7.4 Lifespan Considerations

Newborn

As the brain case bones grow in the fetal skull, they remain separated from each other by large areas of dense connective tissue, each of which is called a fontanelle. The fontanelles are the soft spots on an infant’s head. They are important during birth because these areas allow the skull to change shape as it squeezes through the birth canal. After birth, the fontanelles allow for continued growth and expansion of the skull as the brain enlarges. The largest fontanelle is located on the anterior head, at the junction of the frontal and parietal bones. The fontanelles decrease in size and disappear by age 2.

Pediatric

The pediatric population have growth plates (epiphyseal) located between the middle and the end of the long bones of the skeletal system. During the late teens and early 20s, growth of the cartilage slows and eventually stops. The epiphyseal plate is then completely replaced by bone. Muscle development occurs at the highest rate during the first years of life and during puberty, therefore monitoring growth and development is essential. As they grow, the anteroposterior-transverse ratio, which is typically 1:1, changes as the thoracic muscles develop fully, usually around six years of age.

Older Adults

The aging adult experiences a general slowing in nerve conduction, resulting in slowed motor and sensory interaction. Fine coordination, balance, and reflex activity may be impaired. There may also be a gradual decrease in cerebral blood flow and oxygen use that can cause dizziness and loss of balance.  Decreased bone mass (osteoporosis) is also a common finding in the aging population resulting in decreased bone strength.

Attribution

This chapter is modified from the following sources:

Betts, J.B. et al. (2013). Anatomy and Physiology. OpenStax, https://openstax.org/books/anatomy-and-physiology. CC-BY 4.0.