M1-1 Class Notes Flashcards
Why is ideal posture curved as opposed to straight?
- Anterior concavities provide space for organs in body cavities
- Reduces compressive loads
What other structure aside from the vertebral body helps with load bearing?
Facet joints
What is the WB% of vertebral bodies/facets
- vertebral bodies: 80%
- facet joints: 20%
Curves of the spine are designed to help minimize ______
Compressive load
What does a nearly vertical orientation of facet joints do for movement?
- allows fluid flexion and extension
- limits rotation in higher levels
How do facet joints help guide and limit motion?
- facet orientation in the sagittal plane
- capsule becomes taut during certain motions similar to a ligament
What is it called when the capsule becomes taut similarly to a ligament?
Passive resistance
How does facet compression change with increased lordosis and angle of inclination of the sacrum?
Facet compression increases
Where is lateral flexion and rotation limited most in the lumbar spine?
L5-S1
___% of lateral flexion and rotation occurs at L5-S1
~75%
The angle of inclination results in shear forces. Why?
Gravity is trying to push bottom segments downhill of the sacrum
How does the spine counteract shear forces due to gravity?
Facets of L5-S1 are oriented more in the frontal plane
Movement will increase diffusion of nutrients from ______ to _____
From end plate to discs
About 50-60% of the annulus is composed of _______
Collagen
The only sensory nerves of the discs are located here
Annulus
