Lecture Two - Joints and Bones

Question 1

What is a joint and what its functions.

Answer 1

Joints are created when two bones articulate.
The parts of the bones which articulate to create these joints are called condyles.
How these condyles meet will determine

FUNCTION
- Could provide flexible free movement or support/stability
o Enables mobility and stability
o The function of the joint will determine the amount of mobility vs stability it has.
o The Shoulder Joint does NOT have a deep bony articulation, this allows for more mobility
o The Hip joint takes on the weight of our body, so this joint needs to be very stable, allows for our bipedal locomotion

Question 2

What is connective tissue?

Answer 2

Connective Tissue are soft tissues that connect one structure to another:
Bone –> Bone = Ligaments
Muscle –>Bone = Tendons
Ligament –> Bone.

Question 3

What are the connective tissues found in the body?

Answer 3

Bone: Hard tissue due to inorganic component, creates over all structure and framework of the body
Articular Cartilage: Associated with synovial joints.
Provides a smooth facet/surface
on the bones which the cover and
Facilitates the frictionless movement associated with synovial joints.
DFCT: The fundamental tissue creating all of the ligaments and tendons in the body.
Fibrocartilage: Is an intermediate between articular cartilage and DFCT.
Acts as a cushion within joints, where it helps manage compression forces and reduces stress placed on joints.

Question 4

What are the types of joints

Answer 4

Fibrous Joints
- Stitch like arrangement. Ridges for ligament insertion between the 2 bones
- DFCT tissue forms ligament structures.
- Provides stability and little movement t
- Resists tension and stops pulling
- Found in the Cranial Vault
- Resists tension enough to hold bones together
- Resists compression enough to allow for growth

Cartilaginous Joints:
- Ring of bone around the outside. Inside the bone, where the disc sits, the surface is
slightly rougher but there are no ridges for ligament attachment
- Fibrocartilage
- Provides movement to but also provides stability
- Resists compression and tension.
- Found in the Intervertebral disc and Pubic Symphysis. E.g. Intervertebral Disc, we need a tissue that holds the
vertebrae apart so they can bear the weight of the body

Synovial Joints:
- Free moving joints. Where bone meets bone, or bone moves over bone, the surface is very smoothe as it is covered in articular cartilage stopping bones rubbing together.
- Allows free fluid movement.
- Found in most limb joints, and multiple
tissue types are involved.
DFCT forms the joint capsule
Articular Cartilage goes over the bone ends, and over the surface where the bones will
move over each other
Fibrocartilage is only occasionally present depending on the joint. A disk of fibrocartilage
helps to extend the bony articulation and gives it more support.

Question 5

What creates circumduction of a joint

Answer 5

Circumduction: Flexion, Extension, Abduction, Adduction, but NO rotation. Occurs in the wrist and
hip to increase the range of movement in the joints.

Question 6

During supernation and pronation

Answer 6

Radius crosses over the ulna

Question 7

What is pronation, where does it occur and why can it only occur there?

Answer 7

We get rotation at the hip, shoulder, neck and between the forearm bones (during pronation
and supination). If the end of a long bone is round  Rotation is possible at that point. We do not
get any rotation at the wrist due to the shape of the bone ends.

Question 8

Bone features and functions

Answer 8

Fibrous Stitch like arrangement. Ridges for ligament insertion between the 2 bones.
Cartilaginous Ring of bone around the outside. Inside the bone, where the disc sits, the surface is
slightly rougher but there are no ridges for ligament attachment
Synovial Free moving joints. Where bone meets bone, or bone moves over bone, the surface is
very smooth because it is covered by articular cartilage to stop the bones rubbing together.