Types of Joints, Hilton's Law, and Anastomoses

Question 1

3 Classes of Joints

Answer 1

1. ) Fibrous Joints
2. ) Cartilaginous
3. ) Synovial

Question 2

Joint Functional Classification

Answer 2

1. ) Synarthrosis (immovable)
2. ) Amphiarthrosis (slightly moveable)
3. ) Diarthrosis (freely moveable)

Question 3

Fibrous Joints

Answer 3

connected by fibrous tissue. Amount of movement depends on length of fibers.
3 types - 1.) Sutures 2.) syndesmosis 3.) Gomphosis

Question 4

Synovial Joints

Answer 4

Contains a joint cavity/capsule. Has the greatest variety. These are diarthrotic. Synovial Joints provide free movement achieved by capsule that fuses with tendons and ligaments. Each joint capsule has two parts: an outer fibrous layer or membrane which fuses to ligaments/tendons, and an inner synovial layer or membrane. We then have a inner articular cartilage space that contains Synovial fluid which lubricates joint and is a shock absorber.

*big in locomotion

Question 5

Cartilaginous joints

Answer 5

United by hyaline cartilage or fibrous cartilage. Includes 1.) Synchondroses (Primary) and 2.) Symphyses (Secondary)

Question 6

Types of synovial joints

Answer 6

Includes 1.) Pivot Joints 2.) Ball and Socket (acetabulum in hip, shoulder) 3.) Condyloid Joint 4.) Plane (sliding- acromial clavicular joint) Joint 5.) Saddle Joint 6.) Hinge Joint (knee, elbow)

Question 7

Articular discs

Answer 7

Some synovial joints contain articular discs made out of cartilage. These separate synovial cavities. Ex: meniscus in knee and also the temporomandibular joint

Question 8

Sutures

Answer 8

Type of fibrous joint. Synarthrotic. Bones are close together, either interlocking along a wavy line or overlapping.
ex: Cranium sutures
Anterior fontanella

Question 9

Syndesmosis

Answer 9

Amphiarthrotic, united bones with sheet of fibrous tissue. ex: interosseus membrane between the tibia and fibula
Also between the ulna and radius

Question 10

Gomphosis

Answer 10

Also known as socket joints. Synarthrotic. peg in socket joint
Ex: Dentoalveolar syndesmosis - hold a tooth immobile

Question 11

Primary Cartilaginous Joints

Answer 11

Also called Synchondroses (Primary) are synarthrotic, and the bones are connected by hyaline cartilage to permit minor bending in early life. Our long bones have bony epipheses where the shaft will later join the end of the bone at the ephipheseal plate. This permits growth of the long bone thru out adolescence. When the bone reaches full growth, the primary cartilaginous joint will turn to bone. Becomes diaphysis.

• temporary unions
• development of long bones, fusion of hip bone

Question 12

Secondary Cartilaginous Joints

Answer 12

Also called Symphyses (secondary). amphiarthrotic.

Strong, slightly moveable joints united by fibrocartilage (NOT Hyaline)

ex: Intervertebral discs, pubic symphysis
- Permanent unions that we have at birth (unlike primary)

Question 13

Vascularization of Joints

Answer 13

Articular arteries arise from arteries surrounding the joint.

Articular arteries form periarticular arterial anastomoses = communicating networks

Question 14

Periarticular arterial anastomoses

Answer 14

Consists of consists of several arteries that supply the [elbow joint] and its supporting structures. It functions to allow blood to flow around the elbow joint no mater which position the joint is.

Stagnet because allow for all components of joint to be vascularized in a standard manner

Question 15

Articular Veins

Answer 15

Run as parallel arrangements to the arterial supply or venae comitantes.
This means venous companions for every artery. venae comitantes is an important thermal regulatory arrangement.

Question 16

Anastomoses not only vascularize bony joint and capsule…

Answer 16

ALSO innervate the internal aspect of a joint to vascularize the synovial membranes. In fact synovial membrane is the major supply of blood to the joint - articular cartilage, meniscus, and joint itself

Question 17

Hilton’s Law

Answer 17

Nerves supplying a joint also supply the muscles that move the joint or the skin covering their distal attachment. If a nerve is anywhere near a joint whether its innervating skin or muscle/tendon, it is likely innervating that joint as well.

Ex: Anesthesia - knee joint mostly innervated by femoral nerve. But sciatic nerve is close so therefore we may find that some knee joints are innervated more by the sciatic nerve rather than the femoral nerve.

(cutaneous nerves innervate joints of the hands and feet)