Set of difficulties or abnormalities that occur during the birth process. There are several types of dystocia, which can be the result of alterations in fetal statics (abnormal position of the fetus, prolongation of the second stage of labor) or fetopelvic disproportion (cephalo-pelvic), etc. Many of them have a negative influence on the occipitoatlantal joint.
It consists of the use of mechanical forces applied to the fetus during the expulsive phase of a difficult delivery, with the aim of reducing complications. The deformability of the skull and neck of the fetus is partly responsible for some compressive or deformative alterations of the cranio-cervical structures.
The head of the fetus must be flexed, which stresses the cranial joints and their relationship with the Atlas and Axis. A change in the speed of flexion induces the occipital condyles to absorb this mechanical tension and deform, which can cause respiratory disorders and disorders of the cranium-cervical spine relationship.
An increase in the support of the maternal pubis on the fetal occiput brings the occipital scale closer to the lateral masses of the Atlas. This can lead to the narrowing of the foramen of the skull where the spinal cord travels and bring about significant muscular and fascial problems in the cervicals of the fetus.
The occiput is behind in front of the right iliac. If the amplitude of the rotation is greater than 35º, it increases the probability that the occipital scale, the sphenobasilar symphysis and the occipital condyle make an undesirable rotation that manifests itself with the Condylar Compression Syndrome or increased tension between the occipital condyle and the glenoid cavity of the Atlas.
The fetus presents itself face-on because it has hyperextension of the head. This induces a cephalic deflexion to direct the chin towards the pubic symphysis, and thus, the process of detachment and rotation of the fetus produces the Syndrome of Incompetence of the Junction between the Occipital Condyles and the Superior Articular Facets of the Atlas.
Hyperextension of the head and neck in an infant is balanced by the flexing that occurs by the third month of life. The newborn baby does not yet have the finely tuned compensatory mechanisms and sufficient muscle strength to support its head. Poor head support results in hyperextension that can lead to problems for the occipital condyle and the Atlas.
The force - speed of the impacts - contusions and the injured area are determining factors in predicting the level of damage. If they have an average degree of penetration in the jaw or the base of the skull, they can cause hypertonia in the muscles of the neck and the fascias as well as develop or aggravate atlantooccipital alterations.
Contusion: Non-penetrating physical injury by the action of a violent blow with an object. May be mild to severe.
Penetration: Ability to transmit force or acceleration. This is measured in the complete movement and not only in the resistance to the blow.
The mechanical impacts suffered in the head, especially those that occur at an early age or that have a moderate force momentum, undesirably affect the suboccipital muscles because the injuries are usually transmitted reciprocally between the membranes of the Atlas and Axis anchors and the Occipital-Atlas.
The surprise factor of an impact with an object or a blow makes the damage even greater because by not putting the reflexes into action, the individual lacks sufficient muscle tone to help defend himself. Then, the transmission of acceleration increases and could be very serious for the cranio-cervical joint.
In sports like rugby, the shaking of the head can last for a few milliseconds with a force of 50G. Although players' thresholds vary from person to person (some players have not suffered brain contusions at 90G forces), any cervical MID can be aggravated. In particular, a disruption of the cranio-cervical joint.
Thanks to the elastic adjustment, responsible for the redirection of the waves of the lesions and through the spinal dura mater, the upward elastic tensions coming from the pelvis travel towards the Occiput-Atlas, aggravating the cranio-flow deviation of the Atlas. In turn, the descending elastic tensions coming from the cranium usually travel towards the pelvis.
Whiplash is common after a car accident, slipping a step, or falling while playing certain sports. The inability to absorb energy unbalances the fascia, muscles and dura mater. It is a major cause of compression of the occipitomastoid suture and the condyle-squamous-mastoid pivot.
Phase 1 of Whiplash or Hyperextension: Displacement of the body in the opposite direction of the shock. Posterior ascension of the sacrum. Possible injury to intervertebral discs.
Phase 2 of Whiplash or Hyperflexion: Displacement of the body in the direction of the shock wave. Anteriorization of the sacrum. Increased dysfunction in rotation of C1 (Atlas), C2 (Axis) and C3. Anteriorization of the occipital condyle.
Phase 3 of Whiplash or Repositioning: Displacement of the body to its initial position, before the shock. Absorption of the last inertial forces. Injuries to the soft tissues and vertebrae may begin to become evident.
After a cervical sprain, the fat mass of the cervical muscles often degenerates and this increases the chances of suffering from chronic cervicalgia. If there is a previous cervicopathy, this is usually aggravated after the sprain. Its scope can go from headache, nausea, vertigo and instability to mood disorders, paresthesias in arms and strong back pain.
The fascias have a wide elastic deformation capacity that allows them to recover their shape once the load that deformed them has disappeared. However, if the load is large and the exposure time prolonged, the fascias suffer a plastic deformation that does not allow them to recover their original length and shape. This is known as hysteresis.
Hysteresis: This is the name given to the tendency of a material or tissue to retain one of its properties in the absence of the stimulus that has generated it.