THE IN-BETWEENERS ◆ ISSUE #11 ◆ SERIES II: THE BONE DIVISION
The Lattice
Spongy bone · they / them
“Light, strong, quietly vanishing.”
POWER: Bone strength at a fraction of the weight, from every direction.
WEAKNESS: First to thin out. Lose their struts and the whole bone snaps.
FIBERS: The same mineralized collagenA structural protein in the dermis that provides strength and elasticity. as Captain Concrete.
SECRET IDENTITY: The inside of every bone, and where your blood gets made.
Most of your skeleton is spongy boneA porous bone tissue found inside bones, providing lightweight support., not compact boneDense, strong bone tissue forming the outer layer of bones.. If it were all compact, it would be too heavy for your muscles to move. The Lattice lightens the load without giving up strength.
Chill. Airy. Secretly Holding Up the Whole Building.
Where they live, what they do, and the one thing they can’t do
Where they live
- The ends (epiphyses) and core of long bones, inside the compact bone collar
- Sandwiched inside flat bones between two layers of compact bone (diploëThe spongy bone layer sandwiched between compact bone in flat bones.)
- Wrapped around red bone marrow
Their powers
- TrabeculaeThe lattice-like structures in spongy bone that support stress distribution., curving sheets of lamellae like the trusses of a bridge, run in almost every orientation
- So they take twisting, pulling, and pushing from all directions, better than compact bone
- Every strut is thin enough to reach the marrow, so they need no central canalsA hollow canal in an osteon containing blood vessels and nerves.
Their weakness
Bone is remodeled all your life: osteoclasts resorb, osteoblasts deposit. When depositionThe process of bone matrix formation by osteoblasts. falls behind (for example, when estrogen drops), the thin struts go first.
That is osteoporosis. Calcium, vitamin D, and sunlight: all three, or don’t bother.
Every weakness is the structure.
Mostly Holes. Very Intentional Holes.
Struts of bone with marrow in every gap
The crew: cells
OsteocytesMature bone cells that maintain bone tissue. in lacunae along the trabeculae, osteoblasts laying bone down, and osteoclasts taking it away. The spaces hold marrow: blood-forming cellsThe basic structural and functional units of life. and fat.
The fibers
Mineralized type I collagen, exactly like Captain Concrete.
The matrix
Solid bone matrix, chemically identical to compact bone. Just arranged as struts instead of pillars.
The Hollow Aesthetic
Real slides. Find them in every one.
ID HINT: Branching pink struts of bone with marrow, not solid rings, filling the spaces between.
Exhibit A
Exhibit B
Exhibit C
Micrographs: University of Michigan Histology, licensed under CC BY-NC-SA 3.0.
Prove You Were Actually Paying Attention
Prove you can spot them
Mission 1: Bone quick check
Videos Nobody Asked You to Watch (Watch Them)
Constantly Redecorating
Their whole life is renovation
Remodeling
Once your bones stop getting longer, osteoblasts keep working. OsteoclastsBone-resorbing cells that break down bone matrix. break bone down (resorption) while osteoblasts lay new bone down (deposition). By age 50 you’ve had about five skeletons.
Osteoporosis
Too little osteoblast Bone-forming cells that secrete osteoid. activity: all breakdown, not enough rebuilding. Estrogen strongly influences deposition, which is why risk climbs after menopauseThe natural cessation of menstruation and ovarian function..
Fractures and healing
A break mashes ossification and remodeling together. First comes a blood clot, like a bandage, then a callus that is remodeled again and again until the bone is back to normal. That can take months or even years.
Gets Compared to Their Sibling. A Lot.
Students confuse them with these two. Here’s how to tell.
Captain Concrete
Compact bone. Solid bullseye osteonsThe structural unit of compact bone, consisting of concentric lamellae around a central canal. with central canals. The Lattice is open struts with no central canals.
The Vault
Adipose. The marrow between the struts is often full of fat cells, so look for the pink bony struts around the bubbles.
List of terms
- collagen
- spongy bone
- compact bone
- diploë
- Trabeculae
- central canals
- deposition
- Osteocytes
- cells
- Osteoclasts
- osteoblast
- menopause
- osteons