Abstract:
A device and method for preventing and correcting abnormal shaping of an infant&#39;s cranium by applying external forces over time with the growth of an infant to achieve normal shaping of the infant&#39;s head. The device is a cranial orthosis having a depression with a contact surface in the shape of at least a portion of a normal infantile cranium. The orthosis further provides lateral support surfaces creating points of contact to restrict rotation of the infant&#39;s cranium and provide additional external forces for normal shaping of the infant&#39;s cranium. Because the present invention is non-conforming to the shape of an abnormal skull, the exerted forces cause accelerated expansion of the skull in less prominent areas coincident with brain and skull growth.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This is a continuation-in-part application that claims the benefit of U.S. patent application Ser. No. 12/389,320, filed Feb. 19, 2009 and entitled “Lateral Support Craniocervical Orthosis and Method,” which is a continuation-in-part application that claims the benefit of U.S. patent application Ser. No. 11/449,402, filed Jun. 8, 2006 and entitled “Headrest and Method for Correcting Non-Synostotic Cranial Deformities in Infants.” Each of these applications is incorporated by reference herein. 
    
    
     STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a craniocervical orthosis in which an infant&#39;s cranium is positioned while the infant is sleeping to prevent and correct cranial deformities. More specifically, the invention relates to a craniocervical orthosis and method for preventing and correcting any non-synostotic deformity of the side and posterior aspects of an infant&#39;s head. 
     2. Background of the Invention 
     At birth, the six cranial bones comprising an infant&#39;s skull are spaced far enough apart to allow the skull to rapidly grow during the first months of the infant&#39;s life. This spacing also allows the bones to overlap so the infant&#39;s head can pass through the birth canal without compressing, and thereby damaging, the infant&#39;s brain. Eventually—some time between three and six years of age—the cranial bones will fuse and remain fused for the rest of the child&#39;s life. 
     During an infant&#39;s normal growth, forces within the infant&#39;s skull are directed outward and are constant and equally distributed on the inner surface of the growing skull causing the skull to expand. Accordingly, a decrease of the intracranial pressure will cause a reduced head size. Similarly, an increase in intracranial pressure will cause an increased head size. 
     Fibrous bands of tissue, called cranial sutures, fill the space between the bones and connect the bones of the skull to each other. These cranial sutures are strong and elastic, providing a flexibility to the skull to allow rapid brain growth during the first months of life. Without the sutures, a child would suffer brain damage due to constriction of the brain during the period of normal growth. 
     During the first few months of an infants&#39; life, however, the infant is most susceptible to the formation of synostotic or non-synostotic deformities in the cranium. Synostotic deformities are a result of craniosynostosis, which is a birth defect of the skull characterized by premature closure of one or more of the cranial sutures. Craniosynostosis can be hereditary or the result of a metabolic disease, and is characterized by an abnormally-shaped skull and potential for abnormal intracranial pressure, mental retardation, seizures, and blindness. 
     On the other hand, non-synostotic deformities, in which the cranial sutures remain open, are caused by environmental conditions, including premature birth, torticollis (twisting of the neck muscles beyond their normal position), or the preferred sleeping position of the child. In addition, neurological abnormalities, such as paralysis, cerebral palsy, or some sort of developmental delay, may predispose a child to cranial positioning problems. Non-synostotic deformities are also called positional deformities. 
     Synostotic and non-synostotic deformities manifest themselves in a variety of ways. Plagiocephaly, for example, is a cranial deformity resulting in an asymmetric head shape. Plagiocephaly consists of a focal area of flattening in the anterior or posterior aspect of one side of the head, which also commonly produces additional compensatory deformities in adjacent areas of the skull, skull base, and face, including the orbital (eye) and mandibular (jaw) structures. This deformity most commonly occurs in the posterior aspect of the head (posterior plagiocephaly), resulting in a focal area of flattening on that side and a compensatory prominence, or bulge, on the other side. In addition, the deformity produces anterior displacement of the ear, ear canal, temporomandibular (jaw) joint, forehead and orbital structures on the same side. Cranial deformities may also be classified, inter alia, as brachycephaly (a short, wide head shape), scaphocephaly (a long, narrow head shape), and turricephaly (a pointed head shape). 
     Non-synostotic posterior plagiocephaly is a very common problem for which parents seek evaluation and recommendations from their family physician or pediatrician. The incidence of this abnormality has increased significantly since publication of recommendations by the American Academy of Pediatrics that neonates (infants) should be put to sleep on their back rather than face down. These recommendations were made to reduce the incidence of Sudden Infant Death Syndrome (SIDS) by eliminating airway and respiratory compromise in the prone (face-down) position, which the Academy considered a possible contributor to the SIDS problem. 
     Brain growth is responsible for the growth and shaping of the skull, which results from slow, gradual separation of the bones at the cranial sutures. This separation allows for the addition of new bone onto the peripheral edges of the existing bone, producing gradual bone enlargement and reshaping of each bone. As the head enlarges, new bone is added to each bone in an inwardly directed fashion producing an inner surface concave shape to the overall bone. Any force or pressure applied to the exterior surface of the bone will re-direct the growth of bone added to the edges. New bone will be added in a more linear direction, thus reducing the inner surface concavity or producing “flattening” of the bone. Growth of bone does not stop; rather, it is redirected. Therefore, externally applied pressure (e.g., contact with an orthosis) reduces or stops outward growth or migration in that area, and redirects the growth to occur in a direction that is perpendicular to the applied force, which is tangential to the bone surface in that location. Uniform expansion of the remaining bones and sutures, which comprise the cranial vault, is rare. Instead, relative increased growth and expansion of the areas most adjacent to the “flattened” area tends to occur. 
     Treatment may come in the form of prevention or correction. Regarding prevention, the focus should be to reduce the duration that external pressure is applied to a localized area of the skull. This can be accomplished by moving the same external force to different areas of the skull. This is only achievable by re-positioning the patient&#39;s head, which is not possible in a large number of infants (e.g., those having immobility from torticollis). An alternative way to accomplish this is to enlarge the surface area of contact, which reduces the amount of pressure on the specific area, although it still typically results in at least some contact at the area of desired growth. It is also important to restrict the compensatory overgrowth that forms abnormal prominent areas in locations that are perpendicular and adjacent to the area of applied force. This allows for re-direction of growth and expansion in an appropriate normal direction. Devices used for prevention must maintain these properties, but still allow for expected progressive growth. 
     Prolonged immobility of the head will eventually lead to the development of a positional deformity. The etiology of the immobility may be neurologic/developmental, muscular, skeletal (vertebral) or simply from resting/sleeping preference in the absence of any known cause. Persistent immobility will allow for lateral and posterior deformities to develop. 
     Despite public knowledge and education regarding the development of these deformities and preventative measures, because infants are usually born with normal head shapes, it appears economically irrational to go through the expense and trouble of obtaining a preventative device if no deformity appears to be present. Development of these deformities is insidious, slowly occurring over weeks and easily overlooked. Frequently, only when the condition is obvious is intervention considered. 
     Treatment by “repositioning,” also called “mobilization”—that is, the act of another person moving the infant&#39;s head from side to side at regular intervals—is ineffective for treating or preventing these deformities due to the inherent problems associated with such a method of treatment. Simply put, it is very difficult to keep the child&#39;s head in the same position for extended periods of time, as the natural inclination of the child is to revert to his or her preferred sleeping position. Moreover, because “mobilization” is ideally performed every two to three hours, the infant requires constant attention throughout the night, and it is therefore not a practical treatment option. Similarly, children with torticollis cannot be effectively “mobilized” due to the tendency of the head to rotate as a result of involuntary contraction of the neck muscles. In both of these cases, the resulting position of the head—whether by preference or immobility—is most likely not the desired position for correction of deformities and is, as noted above, the cause of deformity in the first place. 
     To the extent treatment by repositioning might be effective when the above-referenced parameters are satisfied—i.e., a child who does not tend to revert to a preferred sleeping position and is not immobilized due to torticollis, and who can be mobilized regularly every two to three hours—children treated with prevention in this manner still do not obtain a perfectly normal head shape, because the supporting apparatus remains in contact with the skin and conforms the head to an abnormal shape. As a result, forces still act on already-flattened regions of the cranium and inhibit growth at precisely the area of the cranium where growth should be promoted. Due to this ineffectiveness, a large number of these children require additional treatment from five to ten months of age to correct persistent or progressive deformities. 
     The most common adjuncts available to assist with repositioning are flat- and wedge-shaped foam pads. For example, U.S. Pat. No. 6,473,923 (filed Nov. 22, 2000) (issued Nov. 5, 2002) discloses a body pillow and head positioner attached to a mat. The device is intended to maintain the infant&#39;s supine position—i.e., lying on the back, face upward—while reducing the risk of positional plagiocephaly by causing the head to rotate to the side while maintaining the infant&#39;s supine position. 
     One goal for correction of an existing deformity is to eliminate the external forces acting on the flattened area. As with prevention, improved correction can be achieved by providing external forces acting on the compensatory prominent areas of the skull, thereby reducing growth that occurs in these areas and redirecting growth towards a more normal direction and shape. Allowances for growth are also required for correction, but cannot compromise the mechanical ability of a device to correct the existing deformity. 
     Corrective treatment most often is by application of a custom-made external orthosis, or helmet. See, e.g., Corrective Infant Helmet, U.S. Pat. No. 6,592,536 (filed Jan. 7, 2000) (issued Jul. 15, 2003); Therapeutic and Protective Infant Helmets, U.S. Pat. No. 4,776,324 (filed Apr. 17, 1998) (issued Oct. 11, 1998). Such devices provide an expanded area over the site of the deformity, thereby allowing for correction of the deformity over a three to six month period of time related to brain and skull growth and subsequent reshaping. This prolonged time of use is necessary because of the reduced rate of brain and skull growth during the six- to twelve-month time frame. Due to a decrease in the rate of brain and skull growth to approximately fifty percent of the rate from birth to six months and increased stiffness of bones and cranial sutures, the recommendation is to wear the helmet continuously for twenty-three hours each day for up to twelve months. But despite extended use of these helmets, deformities rarely return to a normal shape. In addition, many health insurance companies and programs refuse to pay for these devices, leaving a large number of infants with no available treatment because of the relatively high cost of the helmets. 
     Similar to the preventative approaches discussed supra, another proposed approach to correct existing cranial deformities is to soften the material on which the infant&#39;s head rests by using a foam pad or memory foam pillow. This method allows the redistribution of inwardly directed forces, but fails to adequately correct cranial deformities because the softened material conforms to the already-abnormal head shape. Specifically, the material still contacts, and therefore applies forces to, the already flattened areas of the head and reduces forces that should be applied at the abnormal cranial bulges. Preventing cranial deformities with this approach is also ineffective because forces continue to act directly on a focused area of the head rather than the entire cranial vault. Because these pads and pillows are not shaped like a normal infant cranium, but are generally flat, forces acting on the cranium from these devices result in cranial flattening, and therefore an abnormal head shape, because the head conforms to the shape of the material (i.e., flat) at the point of contact. 
     Still another approach is to suspend the infant&#39;s head on a flexible material, which, for example, may be a net with an open weave that keeps the infant&#39;s head slightly elevated over the resting surface. See Method and Apparatus to Prevent Positional Plagiocephaly in Infants, U.S. Pat. No. 6,052,849 (filed Mar. 18, 1999) (issued Apr. 25, 2000). Although the use of an elastic stretchable material or netting may be slightly better than regular foam for preventing the development of flattened areas, these devices also do not effectively promote normal shaping due to the continuous application of external forces directed at the posterior aspect of the infant&#39;s head. In the case of correction, the flexible material will still conform to the already-abnormal head shape and exert forces on the flattened areas. In the case of prevention, the weight of the cranium on the flexible material will tend to immobilize the cranium, which results in prolonged contact of non-uniform forces around the cranium and, again, is precisely the wrong methodology for maintaining an already normal cranial shape. As with the “softened material” approach previously described, forces acting on a smaller area of the head results in reduced cranial growth and expansion because the head conforms to the shape of the material, thus resulting in an abnormal head shape in which the frontal areas are wider than the posterior aspect of the head because the material is applied only to the posterior aspect of the cranium, with the application of constricting forces. 
     After ten to twelve months of age, little, if any, correction of a cranial deformity can be accomplished with non-operative treatment because of reduced velocity of brain and skull growth, increased thickness of bone, and reduced flexibility of the cranial sutures. Surgical intervention is typically the only effective treatment for moderate to severe deformities in children over twelve months of age. 
     Alternative methods for correcting this condition without the use of a helmet do not directly address the cause of the problem, and therefore do not effectively treat the condition. All other products and devices, including foam, elastic (and therefore flexible) material or netting, merely distribute or disperse forces over a focused area of the head Because these products and devices remain in continuous contact with the skin, they conform the cranium to the abnormal shape, including the abnormally flattened areas. Thus, the prior art does not remove or eliminate the external forces at flattened areas of the cranium, but rather maintains an abnormal cranial shape and promotes a static deformity. 
     Finally, attempts to prevent and correct such deformities with the use of headrests also exist. With the exception of the present invention and U.S. Pat. No. 4,825,487 (issued May 2, 1989) to Eberl (hereinafter “Eberl”), the existing headrests are “low profile” devices, which extend only a maximum of 35 mm anterior of the most posterior position of contact with the infant&#39;s skull (about 30% or less of the anterior-posterior distance) and only contact the very or most posterior area of the head. See, e.g., WO 2006/102407 (published Sep. 28, 2006); European Patent No. EP 1 665 958 (filed Aug. 25, 2004); New Zealand Patent No. 510,421 (filed Mar. 8, 2001). However, the low profile (i.e., posterior only) headrests are ineffective based on bio-mechanics of such devices, as lateral support is necessary in order to achieve effective prevention and treatment 
     These available and proposed low-profile devices provide insufficient support and positioning to overcome the problem of immobility leading to development and progression of positional deformities. These deformities develop despite any differences or modifications in shape, size, or consistency—that is, prevention or any level of correction with low profile devices will require turning of the head, and any prevention or correction achieved would be due to “repositioning” treatment as described supra, thus making the device unnecessary. The treatment provided in this situation is repositioning, not the low profile device. And as noted above, the ability to reposition or turn the head is a luxury and is not possible in a large number of instances. Lateral support, however, allows one to overcome the problem of immobility, which is not achievable with a low-profile device. 
     While Eberl would not be considered a “low profile device” as discussed supra, it also provides insufficient lateral support. As shown in  FIG. 4  and  FIG. 5  of Eberl, the sidewalls are outwardly angled from the longitudinal axis of the device, which inherently means Eberl provides no immediately adjacent lateral support when the infant&#39;s cranium is rotated in either direction. In this manner, Eberl is effectively the same as the low-profile devices, but with an added disadvantage that the Eberl sidewalls are excessively high such that a very young infant placed on the Eberl invention is susceptible to the development of obstructive amblyopia due to the obstruction of the visual field/pathway. In addition, Eberl is made from soft, conforming material, which, as noted with respect to foam mattresses and pads, conforms to an abnormal head shape. 
     Currently there is no specific apparatus available to provide effective corrective and preventative treatment for non-synostotic cranial deformities in the age range of birth to five months. To avoid the difficulties and pitfalls associated with currently available devices aimed at treating non-synostotic cranial deformities, the present invention discloses a corrective headrest for use at the very first recognition of development of a deformity. The headrest and method allow effective treatment during the rapid period of brain and skull growth (birth to six months), thereby providing rapid correction of the deformity. Children with predisposing conditions may require prolonged treatment. Early effective treatment is the key to providing complete correction of these deformities. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention discloses, inter alia, a device and method for correcting and/or preventing an infant&#39;s abnormally-shaped cranium by applying external forces over time with the growth of an infant to achieve normal shaping of the infant&#39;s head. Unlike the prior art, the present invention both 1) prevents abnormal shaping of an infant&#39;s cranium by causing even growth of the infant&#39;s normally shaped head and 2) provides forces that act unevenly across an abnormally shaped cranium to correct existing cranial deformities. The embodiments of the present invention include a solid, one-piece headrest structure of uniform consistency, having a depression that is molded to approximate the posterior and side aspects of the skull and head, with cervical, or neck, support. The material that contacts the infant&#39;s cranium is semi-rigid and relatively non-flexible, maintains its overall shape under stress, and demonstrates minimal superficial focal elasticity only at the site of cutaneous contact. In the preferred embodiment, the hardness of the material the contacts the infant&#39;s cranium is between 65 and 75 (inclusive) on a OO durometer scale. 
     To correct existing cranial deformities, the present invention applies inwardly-directed external forces only to areas of bony prominence and minimizes (or altogether eliminates) these forces on the areas of the skull that are less prominent (or flattened). The present invention is non-conforming to the shape of an abnormal skull. The forces exerted allow for accelerated expansion of the skull in the less prominent (flattened) areas coincident with brain and skull growth, allowing for return to a normal symmetric cranial shape. 
     In addition, the headrest prevents development of abnormal cranial shaping by providing a round, normally-shaped contour for contact with the posterior and side aspects of the head, even if the head is turned slightly to one side or the other. Moreover, because the surface is semi-rigid, the surface will allow for even cranial growth over this area of contact, thereby maintaining the infant&#39;s normal head shape. 
     The preferred embodiment of the present invention is made from an impermeable high-density foam, which provides ease of cleaning as well as flame retardant properties. Other embodiments of the present invention are made from other foam variants, including open cell foam covered with a vinyl or other coating or closed cell foam layered over or applied to more rigid solid or hollow plastic (e.g., PVC or nylon). 
     Therefore, in accordance with one aspect of the present invention, a headrest having a semi-rigid body for correcting the shape of an infant&#39;s abnormally-shaped cranium includes a bottom surface for contact with a resting surface; a top surface for contact with the cranium of the infant; a generally hemi-ellipsoidal depression in the top surface; and a ridge at one end of the depression for supporting the neck of the infant. The shape of the depression corresponds to the shape of a normal infantile cranium. The top surface provides external forces acting on abnormal cranial bulges of the infant&#39;s cranium and eliminates external forces that act on abnormal cranial depressions of the infant&#39;s cranium. 
     Other features of the headrest include a rim that defines a substantial portion of the depression, as well as the headrest having a side surface between the bottom surface and the top surface. Furthermore, an additional feature of the headrest includes a curved front surface that cradles the shoulders and further supports the neck of the infant. 
     According to another feature of the present invention, antero-lateral support provided by the present invention is clearly innovative in its ability to provide treatment from birth to ten months of age while not requiring any enlargement, change, or modification during this period of time. Specifically, according to this feature of the invention, lateral support is provided in conjunction with an anatomically correct shape. Elevated lateral support surfaces allow for continued growth from birth to approximately ten months of age while maintaining or producing a normal head shape, and no change, modification, or enlargement is required for approximately the first year. Because of the lateral support surfaces, the present invention is not only able to correct deformities, but also prevents them from occurring. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective view of the preferred embodiment of the present invention. 
         FIG. 2  is a frontal view of the preferred embodiment of the present invention. 
         FIG. 3  is a sectional view of the craniocervical orthosis along Line  3 - 3  of  FIG. 2 . 
         FIG. 4  is a sectional view along Line  4 - 4  of  FIG. 2 . 
         FIG. 5  and  FIG. 6  depict dimensions of a preferred embodiment of the orthosis. 
         FIG. 7A  and  FIG. 7B  are a rear elevational view and a top elevational view, respectively, of a normally-shaped infant cranium showing the surface area that contacts the headrest when the infant&#39;s head is supinely positioned in the orthosis. 
         FIG. 8A  is a chart showing head circumference-for-age of males from birth to thirty-six months. 
         FIG. 8B  is a chart showing head circumference-for age for females from birth to thirty six months. 
         FIG. 9A  and  FIG. 9B  show infant craniums of approximately 36.5 and 46.5 cm in circumference, respectively, positioned in the preferred embodiment. 
         FIG. 10  is a partial sectional view of the preferred embodiment of the present invention with an infant having a normally shaped cranium is positioned on the contact surface of the headrest. 
         FIG. 11  is a partial sectional view of the headrest through the inclined first plane of  FIG. 10 . 
         FIG. 12  is a partial sectional view of the headrest through the inclined first plane of  FIG. 10  wherein the normal infant cranium is rotated thirty degrees clockwise about its longitudinal axis to contact a lateral support surface thereof. 
         FIG. 13  is a partial sectional view of the orthosis through the first plane of  FIG. 10  of a scaphocephalic cranium. 
         FIG. 14  is a partial sectional view of the headrest through the first plane of  FIG. 10  wherein the scaphocephalic cranium is rotated thirty degrees clockwise about its longitudinal axis to contact a lateral support surface thereof. 
         FIG. 15  is a partial sectional view of the orthosis through the inclined first plane. of  FIG. 10  of a plagiocephalic cranium. 
         FIG. 16  is a partial sectional view of the headrest through the inclined first plane of  FIG. 10  wherein the plagiocephalic cranium is rotated thirty degrees clockwise about its longitudinal axis to contact a lateral support surface thereof. 
         FIG. 17  is a partial sectional view of the headrest through the inclined first plane of  FIG. 10  in use with a brachycephalic cranium. 
         FIG. 18  is a partial sectional view of the headrest through the inclined first plane of  FIG. 10  wherein the brachycephalic cranium is rotated forty-five degrees clockwise about its longitudinal axis to contact a lateral support surface thereof. 
         FIG. 19  is perspective view of an alternative embodiment of the present invention. 
         FIG. 20  is a frontal view of the craniocervical orthosis shown in  FIG. 22 . 
         FIG. 21  is a sectional view along Line  21 - 21  of  FIG. 19 . 
         FIG. 22  is a perspective view of another alternative embodiment of the present invention. 
         FIG. 23  is a sectional view along Line  23 - 23  of  FIG. 22 . 
         FIG. 24  is yet another embodiment of the present invention. 
         FIG. 25  is a sectional view along Line  25 - 25  of  FIG. 24 . 
         FIGS. 26  is a front perspective view of yet another alternative embodiment of the present invention that comprises two spacing members positioned on the rim. 
         FIG. 27  is a side sectional elevation through Line  27 - 27  of  FIG. 26 . 
         FIG. 28  is a sectional elevation through Line  28 - 28  of  FIG. 26 . 
         FIG. 29  is a front perspective view of still another embodiment of the present invention wherein the lateral support surfaces are laterally adjustable. 
         FIG. 30  is a rear section view through plane  30 - 30  of  FIG. 29 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     When referencing the figures, standard anatomical terms of location are used. For example, a sagittal plane is a plane parallel to the sagittal suture  5  and divides the body into sinister and dexter portions. A coronal plane divides the body into posterior and anterior portions. A transverse plane divides the body into superior and inferior portions. 
       FIG. 1  through  FIG. 4  show a headrest  10  that is the preferred embodiment of the present invention. The headrest  10  comprises a bottom surface  12  for contacting a resting surface  14 , and a top surface  16  for contacting an infant&#39;s cranium. The top surface  16  comprises a generally hemi-ellipsoidal depression  18 , a contact surface  19  that corresponds to the shape of a normal infantile cranium, and a rim  22  defining a substantial portion of the depression  18 . At one end of the depression  18 , a ridge  20  is positioned to support the neck of the infant. The top surface  16  is preferably made of a closed cell foam material, but may alternatively be made of open cell foam material covered with a vinyl or other surface coating, closed cell foam layered over higher density foam, open cell foam layered over higher density foam, or closed cell foam layered over a more rigid solid or hollow plastic. 
     A front surface  24 , preferably curved, is positioned to cradle the infant&#39;s shoulders and support the neck of the infant while the infant&#39;s cranium is in contact with the top surface  16 . A preferably-curved side surface  26  extends between the rim  22  and the bottom surface  12 . In this preferred embodiment, the headrest  10  is a continuous, uniform, solid body. However, it is anticipated that variations of the uniformity or continuity of the body could occur and be utilized. 
     In normal operation for correction of an abnormally shaped infant cranium, the headrest  10  is placed on the resting surface  14  so that the bottom surface  12  is in contact therewith. The infant&#39;s head is then placed in the depression  18  with the infant&#39;s cranium resting on the contact surface  19 . Initially, the posterior and part of the side aspects of the infant&#39;s head contact the contact surface  19 , although during the sleep period the infant&#39;s head may roll to one side or the other. Throughout the sleep period, the infant&#39;s neck is supported by the ridge  20 . The infant&#39;s shoulders are aligned in and cradled by the curved front surface  24 . As the infant&#39;s head makes contact with the top surface  16 , the contact surface  19  provides external forces acting on any abnormal bulges of the infant&#39;s cranium and reduces or eliminates external forces that act on abnormal depressions (flattened areas) of the infant&#39;s cranium. This contact reduces the net outward forces from brain and skull growth at these prominences, and redirects the growth to areas of the cranium where the infant&#39;s head is not in contact with the top surface  16 . 
     It should be noted that that amount of contact of the infant&#39;s cranium with the contact surface  19  varies according to the size of the infant&#39;s cranium. For example, a newborn infant&#39;s cranium will contact relatively little of the contact surface  19  and, in a non-rotated position, the contact will occur primarily at the occipital bone and adjacent areas of the left and right parietal bones. As the infant grows over time, the size of the cranium approaches the size of the depression  18 , with an increasingly greater area of contact. 
     The headrest  10  works similarly to prevent cranial deformities. The infant&#39;s head is placed in the depression  18 , the contact surface  19  of which matches the round, normally-shaped contour of the posterior and side aspects of the head, resulting in the head “growing into” the properly-shaped contact surface  19  over time. As the cranium grows, any existing deformities will conform to the normal shape of the contact surface  19  of the depression  18 . Because of its semi-rigid character, the contact surface  19  allows the infant&#39;s cranium to grow evenly and maintain its normal shape. Typically, this occurs as the headrest is used from two to seven months of age, although, due to statistical variations in head circumference of infants, this is more appropriately a function of the cranial circumference (i.e., until the head grows to the same size as the depression  18 ). 
       FIG. 7A  and  FIG. 7B  are a rear elevational view and a top elevational view, respectively, of a normally-shaped infant cranium  400  having a circumference of less than 46.5 cm and a left parietal bone  402  connected to a right parietal bone  404  with the sagittal suture  406 . The left and right parietal bones  402 ,  404  are connected to the frontal bone  412  via the coronal suture  414  and to the occipital bone  416  with the lamboidal suture  418 . The sagittal suture  406  joins the coronal suture  414  at the anterior fontanelle  420 . The lamboidal suture  418  joins the sagittal suture  406  at the posterior fontanelle  422 . When positioned in the preferred embodiment of the headrest  10 , a cranial surface area  424  that includes a portion of the occipital bone  416 , and the posterior portions of the left and right parietal bones  402 ,  404  makes contact with the contact surface  19  of the depression  18 , as described supra. 
       FIG. 8A  shows head circumference-for-age of males from birth to thirty-six months.  FIG. 8B  shows head circumference-for age for females from birth to thirty six months. As can be seen from these figures, less than five-percent of all infants have a head circumference of less than 36.5 cm at two months of age. At seven months, at least ninety-five percent of all infants have a head circumference less than 46.5 cm. Thus, a preferred embodiment of an orthosis having the features of the present invention is configured to address, at a minimum, head circumferences within a range of 36.5 cm to 46.5 cm in circumference. However, it is anticipated that this will accommodate head circumferences within a range from thirty-two (32) to forty-eight (48) centimeters and still provide the benefits described herein. 
       FIGS. 9A and 9B  depict side elevation views of two infants having normally-shaped craniums of differing circumferences positioned in the same preferred embodiment of the cranial orthosis  10 , and show the position of predetermined coronal planes relative to the orthosis  10 . Head circumference for an infant is the largest distance around the head, and generally is found in a plane  47  that intersects the forehead of the infant and the most posterior point  54  of the cranium. 
     More specifically,  FIG. 9A  depicts a first infant&#39;s cranium  49  that has a circumference of 46.5 cm, and has an anterior-posterior distance APD 1 , which is the distance between the most posterior point  54  on the infant&#39;s head and the most anterior point  57  on the infant&#39;s forehead. A first coronal plane  51  is defined as a coronal (i.e., horizontal) plane positioned approximately at forty percent (40%) of the anterior-posterior distance APD 1 , a position which approximates the height of the earhole  52  for an infant having this head size. With respect to the orthosis  10 , the first coronal plane  51  is positioned approximately 6.2 to 6.7 cm above the nadir  23  (i.e., lowest point) of the depression  18 . A third coronal plane  21  is defined as a coronal plane positioned at the most anterior contact point  27  between the infant&#39;s cranium  49  and the headrest  10 . With respect to the headrest  10 , the third coronal plane  21  is positioned approximately 8.0 to 8.6 cm from the bottom surface. Similarly,  FIG. 9B  depicts a second infant cranium  55  of 36.5 cm in circumference. A second coronal plane  56  is defined as a coronal plane positioned at approximately seventy percent (70%) of APD 2  for an infant having this head size. With respect to the orthosis  10 , the second coronal plane is positioned approximately 8.8 to 9.3 cm above the nadir  23  of the depression. 
     As shown in  FIG. 3 , in the preferred embodiment, the contact surface  19  is defined as the surface area of the depression  18  that is (1) superior to an inclined first plane  47  angled between 10 and 20 degrees from vertical in the superior direction and intersecting the nadir  23 , and (2) posterior of the third coronal plane  21 . At a minimum, however, the contact surface  19  is at least the surface area of the depression  18  that is (1) superior to a diagonal plane angled 45-degrees from vertical in the superior direction and intersecting the nadir  23 , and (2) posterior of the third coronal plane  21 . 
       FIG. 5  and  FIG. 6  depict preferred dimensions of a specific embodiment of the orthosis  10 . As shown, the length of the orthosis  10  from its most inferior to its most superior point is 23.3 cm. The height of the ridge  20  above the bottom surface  12  where it intersects the longitudinal axis is 2.9 cm. At its highest point, the rim  22  is 9.4 cm from the bottom surface  12 . The ridge  20  is 6.5 cm from the mid-cranial transverse plane  70 , which is the transverse plane intersecting the nadir  23  of the depression  18 . The mid-cranial transverse plane is 7.5 cm from the most superior contact point  27 . In the preferred embodiment, that superior point  27  is 8.3 cm from the bottom surface  12 . 
     In the preferred embodiment, as shown in  FIG. 6 , in which the shading has been removed for clarity, the width of the curved front surface  24  is 23.3 cm and the width of the ridge  20  is 13.3 cm. The depression has a front portion  37  extending 2.3 cm from the ridge  20  along the horizontal, longitudinal axis  31 , and is bounded on either side with symmetrical protrusions  33 . A middle portion  25  is immediately adjacent the front portion  37  wherein the interior boundary  29  of the rim  22  adjacent the middle portion  25  is substantially straight. An arced rear portion  35  is adjacent the middle portion  25 , wherein the interior boundary  29  of the rim is symmetrically curved to connect one sides of the middle portion  25  to the other. The maximum depth of the arced rear portion  35  from the middle portion  25  to the interior boundary  29  of the rim  22  along the horizontal longitudinal axis  31  is 3.9 cm. The greatest width of the middle portion  25  is at the boundary with the front portion  37  (line B) at 16.3 cm. The middle portion  25  is narrowest immediately adjacent the arced rear portion  35  (line A) at 12.7 cm. The depth of the middle portion  25 —i.e., the distance between the front portion  37  and arced rear portion  35 —is approximately 8.0 cm. The superior- to inferior widening of the middle portion  25  provides space for the ears of an infant who is resting in the headrest  10  in a supine position, which is important to avoid misshaping of the ear. The depth of the depression  18  from the crest of the ridge  20  to the interior boundary of the rim  22  along the horizontal longitudinal axis is 14.2 cm. The thickness C of the rim  22  around the arced portion  35  is approximately 2 cm. Although the dimensions of the preferred embodiment are given with specific measurements, it is understood that the measurements could vary slightly without altering the effectiveness of the device. In that regard, the dimensions provided are understood to be substantial approximations of the preferred embodiment of the device. 
     Returning now to a description of the present invention,  FIGS. 10 and 11  depict the preferred embodiment of the present invention in which an infant  60  having a normally-shaped cranium  62  of approximately forty (40) centimeters in circumference is supinely positioned on the headrest  10 . The first coronal plane  51 —as defined above with respect to the predetermined circumference of 46.5 cm—extends longitudinally, and is parallel to the second coronal plane  56 . The mid-cranial transverse plane  70  is orientated perpendicular to the first coronal plane  51  and extends through the nadir  23 , in which the most posterior point  54  of the cranium  62  rests. An inclined first plane  74 , which is representative of a typical plane in which the head circumference is measured, is positioned superior and inclined relative to the mid-cranial transverse plane  70 , and intersects the nadir  23 , and the most anterior point on the forehead. 
     As noted with respect to  FIG. 1  through  FIG. 4 , the headrest  10  (or orthosis) comprises the bottom surface  12  that contacts the resting surface  14  during use and a contact surface  92  that contacts the infant&#39;s cranium  62 . The generally hemi-ellipsoidal depression  18  is formed in the top surface  16  with at least a contact surface  19  (see  FIG. 3 ) having a shape of a portion of a normal infant cranium  62 . In the preferred embodiment, and as noted with respect to  FIG. 3  supra, the contact surface  19  has a surface area generally corresponding to the posterior aspects of the left and right parietal bones in addition to a substantial portion of the occipital area, as discussed with reference to  FIG. 5 . The top surface  16  is semi-rigid and relatively non-flexible, maintains its overall shape under stress, and demonstrates minimal superficial focal elasticity at the site of cutaneous contact. The ridge  20  at an end of the depression  18  supports, and is contoured to the shape of, the infant&#39;s neck  86 . 
     At least the contact surface  19  of the preferred embodiment has a hardness of between sixty-five and seventy-five when measured with a OO-scale durometer, which is the preferred hardness required for the both prevention and correction of positional deformities as described herein. However, because the headrest  10  is preferably of uniform consistency, it is anticipated that the entire outer surface of the headrest  10  will have the same hardness. It should be noted that prevention only, as opposed to both prevention and correction, can be accomplished with a hardness of between twenty-five and thirty-five on the same scale. 
     Still referring to  FIG. 10  and  FIG. 11 , the contact surface  19  further comprises at least a portion of first and second lateral support surfaces  88 ,  92 . A portion  90  of the first and second lateral support surfaces  88 ,  92  is positioned anterior of the first coronal plane  51  and superior to the mid-cranial transverse plane  70 . In order to prevent obstructive amblyopia, the first and second lateral support surfaces  88 ,  92  do not extend anteriorly of the second coronal plane  56 , as providing a completely unobstructed visual field is imperative to eliminate the risk of iatrogenic-induced neuro-opthalmological injury (i.e., obstructive amblyopia). 
       FIG. 11  is a partial sectional view of the normal infant cranium  62  in the inclined first plane  74  of  FIG. 10 . In the preferred embodiment, the first and second lateral support surfaces  88 ,  92  are substantially vertical at their upper end with slight curvature anterior of the first coronal plane  51 . When the infant&#39;s cranium  62  is in the supine position, contacting forces  96  are applied proximal to the occipital bone  98  at the posterior aspect of the cranium  62  with only minimal application at the most posterior end of the parietal bones  100 ,  102 . As growth occurs, the left and right parietal bones  100 ,  102  expand laterally and eventually contact substantially the entire contact surface  19  when the infant&#39;s cranium  62  grows to a circumferences of 46.5 cm as shown in  FIG. 9A . In this manner the shape of the parietal and occipital regions on the infant&#39;s cranium  62  conforms over time (i.e., months) to the shape of the contact surface  19 . 
       FIG. 12  depicts the normal infant cranium  62  shown in  FIG. 11  rotated thirty degrees clockwise about the longitudinal axis  94 . Such rotation causes a corresponding shift in the area of contact of the cranium  62  with the contact surface  19 , and thus where external forces  96  are applied to the cranium  62 . The contact forces  96  still contact the occipital bone  98  and a greater portion of the posterior right parietal bone  102 . In addition, the second lateral support surface  92  contacts the cranium  62  at the frontal bone  104  anterior of the coronal suture  106 . 
     As overall growth of the cranium  62  occurs, less rotation of the cranium  62  is allowed, which results in further maintenance of the normal head shape. Additional expansion and overall growth causes eventual de-rotation of the cranium  62  back to twenty degrees of rotation or less with the contact surface  19  and first and second lateral support surfaces  88 ,  92  limiting lateral expansion of the parietal bones  100 ,  102 . In other words, as the infant continues to grow and the circumference of the cranium  62  approaches the size of the depression  18 , the head is progressively limited to less rotation, resulting in the head “growing into” the properly-shaped contact surface  19 . For example, if the size of the cranium  62  is identical to the size of the depression  18 , rotation of the cranium  62  will be entirely prohibited. Thus, as the cranium  62  grows, any existing deformities will conform to the normal shape of the contact surface  19  of the depression  18 . 
       FIG. 13  depicts a partial sectional view of the inclined first plane  74  in  FIG. 10  wherein a scaphocephalic cranium  134  of an infant is supinely positioned in the depression  18  in the top surface  16  of the orthosis  10 . In this supine position, the contact surface  19  of the depression  18  causes forces  146  to act on the scaphocephalic cranium  134  at the occipital bone  144 . If this non-rotated, supine position can be maintained, the absence of forces acting on the parietal bones  147 ,  149  will allow the parietal bones  147 ,  149  to grow laterally into a normally-shaped cranium. 
       FIG. 14  depicts the scaphocephalic cranium  134  shown in  FIG. 11  rotated thirty degrees clockwise about its longitudinal axis  148 . In this rotated position, the second lateral support surface  92  contacts the frontal bone  150  and thereby prevents contact between the mid- or upper-right parietal bone  149  with the contact surface  19  of the depression  18 , and allowing for only minimal contact with the right parietal bone  149  at its most posterior point. Once again, the contact surface  19  of the depression  18  contacts and provides forces acting on the occipital bone  144 . The absence of contact and forces  146  acting on the left parietal bone  147  and almost all of the right parietal bone  149  allows for parietal expansion and progression toward a normal head shape. Rotation in the counter-clockwise direction results in similar contact of the cranium  134  with the orthosis  10  on the opposite side of the cranium  134 . 
       FIG. 15  is a partial sectional view of the preferred embodiment through the first plane  74  of  FIG. 8  with an infant having a plagiocephalic cranium  170  with abnormal prominent growth at the left parietal bone  196  and the right side of the frontal bone  198 , in addition to a flattened configuration at the right parietal bone  202  and the occipital bone  200 . In the supine position shown, initial forces  194  are concentrated on the lower end of the left parietal bone  196  and left occipital bone  200 . However, it should be noted that this is an unstable configuration that will inevitably lead to rotation—in this case, clockwise rotation—about the longitudinal axis  192 . 
       FIG. 16  is a partial sectional view within the inclined first plane  74  of  FIG. 10  depicting the infant having a plagiocephalic cranium  170  rotated thirty degrees clockwise about its longitudinal axis  192 . In this rotated position, the contact surface  19  contacts and provides forces  194  acting on the prominent left parietal bone  196 , thereby restricting further lateral growth of that prominent bone. Additionally, the second lateral support surface  92  contacts and provides forces  199  acting on the right side of the frontal bone  198  and also restricting growth in that prominent area. The contact with the second lateral support surface  92  further eliminates all external forces from the flattened occipital bone  200  and right parietal bone  202 , thus redirecting growth to these bones by allowing the bones to expand. In this manner, the infant&#39;s plagiocephalic cranium  170  is allowed to grow into a normal shape. 
       FIG. 17  depicts the preferred embodiment in use with a brachycephalic cranium  204  having a flattened occipital bone  216  and bulging, prominent left and right parietal bones  208 ,  210  resting in a supine position. The contact surface  19  contacts and provides forces  206  acting on both parietal bones  208 ,  210  restricting lateral growth of these parietal prominences. The normal cranial shape of the contact surface  19  eliminates any contact and forces acting on the occipital bone  216 . This redirects growth and expansion in a more frontal direction as well as allows the flattened occipital bone  216  to grow outward, thereby allowing for correction of the deformity over time with growth. 
       FIG. 18  shows the same brachycephalic cranium  204  depicted in  FIG. 17  resting in the preferred embodiment of the orthosis  10  and rotated forty degrees about the longitudinal axis of the headrest  10 . The contact surface  19  of the depression  18  contacts and provides forces acting on the prominent right parietal bone  210  and thereby restricts growth of that bone. At the same time, the first lateral support surface  88  contacts and provides forces  206  acting on the prominent left parietal bone  208  and, once again, restricts growth of that bone  208 . The normal cranial shape of the contact surface  19  provides a gap between the contact surface  19  of the depression  18  and the flattened occipital bone  216 , thereby eliminating forces acting on the occipital bone  216  and, once again, allows for outward growth in that area. The lack of contact forces acting on the frontal bone  211  also allows for forward growth to the cranium  204 . In this manner, the orthosis  10  provides for correction of a brachycephalic cranium  204  resting in a rotated position. 
     Although the invention has thus far been described with reference to only full term infants, the principles and concepts are also applicable to a premature infant&#39;s cranium, albeit on a smaller scale. In fact, the cranial vault of a premature infant is more susceptible to development of positional deformities than a full term infant because the cranial bones are much weaker and more malleable, and the skin more fragile. 
     According to industry data, the mean head circumference of an infant at 26 weeks is about 23.5 centimeters, the mean head circumference of an infant at 36 weeks is roughly 33 cm, and two standard deviations on either side of this 26- to 36-week growth curves is slightly larger than ±2 cm. Thus, by simply “shrinking” the preferred embodiment described herein to accommodate this curve, the same principles are operative to correct and prevent positional deformities in premature infants in the same manner. Because of the weaker and more malleable cranial bones of a premature infant, the top surface should be softer than the top surface as described with reference to the preferred embodiment herein. The inventor has found that the hardness of the surface when used for premature infants is between 20-30 on the OO scale durometer. 
       FIG. 19  through  FIG. 21  show an alternative embodiment of the present invention that requires less material to manufacture. The headrest  300  comprises two beams  302  for contacting a resting surface  304 , and a top surface  306  for contacting an infant&#39;s cranium. The elongated beams  302  are positioned along opposite sides of the headrest  300 . The front and back of the headrest  300  are open, forming an opening  308  defined on either side by the beams  302 . 
     The top surface  306  of the headrest  300  comprises a generally hemi-ellipsoidal depression  310  having the top surface  306  that corresponds to the shape of a normal infantile cranium and a rim  312  that defines a substantial portion of the depression  310 . At one end of the depression  310 , a ridge  314  is positioned to support the neck of the infant. The top surface  306  is preferably made of a closed cell foam material, although other materials may be used as described hereinabove. A pair of side surfaces  316 , only one of which is shown by  FIG. 5 , adjoin the rim  312  to the beams  302 . 
     As shown more clearly by  FIG. 21 , the beams  302  are positioned at opposing sides of the headrest  300  and along the perimeter thereof, thereby forming the opening  308  between the beams  302 . In another embodiment, however, the opposed beams  302  can be positioned at the front and rear of the headrest  300 . 
     After placement of the headrest  300  on the resting surface  304  so that the beams  302  are in contact therewith, the infant&#39;s head is placed in the depression  310  with the infant&#39;s head resting in the depression  310 . Correction and/or prevention of the infant&#39;s abnormally shaped cranium is then accomplished in the same manner as in the preferred embodiment. 
       FIG. 22  and  FIG. 23 , which is a sectional view along Line  23 - 23  of  FIG. 22 , show another embodiment of the present invention. The apparatus of this embodiment comprises a mattress or padded surface  340  and a generally hemi-ellipsoidal depression  342  in a portion of the mattress surface  340 . A top surface  344  in the depression  342  corresponds to the shape of a normal infantile cranium. In this embodiment, the top surface  344  of the depression  342  is semi-rigid, resilient, and made of a closed cell foam material, providing external forces acting on abnormal cranial bulges and minimizing or eliminating external forces acting on abnormal cranial depressions of the infant. However, it is anticipated that other materials could be utilized, such as open cell foam with a vinyl coating. In this embodiment, a ridge  346  at one end of the top surface  344  is shaped and positioned to support the neck of the infant while the infant&#39;s head rests on the top surface  344  of the apparatus. In another version of this embodiment, it is anticipated that the ridge  346  will be eliminated. 
     The embodiment shown by  FIG. 22  and  FIG. 23  is disclosed with a substantially flat mattress or padded surface  340 . However, it is anticipated that the mattress or padded surface  32  could be contoured to prevent an infant from rolling. It is further anticipated that the area of the mattress or padded surface  340  surround the depression  342  could be raised to provide support for the infant&#39;s head in a slightly raised position. 
     As with the already-described embodiments, the infant&#39;s head is placed in the depression  342  formed in the mattress  340  such that the infant&#39;s head is in contact with the top surface  344 . The infant&#39;s neck is supported by the ridge  346 , while the infant&#39;s body is supported in a comfortable resting position by the mattress  340  in a generally supine position. Correction and/or prevention of the infant&#39;s abnormally shaped cranium is then accomplished in the same manner as in the preferred embodiment. 
       FIG. 24  and  FIG. 25 , which is a sectional view along Line  25 - 25  of  FIG. 24 , show another embodiment of the present invention, an apparatus comprised of a semi-rigid body  360  with a hemi-ellipsoidal depression  362  having a contact surface  364  that is in the shape of a normal infantile cranium. A plurality of legs  366  support the semi-rigid body  360  in a position to allow an infant&#39;s head to rest on the contact surface  364 . In this embodiment, there are four legs  366 , as shown in  FIG. 24  and  FIG. 25 . However, it is anticipated that more or fewer legs could be used to support the body  360 . The contact surface  364  is resilient and made of closed cell foam, although in alternative embodiments of the present invention the contact surface  364  may be made of other material, including open cell foam covered with a vinyl coating and other materials as described hereinabove. Furthermore, a ridge  368  at one end of the contact surface  364  is shaped and positioned to support the neck of the infant while the infant&#39;s head rests on the contact surface  364  of the apparatus. 
     After placement of the apparatus on a resting surface so that legs  366  are in contact therewith, the infant&#39;s head is placed in the depression  362  with the infant&#39;s head resting on the contact surface  364  and the infant&#39;s neck being supported by the ridge  368 . Correction and/or prevention of the infant&#39;s abnormally shaped cranium is then accomplished in the same manner as in the preferred embodiment. 
     It should be noted that the smaller the infant cranium, the more angular rotation of the cranium about the longitudinal axis is required to contact one of the lateral support surfaces. In other words, generally speaking, a smaller infant cranium placed in a given headrest and depression will require more rotation about the longitudinal axis than a larger, similarly-shaped cranium positioned in the same headrest and depression. However, it is desirable that rotation of an infant&#39;s cranium located within a depression be limited to approximately the range of angular rotation described with reference to the foregoing figures. Although this concern could be addressed by manufacturing the headrest in various sizes to correspond to the range of expected cranial sizes as set forth supra, for commercialization, it is desirable for cost reduction purposes that fewer variations of the present invention be produced to take advantage of manufacturing economies of scale. 
     This conflict between manufacturing preference and patient treatment preference can be addressed, however, by providing for adjustability of the positions of the lateral support surfaces, thus allowing rotation of the cranium to be limited as desired based on the size of the cranium. For example,  FIG. 26  through  FIG. 28  show another embodiment of a headrest  510  having the features of the present invention wherein the position of the lateral support surfaces is adjustable to accommodate various cranium sizes (i.e., limit the range of possible rotation of the cranium within the depression).  FIG. 26  is a front perspective view of the embodiment.  FIG. 27  and  FIG. 28  are sectional views through ine  27 - 27  and Line  28 - 28 , respectively, of  FIG. 26 . 
     As referenced with respect to the previously-described embodiments, the headrest  510  of this alternative embodiment comprises a bottom surface  512 , and a top surface  516  for contacting an infant&#39;s cranium. The top surface  516  comprises a generally hemi-ellipsoidal depression  518 , a contact surface  519  that corresponds to the shape of a normal infantile cranium, and a rim  522  defining a substantial portion of the depression  518 . A ridge  520  is positioned at one end of the depression  518  to support the neck of the infant. The top surface  516  is preferably made of a closed cell foam material, but may alternatively be made of open cell foam material covered with a vinyl or other surface coating, closed cell foam layered over higher density foam, open cell foam layered over higher density foam, or closed cell foam layered over a more rigid solid or hollow plastic. A curved front surface  524  is positioned to cradle the infant&#39;s shoulders and support the neck of the infant while the infant&#39;s cranium is in contact with the top surface  516 . A preferably-curved side surface  526  extends between the rim  522  and the bottom surface  512 . 
     Two attachable spacing members  550  are positioned over the rim  522  and preferably centered at preferably approximately sixty degrees from the longitudinal axis  531 . Preferably, the spacing members  550  are substantially U-shaped and sized to fit snugly over the rim  522 , and each has a first leg  551  which extends into the depression  518  and contacts the lateral support surfaces  588 ,  592 , and a second leg  552  extending downward adjacent to and contacting the sidewall  526  of the headrest  510 . The spacing members  550  are made of a closed cell foam material, but may alternatively be made of open cell foam material covered with a vinyl or other surface coating, closed cell foam layered over higher density foam, open cell foam layered over higher density foam, or closed cell foam layered over a more rigid solid or hollow plastic. 
     As shown in  FIG. 28 , in this specifically-described embodiment, the outer portion  552  of the spacing member  550  is removeably attached to the body of the headrest  510  with a hook-and-loop fastener  554 . Alternative embodiments contemplate other fastening hardware and adhesives. Placement of the spacing members  550  on the rim  522  provides the ability to alter the rotation range of the infant&#39;s head when placed in the headrest  510 . 
     Normal operation for correction of an abnormally shaped infant cranium is as referenced with respect to the previously-described embodiments. The headrest  510  is placed on a resting surface (not shown) so that the bottom surface  512  is in contact therewith. The infant&#39;s head is then placed in the depression  518  with the infant&#39;s cranium resting on the contact surface  519 . The effective distance between the lateral support surfaces  588 ,  592  can be altered by attaching one or more of the spacing members  550  for proper fitting of the infant&#39;s cranium within the headrest  510 . In this specific embodiment, it is preferred that the maximum thickness T 1  of the leg  551  of the spacing members  550  extending into the depression  518  and along a sagittal axis is approximately eight millimeters. 
     Initially, the posterior and part of the side aspects of the infant&#39;s head contact the contact surface  519 , although during the sleep period the infant&#39;s head may roll to one side or the other. When this occurs, the side of the infant&#39;s head will contact the interior surface  553  of the first leg  551  of one of the spacing members  550 . In this manner, the interior surface  553  acts as an adjusted lateral support surface. Throughout the sleep period, the infant&#39;s neck is supported by the ridge  520 . The infant&#39;s shoulders are aligned in and cradled by the curved front surface  524 . As the infant&#39;s head makes contact with the top surface  516 , the contact surface  519  provides external forces acting on any abnormal bulges of the infant&#39;s cranium and reduces or eliminates external forces that act on abnormal depressions (flattened areas) of the infant&#39;s cranium. As referenced with respect to the previously described embodiments, this contact reduces the net outward forces from brain and skull growth at these prominences, and redirects the growth to areas of the cranium where the infant&#39;s head is not in contact with the top surface  516 . As the infant&#39;s cranium grows, the spacing members  550  can be removed or replaced with spacing members having a thinner first leg  551 . 
     Although in this embodiment the spacing members  550  are described as being substantially U-shaped, it is anticipated that the spacing members  550  could have varying shapes and attachment locations on the headrest  510 . For example, the spacing members  550  could be a circular or rectangular pad having a flat interior surface to act as an adjusted lateral support surface and a flat exterior surface for adhesion to the lateral support surfaces of the headrest. 
       FIG. 29  and  FIG. 30  show an alternative embodiment of a “low profile” headrest  610  with first and second laterally adjustable siderails  626 .  FIG. 29  is a perspective view of the embodiment, while  FIG. 30  is a rear section view through plane  30 - 30  of  FIG. 29 . The “low profile” headrest  610 , as described supra, is provided that otherwise has some of the features of the present invention, such as the top surface  616 , depression  618 , and the like. However, as discussed supra, this “low profile” headrest  610  does not itself provide lateral support with lateral support surfaces. 
     As shown in  FIG. 29  and  FIG. 30 , the laterally-adjustable siderails  626  are fixable to the top surface  616  of the “low profile” headrest  610  with hook-and-loop  630  or other fastening methodology and positioned to provide lateral support to an infant&#39;s cranium resting in the headrest  610  with lateral support surfaces  688 ,  692  on the interior sidewalls of the siderails  626 . The laterally adjustable siderails  626  are positioned such that the lateral support surfaces  688 ,  692  are positioned anterior of the first coronal plane and superior to the mid-cranial transverse plane, as described with reference to the other embodiments. The first and second lateral support surfaces  688 ,  692  do not extend anteriorly of the second coronal plane, as providing a completely unobstructed visual field is imperative to eliminate the risk of iatrogenic-induced neuro-opthalmological injury (i.e., obstructive amblyopia). In addition, the laterally-adjustable siderails  626  allow for adjustment of the distance between the lateral support surfaces  688 ,  692  by repositioning both laterally-adjustable siderails  626  toward the infantile cranium and reattaching them to the top surface  616 . 
     The present invention is described above in terms of a preferred illustrative embodiment of a specifically described headrest, as well as alternative embodiments of the present invention. Those skilled in the art will recognize that alternative constructions of such a headrest can be used in carrying out the present invention. Other aspects, features, and advantages of the present invention may be obtained from a study of this disclosure and the drawings, along with the appended claims.