Biomechanics of Fetal Development

Weekly Learning Outcomes

• Understand the biomechanical interactions between the embryo/fetus and the uterine environment.
• Learn the significance and patterns of fetal movements.
• Identify pathologies related to insufficient fetal movement.
• Explain the biomechanical properties and effects of pregnancy.

About the Previous Course

• Examined the developmental processes of the nervous system and musculoskeletal system in the fetal period.
• Evaluated the role of brain and spinal cord structures in motor skill development and nervous functions.
• Discussed how bones and muscles form during the fetal period and their impact on the fetus.
• Examined muscle tone changes during the fetal period.

Kinesiology of Normal Motor Movement

• Kinesiology is the study of human movement.
• Kinesiology combines understanding of anatomy, biomechanics, and physiology.

Embryo, Fetus, and Uterus Biomechanics

• Embryo movement occurs on a microscopic level before the mother is aware.
• Embryo/fetus development is influenced by mechanical forces in the environment.

Fetal Movements

• Specific fetal movements like head and neck flexion are observed in the 10th week.
• Regular body movements start at 15 weeks.
• Fetal movements are detected by the mother at around 17-20 weeks.
• Precise measurement techniques are required for observing and measuring fetal mechanics.

Physical Factors Affecting Fetal Movements

• Fetal movement is influenced by intrauterine space, amniotic fluid, fetal position, and the sex of the fetus.

External Factors Affecting Fetal Movements

• A mother's diet and acoustic stimuli can influence fetal movement.

Arthrogryposis

• Multiple congenital contractures are a characteristic of this syndrome.
• Reduced fetal movement is a key component of this condition.

Hip Instability, Dysplasia, or Dislocation

• Hip instability involves a poor fit between the femoral head and acetabulum.
• Abnormal femoral head movement is a key component of this condition.

Developmental Hip Dysplasia and Dislocation

• The acetabulum and femur are unstable, and the femoral head dislocates.

Dislocation

• Dislocation involves a loss of contact between the femoral head and acetabulum.
• Paralytic dislocation is linked to neuro-muscular problems and occurs early in pregnancy.
• Typical dislocation occurs naturally.

Pregnant Biomechanics

• Pregnancy is a natural process. Pregnancy weight gain makes musculoskeletal adaptation difficult.
• Posture and gait are affected due to changing center of mass.
• Body's kinematic adjustments aid in stability during pregnancy.

A Series of Biomechanical and Hormonal Changes

• Pregnancy-related hormonal changes affect back pain and risk of falls.
• Pregnancy impacts quality of life in a negative way.
• Progesterone and relaxin hormones contribute to changes in spinal curves (lordosis & kyphosis).
• Pregnancy causes reduced abdominal muscle strength.
• Pregnancy-related shifts in pelvic tilt affect movement.

While Walking

• Step width increases.
• Stride distance decreases.
• Walking speed slows down.

Postural Changes During Pregnancy

• Pelvic tilt, lumbar lordosis, gravity line shifts and spinal curves (kyphosis and lordosis) alter.
• Shoulder and cervical regions are also affected.

Mechanical Forces Affecting Fetal Development

• Internal and external forces influence fetal development.
• Internal forces like tendon, ligaments, and muscle contraction are relevant.
• External forces like gravity are also significant.

Gross Motor

• During pregnancy, primitive reflexes appear.
• As the central nervous system (CNS) develops, reflex-based movements are suppressed.
• Asymmetric Tonic Neck Reflex affects full rotation and midline hand use.
• The Moro reflex impacts sitting and head control in infants.

Corrective and Balance-Preserving Reactions

• Corrective and balance-preserving reflexes appear along with primitive reflexes.
• These reactions help infants to sit up and establish head and body control.

Movement of Arms and Legs / Walking

• Motor skills develop to include movement of arms and legs independently.
• Walking backwards and kicking objects occurs after 2 years of age.

What to Take Home?

• Motor development during pregnancy was covered.
• Details about embryonic, fetal and uterine development was established.
• Developmental significance of fetal movements was explored.
• Conditions arising from insufficient fetal movement were explored.
• Biomechanical interactions between mothers and fetuses were discussed.

Questions and Suggestions

• Which hormone is linked to increased back pain during pregnancy?
• Are biomechanical and hormonal changes related to back pain and falls in elderly?
• When is the first fetal movement (head and neck flexion)? and (genu varum to genu valgum) change?
• When do distinct patterns of fetal movement appear?

Explore the fascinating biomechanical interactions between embryos, fetuses, and the uterine environment. This quiz will cover fetal movements, the significance of these movements, and associated pathologies, along with the effects of pregnancy on biomechanical properties. It's an insightful look into normal motor movements and their implications during the fetal period.