HESI Skeletal System

How many bones in the adult body?

206

Long bone

Long longitudinal axis

Short bone

Short longitudinal axis and cubed

Flat bones

Thin & curved

Sesamoid bone

Found in ligaments, embedded with tendons

Sutural bones

Small bones in the sutures of the skull

Compact bone

Dense

Cancellous bone

Spongy bone found in central skull or ends of long bones

Spongy bone

A Meshwork of plates that contains lamellae and osteocytes between each layer

Osteons

Structural unit of compact bone

Haversian canal

Pathway for blood vessels and nerves

Lamellae

Rings around the central canal, sites of lacunae

Lacunae

Contains fluid & osteocytes

Osteoblasts

Bone cells that undergo mitosis & secrete osteoid

Osteocytes

Inactive mature osteoblasts in lacunae that cannot divide by mitosis

Osteoclasts

Breaks down bone and sends calcium from bone to blood

Epiphysis

End of a long bone (spongy bone)

Diaphysis

Shaft of a long bone (compact bone)

Metaphysis

Where diaphysis & epiphysis meet

Periosteum

Outer membrane covering the surface of bones

Medullary cavity

Within the shaft of the long bones filled with bone marrow

Where is the growth plate located?

Epiphysis

Tubercle

A rounded bump mostly for muscle & ligament attachment

Tuberosity

A rounded bump with a more gradual slope

Styloid process

Pointy process

Trochanter

Very large bump found on the femur bones

Condyle

A large rounded process

Foramen

A hole for arteries, veins and nerves

Sinus

A hollow cavity within a bone

How many vertebrae are in the spine?

24

Lordosis

Cervical & lumbar curves (secondary - after birth)

Kyphosis

Thoracic & pelvic curves (primary - at birth)

True ribs

1-7

False ribs

8-10

Floating ribs

11-12

Sacrum

5 fused vertebrae

Coccyx

3-5 small fused vertebrae

Fibrous joints

Held together by dense connective tissue

Cartilagenous joints

Bones united by cartilage

Synovial joints

Freely movable joints with synovial fluid

Functions of the skeletal system

Support, Movement, Hematopoiesis, Mineral storage & Fat storage

Tendon

Connects muscle to bone

Ligament

Connects bone to bone

Cartilage

Connective tissue found between bones in a joint