made of white fibrous tissue that attaches muscles to bones.

Goniometer

A tool used to measure angles for joints or the skull

Depression

A movement of a joint in an inferior direction.

Elevation

A movement of a joint in a superior direction.

Rotation

A movement of a bone around its own axis.

Circumduction

A circular movement of a limb. This is different from rotation because the bone/limb is not moving around its own axis, it is just moving in a circular motion.

Flexion

A bending movement at a joint that results in a decreased angle between the bones connected to the joint.

Extension

A reversal of a bending movement of a joint that results in an increased angle between the bones connected to the joint.

Hyperextension

A joint being extended beyond its usual range of motion.

Abduction

A joint moving a limb away from the medial region of the body.

Adduction

A joint moving a limb towards the medial region of the body.

Plantar flexion

Bending the foot inferiorly towards the sole.

Dorsiflexion

Bending the foot superiorly towards the leg.

Fulcrum

The axis of the goniometer, placed at the joint.

Moving arm

The part of a goniometer that moves to measure the angle of a joint or the skull.

Stationary arm

The part of the goniometer that stays aligned to the limb without movement.

How do you use a goniometer?

1. Have the subject lay the joint at rest, so the goniometer can be placed at zero degrees.

2. Have the person raise their joint and hold it.

3. Move the moving arm (only!!) to the new placement. Measure the degree based on the degrees in the central dial.

Note: The other side is a question if you’re using learning or spaced repetition