35-Slides - Spine Biomechanics

Section 35: Spine – Structural
Components
35-1
Human Spine
• Functions to protect the spine
spine, transfers
loads from head and trunk to pelvis
• 24 vertebrae that permit motion in all 3
planes
• Stability
St bilit comes from:
f
– Intrinsic: intervertebral discs and ligaments
– Extrinsic: muscles
35-2
From: Iatridis
35-3
From: Peeler
35-4
From: Yoon
Cervical Spine
• Seven vertebrae
• C 1-7
• More flexible
• Supports the head
• Wide range of motion
– Rotation
R t ti tto lleft
ft and
d right
i ht
– Flexion
• Up
p and down
• Peripheral nerves
– Arms
– Shoulder, Chest and diaphragm
35-5
From: Ziv
Thoracic Spine
• Mid
Mid-back
back or dorsal region
• Twelve vertebrae
– T 1-12
1 12
• Ribs attached to vertebrae
• Relatively immobile
• Peripheral
e p e a nerves
e es
– Intercostal
35-6
From: Ziv
Lumbar Spine
• Lower back
• Five vertebrae
– L 1-5
15
• Carries the the weight of the upper body
– Larger, broader
• Peripheral
p
nerves
– Legs
– Pelvis
35-7
From: Ziv
Sacral and Coccygeal region
• Sacrum
– Triangular structure
– Base of the spine
– Connects spine to pelvis
– Nerves to pelvic organs
• Coccyx
– Few small bones
– Remnant of tail
35-8
From: Ziv
35-9
From: Peeler
35-10
From: Iatridis
35-11
From: Peeler
35-12
From: Iatridis
35-13
From: Peeler
Intervertebral Disc
• Soft fibro-cartilaginous
fibro cartilaginous cushions
– Between two vertebra
– Allows some motion
– Serve as shock absorbers
• Total – 23 discs
• ¼ th of the spinal column's length
• Avascular
• Nutrients diffuse through end plates
35-14
From: Ziv
Intervertebral Disc Anatomy
• Spongy center
– Nucleus pulposus
• Surrounded by a
tougher outer
fibrous ring
– Anulus fibrosus
35-15
From: Ziv
Anulus Fibrosus
• Strong radial tire–like
tire like structure
• Series of lamellae
• Concentric sheets of collagen
fibers
– Connected to end plates
p
– Orientated at various angles
– Under compression
• Become horizontal
• Encloses nucleus pulposus
35-16
From: Ziv
35-17
From: Yang
35-18
From: Iatridis
35-19
From: Iatridis