Developmental Aspects Developmental Aspects At birth the skull

Developmental Aspects

Developmental Aspects • At birth, the skull bones are still incomplete • The un-ossified remnants of fibrous membranes between skull bones are called fontanels

Developmental Aspects • Fontanels – Allow for infant’s head to be slightly compressed during birth – Allows for growth of brain of fetus and infant

Developmental Aspects • A baby’s pulse may be felt in fontanels – – Fontanel means little fountain

Developmental Aspects • The large diamond shaped fontanel called anterior fontanel is soft up to 2 years old. • Other fontanels are replaced by bone by the end of 1 st year

Developmental Aspects Fetal Skull • Bones such as the mandible and maxilla are unfused in fetal skeleton – fuse by about 2 years Figure 7. 33

Developmental Aspects Growth Rates • At birth, the cranium is huge relative to the face • Mandible and maxilla are short - but lengthen with age Figure 7. 34

• By 9 months, the cranium is half of its adult size • By 8 or 9 years, cranium has almost reached adult proportions • Between 6 and 13, face grows more rapidly to adult proportions

Developmental Aspects: Spinal Curvature • Only thoracic and sacral curvatures are present at birth • The primary curvatures are convex posteriorly, causing the infant spine to arch like a four-legged animal

Developmental Aspects: Spinal Curvature • Secondary curvatures – cervical and lumbar – are convex anteriorly and are associated with the child’s development – Cervical at 3 months when infant starts to raise head, and lumbar at 12 months when baby starts to walk

Growth Rates • At birth, the head and trunk are about 1 ½ times as long as the lower limbs • The arms and legs grow at a faster rate than the head and trunk, leading to adult proportions, so… • By 10, the head and trunk are approximately the same height as the lower limbs.

Growth Rates • During puberty, female pelvis broadens • During puberty, male skeleton becomes more robust • Once adult height is reached, skeleton changes very little until old age

Developmental Aspects: Old Age • Intervertebral discs become thin, less hydrated, and less elastic • Risk of disc herniation increases

Developmental Aspects: Old Age • Loss of stature by several centimeters is common after age 55 • Further shortening can be produced by osteoporosis or by kyphosis • Costal cartilages ossify causing the thorax to become rigid

Developmental Aspects: Old Age • All bones lose mass – cranial bones lose less mass than most, but changes in facial contours with age are common • As bones become more porous, they are more likely to fracture – especially the vertebrae and the neck of the femur

Our skeleton is the protector and supporter of other body systems All systems are connected

Skeletal and Muscular Systems • Without our skeletal system, our muscles would be almost useless • Muscle pull on bones increases bone strength and viability, and helps determine bone shape • Skeletal system provides levers for our muscles and ionic calcium for muscle activity

Skeletal and Integumentary Systems • Our integumentary system provides vitamin D needed for proper calcium absorption

Skeletal and Nervous Systems • Skeletal system protects brain and spinal cord and provides calcium ions needed for neural function

Skeletal and Endocrine Systems • Endocrine system provides hormones that regulate uptake and release of calcium frm bone and hormones that promote long bone growth and maturation

Skeletal and Cardiovascular Systems • Bone marrow cavities provide site for blood cell formation • Cardiovascular system delivers nutrients and oxygen to bones and carries away wastes