Asymmetrical tonic neck reflex
Encyclopedia
The asymmetrical tonic neck reflex (ATNR) is a primitive reflex found in newborn humans, but normally vanishes around six months of age.
It is also known as the "fencing
reflex" because of the characteristic position of the infant's arms and head, which resembles that of a classically trained fencer. When the face is turned to one side, the arm and leg on the side to which the face is turned extend and the arm and leg on the opposite side bend.
The presence of the ATNR, as well as other primitive reflexes, such as the tonic labyrinthine reflex
(TLR), beyond the first months of life may indicate that the child has developmental delays, at which point the reflex is atypical or abnormal. For example, in children with cerebral palsy
, the reflexes may persist and even be more pronounced. As abnormal reflexes, both the ATNR and the TLR can cause problems for the growing child. The ATNR and TLR both hinder functional activities such as rolling, bringing the hands together, or even bringing the hands to the mouth. Over time, both the ATNR and TLR can cause serious damage to the growing child's joints and bones. The ATNR can cause the spine to curve (scoliosis
). Both the ATNR and TLR can cause the head of the thighbone
to partially slip out (subluxation
) or completely move out of the hip socket
(dislocation
). When abnormal reflexes persist in a child, early intervention involving extensive physical therapy can be beneficial.
The "Fencing Response
" occurs in adults as a result of mechanical forces applied to the head, typically associated with contact sports. The Fencing Response is transient and indicates moderate forces applied to the brainstem, resulting in a traumatic brain injury.
It is also known as the "fencing
Fencing
Fencing, which is also known as modern fencing to distinguish it from historical fencing, is a family of combat sports using bladed weapons.Fencing is one of four sports which have been featured at every one of the modern Olympic Games...
reflex" because of the characteristic position of the infant's arms and head, which resembles that of a classically trained fencer. When the face is turned to one side, the arm and leg on the side to which the face is turned extend and the arm and leg on the opposite side bend.
The presence of the ATNR, as well as other primitive reflexes, such as the tonic labyrinthine reflex
Tonic labyrinthine reflex
The tonic labyrinthine reflex is a primitive reflex found in newborn humans. With this reflex, tilting the head back while lying on the back causes the back to stiffen and even arch backwards, the legs to straighten, stiffen, and push together, the toes to point, the arms to bend at the elbows...
(TLR), beyond the first months of life may indicate that the child has developmental delays, at which point the reflex is atypical or abnormal. For example, in children with cerebral palsy
Cerebral palsy
Cerebral palsy is an umbrella term encompassing a group of non-progressive, non-contagious motor conditions that cause physical disability in human development, chiefly in the various areas of body movement....
, the reflexes may persist and even be more pronounced. As abnormal reflexes, both the ATNR and the TLR can cause problems for the growing child. The ATNR and TLR both hinder functional activities such as rolling, bringing the hands together, or even bringing the hands to the mouth. Over time, both the ATNR and TLR can cause serious damage to the growing child's joints and bones. The ATNR can cause the spine to curve (scoliosis
Scoliosis
Scoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an X-ray, viewed from the rear, the spine of an individual with scoliosis may look more like an "S" or a "C" than a straight line...
). Both the ATNR and TLR can cause the head of the thighbone
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
to partially slip out (subluxation
Subluxation
A subluxation may have different meanings, depending on the medical specialty involved. It implies the presence of an incomplete or partial dislocation of a joint or organ. The World Health Organization defines both the medical subluxation and the chiropractic subluxation...
) or completely move out of the hip socket
Acetabulum
The acetabulum is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.-Structure:...
(dislocation
Dislocation
In materials science, a dislocation is a crystallographic defect, or irregularity, within a crystal structure. The presence of dislocations strongly influences many of the properties of materials...
). When abnormal reflexes persist in a child, early intervention involving extensive physical therapy can be beneficial.
The "Fencing Response
Fencing response
The fencing response is a peculiar position of the arms following a concussion. Immediately after moderate forces have been applied to the brainstem, the forearms are held flexed or extended for a period lasting up to several seconds after the impact...
" occurs in adults as a result of mechanical forces applied to the head, typically associated with contact sports. The Fencing Response is transient and indicates moderate forces applied to the brainstem, resulting in a traumatic brain injury.