Section 35: Spine Structural Components 35-1 Human Spine Human - - PowerPoint PPT Presentation

Section 35: Spine – Structural Components

35-1

Human Spine Human Spine

• Functions to protect the spine transfers

Functions to protect the spine, transfers loads from head and trunk to pelvis

• 24 vertebrae that permit motion in all 3
• 24 vertebrae that permit motion in all 3

planes St bilit f

• Stability comes from:

– Intrinsic: intervertebral discs and ligaments – Extrinsic: muscles

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Cervical Spine Cervical Spine

• Seven vertebrae
• C 1-7
• More flexible
• Supports the head
• Wide range of motion

R t ti t l ft d i ht – Rotation to left and right – Flexion

• Up and down

p

• Peripheral nerves

– Arms

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– Shoulder, Chest and diaphragm

Thoracic Spine Thoracic Spine

• Mid-back or dorsal region

Mid back or dorsal region

• Twelve vertebrae

T 1 12 – T 1-12

• Ribs attached to vertebrae
• Relatively immobile
• Peripheral nerves

e p e a e es

– Intercostal

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Lumbar Spine Lumbar Spine

• Lower back

Lower back

• Five vertebrae

L 1 5 – L 1-5

• Carries the the weight of the upper body

– Larger, broader

• Peripheral nerves

p

– Legs – Pelvis

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Sacral and Coccygeal region Sacral and Coccygeal region

• Sacrum

Sacrum

– Triangular structure Base of the spine – Base of the spine – Connects spine to pelvis Nerves to pelvic organs – Nerves to pelvic organs

• Coccyx

– Few small bones – Remnant of tail

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Intervertebral Disc Intervertebral Disc

• Soft fibro-cartilaginous cushions

Soft fibro cartilaginous cushions

– Between two vertebra – Allows some motion Allows some motion – Serve as shock absorbers

• Total – 23 discs

Total 23 discs

• ¼ th of the spinal column's length
• Avascular
• Avascular
• Nutrients diffuse through end plates

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Intervertebral Disc Anatomy Intervertebral Disc Anatomy

• Spongy center

Spongy center

– Nucleus pulposus

• Surrounded by a

Surrounded by a tougher outer fibrous ring

– Anulus fibrosus

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Anulus Fibrosus Anulus Fibrosus

• Strong radial tire–like structure

Strong radial tire like structure

• Series of lamellae
• Concentric sheets of collagen

Concentric sheets of collagen fibers

– Connected to end plates p – Orientated at various angles – Under compression

• Become horizontal
• Encloses nucleus pulposus

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