Long Bone Anatomy, Cell Types, and Skeletal Structures Quiz

Shaft of a long bone

Diaphysis

Ends of a long bone

Epiphyses

Where the shaft and ends meet

Metaphysis (contains the epiphyseal plate/line)

Membranous structure that covers the diaphysis

Periosteum

Osteoprogenitor cell

Stem cell; can differentiate into osteoblasts

Osteoblast

Bone-forming cell; secretes matrix (osteoid)

Osteocyte

Mature bone cell; maintains bone matrix, lives in lacunae

Osteoclast

Bone-resorbing cell; multinucleated, breaks down matrix

Development of osteoclasts

Osteoclasts come from monocyte/macrophage lineage, not osteoprogenitors.

Canals allowing blood vessels to penetrate bone

Volkmann's (perforating) canals and Haversian (central) canals

Mineral salts that make up bone

Calcium phosphate (mainly hydroxyapatite crystals) and Calcium carbonate

Lacunae

Small spaces housing osteocytes.

Compact bone osteocytes

Osteocytes live in lacunae; canaliculi are small channels that connect them.

Endochondral ossification

Deals with the formation of bone from cartilage.

Intramembranous ossification

Forms directly from mesenchymal tissue.

True statements about compact bone

Endosteum lines medullary cavity, periosteum has inner osteogenic + outer fibrous, articular cartilage covers epiphysis.

Axial skeleton articulation

Atlas articulates with occipital condyles of the occipital bone.

Ethmoid bone features

Ethmoid has crista galli and cribiform plate.

Three parts of sternum

Manubrium, Body, Xiphoid process

Floating rib definition

It does not attach to sternum at all (only to vertebrae).

Exaggerated spinal curvatures

Lateral curvature → Scoliosis, Exaggerated thoracic curvature → Kyphosis, Exaggerated lumbar curvature → Lordosis.

Sesamoid bones

Small bones embedded in tendons (e.g., patella).

Sutural bones

Extra small bones within cranial sutures.

Superior & inferior nuchal lines location

Occipital bone.

Hyoid bone articulation

None; it's a free-floating bone, attached by muscles & ligaments.

Landmark on sacrum for anesthetics

Sacral hiatus.