Cranial system

Cranial nerves are nerves that emerge directly from the brain, in contrast to spinal nerves, which emerge from segments of the spinal cord. In humans, there are traditionally twelve pairs of cranial nerves. Only the first and the second pair emerge from the cerebrum; the remaining ten pairs emerge from the brainstem.

Disorders

Skull

The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain, is composed of two parts: the cranium and the mandible.

Functions of the skull include protection of the brain, fixing the distance between the eyes to allow stereoscopic vision, and fixing the position of the ears to help the brain use auditory cues to judge direction and distance of sounds.

Acrania

is a cephalic disorder of a human fetus characterised by a partial or complete absence of the cranium. The condition is frequently, though not always, associated with anencephaly. The anomaly Acrania is a partial or complete absence of the calvarium with abnormal brain tissue development. This anomaly is lethal in all cases and has important implications for obstetrical management and counseling. Acrania can be diagnosed early in pregnancy through an ultrasound. The fetus is said to suffer from acrania if it meets the following criteria: the fetus should have a perfectly normal facial bone, a normal cervical column but without the fetal skull and a volume of brain tissue equivalent to at least one third of the normal brain size. When no brain or little traces of it are detected, the anomaly is referred to as Anencephaly.

Craniosynostosis

is a condition in which one or more of the fibrous sutures in an infant skull prematurely fuses by ossification, thereby changing the growth pattern of the skull. Because the skull cannot expand perpendicular to the fused suture, it compensates by growing more in the direction parallel to the closed sutures. Sometimes the resulting growth pattern provides the necessary space for the growing brain, but results in an abnormal head shape and abnormal facial features. In cases in which the compensation does not effectively provide enough space for the growing brain, craniosynostosis results in increased intracranial pressure leading possibly to visual impairment, sleeping impairment, eating difficulties, or an impairment of mental development combined with a significant reduction in IQ. leading possibly to visual impairment, sleeping impairment, eating difficulties, or an impairment of mental development combined with a significant reduction in IQ.

Spina bifida

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. If the opening is large enough, this allows a portion of the spinal cord to protrude through the opening in the bones. There may or may not be a fluid-filled sac surrounding the spinal cord. Other neural tube defects include anencephaly, a condition in which the portion of the neural tube that will become the cerebrum does not close, and encephalocele, which results when other parts of the brain remain unfused.

Spina bifida malformations fall into three categories: spina bifida occulta, spina bifida cystica with meningocele, and spina bifida cystica with myelomeningocele. The most common location of the malformations is the lumbar and sacral areas. Myelomeningocele is the most significant and common form and it is this that leads to disability in most affected individuals. The terms spina bifida and myelomeningocele are usually used interchangeably.

Deformities of the feet

is a disorder of the foot that can be congenital or acquired. Such deformities can include hammer toe, club foot, flat feet, pes cavus, etc.

Heels

The heel is the prominence at the posterior end of the foot. It is based on the projection of one bone, the calcaneus or heel bone, behind the articulation of the bones of the lower leg.