Functions and Structure of the Skeletal System

These flashcards cover key terms and definitions from the skeletal system lecture notes, including functions, structure, types of bones, and common disorders.

What are the main functions of the skeleton?

Support, Protection, Movement, Storage, Hematopoiesis.

Diaphysis

The shaft of a long bone made of compact bone.

Epiphysis

The end of a long bone made of spongy bone containing red marrow.

Medullary cavity

The hollow space inside the diaphysis that stores yellow marrow.

Periosteum

The dense outer covering of a bone that contains blood vessels and nerves.

Endosteum

The thin membrane lining the medullary cavity.

Trabeculae

Lattice beams found in spongy bone.

Osteon

The structural unit of compact bone consisting of concentric lamellae around a central canal.

Osteoblasts vs Osteoclasts

Osteoblasts build bone, whereas osteoclasts break down bone during remodeling.

Epiphyseal plate

The growth cartilage that becomes the epiphyseal line when fused.

Axial skeleton

Includes the skull, spine, ribs, sternum, and hyoid (80 bones total).

Appendicular skeleton

Comprises limbs and girdles totaling 126 bones.

Atlas

C1 vertebra that nods 'yes'.

Axis

C2 vertebra that pivots 'no' with the dens.

True ribs

Ribs 1–7 that attach to the sternum via cartilage.

Floating ribs

Ribs 11–12 that are not attached to the sternum.

Synarthroses

Joints that allow no movement, such as skull sutures.

Amphiarthroses

Joints that allow slight movement, like the pubic symphysis and vertebrae.

Diarthroses

Freely movable synovial joints that contain synovial fluid.

Osteoporosis

A condition characterized by low mineral density, which increases the risk of fractures.

Osteoarthritis

A degenerative joint disease involving the loss of cartilage and formation of bone spurs.

Rheumatoid arthritis

An autoimmune disorder causing inflammation of the synovial joints, leading to deformity.

Greenstick fracture

A partial fracture that is common in children.

Types of bones

Long, Short, Flat, Irregular, and Sesamoid (e.g., patella).

Bone Remodeling

The process by which osteoblasts build bone and osteoclasts break down bone.

Endochondral ossification

The process of bone formation from cartilage, typically occurring in growth plates.

Intramembranous ossification

The process of bone formation for skull bones and fontanels in newborns.

Coxal bones

The hip bones consisting of ilium, ischium, and pubis.

Vertebral column

Consists of cervical (C7), thoracic (T12), lumbar (L5) vertebrae, sacrum, and coccyx.

Paranasal sinuses

Air-filled spaces that help lighten the skull and improve voice resonance.

Normal spinal curves

Convex curves in the thoracic and sacral regions, and concave curves in the cervical and lumbar regions.

Types of fractures

Include simple, compound, complete, incomplete (greenstick), comminuted, impacted, spiral, transverse, and oblique.

Joint disorders

Includes osteoarthritis, rheumatoid arthritis, gouty arthritis, and infectious arthritis.