Bone development and ageing Flashcards
What is a centre for ossification?
Site where bone begins to develop
Where are primary centres for ossification found?
When do they appear?
Found in the diaphysis of bones.
Usually all present at birth.
Development occurs in an orderly sequence.
Where are secondary centres for ossification found?
When do they appear?
Found at the ends of long bones, formed in the epiphysis.
They appear after birth
Where is the epiphyseal line/plate?
From which side of the plate does growth mainly occur?
Between the epiphysis and the diaphysis.
The diaphysis side of the epiphyseal plate.
Ribcage
At roughly what age does the xiphoid process fuse with the body?
At roughly what age does the Manubrium fuse with the body? What implication does this have?
What happens to costal cartilages in old age? What implications does this have?
Middle age or later
Old age - Restricts breathing - Pump handle mechanism
Ossify in old age. This makes the ribs of the elderly vulnerable to fracture
Upper Limb
How does the scapula change with age?
Where does most growth occur in the humerus?
Where does most growth occur in the Radius and ulna?
Which is the first and last of the carpals to form?
Scapula is wide in children. This may be absorbed and thins out
Superior end
Inferior end
Capitate is first to develop (6 months), Pisiform is the last (9-14 years)
Lower limb
What are the dates of the apperance of the primary centres of ossification of the hip bones?
At what age do the three hip bones fuse?
When do lower limbs begin growing rapidly?
Which joints will osteoarthiritis commonly occur on?
Ilium (3 months), Ischium (4 months), Pubic bone (5 months)
20-25 years
When babies begin walking
Hip and knee joint
Foot size
At what age do children have growth spurts?
How do you know when the growth plates in the foot have closed?
Girls have growth spurts at 5 and 10 years, boys a little later.
The closing of growth plates in the foot matches the last time you got a larger shoe size
Neonatal Skull
Describe the neonatal skull?
Skull relatively large, face relatively small Lack of teeth Small mandible Small sinuses Inner and middle ears are of adult size
Postnatal skull growth
Where and how does growth of the skull occur?
How do the sutures accommodate expansion?
At what age do the different fontanelles close?
When do the frontal hemispheres fuse?
When has the orbital cavity reached adult size?
Growth occurs along the periphery of bones by absorbing the inner bone layer and depositing it on the external surface.
Sutures are set at an oblique angle to accommodate expansion
Posterior (2 months), sphenoidal (3 months), mastoid (1 year), anterior (2 years). Parts of occipital bone fuse (3 years).
Frontal hemispheres fuse at 6 years old.
Orbital cavity reaches adult size at 7 years old.
Mastoid Process
How and when does the mastoid process begin to protrude?
What is the sternocleidomastoid?
Mastoid process begins to protrude when the baby starts lifting their head at three months.
The muscle that attaches to the mastoid processes.
Adult skull growth
When does the saggital suture fuse?
When does the coronal suture fuse?
When does the Lamboid suture fuse?
Saggital - 22-31 years
Coronal - 24-40 years
Lamboid - 26-40 years
When do teeth begin to erupt?
See table
Describe mandibular development.
- Increases in length, height and thickness
- Thickness usually by addition on the outside
- Growth mainly occurs at alveolar border
- Lengthening is usually posteriorly
- Mental foramen grows by moving backwards
Describe postnatal mandibular development.
- Mandible starts as two halves at birth until about 2 years
- Mandible bone covers the teeth
- Mandible angle is very obtuse
- Alveolar arches elogate behind the mental foramen to make space for more teeth
- Chewing strengthens the mandible.
