Bone Anatomy, Classification, Ossification, and Blood Supply

Vocabulary flashcards covering bone structure, classification by shape, development, region, and microscopic features, along with ossification, bone functions, clinical conditions, and blood supply.

Compact Bone (Cortical Bone)

Dense, ivory-like outer shell of bone that provides mechanical strength.

Cancellous Bone (Spongy / Trabecular Bone)

A meshwork of trabeculae filled with red or yellow bone marrow that provides lightness, shock absorption, and haematopoiesis.

Lamellar Bone

Mature bone organized in concentric lamellae around Haversian canals (osteons), creating a strong and durable structure.

Woven Bone

Immature, temporary bone with randomly arrayed collagen fibers and less strength, seen in foetal life, fracture healing, and pathological states such as osteosarcoma.

Long Bones

Bones composed of a shaft (diaphysis) and two expanded ends (epiphyses) that generate force, provide leverage, and support weight (e.g., femur, humerus, tibia).

Short Bones

Cube-shaped bones featuring a spongy bone core surrounded by a thin cortex, providing stability with limited movement (e.g., carpals, tarsals).

Flat Bones

Bones consisting of two compact layers with diploë in between, which protect organs and provide a large surface area for muscle attachment (e.g., skull, sternum, ribs).

Irregular Bones

Bones with complex shapes that provide protective and supportive functions (e.g., vertebrae, hip bone, sphenoid).

Sesamoid Bones

Bones that develop inside tendons to modify the force of pull and reduce friction (e.g., patella, pisiform).

Pneumatic Bones

Bones containing air-filled cavities lined by mucous membranes that make the bone light and act as resonating chambers (e.g., maxilla, sphenoid, frontal, ethmoid).

Accessory Bones

Extra bones formed from ununited ossification centres (e.g., accessory navicular, sutural/wormian bones).

Membranous Bone (Dermal Bone)

Bone formed via direct intramembranous ossification from mesenchyme (e.g., flat skull bones, clavicle).

Cartilaginous Bones

Bones formed through endochondral ossification from a cartilage template (e.g., long bones like femur and humerus).

Membrano-cartilaginous Bones

Bones derived from both membrane and cartilage ossification (e.g., clavicle).

Somatic Bones

Bones derived from mesoderm that form the majority of the skeleton.

Visceral Bones

Bones derived from pharyngeal arches (e.g., ear ossicles, hyoid bone, styloid process).

Axial Skeleton

The main framework of the body, including the skull, vertebrae, ribs, and sternum, which provides support and protects major central organs.

Appendicular Skeleton

The skeleton component comprising the pectoral girdle, pelvic girdle, and limbs, responsible for mobility.

Intramembranous Ossification

Bone development directly derived from mesenchyme, forming flat bones and the clavicle.

Endochondral Ossification

Bone formation from a precursor cartilage template, characteristic of long bones.

Primary Ossification Centre

The initial site of bone formation during endochondral ossification, appearing in the diaphysis.

Secondary Ossification Centre

The site of ossification that appears in the epiphysis of a developing long bone.

Dentine and Cementum

Tooth-supporting hard tissues related in structure to bone.

Mineral Storage Function of Bone

The role of bone in storing key minerals such as calcium ($Ca$) and potassium ($K$).

Fracture Healing Sequence

The stage-based process of repair involving haematoma formation, soft callus development, and eventual remodeling.

Osteomyelitis

A pathological infection of the bone.

Achondroplasia

A pathological bone condition characterized as a disorder of growth.

Bone Necrosis

Death of bone tissue and cells resulting from a disturbance or loss of blood supply.

Nutrient Artery

The chief source of blood for bone; it enters through the nutrient foramen, is directed away from the growing end (towards elbow, away from knee), divides into ascending and descending branches in the medullary cavity, and forms hairpin loops at the metaphysis and epiphysis.

Four Blood Arteries of Bone

The main vascular routes supplying living bone tissue: Nutrient Artery, Periosteal Artery, Metaphyseal Artery, and Epiphyseal Artery.