Anatomy Unit 2 Concept 2

How are joints classified functionally?

By how much movement they allow

• Synarthrosis

• Amphiarthrosis

• Diarthrosis

How are joints classified structurally?

By what connects the bones and whether a joint cavity is present

• fibrous

• cartilagnious

• synovial

What are the 3 functional classifications of joints?

Synarthrosis, amphiarthrosis, and diarthrosis

What is a synarthrosis?

An immovable joint, maximum stability

What is an amphiarthrosis?

A slightly moveable joint, good stability

What is a diarthrosis?

A freely moveable joint, least stability

What are the three structural classifications of joints?

Fibrous, cartilaginous, and synovial

What is a fibrous joint?

Bone are connected by fibrous connective tissue; little or no movement

What is a cartilaginous joint?

Bones are connected by cartilage; allowing little movement

What is a synovial joint?

Bones are seperated by a fluid-filled joint cavity; allows the most movement

What is the relationship between movement and stability in joints?

More movement usually means less stability; less movement means more stability

Give an example of a highly mobile joint

Shoulder joint

Why is the shoulder less stable than many joints?

It allows movement in many directions

Give an example of a highly stable joint

Hip joint

Why is the hip more stable than the shoulder?

The socket is deeper and movement is more limited

How are bones able to create movement

Bones can’t move without the joints that connect them and the muscles that stretch over those joints and contract to create movement

Two types of muscle contraction

Isotonic and Isometric

Isontonic contraction

causes a chnage in the length of the muscles, like when you do a push-up

Isomentric contraction

does not cause a change in the length of the muscles, like when you hold a plank

Example of a muscle contraction in a lower appendage joint and identify the bones of origin and instertion

when you flex your foot, a muscle contraction occurs in your soleus, whose origin is in both the fibula and tibia and its instertion is in the calcaneus