Skeletal System, Bone Remodelling, and Surface Anatomy

Vocabulary flashcards covering key structural components, developmental processes, remodelling cellular activity, fracture repair stages, and surface bony landmarks based on anatomy lecture notes.

Axial Skeleton

The division of the skeleton consisting of 80 bones that forms the longitudinal central axis of the body, including the skull, vertebral column, ribs, and sternum.

Appendicular Skeleton

The division of the skeleton comprising the bones of the upper and lower limbs along with their attachments, including the clavicle, scapula, arms, and legs, primarily involved in movement.

Compact (Cortical) Bone

Dense bone tissue that forms the outer shell of all bones, providing protection, strength, and structural support for weight-bearing.

Spongy (Cancellous) Bone

Highly porous and vascularised bone tissue containing a lattice-like matrix called trabeculae, which maintains skeletal strength while keeping bones lightweight.

Diaphysis

The elongated shaft of a long bone, primarily constructed of thick compact bone surrounding the central medullary cavity.

Medullary Cavity

The internal cavity inside the diaphysis of a long bone that houses bone marrow responsible for producing red blood cells and immune cells.

Epiphysis

The expanded end region of a long bone, composed of an outer shell of compact bone surrounding internal spongy bone.

Epiphyseal Growth Plate

A layer of hyaline cartilage located between the diaphysis and epiphysis of a growing long bone that proliferates to allow lengthening of the bone.

Epiphyseal Line

The completely ossified remnant of the epiphyseal growth plate indicating that growth in bone length has permanently ceased.

Endochondral Ossification

The process of bone development where a hyaline cartilage model is progressively broken down and replaced by bone tissue, forming long, short, and most irregular bones.

Intramembranous Ossification

The mechanism of bone formation where bone develops directly within a connective tissue membrane without a preceding cartilage model, forming flat bones such as those of the skull.

Appositional Growth

The process that increases bone diameter or thickness by adding new bone layers (circumferential lamellae) to the outer surface via osteoblasts while osteoclasts resorb bone internally.

Osteon

The fundamental structural unit of compact bone, consisting of concentric lamellae surrounding a central canal containing blood vessels and nerves.

Wolff's Law

The physiological principle stating that bone remodels and structural density adapts according to the mechanical loads and physical stresses placed upon it.

Osteoblasts

Bone-building cells that synthesize the collagen-rich organic matrix (osteoid), help mineralise new bone, and increase activity in response to heightened mechanical loading.

Osteoclasts

Bone-resorbing cells that dissolve bone tissue and release stored calcium and phosphate into the bloodstream, showing elevated activity when mechanical loading is reduced.

Osteoporosis

An age-related skeletal disease characterized by diminished bone mass and structural weakening due to the rate of bone resorption exceeding the rate of bone formation.

Fibrocartilaginous Callus

A temporary bridge composed of collagen fibers and cartilage created by fibroblasts and chondroblasts within approximately 48 hours following a bone fracture.

Bony Callus

A hard callus structure formed during fracture healing when osteoblasts replace the temporary fibrocartilaginous callus with trabecular (spongy) bone.

Mastoid Process

A prominent bony projection of the temporal bone located posterior to the ear on the lateral aspect of the skull, serving as the insertion point for the sternocleidomastoid muscle.

Medial Epicondyle

A distinct bony projection on the distal medial aspect of the humerus, posterior to which the ulnar nerve passes.

Anterior Superior Iliac Spine (ASIS)

A prominent bony landmark located at the anterior and superior end of the iliac crest, used as a surface reference for locating internal structures such as the appendix.

Medial Malleolus

The bony prominence on the medial aspect of the ankle formed by the distal end of the tibia, serving as a landmark anterior and superior to the posterior tibial artery pulse.