Anatomy of the Long Bone

Proximal Epiphysis

1

Proximal Epiphysis

The proximal and expanded end of a long bone. Made mostly of spongy bone and ends at the epiphyseal line

Diaphysis

2

Diaphysis

The shaft of a long bone. Composed of compact bone.

Distal Epiphysis

3

Distal Epiphysis

The distal and expanded end of a long bone. Made mostly of spongy bone and ends at the epiphyseal line.

Spongy Bone

9

Spongy Bone

Light, porous bone enclosing numerous large spaces that give a honeycombed or spongy appearance. It is softer and weaker bone but highly flexible and vascular.

Articular Cartilage

8

Articular Cartilage

The cartilage covering the articular surfaces of the bones forming a synovial joint

Epiphyseal Line

7

Epiphyseal Line

The line marking the site of the epiphyseal plate

Periosteum

6

Periosteum

The dense fibrous connective tissue membrane covering the surface of bones except at the joints and serving as an attachment for muscles and tendons.

Compact Bone

5

Compact Bone

Dense bone in which the bony matrix is solidly filled with organic ground substance and inorganic salts, leaving only tiny spaces (lacunae).

Medullary Cavity

5

Medullary Cavity

The central cavity of bone shafts where red bone marrow and/or yellow bone marrow (adipose tissue) is stored.

Bone Marrow

What is the yellow substance within #4?

Bone Marrow

Flexible tissue in the interior of bones that produce red blood cells (described as red) or store fat (described as yellow).

Bone Marrow

B

Bone Marrow

Flexible tissue in the interior of bones that produce red blood cells (described as red) or store fat (described as yellow).

Compact Bone

C

Compact Bone

Dense bone in which the bony matrix is solidly filled with organic ground substance and inorganic salts, leaving only tiny spaces (lacunae).

Periosteum

E

Periosteum

The dense fibrous connective tissue membrane covering the surface of bones except at the joints and serving as an attachment for muscles and tendons.

Nutrient Arteries

F

Nutrient Arteries

Arteries which bring nutrients.

Skeleton System Functions

-support: structural framework, points of attachment for tendons and muscles

-provides protection: internal organs (cranium, vertebrae, rib cage, pelvis)

-movement: muscle pull on bones, together bones and muscle produce movement

-mineral homeostasis: storage of Calcium and Phosphorus, body can draw on minerals when needed

-hematopoiesis: red bone marrow produces red/white blood cells/platelets (found in pelvis, ribs, sternum, humerus, femur)

-fat storage: yellow bone marrow → composed of adipose cells, long term place for storage of energy

Organization of Skeleton

appendicular and axial

Axial

skull, sternum, ribs, vertebral column

appendicular

upper extremities, lower extremities, shoulder girdle, pelvic girdle

long bones

longer than they are wide and work as levers (90) --> humerus, tibia

short bones

are cube shaped and have thin layer of compact bone, with inner spongy bone (30) --> wrist/ankles

flat bones

thin and usually curved, provide protection of organs (29) --> scapula, ribs

irregular bones

do not fit in any other category, shape usually has to do with specific function of the bone (53) --> vertebrae

sesamoid bones

bones that are embedded in tendons (4) --> patella

How do bones break

break/fracture because of stress on the bone (overtime or suddenly)

What type of cells are involved in healing a bone fracture?

-Phagocytes - cleans the bone fracture and kill germs, connective tissue

-Chondroblasts - makes soft callus, cartilage

-Osteoblast - makes hard callus, connective tissue

-Osteoclasts - dissolve hard callus, helps bone return to original shape, connective tissue

What is the role of blood in healing a bone fracture?

-Hematoma - blood clot formed around the bone

-Cleans the bone fracture

What is a hematoma?

-When a blood clot forms around break to help clean the area

-Happens a couple hours after bone is broken

What is the role of cartilage in the bone healing process?

Chondroblasts will form soft callus and then bone tissue follows to replace the soft callus

What is a soft callus?

-Provides stability at the fracture site for new blood vessels to form

-Made of collagen

-Created by chondroblasts

-Happens a couple weeks after the break

What is a hard callus?

-Formed into cartilage tissue then a bridge over the fracture site

-Phosphate and calcium

-Covers the fracture site

What is remodeling? When does it happen?

-Excess callus material is removed

-Osteoclasts break down old bone to replace it will new bone tissue

-3-6 month after depending on type of break

What role do osteoblasts play in bone healing?

-Cells that make bone tissues, produce bone cells (hard shell)

-Second to last stage of healing process

What role do osteoclasts play in bone healing?

-Breaks down the excess bone material made by hard callus

What is meant by setting the bone?

-Doctors make it so the bone will line it up correctly so it will heal in the right place

-Consequences if it is not set is the bone will heal in the wrong spot and be out of place

Why is immobilizing a break important?

-Casts and splints keep broken bones from moving so they heal and keep muscles from moving to reduce swelling when a cast would be too tight which would cause more swelling