Types of Bone and Bone Tissue

Vocabulary flashcards covering the classifications, characteristics, counts, tissues, and examples of bones in the human body.

Total Bones in Average Adult

The average adult skeleton contains $206$ bones, consisting of $90$ long bones, $28$ short bones, $36$ flat bones, $4$ sesamoid bones, and $48$ irregular bones.

Compact Bone

A hard, dense, outer layer of bone tissue found in a pattern of circles.

Spongy Bone

A less dense, inner layer of bone tissue containing open spaces and small areas of bone.

Long Bones

Bones that are typically longer than wide, possess a shaft with heads at both ends, contain mostly compact bone, and provide support and strength (e.g., femur, humerus, metacarpals, phalanges).

Short Bones

Bones that are generally cube-shaped, contain mostly spongy bone, and provide movement and stability (e.g., carpals of the wrist and tarsals).

Flat Bones

Thin, flat, and usually curved bones composed of compact bone around a layer of spongy bone that function to protect organs (e.g., skull, ribs, sternum, hips).

Irregular Bones

Bones that do not fit into other bone classifications and function to protect internal organs and structures (e.g., vertebrae, jaw bones, sacrum, coccyx, face bones).

Sesamoid Bones

A classification of bones that totals $4$ bones in the average adult skeleton.

Humerus

A bone of the arm classified as a long bone.

Sternum

An anterior chest bone classified as a flat bone.

Vertebrae

Bones of the spine classified as irregular bones that protect internal structures.