3. Motor-functional analysis of reflexes (primitive,
ﾊﾊpathological, and abnormal postural reflexes) [Table.1]
ﾊﾊIt is truly difficult to understand the motor-functional meaning of
the reflexes, including postural reflexes. Fortunately, we have an
opportunity to understand this through surgical correction of
abnormal neck position of asymmetric tonic neck reflex (ATNR)
(Fig. 18AB).
Originally at the corrective surgery of hyperextended neck, we
noticed an interesting fact that the hypertonic extensors such as the
longissimus capitis and cervicis are more predominantly hyperactive,
on the side to which the face is turned and the neck is extended
(Fig. 18AB).45 It had also been observed that the neck was
extended on the side to which the face was turned. We also noticed
the fact that when release of these muscles was conducted,
asymmetric position of the head and neck was controlled and
deformity corrected (Fig. 18B).35,45,61 This meant that
predominant hypertonicity of the extensors such as the longissimus
capitis and cervicis was responsible for such an extended position of
the neck on the side to which the face is turned.
In these patients, spinal muscles such as the longissimus capitis,
longissimus cervicis, longissimus thoracis and iliocostalis were also
predominantly contracted on the side to which the face is turned and
on the concave side of scoliosis.46,61 Here, the multiarticular
longissimus thoracis and iliocostalis were noted as hyperactive
extensors. It was also interesting to note that when these
multiarticular extensors of the trunk were released, scoliosis and
truncal deformity in asymmetric tonic neck reflex could be
corrected.44,46 It can be said that predominant contraction of these
cervical and thoraco lumbar extensors causes a part of the
asymmetric tonic neck reflex.45,46 It is also suggested that in
patients with asymmetric tonic neck reflex, extensors in cervical,
thoracic and lumbar spine are all predominantly contracted on the
side to which the face is turned and where the trunk is concave.
Detailed observations further disclosed that in these same
patients, hypertonicity of the extensors was predominant even in the
upper and lower extremities of the same side to which the face turns,
and the neck and trunk extend. These facts clearly demonstrated that
in patients with asymmetric tonic neck reflex, one side of the entire
body was totally extended, while the opposite side was totally
flexed. This analysis led us to the conclusion that asymmetric tonic
neck reflex is a motor-functional entity involved in primitive
movement pattern in which one side of the entire body is totally
extended and the opposite side is totally flexed (Fig. 17, 18A).46,
47,61
Fig. 17 Motor functional meaning of ATNR
This observation combined with the following interpretation
enabled us to arrive at a new concept that abnormal postural reflexes
are a kind of totally patterned movement for propelling the body
forwards in less separated and immature form. Similar analysis by
Sherington was quoted by Rushmorth 1964 and by Bleck 1987.
These observations provided us enormous benefits in the treatment
of cervical deformity, cervical radiculomyelopathy, scoliosis and
ATNR by the use of selective release surgery. Promising results
shown by selective release prove that this observation is rational
and will become a clue to understanding of postural reflex involved
in motor function. In order to understand the essentials of
hypertonicity, analysis of the reflexes involved in motor function
should be continued.
Totally involved posture
Totally involved extension:
In the totally involved patients, totally extended posture without
flexion (Fig.15, 21-A) is the most primitive posture, which is not
affected by postural change. This occurs when most of the central
nervous system is damaged, most of the antigravity muscles are
paralyzed, and the multiarticular muscles are contracted excessively
due to hyperirritability of the upper motor neurons in the brain stem
and spinal cord. Since both flexors and extensors contract
simultaneously, rigidity is caused in the whole body, and alternate
and reciprocal movements are inhibited. The extensors are more
predominant than the flexors in the totally involved extension.
Hypertonicity of the extensors, such as the longissimus capitis, the
longissimus thoracis and iliocostalis in the trunk, the triceps brachii
and latissimus dorsi in the shoulder and elbow, semimembranosus
in the hip and rectus femoris in the knee, are more predominant,
than that of the flexors. However, clinically, there seldom is a
typical form of total extension posture. Posture is usually
influenced with gravity and body position, and modified postures
such as tonic labyrinthine reflex (Fig. 13A), asymmetric tonic neck
reflex (Fig. 17, 18A) and the symmetric tonic neck reflex
(Fig. 21A) are common. Thus, all abnormal postures can be mostly
categorized in the following postural reflexes.
Tonic labyrinthine reflex (TLR):
Tonic labyrinthine reflex is a primitive and pathological reflex
that is seen in totally involved patients due to abnormal
simultaneous contraction of extensors and flexors in the whole body.
Motor-function-wise, posture can be changed into two different
phases: flexor dominant phase and extensor dominant one: Flexed
posture is exaggerated in prone position, in which contraction of the
flexors is predominant, whereas extended posture is exaggerated in
supine posture, in which contraction of the extensors is predominant.
Hypertonicity of the extensors, such as longissimus muscles, triceps
brachii and hip extensors located on the posterior side of the body is
exaggerated by gravity in the supine position; therefore,
extension-hypertonicity becomes predominant in supine position.
On the other hand, hypertonicity of the flexors such as rectus
abdominis, psoas and biceps brachii located on the anterior side of
the body is exaggerated by gravity in the prone position; therefore,
flexion hypertonicity become predominant in prone position.
Motor-function-wise, tonic labyrinthine reflex can be defined, as a
posture with extremely limited flexion-extension movements of the
whole body, in which simultaneous co-contraction of the hypertonic
flexors and extensors causes rigidity and, inhibits smooth reciprocal
flexion-extension movements.
In a normally developed human body, tonic labyrinthine reflex
posture is overwhelmed by antigravity activities of
well-differentiated monoarticular muscles located on the antagonist
side, and it is usually difficult to find out where it exists. But, we
can still see this reflex posture of different types, in various phases
of activities of cerebral palsy. It is difficult to see pure form of
tonic labyrinthine reflex, since most of the cerebral palsied patients
are alive with some antigravity activities. In order to control and
reduce this reflex, it is necessary to understand existence of tonic
labyrinthine reflex in its modified form in movements and in
postures.
This is a severely involved child, with a tonic labyrinthine reflex
posture (Fig. 13A). In supine position, he is totally hyperextended,
and hence has a totally involved extension posture. However, when
he is turned into prone position, both his upper extremities show
some degrees of flexion in the elbow. This change in position
demonstrates that flexor activities were mildly provoked by gravity
in prone position. This change in posture can be called, as a tonic
labyrinthine reflex in neurology. On the contrary, this can be called
as a flexion-extension movements of the whole body
motor-function-wise. We can observe this reflex, in the modified
form in almost all diplegic, triplegic and quadriplegic patients.
This tonic labyrinthine reflex posture can be a candidate for
treatment by spasticity control surgery.43,45 Here, motor
functional analysis of the reflex posture should be done prior to
surgery. Hypertonic muscles are selectively released at the neck,
trunk, shoulders, elbows, wrists, thumb and fingers, hips and
knees, and feet and ankles appropriately, and then, this reflex
posture can be controlled (Fig. 13B).
Fig. 13A. Tonic labrinthine reflex
Fig. 13B. Control of TLR
After OSSCS on the neck, thunk, shoulders, elbows,
hips and knees, TLR posture is controlled.
This is another modified form of tonic labyrinthine reflex
(Fig. 14A). He shows flexed posture mostly, in prone posture.
However, he shows hyperextended posture with scissors posture,
when he is in supine position. This level of tonic labyrinthine
reflex posture could also be a candidate for orthopaedic selective
spasticity-control surgery. Hyperextended and hyperflexed postures
can be controlled and alternate movements of the extremity can be
facilitated (Fig. 14B).
Fig. 14A TLR posture.
Fig. 14B. After OSSCS on the trunk and hips,
ATNR and TLR posture were blocked, and
turn-over exercises were initiated.
(See Clause of turn-over exercise.)
(
[Considerations]
Functional entity of extension posture, in supine position:
When we place a totally involved child on bed in supine
position, we can see a phenomenon by which she propels herself to
the cranial end of the bed by extending her whole body. She is
likely to get hurt by hitting her head against the bed-fence. This
attitude of the baby in the bed can be considered to be an extension
posture of the tonic labyrinthine reflex in supine position. The
forward movements of this baby can be considered to be a
reproduction of the most primitive level of forward-propelling
locomotion. As reciprocal movements are extremely limited with
co-contraction of flexors and extensors in severely paralyzed
patients, this condition cannot be recognized as a movement. This
condition has been recognized, as a posture. However,
motor-function-wise, extended posture of the tonic labyrinthine
reflex in supine position could be recognized, as an ultimate
immobile form of primitive and ineffective locomotion. Thus,
extension phase in tonic labyrinthine reflex in supine position is
fundamentally considered to be a form of primitive locomotion.
We can see this kind of primitive locomotion in nature.
Fishes have developed a slight antigravity mechanism with small
antigravity muscles near their fins. They can keep their bodies in
prone position in water with activities of these small fins. But this
mechanism acts only in water where the earth's gravity has no effect
on their bodies. When a fish is taken out of water and placed on the
ground, the strong earth's gravity will act on its whole body. But
antigravity mechanism of the fish is too small to counteract this
gravity. So in order to escape from danger, they will jump,
extending their trunk with quick contraction of the multiarticular
paravertebral muscles, and will fall on the ground without body
supporting movements (Fig. 15). This jumping is a kind of
flexion-extension movement without antigravity activities, caused
by symmetrical contractions of the paravertebral extensors and
abdominal flexors. There is no such antigravity activity in the fish,
as seen in amphibians, reptiles and mammals. This is the most
primitive locomotion in which the head is forced to hit against the
ground, without any protective movements (Fig. 15).
Fig. 17. Extesion pattern without antigravity activity
These total
extension and flexion movements of the entire body could be an
original form of movement pattern observed in the tonic
labyrinthine reflex (Fig. 13A, 14A).
We can observe similar flexion-extension locomotion style in the
human baby. Babies below 3 months move themselves forward, by
kicking their legs, with extension movements of the trunk and
extremities in supine position. This is a primitive locomotion, using
flexion-extension pattern of the tonic labyrinthine reflex.
The starting jump in supine position at the backstroke in swimming
is also a primitive and most propulsive locomotion, without any
antigravity support. Thus, an extension pattern of the tonic
labyrinthine reflex could be observed in primitive movements of
human being both in children with cerebral palsy and in normal
babies and adults.
Flexion posture in prone position:
Flexor pattern in tonic labyrinthine reflex can also be seen in
various phases of human posture and in locomotion. In normal
human being, when they carry out highly propulsive movements,
such as running or jumping, crouched flexed posture emerges.
Motor-function-wise, this can be interpreted as a sudden emergence
of flexed posture of the tonic labyrinthine reflex. Flexed posture in
crawling and kneeling is also similar. A newborn baby keeps the
body in a ball posture in prone position. This is a basic form of
flexion pattern of tonic labyrinthine reflex. From ontogenesis point
of view, motor activities in the human body have originated from
totally involved flexion posture in tonic labyrinthine reflex, where
flexor activity is predominant in prone position. The antigravity
extensors are facilitated during growth, which overcome flexor
hyperactivity in the tonic labyrinthine reflex resulting in antigravity
postures such as kneeling, and standing.
In cerebral palsied patients, we can see various phases of the
flexion posture in the tonic labyrinthine reflex. Most of the severely
involved patients show some flexion attitude in prone position and
cannot maintain upright posture such as in sitting (Fig. 20A). In a
child at the level of mermaid crawl, we also see a flexor-dominant
posture. In this condition, the flexion form of the tonic labyrinthine
reflex is predominant. In the prone position, hypertonicity of the
flexors in the trunk and extremities are more exaggerated by gravity.
This combined force induced with hypertonicity of the flexors and
gravity inhibits body-supporting activities of the antigravity
extensors, such as the suboccipital and multifidus muscles (Fig. 31).
In the more mature patients, you can see more mature
flexor-dominant posture in symmetric on-hands and on-knees
crawling (Fig. 16A). In these patients, the flexor-dominant posture
of the tonic labyrinthine reflex is well controlled, and a more
matured four point crawl posture is achieved (Fig. 16B).
Fig. 16A. Symmetric on-hand and -knee crawling
Fig. 16B. After OSSCS on the hips
Symmetric pattern is controlled and
alternate crossed pattern on crutch
gait was achieved.
Even in
patients who can stand, this flexor pattern such as a crouched
posture can often be predominant. Crouched posture can be
interpreted as a matured form of this flexion attitude of the tonic
labyrinthine reflex in standing in which antigravity activities of the
extensors overwhelms hypertonicity of multiarticular flexors in
tonic labyrinthine reflex in prone position (Fig. 2A, 3A, 5A, 6A,
82A). Thus, we can now recognize that the tonic labyrinthine reflex
can be interpreted motor-function-wise, as a form of propulsive
movement and is caused by activities of hypertonic muscles in the
entire body. With excessive co-contractions of the hypertonic
muscles, movements are limited and the body seems to be fixed in a
particular posture. Accordingly, we can control this hypertonic
entity, by using orthopaedic selective spasticity-control surgery.
Control of hypertonicity of the psoas in the hip joint by the use of
selective release can be considered, as a form of spasticity-control
procedure for control of the flexor pattern in tonic labyrinthine
reflex. If this reflex is controlled surgically, a more matured
standing posture is attained (Fig. 3B, 6B, 82B). Thus, we have to
analyze the motor function of the postural reflex in these manners,
and then we will be able to use this analysis for the orthopaedic
selective spasticity-control surgery in tonic labyrinthine reflex.
Asymmetric tonic neck reflex (ATNR):
Motor function analysis also disclosed another interesting
finding. Asymmetric tonic neck reflex can be interpreted as a
physical condition in which the whole body is longitudinally
separated into two parts: left side and right side. This is also a
condition where one side of the entire body is totally extended and
the other side is totally flexed (Fig. 17, 18A Under construction). Clinical analysis of
the hypertonicity of the neck and trunk has made this interesting
and exciting interpretation possible.
On clinical analysis of the spastic scoliosis, we noted the fact
that the concave deformity is the result of hypertonic activity of the
paravertebral muscles on the concave side. We could understand
that concave side is the extensor-predominant side. We also noted
the fact that in asymmetric tonic neck reflex posture, the face is
forced to turn to the side where hypertonicity of the neck extensors
such as the longissimus capitis and cervicis muscles is
predominant. Here, we also noticed the fact that the side to which
the face is turned is the extensor predominant side. This fact
clearly explains the question, why the extremities extend on the
side to which the face turns in ATNR. In asymmetric tonic neck
reflex, on the side where the face of the patients turn, hypertonicity
of the extensors of the neck, trunk, upper extremity and lower
extremity is concomitantly predominant. So the hypertonic
extensors of the trunk, upper extremity and lower extremity in the
same side act together simultaneously and cause the ATNR posture.
This fact means that the head, trunk, upper extremity and lower
extremity on one side cannot move separately because of their
immaturity in movement. This is a situation where the neck, trunk,
upper extremity and lower extremity are simultaneously extended,
as an extensor block, whereas the neck, trunk, upper extremity and
lower extremity on the opposite side are simultaneously flexed, as a
flexor block (Fig. 17, 18A).
Thus, from these clinical observations, an interesting conclusion
could be deduced that the asymmetric tonic neck reflex is a
manifestation of the primitive locomotion, where the body is
divided into two parts, which act alternately to drive the body
forwards. The treatment of the asymmetric tonic neck reflex is
therefore, to bring the ineffective body movements caused by the
two blocks of the body, into an effective crossed alternate
movements in the four parts of the body. The approach will be to
reduce the hypertonicity of the trunk by release of the hypertonic
muscles, making movement of the upper trunk free from the ones of
the lower trunk on the same side, and to facilitate the independent
and separate movements of each extremity (Fig. 14B, 18B).
Phylogenetically, there is no vertebrate with such a primitive
level of locomotion. Therefore, this asymmetric pattern cannot be
considered, as a locomotion pattern of some specific animal.
However, as shown in the case of tonic labyrinthine reflex, we
could see a similar locomotion pattern in jumping of fish when
taken out of water and placed on the ground. The fish placed on the
ground often makes jumping movement in a characteristic pattern,
in which one side of the body is totally extended and opposite side
is totally flexed (Fig. 17). This pattern observed in fishes when
taken out of water is a decisively primitive and immature
locomotion pattern. Here, one side of the body is totally flexed and
the other side is extended. This longitudinally separated movements
are functionally almost the same as the movements of asymmetric
tonic neck reflex, observed in cerebral palsy (Fig. 14A, 17, 18A).
Fig. 17. Motor functional meaning of ATNR
On the basis of these clinical, phylogenetical, and ontogenetical
analysis, asymmetric tonic neck reflex can be considered, as a form
of primitive propulsive movement. The original form of asymmetric
tonic neck reflex can be a movement with propelling activity.
However, when it is seen in severely involved cerebral palsy
patients, it is usually associated with hypertonicity such as rigidity,
resulting in fixed body postures with limited movements. Patients
with asymmetric tonic neck reflex can be candidates for the surgical
treatment. All extension hypertonicity, such as extension deformity
of the neck and trunk, shoulder retraction, extension of the elbow
and extension in the hip, knee and ankle which cause create
asymmetric tonic neck reflex as a whole, are relieved by release of
the hypertonic extensors, whereas all flexor hypertonicity on the
opposite side, such as flexion of the neck and trunk, flexion of the
elbow and flexion hypertonicity in the hip, knee and ankle, are
similarly relieved by selective release of the hypertonic flexors. By
these releases, the asymmetric tonic neck reflex can be controlled
decisively, and voluntary movements in the entire body can be
facilitated (Fig. 14B, 18B).
A. ATNR before OSSCS
B. After OSSCS on the neck, trunk, shoulders,
elbows, hips and knees,
ATNR posture is corrected.
18AB. Control of ATNR posture
Symmetric tonic neck reflex:
Symmetric tonic neck reflex is another posture in which the
symmetrically positioned upper body moves separately and
alternately against the symmetrically positioned lower body. This is
a phenomenon where the upper extremities extend simultaneously
with passive extension of the neck, but the lower extremities flex
(Fig. 19A, Bottom), whereas with flexion of the neck, the upper
extremities flex simultaneously but the lower extremities extend
(Fig. 19A, Top).
Fig.19A. STNR pattern movements.
The head is already matured and is not influenced by STNR.
Fig.19B. After OSSCS on both the hips.
Alternate crossed pattern movements
are observed
This is another primitive motor activity with less separated
movements. In this mode of locomotion the body propels itself
with symmetrical extension of the upper trunk and upper extremities,
while the lower trunk and lower extremities symmetrically flex
(Fig. 20A, Top). Then, the lower trunk and lower extremities
symmetrically extend, while the upper trunk and upper extremities
symmetrically flex, driving the body forwards (Fig. 20A Bottom).
In this locomotion the driving phases in upper or lower extremities
can be seen alternately in all the phases of locomotion.
Phylogenetically, the original form of symmetric tonic neck reflex
is mostly seen in more propulsive movements such as swimming of
the frog, leap of the frog, and symmetrical quadrupedal locomotion
of the kangaroo.
A. Typical STNR before OSSCS
B. STNR is controlled after OSSCS on both the hips
20AB. Treatment of STNR with OSSCS
In the human being, we can see this form in breaststroke
swimming and in a vaulting horse activity. These are symmetrical
locomotion patterns in which a phase of upper body flexion and
lower body extension and a phase of upper body extension and
lower body flexion emerge alternately, and propel the body
forwards. In the patients with cerebral palsy, we can see the
symmetric tonic neck reflex pattern in various levels, such as no
rolling level (Fig, 21A), mermaid crawl level (Fig. 19A), four-point
crawl level (Fig. 16A), standing level and in the form of symmetric
deformities such as spastic diplegia (Fig. 5A, 6A).
STNR can be observed in the most primitive level. In this level,
the elbows are symmetrically flexed, whereas the lower extremities
are totally extended. Although the posture is not typical, a
symmetrical pattern is observed (Fig. 21A).
21A. STNR posture (Symmetric flexion of the upper extremities
and extension of the lowerextremity.
You can see a STNR in a symmetric mermaid crawl on abdomen
in which a pattern of upper-body-flexion and lower-body-extension
and a pattern of upper-body-extension and lower-body-flexion
emerge alternately to drive the body forwards (Fig. 19A).
In another form of STNR, the upper trunk and upper extremities
are extended with neck extension (Fig. 20A, Top) while the lower
extremity is flexed. When neck and upper extremities are flexed,
the lower extremities are extended (Fig. 20A Bottom). This
movement can be called as symmetric tonic neck reflex posture. By
the use of spasticity control surgery, hypertonicity is controlled and
alternate-movement exercises can be given to achieve a four-point
crawl position (Fig. 20B).
You can also see STNR in a form of symmetric four-point crawl;
this is a matured locomotion (Fig. 16A). Symmetrical spastic
diplegia is also an expression of STNR in a more matured level
(Fig. 6A).
STNR in all the levels are candidates for orthopaedic selective
spasticity-control surgery in order to achieve alternate crossed crawl
pattern, to accomplish alternate bipedal locomotion and to gain
individual movement in each extremity (Fig. 6B, 16B, 19B, 20B,
21B)).
21B. After OSSCS on both the hips
STNR (Flexion of the upperextremities and extension of
the lower extremities) is corrected. Flexion on both the
upper and lower extremities are achieved.
Segmental localized hypertonicity (Diplegia)
When the brain is not so severely damaged, antigravity and
voluntary activities of the body will be gradually activated from the
cranial end of the body to the caudal end, in course of the
ontogenetic development of a baby. In such a case, hypertonicity is
mostly localized segmentally in lower part of the trunk while the
upper part of the body has decreased hypertonicity. This localized
hypertonicity is considered, as a reflex-complex, formed by a
combination of many local reflexes. We can see this segmentally
localized hypertonicity, in crouched posture, windswept deformity
and scissors posture (Fig. 3A, 22A, 40A). Neurologically, this
condition is called as segmental static reaction.
Windswept deformity:
This deformity is an asymmetrical posture observed in the lower
extremities in diplegia, triplegia, and quadriplegia where the lower
extremities are more severely involved than the upper extremities.
In this deformity, flexion, abduction and external rotation of the hip
is predominant on the one side, whereas extension, adduction and
internal rotation of the hip are predominant on the opposite side
(Fig. 22A). Motor-function-wise, the side with the flexion,
abduction and external rotation deformity is said to be in the flexion
phase of the hip at locomotion, whereas the side with the extension,
adduction and internal rotation deformity is in the extension phase
of the hip.
22A. Crouched posture with wind-swept deformity
22B. After OSSCS on the hips, knees and rt foot.
Developmentally, this deformity can be considered, as a
subgroup of the asymmetric tonic neck reflex. In patients, in whom
antigravity and voluntary movements of the upper extremities and
upper trunk have matured, and hypertonicity of the upper trunk and
upper extremities are decreased, the typical asymmetric posture of
the upper trunk and upper extremities is overwhelmed, and a fixed
asymmetrical neck reflex posture such as windswept deformity
remains only in the lower extremities. This is called as a windswept
deformity (Fig. 22A). Thus, windswept deformity is a kind of
asymmetric tonic neck reflex deformity segmentally localized in the
lower trunk and lower extremities. Treatment of the windswept
deformity can be carried out by correcting the asymmetric
deformities of the hips, knees and feet (Fig. 22B), by using OSSCS.
Scissors posture:
Scissors posture is a symmetrical posture observed in the lower
extremities in diplegia, triplegia, and quadriplegia. Extension and
adduction attitudes of the hip are predominant in both hips
(Fig. 19A, 23A). Dislocation of the hip is also a frequent
accompaniment. This deformity is called, as scissors posture.
Developmentally, this deformity can be considered, as a subgroup
of the symmetric tonic neck reflex posture. In the patients in whom
antigravity and voluntary movements of the upper trunk and upper
extremities have matured, typical symmetric posture of the upper
trunk and upper extremities disappears, and fixed symmetric posture
in extension remains only in the lower trunk and lower extremities,
as a scissors posture. This scissors posture can be considered as
remains of the primitive symmetric locomotion.
Fig.23A. Scissor posture on dipledic boy
Fig. 23B. After OSSCS on the hips, knees and feet,
crutch walk was achieved.
In scissors posture, bilateral dislocation of the hips can be easily
caused by hypertonicity in extension and adduction of the hip,
which could disturb basic motor functions such as turnover,
crawling and sitting. To prevent dislocation and to facilitate
reciprocal flexion and extension movements of the hips and to attain
basic motor functions, control of hypertonicity of the hip is
essential (Fig. 19B, 23B).
Crouched posture:
Crouched posture is a flexed posture in both the lower
extremities, observed in standing and walking, and is also
considered as a segmental localized hypertonicity (Fig. 3A, 96A).
This is also a situation, in which antigravity activity of the
monoarticular extensors are not fully matured. Fundamentally, all
locomotion in upright posture can be considered to start from
flexor-dominant posture of the tonic labyrinthine reflex, which is an
original form of locomotion. Raising of the head and neck can be
possible when antigravity activities of the neck extensors have
overcome the original flexor-dominant posture of the tonic
labyrinthine reflex at the neck. With extension activities of the
antigravity extensors, children gradually begin to raise the head and
upper trunk, from flexor dominant posture of the tonic labyrinthine
reflex and then begin to crawl. According to the development of
antigravity extensors, children advance to quadrupedal locomotion,
crouched standing and mature upright standing, overcoming
flexor-dominant posture of the tonic labyrinthine reflex.
In matured human body, antigravity monoarticular extensors
such as the gluteus maximus, vastus medialis and lateralis and
soleus have fully developed. Well-developed extension attitude in
human body is a posture in which antigravity extensors ultimately
overcome the original flexor-dominant posture of the tonic
labyrinthine reflex. In normal human body, flexor-dominant posture
of the tonic labyrinthine reflex becomes latent in prone position,
since this reflex is fully depressed with vivid activity of the
antigravity extensors. Crouched posture can be understood as a
condition in which development of antigravity extensors are
somewhat depressed by cerebral damage, and where a
flexor-dominant posture of the tonic labyrinthine reflex is revealed
somewhat in prone position. So, it is concluded that crouched
posture is caused by excessive hypertonicity of the multiarticular
flexors as against weak antigravity extensors.
Since this crouched posture is a mild form of the tonic
labyrinthine reflex, extensor-dominant posture can also be easily
elicited, when this patient is turned to the supine position. This
extended posture can be caused by predominant hypertonicity of the
multiarticular extensors as against the antigravity flexors at the hips,
knees and feet in the same patient. Selective release of the both
hypertonic flexors and extensors in the hips and knees and plantar
flexors of the feet is essential for correction (Fig. 3B, 96B).
Reflex-complex localized in a limb
(Local static reaction: Hemiplegia)
This reflex-complex posture is called, as a local static reaction in
neurological terms.
Motor-function-wise, there are characteristic postures localized
either in the entire upper limb or in the entire lower limb, such as a
withdrawal posture of the upper limb, and an extended posture
called a positive supporting reaction or an extensor thrust of the
lower limb. The withdrawal posture of the upper extremity seen
often in hemiplegic and quadriplegic patients is a combination of
shoulder retraction, flexion of the elbow, pronation of the forearm,
flexion of the wrist, and flexion deformities of the thumb and
fingers (Fig. 71A, 73A). The extended posture of the lower
extremity seen in hemiplegic and diplegic patients (Fig. 23A, 24A)
is a combination of flexion of the hip, extension or flexion of the
knee, and equinus deformities of the ankle and foot.
Fig. 24A. Equinus deformity
due to exxagerated Achilles tendon reflex
Fig. 24B. After OSSCS, Achilles tendon reflex
was reduced, and deformity corrected.
This reflex-complex posture localized in an entire limb in
cerebral palsy is fundamentally a combination of exaggerated
reflexes in each joint caused by hypertonicity of the multiarticular
muscles. This posture can be controlled by OSSCS at all the
involved joints (Fig. 23B. 24B. 71B, 73B).
Local reflexes
Significance of the stretch reflex in human movement
Neurologically, reflex is a contraction response of muscles to
prevent over-stretching of these muscles, when they are stretched
too much. Stretch reflexes such as the patellar tendon reflex, the
Achilles tendon reflex, the biceps reflex and the triceps brachii
reflex are considered, as a quick contraction of the muscles, to
prevent over-stretching of these muscle while protecting normal
joint structures. Motor-function-wise, this stretch reflex can also be
interpreted, as a quick movement of the joint caused by contraction
of the muscle, while preventing over-extension or over-flexion of
the joint. So the patellar tendon reflex can be interpreted, as a quick
extension movement of the knee joint by contraction of the
quadriceps muscle, while preventing over-flexion (collapse) of the
knee joint. Achilles tendon reflex is also considered as a quick
plantar flexion movement of the ankle, while preventing
over-dorsiflexion (collapse) of the ankle. What then can be the
functional meaning of a stretch reflex?
Dexterity of the joint and reciprocal movement
"Reciprocal innervation" is a neurological term. This is called as
reciprocal movements in motor-functional term. This is a
phenomenon in which the extensors relax when the flexors contract,
and the flexors relax when the extensors contract. Human joints can
move smoothly because of this reciprocal muscle activity. In the
knee joint, when the hamstrings act as flexors and the antagonistic
quadriceps responds by relaxing, then, a smooth flexion movement
becomes feasible. On the other hand, when the quadriceps acts as
an extensor, and the antagonistic hamstrings relax simultaneously,
a smooth extension is taken place. With these reciprocal
movements, a quick conversion of movements from flexion to
extension, or from extension to flexion can be feasible and so an
effective locomotion is achieved.
Stretch reflexes for protection of the joints from overstretching
When the flexors alone act on one-side, the joint flexes beyond
the normal range of motion, resulting in the capsule being stretched
and torn with a possible joint dislocation. In the vertebrates in such
a situation, a preventive mechanism has developed in which the
extensors respond quickly by contraction to prevent over-flexion of
the joint.
On the other hand, if the extensors alone act too much on
one-side, the joint overextends beyond the normal range of motion,
resulting in the capsule being stretched and torn, causing a possible
dislocation. Then, similarly, a preventive mechanism has developed
in which the flexors respond quickly by contracting to prevent
hyperextension of the joint. This quick contraction of the
antagonistic muscles which prevent hyperextension or too much
flexion of the joint, are called, as a stretch reflex, in the field of
neurology.
Motor-function-wise, the stretch reflex is interpreted, as a
protective mechanism, which prevents overactivity of the
antagonistic muscles and limits hypermobility of the joint, thereby
protecting the joint. Thus, the joints of the human body have
acquired smooth motion with reciprocal movements, and have also
developed elaborate mechanism in which stretch reflex acts to
prevent excessive flexion or extension as well.
Exaggerated stretch reflex
When central nervous system is damaged, the nature of the
stretch reflex changes significantly. Exaggeration in the stretch
reflex becomes obvious with inhibition of reciprocal movements.
Our clinical observation explains that increase in patellar tendon
reflex is caused by hypertonicity of the multiarticular rectus femoris
(Fig. 23A, 25A). Exaggerated Achilles tendon reflex is caused by
hypertonicity of the multiarticular gastrocnemius (Fig. 23A, 24A).
Similarly, increase in the biceps brachii reflex and triceps brachii
reflex is caused by hypertonicity of the biceps brachii and triceps
brachii (Fig. 66A, 68A, 70A). Flexion deformity of the fingers and
toes are other forms of the exaggerated grasp reflex. Thus, the
exaggerated stretch reflexes are clinically considered to be caused
mostly by hypertonicity of the multiarticular muscles of the affected
limbs.
Fig. 25A. Stiff-knee gait due to
exaggerated patellar tendon reflex
After OSSCS on exaggerated PTR, stiff-knee gait disappeared.
On the basis of these observations, it can be concluded that
deformity of each joint is caused by an exaggerated stretch reflex.
Stiff-legged knee or recurvatum deformity of the knee is considered
to be caused by an exaggerated patellar tendon reflex.
Thus, stretch reflex is not a different entity from muscle
contraction. Motor-function-wise, stretch reflexes are a quick
movement of joint caused by quick contraction of the muscle.
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