Bones Flashcards
Functions of Bone
- Structure
- Assist Movement
- Protection
- Blood cell production
- Mineral Storage
- Energy Storage
Classification of Bones
- Long
- Short
- Flat
- Irregular
- Sesamoid
Long Bone
- Hard, dense bones that provide strength, structure, and mobility
- Longer than wide
- Most bones of the appendicular skeleton
Short Bone
- As wide as they are long
- Primary function is to provide support and stability with little to no movement
- Carpals and tarsals (that all?)
Flat Bone
- Principal function is either extensive protection or the provision of broad surfaces for muscular attachment
- Parietal, frontal, occipital, ribs, sternum (that all?)
Irregular Bone
- Bones that don’t fit into the other categories
- Ethmoid, sphenoid, vertebrae, pelvic bones (that all?)
Sesamoid Bone
- Bone embedded in a tendon
- Patella, pisiform, big toe, thumb (that all?)
Diaphysis
- Shaft of long bone
- Outer surface is lined by periosteum
- Lined by the endosteum on the inside
Epiphysis
- Articulating ends of long bone
- Outer surface is cortical (compact or lamellar) bone
- Inner surface is spongy (cancellous or trabecular) bone
Metaphysis
- Portion between the shaft and the wide parts of the ends
- Corresponds to the area of the epiphyseal line in ossified bone
Epiphyseal Plate
- Responsible for longitudinal growth
- A hyaline cartilage plate in the metaphysis at each end of a long bone
- Plate is found in children and adolescents
- The plate is replaced by an epiphyseal line in adults
- Usually closes by 25th year
Periosteum
- Lines the outer surface of the diaphysis, except the articular surface, points of ligament/tendon insertion, and surface of sesamoid bones
- Made up of 2 layers:
- Inner reproductive layer (stratum osteogeneticum)
- Outer fibrous layer (stratum fibrosum)
Functions of the Periosteum
- Nutrition: ?
- Protection: ?
- Growth: responsible for diametric growth and critical for callus formation after a fracture
Osteon
The basic unit of structure in compact bone
Structure of an Osteon
- Lamellae
- Central (Haversian) canal
- Perforating canals
- Lacuna
- Canaliculi
Lamella
- Concentric rings that runs parallel to the long axis of the bone
Central (Haversian) Canal
- Runs through the core of osteon, parallel to long axis of the bone
- Contains nerves, arterioles, and venules
Perforating Canal
- Connects the central canals
- Contains nerves, arterioles, and venules?
Lacuna
?
- The space withing lamella that contains osteocytes (mature bone cells)
Canaliculi
- Tiny canals which interconnect lacunae
- They provide a pathway for nutrients to diffuse from the central canal to osteocytes within their own osteon
Osteoblast
Young bone-forming cells that cause the hard extracellular matrix of bone to develop
Osteocyte
Mature bone cells that maintain the structure of bone
Osteoclasts
Bone-dissolving cells
Compact Bone
- AKA cortical or lamellar bone
- Hard, dense bone
- Made up of the Haversian system, in concentric layers
- Forms the surface of all bones
- Forms the shaft of long bones
Spongy Bone
- AKA cancellous or trabecular bone
- Lamellae are not arranged in concentric layers
Lamellae are arrange in lines that correspond with the lines of maximal stress - Contains red bone marrow, responsible for red blood cell production
Fontanels
- 6 fibrous membranes that form the “soft spots” on a babies skull
- Allows the skull to deform during birth
Anterior (Frontal) Fontanel
- Between the 2 parietal bones
- Largest and last to close (18-24 months)
Posterior (Occipital) Fontanel
- Between the 2 parietal and occipital bone
- Closes in about 2 months
Anterolateral (Sphenoidal) Fontanel
Usually closes by about 3 months
Posterolateral (Mastoid) Fontanel
Usually closes by about 12 months
Bones of the Orbit
7 bones:
- Sphenoid
- Lacrimal
- Zygomatic
- Frontal
- Maxilla
- Palatine
- Ethmoid
Angle of Inclination
- The angle formed between the femoral neck and femoral shaft in the frontal plane
- Normal: ~ 125 degrees in an adult, ~ 120 in elderly
Coxa Varum
Angle of Inclination of < 120 degrees
Coxa Valgum
Angle of Inclination of > 135 degrees
Angle of Torsion
- The angle formed between the femoral neck and femoral shaft in the transverse plane
- Normal: ~ 15 degrees in adults
- Head and neck of femur rotate outward from shaft of femur
Femoral Anteversion
- Torsion angle > 15 degrees
- Possible cause of pigeon toe
- Also causes winking patella
Femoral Retroversion
- Torsion angle < 15 degrees
- Possible cause of duck walk
