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At least 19 recordsLinked to original sources
PubMed1992

Chin-marking behavior in male and female New Zealand rabbits: onset, development, and activation by steroids.

Chin marking (chinning) frequency was determined daily in 25 male and 24 female New Zealand rabbits aged 31-150 days. Chinning appeared earlier in females (mean +/- SD = 41 +/- 16 days) than in males (47 +/- 13 days). Between days 30-50, females displayed chinning more frequently than males. Thereafter, chinning increased steadily in both sexes up to day 100. Chinning curves levelled on days 100 and 140 in males and females, respectively. Profile analysis of male and female chinning curves showed significant differences in their slopes and in their population means (p < 0.001). At 7 months of age (days 210-224), both sexes displayed adult chinning frequencies: mean of means +/- SD = 103 +/- 18 and 79 +/- 14 marks/10 min in males (n = 8) and females (n = 8), respectively. The administration of testosterone propionate (TP, 1 mg/day) or estradiol benzoate (EB, 1 microgram/day) to males and females, respectively, from days 31-50, stimulated higher chinning frequencies than those displayed by untreated animals. Results suggest that chinning frequency increases throughout development largely as a consequence of a concomitant increase in sex steroid secretion.

Aging↗
PubMed1979

The human chin and its relationship to mandibular morphology.

This study evaluated the proportion of the external chin (protuberantia mentalia) in relation to the total symphyseal area in normal jaws and those with a diverse morphology. A sample of 60 cases was randomly selected and divided into three groups of 20 each on the basis of normal growth, horizontal growth and vertical growth with an open bite. Tracings of lateral dn frontal radiographs were used to describe general mandibular form and to determine the percentage of external/total symphyseal area. Dental casts were also examined to determine a basal arch form ratio. The results of this study indicate that the amount of bony chin present is related to certain morphologic features of the mandible. The most significant findings illustrate: 1. The chin increases in size as the mandibular type varies from a vertical type, to a normal type, to a horizontal type of growth pattern. 2. With dental "hypofunction" in combination with an exaggerated vertical development of the mandible, a smaller proportion of the protruding chin is present. 3. The chin increases in size as the mandibular basal arch form varies from a tapered shape for the vertical cases to a more square form in the horizontal cases. 4. The degree of lateral ramal flair does not appear to influence the proportion of protruding chin present. Several models have been presented which attempt to explain protuberantia mentalia variation. The evidence in this study supports the concept that mandibular morphology is the result of the action of compensative adaption in a developing structure. There appears to be an implied polygenic influence on symphyseal morphology operating from the cartilaginous cranial base and mandibular basilar bone. This may be manifested in the relative proportion of mandibular basal bone to cranial base width, and to the vector of cranial base growth. The ultimate proportion of the bony chin is viewed to be the result of mandibular adaption to a functional musculoskeletal balance in the craniofacial complex. The extreme variability of chin form in man may be considered to be the result of compensative growth developing in response to the most structurally efficient jaw form, the contiguous soft and hard tissue environment, and the intrinsic genotype of the mandible.

Adolescent↗
PubMed1992

The ptotic (witch's) chin deformity: an excisional approach.

Ptosis of the chin pad is common and can be seen in patients of all ages. It may be associated with too little or (at times) too much anterior chin projection. Often there is an associated deep submental skin crease present. Frequently, the primary concern of the patient is the appearance or exaggeration of chin ptosis in smiling ("dynamic" ptosis). This report describes a flexible approach to the correction of developmental (and some iatrogenic) ptotic chin deformities. The key element in the approach is the direct excision of sagging or excess chin fat, muscle, and skin. No attempt is made to reposition or lift ptosis-prone soft tissues. If a deep submental skin crease is present, it too is excised. If the chin needs added anterior projection, it is accomplished with a stable alloplastic chin implant. The approach is uniquely suited to correct anterior overprojection caused by an excess of soft tissue at the front of the chin and has been successful in correcting the "dynamic" ptosis that appears with smiling.

Adult↗
PubMed1991

Pediatric chin injury: occult condylar fractures of the mandible.

The diagnosis of occult mandibular condylar fractures in children is often missed or delayed on initial examination when children present with a laceration to the chin. A clue to the diagnosis of this type of skeletal injury to the mandible is the knowledge of a commonly occurring pattern of injury associated with chin trauma. Chin laceration, fracture of the parasymphyseal region near the chin, and fracture of the condyles are often concomitant injuries of the mandible. This article reviews three case reports of children who sustained a chin laceration, fracture in the region near the chin, and fracture to the mandibular condyles secondary to chin trauma that were not initially diagnosed on clinical examination.

Child↗
PubMed1992

Chin position in profile analysis. Comparison of techniques and introduction of the lower facial triangle.

Many patients undergoing rhinoplasty can benefit from chin augmentation, yielding a more balanced appearance. Preoperative facial analysis identifies patients with retrusive chins and suggests optimal chin position. Current profile analysis methods depend on subnasale position (Legan's angle) or require estimation of bony landmarks from soft-tissue photographs (Goode's alar crease perpendicular, Gonzalez-Ulloa's zero meridian, and Merrifield's Z-angle). We describe a technique for determining ideal chin position using soft-tissue landmarks. We compare this technique with Legan's, Goode's, Gonzalez-Ulloa's, and Merrifield's techniques in 35 women and conclude that this method provides accurate and rapid determination of ideal chin position.

Adult↗
PubMed1991

A surgical system for the correction of bony chin deformity.

Because the chin, like the nose, occupies a prominent position in the face, it must also be assessed in planning any changes in the facial profile. For example, a large nose associated with a microgenia does not appear as large when the chin is augmented. A chin increased in the vertical dimension confers an excessively long appearance to the face. Finally, a microgenia is associated with the stereotype of a sluggish personality, and a large chin in women connotes a masculine personality. The authors provide guidelines for assessing these variables and including them in surgical plan.

Chin↗
PubMed1991

Bone resorption, stability, and soft-tissue changes following large chin advancements.

Large advancement genioplasties were performed in 10 patients (mean advancement, 11.7 mm) by horizontal osteotomy of the inferior border of the mandible, with preservation of a musculoperiosteal pedicle to the advanced genial segment. Preoperative, immediate postoperative, and long-term follow-up lateral cephalometric radiographs were retrospectively analyzed to evaluate the osseous and soft-tissue changes of the chin. After a mean follow-up period of 15 months, 76% of the initial advancement was preserved, representing 24% osseous resorption. The enveloping soft tissues of the chin followed the bony movement in a ratio of 1:0.88. Horizontal osteotomy of the inferior border of the mandible was a relatively stable procedure when used for large chin advancements. The broadcast possible musculoperiosteal pedicle should remain attached to the advanced genial segment to minimize osseous resorption and to achieve more predictable soft-tissue changes.

Adolescent↗
PubMed1991

Reconstruction of the lower lip and chin with the composite radial forearm-palmaris longus free flap.

Four cases of total lip and chin reconstruction are presented. In three, the composite radial forearm-palmaris longus free flap was used for reconstruction. In the fourth case, the palmaris longus was separated from the flap but still used as a lower lip sling. In all cases, the entire lower lip and the soft tissue of the chin were reconstructed in one stage. All patients healed primarily, and the three who underwent radiotherapy tolerated it without complications. Lip seal and speech were good, and there was no problem with drooling. Postoperative results emphasize the importance of respecting the aesthetic unit of the lower lip and chin.

Adult↗
PubMed1991

Trembling chin--a report of this inheritable dominant character in a four-generation Canadian family.

Trembling chin is an unusual, benign, dominant trait. We describe the condition in a four-generation Canadian family. Investigations, which included E.E.G., electromyograph and facial nerve conductance studies on affected and unaffected individuals, were normal. Premature hearing loss, present in all affected members of this family over age 50, strongly suggests an association of trembling chin with otosclerosis. The merits of early diagnosis and preventive treatment for otosclerosis in persons affected by trembling chin are discussed.

Canada↗
PubMed1992

Densitometric evaluation of changes in the soft tissue of the chin and the lower lip during the treatment of Class III malocclusion.

The aim of this study was to use densitometry of lateral skull teleradiographs to evaluate the changes that occurred in the lower lip and chin after orthodontic or orthodontic-surgical treatment of Class III malocclusion. Forty teleradiographs from 20 patients with mandibular prognathism were made at the beginning and end of treatment. In ten of these patients the treatment was exclusively orthodontic with an edgewise appliance, and in another ten the treatment was orthodontic with a straight wire appliance combined with orthognathic and mentoplastic surgery. In the patients who were only treated orthodontically, a significant increase in density of the lower lip and the chin was found after treatment. This seemed to be related to an increase of muscular tension in these areas. Patients treated with orthognathic surgery and the straight wire appliance showed a decrease in density of the chin after treatment, but not of the lip. This can be interpreted as a consequence of muscular normalization after this procedure was accomplished.

Absorptiometry, Photon↗
PubMed1991

Chin rub CRs may reflect conditioned sickness elicited by a lithium-paired sucrose solution.

Rats were given a single conditioning trial in which 20% sucrose solution was paired with an intraperitoneal (IP) injection of lithium chloride (127.2 mg/kg), d-amphetamine (3 mg/kg) or physiological saline. Thirty min before a subsequent 10-min taste reactivity (TR) test and a 1-h conditioned taste avoidance (CTA) test the rats were injected IP with either the antiemetic agent, trimethobenzamide (5 mg/kg) [corrected] or with physiological saline solution. The lithium-paired, but not the amphetamine- or saline-paired, sucrose solution elicited the aversive TR responses of chin rubs, paw pushes and gapes. Trimethobenzamide suppressed the aversive TR response of chin rubs in the lithium-conditioned group, but not in a group given unconditionally aversive quinine solution. The CTA test was not sensitive to the antiemetic properties of trimethobenzamide, although the drug enhanced sucrose preference overall. The results suggest that chin rub responses may measure conditioned sickness.

Animals↗
PubMed1992

Mental neuropathy (numb chin syndrome). A harbinger of tumor progression or relapse.

The authors report four patients whose initial symptom of tumor recurrence or progression was unilateral numbness of the chin. Two patients had Hodgkin lymphoma, one had malignant melanoma, and one had prostate cancer. Physical examination was notable only for unilateral anesthesia of the chin and lower lip. Diagnostic evaluation, including computed tomography (CT) scan and magnetic resonance imaging (MRI) of the brain, plain radiographs of the mandible, and cerebrospinal fluid analysis for protein, glucose, and cytology were normal. Bone scans revealed osseous lesions in the axial skeleton of all patients, whereas only two patients had abnormal uptake in the mandible. The authors conclude that in the setting of a negative evaluation for central nervous system (CNS) or local mandibular disease, mental neuropathy is associated with recurrent or progressive skeletal disease. In addition, to document relapsed or progressive cancer, the skeletal system may have to be examined at sites distant from the mandible.

Adult↗
PubMed1977

Tooth, chin, bone and body size correlations.

Correlations of size of teeth, chin, bone and body were investigated in 118 males and 102 females of the Burlington Growth Centre. In the males, the mesiodistal widths of the mandibular lateral incisors and canines were independently related to the thickness of the cortex of the second metacarpal and to body weight. Bone cortex thickness was significantly related to metacarpal width in males and to body weight in females. Chin depth of the males was significantly related to bone width and to body height, negatively related to tooth width when bone width or body weight was held constant in partial correlations. Bone width and length were significantly related to body height in both sexes.

Adolescent↗
PubMed1978

EMG activity of cricothyroid and chin muscles during wakefulness and sleeping in the sleep apnea syndrome.

The authors studied the direct and integrated EMG activities of the cricothyroid (CT) and chin muscles in 7 patients with the sleep apnea syndrome. They noted: (1) A tonic activity with phasic inspiratory reinforcements in the CT during wakefulness. (2) A decrease in the tonic activity without any modification of the phasic inspiratory reinforcement during sleep. (3) A decrease or even disappearance of the phasic activity during sleep-induced hypopneas. (4) A complete cessation of both the tonic and the phasic activities of the CT during obstruction apneas: resumption of respiration is marked by the reappearance first of the phasic inspiratory activity and secondly of the tonic one. (5) In some patients similar activities are recorded in the chin muscles during wakefulness, sleep and sleep apnea. These results favor possible obstruction of the upper airway at the laryngeal level: the conjunction of inhibition of the inspiratory activity of the laryngeal muscles with the subsequent closing of the glottis and inspiratory depressure could produce an obstruction.

Adult↗
PubMed1977

Introduction of the sagittal symphysotomy in the treatment of chin deformities.

The management of chin problems occasionally presents a surgical problem to the clinician because of certain anatomic and clinical considerations. This article reviews and discusses some of the conventional surgical procedures in treating chin deformities. The new and versatile sagittal symphysotomy is introduced and described. Three case reports are presented.

Adult↗
PubMed1991

The numb chin.

An apparently innocuous complaint such as a numb chin may be associated with malignant disease, either as heralding symptom or as a manifestation of metastasis. A series of 15 patients with numbness of the chin is presented in which a malignancy was diagnosed prior to the numbness. The numbness diminished or disappeared in 66% of the patients following either systemic chemotherapy or radiotherapy.

Adolescent↗
PubMed1992

The chin as a donor site in early secondary osteoplasty: a retrospective clinical and radiological evaluation.

26 unilateral cleft palate patients received an autogenous bicortical chin bone graft for early reconstruction of the alveolar process. In the evaluation of the donor site, 4% of the anterior teeth showed a negative pulpal sensibility, less than 1% a peri-apical granuloma and 12% pulp canal obliteration. The tooth buds of the canines showed developmental disturbances in 6%. Exposure of unerupted canines should be avoided, and a 5 mm safety margin is advised. Based on its architecture, topographic accessibility, minimal post-operative morbidity and absence of visible scars, the chin can be considered to be a very useful donor site in bone grafting procedures.

Alveolar Process↗
PubMed1979

Complete reconstruction of the chin and floor of the mouth.

A method of reconstruction of the entire floor of the mouth and chin is presented, utilizing interdigitated ventral tongue flaps for reconstruction of the floor of the mouth, and a deltopectoral flap for reconstruction of the chin, which, even with loss of bony support of the mandible, provides a watertight, competent oral sphincter with adequate communication and nutrition.

Chin↗