Bone Markings Overview

Overview

This lecture covers the main types of bone markings, their definitions, and functions, focusing on projections, depressions, and openings that serve as essential anatomical landmarks.

Parts of a Bone

• Long bones have four parts: head (epiphysis), neck (metaphysis), body (diaphysis), and articular surface.
• The epiphysis is the rounded end; metaphysis is the widest part; diaphysis is the shaft; articular surface contacts neighboring bones.

Projections and Parts

• Projections are raised bone areas where muscles and ligaments attach.
• A condyle is a rounded knob forming a joint, e.g., lateral condyle of femur.
• An epicondyle is a projection above a condyle for muscle or ligament attachment, e.g., humerus' medial epicondyle.
• A process is a bulging outgrowth, e.g., mastoid process behind the ear.
• A protuberance is a swelling or protruding part, e.g., external occipital protuberance.
• Tubercle is a small rounded prominence; tuberosity is larger and rough, both are attachment sites.
• Trochanter is a large, irregular process found only on the femur, e.g., greater and lesser trochanter.
• Spine (spinous process) is a sharp, slender projection, e.g., sphenoid bone spine.
• Linea (line) is a subtle, narrow ridge, e.g., linea aspera of femur.
• Facet is a flat smooth articular area, e.g., acromial facet of clavicle.
• Crests are prominent raised edges, e.g., iliac crest; ridges are linear elevations, e.g., lateral supracondylar ridge of humerus.

Depressions and Openings

• Foramen is a hole for nerves/vessels, e.g., jugular foramen; fissure is a groove or slit, e.g., inferior orbital fissure.
• Meatus is a tube-like channel, e.g., external acoustic meatus (ear canal).
• Fossa is a broad, shallow depression, e.g., temporal fossa; fovea is a small pit, e.g., fovea capitis.
• Notch (incisure) is an indentation at a bone's edge, e.g., scapular notch.
• Sulcus (groove) is a furrow along a bone for nerves/vessels, e.g., groove for the transverse sinus.
• Sinus is a hollow cavity, e.g., paranasal sinuses.

Key Terms & Definitions

• Epiphysis — rounded end of a long bone.
• Metaphysis — widest part between epiphysis and diaphysis.
• Diaphysis — shaft or central part of a long bone.
• Condyle — rounded articular bone projection.
• Epicondyle — projection above a condyle.
• Process — bulging outgrowth of bone.
• Protuberance — swelling or protruding part of bone.
• Tubercle/Tuberosity — small/large rounded bony prominence.
• Trochanter — large, irregular process unique to femur.
• Spine — sharp, slender projection.
• Linea — narrow, subtle ridge.
• Facet — flat articular surface.
• Crest/Ridge — raised edge or linear elevation.
• Foramen — bone opening for nerves/vessels.
• Fissure — slit or groove in bone.
• Meatus — tube-like channel.
• Fossa/Fovea — shallow depression/small pit.
• Notch/Sulcus — indentation/furrow or groove.
• Sinus — cavity in bone.

Action Items / Next Steps

• Review skeletal diagrams and quizzes to reinforce bone marking identification.
• Memorize key terms and their examples for each type of bone marking.