Sagittal plane kinematics of the adult hyoid bone

The hyoid bone is a unique bone in the skeleton not articulated to any other bone. The hyoid muscles, which attach to the hyoid bone, may play a role in neck mechanics, but analysis of their function requires quantifying hyoid bone mechanics. The goal of this study was to obtain the detailed kinematics of the hyoid bone over a large range of flexion-extension motion using radiographs at 5 postures. The position of the hyoid bone in the sagittal plane was characterized with respect to head, jaw, and vertebral movements. Sex differences in hyoid kinematics were also investigated. We hypothesized that (1) the position of the hyoid bone in the sagittal plane is linearly correlated with motion of the head, jaw, and vertebrae, and (2) the hyoid position, size, and kinematics are sex-specific. We found that the hyoid bone X, Y, and angular position generally had strong linear correlations with the positions of the head, jaw, and the cervical vertebrae C1-C4. Hyoid X and angular position was also correlated to C5. Sex differences were found in some regressions of the hyoid bone with respect to C1-C5. The angular and linear measurements of the hyoid bone showed sex differences in absolute values, which were not evident after normalization by posture or neck size. Incorporating these results to neck models would enable accurate modeling of the hyoid muscles. This may have implications for analyzing the mechanics of the cervical spine, including loads on neck structures and implants.     

Mandible position and activation of submental and masseter muscles during sleep.

Movement of the mandible could influence pharyngeal airway caliber because the mandible is attached to the tongue and to muscles that insert on the hyoid bone. In normal subjects and patients with obstructive sleep apnea (OSA) we measured jaw position during sleep with strain gauges, as well as masseter and submental electromyograms, airflow, esophageal pressure, oximetry, electroencephalograms, and electrooculograms. Jaws of patients with OSA were open more than those of normal subjects at end expiration and opened further at end inspiration, particularly at the termination of apneas when the masseter and submental muscles contracted. Masseter activation occurred only in patients with OSA and in a pattern similar to that of submental muscles. Jaw opening at end expiration could narrow the upper airway, whereas opening at end inspiration could reflect efforts to expand the airway with tracheal tug and with submental muscle activation and efforts to open the mouth to allow mouth breathing. Masseter contraction does not close the jaw but may serve to stabilize it.     

The effect of surface electrical stimulation on hyolaryngeal movement in normal individuals at rest and during swallowing.

Surface electrical stimulation is currently used in therapy for swallowing problems, although little is known about its physiological effects on neck muscles or swallowing. Previously, when one surface electrode placement was used in dysphagic patients at rest, it lowered the hyolaryngeal complex. Here we examined the effects of nine other placements in normal volunteers to determine 1) whether movements induced by surface stimulation using other placements differ, and 2) whether lowering the hyolaryngeal complex by surface electrical stimulation interfered with swallowing in healthy adults. Ten bipolar surface electrode placements overlying the submental and laryngeal regions were tested. Maximum tolerated stimulation levels were applied at rest while participants held their mouths closed. Videofluoroscopic recordings were used to measure hyoid bone and subglottic air column (laryngeal) movements from resting position and while swallowing 5 ml of liquid barium, with and without stimulation. Videofluoroscopic recordings of swallows were rated blind to condition using the National Institutes of Health-Swallowing Safety Scale. Significant (P < 0.0001) laryngeal and hyoid descent occurred with stimulation at rest. During swallowing, significant (P 相似文献   

Face lifting: problems, solutions, and an outcome study

The superficial musculoaponeurotic system (SMAS) platysma rotation flap with platysmal transection from the deep surface has been the author's face-lift technique to correct jowls, submental laxity, and platysma bands since 1982. An outcome study of 10 consecutive face-lift operations is presented to demonstrate the efficacy of correction of lower face and neck aging and the duration of the improvement. Reappearance of platysma bands has been the earliest and most frequent sign of recurrent aging changes. A technique for directly dealing with platysma bands in the submental and cervicomental location is described, and follow-up results up to 3 years are shown.     

Submandibular gland I: an anatomic evaluation and surgical approach to submandibular gland resection for facial rejuvenation

Submandibular gland resection for aesthetic reasons has been hotly debated. Detractors maintain that the procedure is dangerous because it puts too many important structures at risk, notably motor nerves. The present study was undertaken to elucidate the neurovascular and soft-tissue anatomy of the digastric triangle via cadaver dissections so that a surgical approach to achieve safe aesthetic submandibular resection could be performed. Fifteen digastric triangles dissections were performed in fixed and fresh cadaver specimens. The dissection focus was to understand the submandibular neurovascular relationships, capsule as well as fascial layers, and measurements to known structures. The marginal mandibular nerve is located external to the submandibular capsule, approximately 3.7 cm cephalad to the inferior margin of the gland. The hypoglossal nerve is posterior to the digastric sling in a position that is protected deep within the visceral layer of the neck. The lingual nerve is located underneath the mandibular border, crossing anterior to the submandibular duct. The vascular supply is variant, but with an average of one and a half vessels entering medially to the superficial lobe of the gland, one intermediate vessel entering medially to supply the superficial and deep lobes, and one deep perforator that runs from the central portion of the deep lobe to the superficial lobe. Appreciation of this anatomy is critical in the submental approach for partial resection. Although it can be technically challenging, the anatomy is straightforward and partial submandibular gland resection can be executed via a consistent, safe approach to optimize facial rejuvenation in certain patients.     

Anatomy of the lymph vessels and nodes of the head and neck in green marmosets]

In 50 mature green monkeys, the lymphatic system of the skin on the hairy part of the skull (occipital, parietal, frontal) and on the face was studied. The lymphatic vessels of cranial and cervical organs flow into submental, submandibular (anterior, medial, posterior) lymph nodes and into profound cervical (cranial, medial, caudal) lymph nodes. Lymph nodes together with efferent lymphatic vessels form lymph collectors of the neck which follow the blood vessels branching: superficial jugular, profound jugular and paratracheal network.     

Regional differences in hyoid muscle activity and length dynamics during mammalian head shaking

The sternohyoid (SH) and geniohyoid (GH) are antagonist strap muscles that are active during a number of different behaviors, including sucking, intraoral transport, swallowing, breathing, and extension/flexion of the neck. Because these muscles have served different functions through the evolutionary history of vertebrates, it is quite likely they will have complex patterns of electrical activity and muscle fiber contraction. Different regions of the SH exhibit different contraction and activity patterns during a swallow. We examined the dynamics of the SH and GH muscles during an unrestrained, and vigorous head shaking behavior in an animal model of human head, neck, and hyolingual movement. A gentle touch to infant pig ears elicited a head shake of several revolutions. Using sonomicrometry and intramuscular EMG, we measured regional (within) muscle strain and activity in SH and GH. We found that EMG was consistent across three regions (anterior, belly, and posterior) of each muscle. Changes in muscle length, however, were more complex. In the SH, mid-belly length-change occurred out-of-phase with the anterior and posterior end regions, but with a zero lag timing; the anterior region shortened before the posterior. In the GH, the anterior region shortened before and out-of-phase with the mid-belly and posterior regions. Head shaking is a relatively simple reflex behavior, yet the underlying patterns of muscle length dynamics and EMG activity are not. The regional complexity in SH and GH, similar to regionalization of SH during swallowing, suggests that these anatomically simple hyoid strap muscles have more complex function than textbooks often suggest.     

The mechanism of frill erection in the bearded dragon Amphibolurus barbatus with comments on the jacky lizard A. muricatus (Agamidae)

Amphibolurus barbatus has a threat display which includes the erection of the gular regions as a frill and may also include wide opening of the mouth to display a yellow mouth lining. Frill erection involves protraction, depression, and lateral expansion of the hyoid apparatus. Electrical stimulation of the hyoid muscles and dissection of the hyoid apparatus were used to examine specializations for producing frill erection. Specializations of the hyoid skeleton include the absence of a ceratobranchial II, presence of a synovial joint between the ceratohyal and body of the hyoid, and combined shortening of the entoglossal process and lengthening of the posterior arches. The only apparent specialization of the hyoid musculature is the anterior displacement of the origin of m. hyomandibularis. All of the hyoid muscles are involved in some way in frill erection and the actions of each muscle is described. The characteristic frill erection in the threat display of Amphibolurus barbatus is possible because of the 1:2 ratio of the anterior and posterior parts of the apparatus and the absence of the ceratobrnchial II.     

The Dimension of Hyoid Bone Is Independently Associated with the Severity of Obstructive Sleep Apnea

Introduction

We hypothesized that the size of the hyoid bone itself may affect the severity of sleep apnea. The aim of this study was to identify the relationship between hyoid bone dimensions and the severity of sleep apnea using computerized tomography (CT) axial images.

Methods

We retrospectively measured the hyoid bone in axial images of neck CTs and correlated these measurements with results of polysomnography in a total of 106 male patients. The new hyoid bone parameters studied in this study were as follows: distance between bilateral lesser horns (LH-d), distance between bilateral greater horns (GH-d), distance from the most anterior end of the hyoid arch to GH-d (AP), distance from the greater to the lesser horn on right and left sides (GH-LH), and the anterior angle between bilateral extensive lines from the greater to the lesser horn (H-angle). Data was analyzed using univariate and multivariate logistic regression, and Pearson correlation tests.

Results

We found a significant inverse correlation between the apnea-hypopnea index (AHI) and GH-d or AP. Neither the LH-d, GH-LH, nor H-angle were associated with the AHI. The patient group that met the criteria of both GH-d<45.4 and AP<33.4 demonstrated the most severe AHI.

Conclusion

The lateral width or antero-posterior length of hyoid bone was associated with AHI and predicted the severity of sleep apnea in male patients. This finding supports the role of expansion hyoidplasty for treatment of sleep apnea. Pre-operative consideration of these parameters may improve surgical outcomes in male patients with sleep apnea.     

Anatomical anomaly of human digastric muscles

In the submandibular region an anatomical anomaly of muscle arrangement was found. Between the left and right digastric muscles, asymmetric accessory digastric muscles were detected, which all arose from the mandible and were attached to the hyoid bone. Furthermore, the right anterior digastric muscle had an accessory belly. These anomalies of digastric muscles may be anatomical manifestations of a functional support of the mylohyoid muscle.     

Action of neck accessory muscles on rib cage in dogs

To investigate the action of the neck accessory muscles on the rib cage, we stimulated the sternocleidomastoid and the scalenus muscles separately in supine anesthetized dogs. Hooks screwed into the sternum and ribs were used to measure their axial displacements and the changes in anteroposterior (AP) and transverse (T) diameters of the rib cage. We found that the sternocleidomastoid and scalenus muscles, when they contract alone, cause a large axial displacement of the sternum and the ribs in a cephalad direction and expand the rib cage along both its AP and T diameters. Opening the abdomen increased the cephalad displacement of the ribs and the expansion of the lower rib cage, particularly along its T diameter, but reduced the increase in lung volume. These experiments indicate 1) that the action of the sternocleidomastoid and scalenus muscles on the rib cage is essentially the consequence of a rotation of the ribs' neck axes, resulting from the cephalad displacement of the ribs, and 2) that the fall in abdominal pressure, almost certainly by acting through the zone of apposition of the diaphragm to the rib cage, has a deflationary action on the lower rib cage, more markedly so on its lateral than its anterior wall. The experiments also suggest that the fall in abdominal pressure prevents the diaphragm from moving cephalad and aids the neck accessory muscles in inflating the lungs.     

Electromyography of superficial and deep neck muscles during isometric, voluntary, and reflex contractions

Increasingly complex models of the neck neuromusculature need detailed muscle and kinematic data for proper validation. The goal of this study was to measure the electromyographic activity of superficial and deep neck muscles during tasks involving isometric, voluntary, and reflexively evoked contractions of the neck muscles. Three male subjects (28-41 years) had electromyographic (EMG) fine wires inserted into the left sternocleidomastoid, levator scapulae, trapezius, splenius capitis, semispinalis capitis, semispinalis cervicis, and multifidus muscles. Surface electrodes were placed over the left sternohyoid muscle. Subjects then performed: (i) maximal voluntary contractions (MVCs) in the eight directions (45 deg intervals) from the neutral posture; (ii) 50 N isometric contractions with a slow sweep of the force direction through 720 deg; (iii) voluntary oscillatory head movements in flexion and extension; and (iv) initially relaxed reflex muscle activations to a forward acceleration while seated on a sled. Isometric contractions were performed against an overhead load cell and movement dynamics were measured using six-axis accelerometry on the head and torso. In all three subjects, the two anterior neck muscles had similar preferred activation directions and acted synergistically in both dynamic tasks. With the exception of splenius capitis, the posterior and posterolateral neck muscles also showed consistent activation directions and acted synergistically during the voluntary motions, but not during the sled perturbations. These findings suggest that the common numerical-modeling assumption that all anterior muscles act synergistically as flexors is reasonable, but that the related assumption that all posterior muscles act synergistically as extensors is not. Despite the small number of subjects, the data presented here can be used to inform and validate a neck model at three levels of increasing neuromuscular-kinematic complexity: muscles generating forces with no movement, muscles generating forces and causing movement, and muscles generating forces in response to induced movement. These increasingly complex data sets will allow researchers to incrementally tune their neck models' muscle geometry, physiology, and feedforward/feedback neuromechanics.     

Mandibular reconstruction in the radiated patient: the role of osteocutaneous free tissue transfers

This paper discusses our experience with the second metatarsal and iliac crest osteocutaneous transfers for mandibular reconstruction. The prime indication for this type of reconstruction was for anterior mandibular defects when the patient had been previously resected. Midbody to midbody defects were reconstructed with the metatarsal and larger defects with the iliac crest. In most cases, an osteotomy was done to create a mental angle. The evaluation of speech, oral continence, and swallowing revealed good results in all patients unless lip or tongue resection compromised function. Facial contour was excellent in metatarsal reconstructions. The iliac crest cutaneous flap provided a generous supply of skin for both intraoral reconstruction and external skin coverage but tended to be bulky, particularly when used in the submental area. Thirty three of 36 flaps survived completely. Flap losses were due to anastomosis thrombosis (1), pedicle compression (1), and pedicle destruction during exploration for suspected carotid blowout (1). Ninety three percent of bone junctions developed a solid bony union despite the mandible having had a full therapeutic dose of preoperative radiation. Despite wound infections in 8 patients, and intraoral dehiscence with bone exposure in 12 patients, all but one of these transfers went on to good bony union without infection in the bone graft.     

Lateral cervical advancement flaps for the correction of webbed-neck deformity

In the webbed-neck deformity, a horizontal excess of cervical skin creates bilateral and often asymmetrical skin webs from the mastoid to the acromion. Hair extends laterally to the free edge on the posterior web surface, creating a wide nuchal hairline. A technique of correction is presented. Through an incision along or within the hairline, the glabrous anterior web surface is undermined with the platysma muscle into the anterior cervical triangle until posterosuperior traction will obliterate the web. The posterior hair-bearing web surface is also elevated, and an excess of scalp is excised anterior to the new hairline position determined by the surgeon. The anterior glabrous flap is advanced posteriorly to resurface the scalp defect and recreate a normal neck contour and symmetrical hairline. A Szymanowski triangle of scalp is excised to equalize wound margins creating two "lazy" Y incisions that join in the scalp midline on completion of the opposite neck web. All scars lie within or along the hairline or extend onto the posterolateral shoulder. The method allows precise control of bilateral neck contour and hairline position without intraoperative repositioning and avoids scars on the exposed anterolateral cervical surface. There has been no recurrence of the neck deformity after 2 years.     

Development of the mandibular, hyoid arch and gill arch skeleton in the Chinese barb Puntius semifasciolatus: comparisons of ossification sequences among Cypriniformes

The morphogenesis and sequence of ossification and chondrification of skeletal elements of the jaws, and hyoid arch and gill arches of Puntius semifasciolatus are described. These data provide a baseline for further studies and enable comparisons with other described cypriniforms. Some general patterns of ossification in the hyoid arch and branchial arches in cypriniforms were notable. First, the overall development is from anterior to posterior, with the exception of the fifth ceratobranchial bone, which ossifies first. Second, where ossification of iterated elements is sequential, it tends to proceed from posterior to anterior, even when more posterior chondrifications are the smallest in the series. Ossification of the ceratobranchial, epibranchial and pharyngobranchial bones tends to proceed from ventral to dorsal. The comparisons revealed small sets of skeletal elements whose ossification sequence appears to be relatively conserved across cyprinid cypriniforms. Several potentially key timing changes in the ossification sequence of the jaws, hyoid arch and gill arches were identified, such as the accelerated timing of ossification of the fifth ceratobranchial bone, which may be unique to cypriniforms.     

EMG of the digastric muscle in gibbon and orangutan: Functional consequences of the loss of the anterior digastric in orangutans

Unlike all other primates, the digastric muscle of the orangutan lacks an anterior belly; the posterior belly, while present, inserts directly onto the mandible. To understand the functional consequences of this morphologic novelty, the EMG activity patterns of the digastric muscle and other potential mandibular depressors were studied in a gibbon and an orangutan. The results suggest a significant degree of functional differentiation between the two digastric bellies. In the gibbon, the recruitment pattern of the posterior digastric during mastication is typically biphasic. It is an important mandibular depressor, active in this role during mastication and wide opening. It also acts with the anterior suprahyoid muscles to move the hyoid prior to jaw opening during mastication. The recruitment patterns of the anterior digastric suggest that it is functionally allied to the geniohyoid and mylohyoid. For example, although it transmits the force of the posterior digastric during mandibular depression, it functions independent of the posterior digastric during swallowing. Of the muscles studied, the posterior digastric was the only muscle to exhibit major differences in recruitment pattern between the two species. The posterior digastric retains its function as a mandibular depressor in orangutans, but is never recruited biphasically, and is not active prior to opening. The unique anatomy of the digastric muscle in orangutans results in decoupling of the mechanisms for hyoid movement and mandibular depression, and during unilateral activity it potentially contributes to substantial transverse movements of the mandible. Hypotheses to explain the loss of the anterior digastric should incorporate these functional conclusions. © 1994 Wiley-Liss, Inc.     

Active muscle migration during insect metamorphosis

The R1 abdominal retractor muscles of the insect Tenebrio molitor change position during the course of metamorphosis. These muscles detach from the epidermal tendon cells at their anterior ends, and migrate in a posterior direction, parallel to the body axis, to form completely new attachments shortly before adult emergence. Movement is preceded by the loss of sarcomere structure, and the muscles migrate in a partially dedifferentiated condition, closely accompanied by satellite cells and haemocytes. Movement appears to result from the extension of muscle processes towards the epidermis posterior to the larval attachment sites, which contact reciprocal processes extended from the epidermis. Contacts at the new posterior sites are then reinforced, and relinquished at the anterior. This cycle is subsequently repeated. It is envisaged that migration ceases when the muscles encounter a contour in the epidermal gradient known to specify the position of the adult muscle attachment sites. This positional information may be encoded in the epidermal basal lamina. The muscles then redifferentiate, with concurrent differentiation of new epidermal tendon cells. Development of adult muscle attachments appears to require reciprocal morphogenetic interactions between muscle and epidermis.     

Anatomic study of the vasculature of the submental artery flap

The submental artery island flap is a versatile option in head and neck reconstruction. This flap may be used for the coverage of perioral, intraoral, and other facial defects, leaving a relatively acceptable donor-site scar. In this study, the submental region of 13 formalin-fixed cadavers was dissected bilaterally. Comprehensive anatomical information regarding the pedicle of the flap and its relationship with the important adjacent structures is provided. The mean values of the measurements of the facial and submental arteries were as follows: the facial artery was 2.7 mm in diameter at the origin, and it crossed the mandibular border 26.6 mm from the mandibular angle. The origin of the submental artery was 27.5 mm from the origin of the facial artery, 5.0 mm from the mandibular border, and 23.8 mm from the mandibular angle. The diameter of the submental artery was 1.7 mm at the origin. The artery was found mostly to course superficial to the submandibular gland. In one case, the artery passed through the gland. The total length of the submental artery was 58.9 mm. The artery anastomosed with the contralateral artery in 92 percent of the cadavers. The submental artery was deep to the anterior belly of the digastric muscle in 81 percent of the cases. This study presents detailed anatomical data about the location, dimension, and relationship of the facial artery, the submental artery, and the submental vein that may be useful during dissection of the submental artery island flap.     

Clinical applications of the posterior rectus sheath-peritoneal free flap

Soft-tissue injuries involving the dorsum of the hand and foot continue to pose complex reconstructive challenges in terms of function and contour. Requirements for coverage include thin, vascularized tissue that supports skin grafts and at the same time provides a gliding surface for tendon excursion. This article reports the authors' clinical experience with the free posterior rectus sheath-peritoneal flap foil dorsal coverage in three patients. Two patients required dorsal hand coverage; one following acute trauma and another for delayed reconstruction 1 year after near hand replantation. A third patient required dorsal foot coverage for exposed tendons resulting from skin loss secondary to vasculitis. In all three patients, the flap was harvested through a paramedian incision at the lateral border of the anterior rectus sheath. After opening the anterior rectus sheath, the rectus muscle was elevated off of the posterior rectus sheath and peritoneum. When elevating the muscle, the attachments of the inferior epigastric vessels to the posterior rectus sheath and peritoneum were preserved while ligating any branches of these vessels to the muscle. Segmental intercostal innervation to the muscle was preserved. The deep inferior epigastric vessels were then dissected to their origin to maximize pedicle length and diameter. The maximum dimension of the flaps harvested for the selected cases was 16 X 8 cm. The anterior rectus sheath was closed primarily with non-absorbable suture. Mean follow-up was 1 year, and all flaps survived with excellent contour and good function in all three patients. Complications included a postoperative ileus in one patient, which resolved after 5 days with nasogastric tube decompression.     

The suction mechanism of the pipid frog,Pipa pipa (Linnaeus, 1758)

Most suction‐feeding, aquatic vertebrates create suction by rapidly enlarging the oral cavity and pharynx. Forceful enlargement of the pharynx is powered by longitudinal muscles that retract skeletal elements of the hyoid, more caudal branchial arches, and, in many fish, the pectoral girdle. This arrangement was thought to characterize all suction‐feeding vertebrates. However, it does not exist in the permanently aquatic, tongueless Pipa pipa , an Amazonian frog that can catch fish. Correlating high‐speed (250 and 500 fps) video records with anatomical analysis and functional tests shows that fundamental features of tetrapod body design are altered to allow P. pipa to suction‐feed. In P. pipa , the hyoid apparatus is not connected to the skull and is enclosed by the pectoral girdle. The major retractor of the hyoid apparatus arises not from the pectoral girdle but from the femur, which lies largely within the soft tissue boundaries of the trunk. Retraction of the hyoid is coupled with expansion of the anterior trunk, which occurs when the hypertrophied ventral pectoral elements are depressed and the urostyle and sacral vertebra are protracted and slide forward on the pelvic girdle, thereby elongating the entire trunk. We suggest that a single, robust pair of muscles adduct the cleithra to depress the ventral pectoral elements with force, while modified tail muscles slide the axial skeleton cranially on the pelvic girdle. Combined hyoid retraction, axial protraction, and pectoral depression expand the buccopharyngeal cavity to a volume potentially equal to that of the entire resting body of the frog. Pipa may be the only tetrapod vertebrate clade that enlarges its entire trunk during suction‐feeding.