Injuries and Disorders of the Skeleton

Spina Bifida

Spina bifida is a developmental congenital disorder caused by the incomplete closing of the embryonic neural tube.

Learning Objectives

Describe spina bifida and why fewer babies are being born with it

Key Takeaways

Key Points

  • In spina bifida, some vertebrae overlying the spinal cord are not fully formed and remain unfused and open.
  • There is neither a single cause of spina bifida nor any known way to prevent it entirely; however, dietary supplementation with folic acid prior to pregnancy has been shown to be helpful in reducing the incidence of spina bifida.
  • Neural tube defects can usually be detected during pregnancy by testing the mother’s blood (AFP screening) or by a detailed fetal ultrasound.

Key Terms

  • neural tube: A hollow longitudinal dorsal tube formed in the folding and subsequent fusion of the opposite ectodermal folds in the embryo that gives rise to the brain and spinal cord.
  • AFP: Alpha-Fetal Protein (AFP); a major plasma protein produced by the yolk sac and the liver during fetal development that is thought to be the fetal form of serum albumin. AFP is measured in pregnant women through the analysis of maternal blood or amniotic fluid as a screening test for a subset of developmental abnormalities; it is principally increased in open neural tube defects and omphalocele and is decreased in Down syndrome.
This image is a drawing of an infant with spina bifida. The infant is sitting in profile. You can see a donut-shaped protrusion from the infant's lower back, which is the location of spina bifida.

Spina bifida: Location of spina bifida on an infant.

Spina bifida (Latin: “split spine”) is a developmental congenital disorder caused by the incomplete closing of the embryonic neural tube. Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open.

The protruded portion of the spinal cord and the nerves that originate at that level of the cord are damaged or not properly developed. As a result, there is usually some degree of paralysis and loss of sensation below the level of the spinal cord defect. Thus, the higher the level of the defect, the more severe the associated nerve dysfunction and resultant paralysis may be. People may have ambulatory problems; loss of sensation; deformities of the hips, knees, or feet; and loss of muscle tone.

Treatment for Spina Bifida

Spina bifida can be surgically closed after birth, but this does not restore normal function to the affected part of the spinal cord. Intrauterine surgery for spina bifida has also been performed; the safety and efficacy of this procedure is currently being investigated. The spinal cord lesion or the scarring due to surgery may result in a tethered spinal cord. In some individuals, this causes significant traction and stress on the spinal cord. This may lead to a worsening of associated paralysis, scoliosis, back pain, and worsening bowel and/or bladder function.

Causes of Spina Bifida

This image shows a drawing of a spinal cord affected by spina bifida. There is a line of vertebrae, and in the middle, exposed spinal cord (which looks like threads) in a cerebrospinal fluid sac between two vertebrae.

Spina Bifida: Spina bifida in the lumbar area. (1) External sac with cerebrospinal fluid. (2) Spinal cord wedged between the vertebrae.

There is neither a single cause of spina bifida nor any known way to prevent it entirely. However, dietary supplementation with folic acid prior to pregnancy has been shown to be helpful in reducing the incidence of spina bifida. Natural sources of folic acid include whole grains, fortified breakfast cereals, dried beans, leafy vegetables, and fruits. Neural tube defects can usually be detected during pregnancy by testing the mother’s blood (AFP screening) or by a detailed fetal ultrasound. Ultrasound screening for spina bifida is partly responsible for the decline in new cases because many pregnancies are terminated out of fear that a newborn might have a poor future quality of life. With modern medical care, the quality of life of patients has greatly improved.

Fractures

A bone fracture is a medical condition in which there is damage to the continuity of a bone.

Learning Objectives

Describe the different types of bone fractures

Key Takeaways

Key Points

  • A spinal fracture is a fracture of the vertebral column. A compression fracture is the collapse of vertebrae, while a cervical fracture is a fracture of any of the vertebral bones in the neck.
  • A rib fracture is a break or fracture in one or more of the bones making up the rib cage.
  • A hip fracture is a fracture that occurs in the proximal end of the femur, near the hip.
  • A clavicle fracture is a bone fracture in the clavicle, or collarbone.

Key Terms

  • fracture: Damage to the continuity of a bone.

A bone fracture is a medical condition in which there is damage to the continuity of a bone. A bone fracture can be the result of high force impact or stress, or a minimal trauma injury as a result of certain medical conditions that weaken the bones, such as osteoporosis or bone cancer. Although broken bone and bone break are common colloquialisms for a bone fracture,”break” is not a formal orthopedic term. Fractures can occur in bones throughout the body.

Fractures of the Vertebral Column

A spinal fracture (or vertebral fracture) is a fracture affecting the bones of the spinal column. They can affect the cervical vertebrae (a cervical fracture), the thoracic, or the lumbar regions.

Compression Fractures

A compression fracture is a collapse of vertebra. It may be due to trauma or a weakening of the vertebra. This weakening is seen in patients with osteoporosis or osteogenesis imperfecta, lytic lesions from metastatic or primary tumors, or infection. In healthy patients, it is most often seen in individuals suffering extreme vertical shocks, such as ejecting from an ejection seat. Seen in lateral views in plain x-ray films, compression fractures of the spine characteristically appear as wedge deformities, with greater loss of height anteriorly than posteriorly and intact pedicles in the anteroposterior view.

Cervical Fractures

image

Vertebral fracture: Lateral spine X-ray showing osteoporotic wedge fractures of the spine.

A cervical fracture is commonly called a broken neck. There are seven cervical vertebrae (neck bones) in the human neck, and the fracture of any can be catastrophic. The most common causes are traffic accidents or diving into shallow water. Abnormal movement of bones or pieces of bone can cause spinal cord injury resulting in loss of sensation, paralysis, or death. Considerable force is needed to cause a cervical fracture. Motor vehicle collisions and falls are common causes. A severe, sudden twist to the neck or a severe blow to the head or neck area can cause a cervical fracture. Sports involving violent physical contact carry a risk of cervical fracture.

Rib Fracture

A rib fracture is a break or fracture in one or more of the bones making up the rib cage. Fractures of the first and second ribs may be more likely to be associated with head and facial injuries than other rib fractures. The middle ribs are the ones most commonly fractured. Fractures usually occur from direct blows or from indirect crushing injuries. A rib fracture has the complication of potentially causing a pulmonary contusion. Rib fractures are usually quite painful because the ribs have to move to allow for breathing. When several ribs are broken in several places a flail chest results, and the detached bone sections will move separately from the rest of the chest.

Hip Fracture

A hip fracture is a serious femoral fracture that occurs in the proximal end of the femur (the long bone running through the thigh), near the hip. The term “hip fracture” is commonly used to refer to four different fracture patterns and is often due to osteoporosis; in the vast majority of cases, a hip fracture is a fragility fracture due to a fall or minor trauma in someone with weakened osteoporotic bone. Most hip fractures in people with normal bone are the result of high-energy trauma such as car accidents, falling from heights, or sports injuries.

Clavicle Fracture

A clavicle fracture is a bone fracture in the clavicle, or collarbone. It is often caused by a fall onto an outstretched upper extremity, a fall onto a shoulder, or a direct blow to the clavicle. Many research projects are underway regarding the medical healing process of clavicle fractures.