Introduction to Bone Markings

Process:
- Definition: Projection or bump that serves as a site for muscle, tendon, or ligament attachment.
Ramus:
- Definition: Part of a bone that forms an angle with the rest of the structure, often seen in the pelvis.
Projections for Forming Joints:
- Head:
- Definition: Expanded articular end of an epiphysis, often separated from the shaft by a narrower neck.
- Reference to Figure 6-3a for visual understanding.
- Neck:
- Definition: Narrow connection between the epiphysis and diaphysis, also referenced in Figure 6-3a.
- Condyle:
- Definition: Smooth, rounded articular process.
- Trochlea:
- Definition: Smooth, grooved articular process shaped like a pulley.
- Facet:
- Definition: Small, flat articular surface.
Additional Projections:
- Tubercle:
- Definition: Small, rounded projection.
- Tuberosity:
- Definition: Rough projection.
- Crest:
- Definition: Prominent ridge.
- Spine:
- Definition: Pointed process.
- Line:
- Definition: Low ridge.
- Sulcus:
- Definition: Narrow groove.
- Fossa:
- Definition: Shallow depression.
- Trochanter:
- Definition: Large, rough projection.

Fissure:
- Definition: Deep furrow, cleft, or slit.
Meatus:
- Definition: Passage or channel, especially the opening of a canal.
Sinus:
- Definition: Chamber within a bone, normally filled with air.
Foramen:
- Definition: Rounded passageway for blood vessels and/or nerves.
Canal:
- Definition: Duct or channel, allowing for passage of structures.

Chemical Composition:
- Primary mineral structure: The primary mineral component of bone is calcium phosphate, which forms a compound with hydroxide to create hydroxyapatite, specifically written as $Ca<em>5(PO</em>4)_3(OH)$ .
- As hydroxyapatite crystals form, they also include other calcium salts such as calcium carbonate ( $CaCO_3$ ) and various ions, including sodium, magnesium, and others.
Bone Makeup:
- Collagen fibers constitute 98% of the typical bone mass.
- Bone cells contribute only 2% to the overall mass.
Physical Properties:
- Calcium phosphate crystals are notably hard but relatively inflexible and brittle. While they can withstand compressive forces, they are prone to shattering under twisting, bending, or sudden impacts due to their brittleness.