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MODULE 6:
Skeletal Tissue
PART 3 OF 7
Adult exam: lacy purple mottling (livedo) concentrated over the shins and ankles, where bone sits just under the skin. Filed as “cold-sensitive circulation.”
Slide 1 Transcript
PATIENT CHART
STINA
THIS PART
Ages 4-38
PRESENTING WITH
Bone tenderness & pain, failed piercings, synovitis
TESTS ORDERED
DEXA (Bone density)
DRUGS PRESCRIBED
IL-6 Blocker
CHART CLUES
COLLECTED AS YOU GO
Lifelong Nocturnal Bone & Leg Pain
Exertional Bone & Periosteal Tenderness After Effort
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Put your money down: Why does the purple net sit right over her bones?
Bet before the legs. Stina’s lower legs carried a lacy purple net that deepened in the cold and clustered over the shins, where bone sits just under the skinThe body’s largest organ, providing protection and regulation. — and she was handed compression socks. Two quick fact-checks on bone as a living, blood-fed tissue; then the ask: is this just cold-sensitive circulation — or inflamed vessels shared by skin and bone?
Pick the answer you believe now. We’ll come back to it later!
A Violet Net Over the Shins
By her thirties Stina had a lacy, violet net across the front of her lower legs that deepened in the cold and never fully faded. What struck one careful clinician was where it sat: right over the shins and ankles, where bone lies a thin skin’s width below the surface. She’d been handed compression socks and a note about “cold-sensitive circulation.” But the mottling clustered over bone, not muscle, and that location was a clue nobody followed.
Remodeling Throughout Life
Your skeleton is rebuilt for life — a few percent recycled every week.
Slide 2 Transcript
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Single Choice: About how much of the skeleton is remodeled, and how often?
One Remodeling Cycle
One cycle, four phases: rest, resorb, reverse, rebuild.
Slide 3 Transcript
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Drag the Words: Drop the four phases of a remodeling cycle into order.
Bone Is Rebuilt for Life
This page connects two tissues that share a neighborhood. The periosteum and the overlying dermisThe thick inner layer of the skin that contains blood vessels, nerves, and connective tissue. are fed by a continuous vascular network; over the shin, only a sliver of soft tissue separates skin from periosteum, so their small vessels are nearly one system. Livedo reticularis is a pattern of uneven small-vessel tone and flow — not a blockage — and it appears wherever endotheliumThe innermost layer of blood vessels, composed of simple squamous epithelial cells, which reduces fr is irritated. In Stina, the same IL-1β that inflamed her dermal vessels (the Integumentary module) also irritated the vessels feeding bone and periosteum, so the inflammation surfaced as visible mottling precisely over bone. The skin was acting, again, as a billboard — this time advertising inflammation in the circulation that bone and periosteum depend on.
Build vs Break Down
Build equals break-down, and density holds — until the balance tips.
Slide 4 Transcript
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Fill in the Blanks: Fill in what keeps bone density stable, and what tips it.
When Inflammation Tips It
Chronic inflammation tips the balance toward resorption — bone lost too soon.
Slide 5 Transcript
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Mark the Words: Mark what happens when inflammation tips the remodeling balance.
Inflamed Vessels, Skin to Bone
That shared plumbing is why Stina’s mottling meant more than cold feet. The same IL-1β that inflamed her dermal vessels in the Integumentary module also irritated the vessels feeding bone and periosteum — one endothelium, skin to bone — so the inflammation surfaced as a visible violet net precisely over her shins and ankles. The skin was doing what it did throughout the last module: acting as a billboard, this time advertising inflammation in the very circulation that living, constantly-rebuilt bone depends on. The location everyone overlooked was the whole point.
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Slide 6 Transcript
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Slide 7 Transcript
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FINDING!
Livedo Reticularis Concentrated Over Bone — Inflamed Periosteal & Dermal Vessels
Concrete sign: lacy purple mottling (livedo reticularis) over the shins and ankles, worst in cold, misfiled as ‘cold-sensitive circulation.’ Over the shin, only a sliver of tissue separates skin from periosteum, so their small vessels are nearly one system. Livedo is uneven small-vessel tone — not a blockage — wherever endothelium is irritated. Chart entry: the same IL-1β endothelial irritation that mottled her skin (the Integumentary module) inflames the vessels feeding bone — livedo over bone, linking the skin and skeletal vascular beds.
Confirm or refute your bet: Why does the purple net sit right over her bones?
Having seen bone as a living tissue rebuilt for life on a shared blood supply, return to the bet. The periosteum and overlying dermis are fed by one continuous network, so over the shin they are nearly one system — and livedo is inflamed, uneven small-vessel tone, not a blockage.
Slide 7 Transcript
NEXT PART
Inflammation in bone’s vessels could mottle the skin — but bone at least has a blood supply to inflame. Some of Stina’s tissues had none at all, and those were the ones that simply refused to heal.
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All pages for Module 6 — The Skeletal System
6.0 Module Overview
6.1 Growing Pains That Never Stopped
6.2 The Presidential Mile
6.3 Livedo Over Bone
6.4 Piercings That Won’t Heal
6.5 Osteoclasts Gone Wild
6.6 Synovitis and Effusion
6.7 Recurrent Sterile Synovitis
6.8 Conclusion and Assessment
6.9 The evidence behind Stina’s skeleton
All Modules
- Anatomical Language, Membranes & Homeostasis
- Just Enough Chemistry
- The Cell & Its Transport
- Making Cells & Proteins
- The Integumentary System
- The Skeletal System
- The Muscular System
- Nervous Tissue & the Senses
- The Spinal Cord
- The Brain & the Blood–Brain Barrier
- The Autonomic Nervous System
- Special Senses (in developmentThe process of growth and differentiation.)
- The Endocrine System
- Blood
- The Heart
- Blood Vessels
- The Digestive System
- The Respiratory System
- The Urinary System
- Fluids, Electrolytes & Acid–Base Balance
- The Reproductive System
- The Immune System
List of terms
- skin
- dermis
- endothelium
- development