The mandible, lower jaw or jawbone is the largest and lowest bone in the human face. It holds the lower teeth in place; the mandible sits beneath the maxilla. It is the only movable bone of the skull; the bone is formed in the fetus from a fusion of the left and right mandibular prominences, the point where these sides join, the mandibular symphysis, is still visible as a faint ridge in the midline. Like other symphyses in the body, this is a midline articulation where the bones are joined by fibrocartilage, but this articulation fuses together in early childhood; the word "mandible" derives from the Latin word mandibula, "jawbone", from mandere "to chew" and -bula. The mandible consists of: The body, found at the front A ramus on the left and the right, the rami rise up from the body of the mandible and meet with the body at the angle of the mandible or the gonial angle; the body of the mandible is curved, the front part gives structure to the chin. It has two borders. From the outside, the mandible is marked in the midline by a faint ridge, indicating the mandibular symphysis, the line of junction of the two pieces of which the bone is composed at an early period of life.
This ridge divides below and encloses a triangular eminence, the mental protuberance, the base of, depressed in the center but raised on either side to form the mental tubercle. On either side of the symphysis, just below the incisor teeth, is a depression, the incisive fossa, which gives origin to the mentalis and a small portion of the orbicularis oris. Below the second premolar tooth, on either side, midway between the upper and lower borders of the body, is the mental foramen, for the passage of the mental vessels and nerve. Running backward and upward from each mental tubercle is a faint ridge, the oblique line, continuous with the anterior border of the ramus. From the inside, the mandible appears concave. Near the lower part of the symphysis is a pair of laterally placed spines, termed the mental spines, which give origin to the genioglossus. Below these is a second pair of spines, or more a median ridge or impression, for the origin of the geniohyoid. In some cases, the mental spines are fused to form a single eminence, in others they are absent and their position is indicated by an irregularity of the surface.
Above the mental spines, a median foramen and furrow are sometimes seen. Below the mental spines, on either side of the middle line, is an oval depression for the attachment of the anterior belly of the digastric. Extending upward and backward on either side from the lower part of the symphysis is the mylohyoid line, which gives origin to the mylohyoid muscle. Above the anterior part of this line is a smooth triangular area against which the sublingual gland rests, below the hinder part, an oval fossa for the submandibular gland. Borders The superior or alveolar border, wider behind than in front, is hollowed into cavities, for the reception of the teeth. To the outer lip of the superior border, on either side, the buccinator is attached as far forward as the first molar tooth; the inferior border is rounded, longer than the superior, thicker in front than behind. The ramus of the human mandible has four sides, two surfaces, four borders, two processes. On the outside, the ramus marked by oblique ridges at its lower part.
On the inside at the center there is an oblique mandibular foramen, for the entrance of the inferior alveolar vessels and nerve. The margin of this opening is irregular. Behind this groove is a rough surface, for the insertion of the medial pterygoid muscle; the mandibular canal runs obliquely downward and forward in the ramus, horizontally forward in the body, where it is placed under the alveoli and communicates with them by small openings. On arriving at the incisor teeth, it turns back to communicate with the mental foramen, giving off two small canals which run to the cavities containing the incisor teeth. In the posterior two-thirds of the bone the canal is situated nearer the internal surface of the mandible, it contains the inferior alveolar vessels and nerve, from which branches are distributed to the teeth. Borders The lower border of the ramus is thick and continuous with the inferior border of the body of the bone. At its junction with the posterior border is the angle of the mandible, which may be either inverted or everted and is marked by rough, oblique ridges on each side, for the attachment of the masseter laterally, the medial pterygoid muscle medially.
The anterior border is thin above, thicker below, continuous with the oblique l
Uvulopalatopharyngoplasty is a surgical procedure or sleep surgery used to remove tissue and/or remodel tissue in the throat. This could be because of sleep issues. Tissues which may be removed include: The tonsils The adenoidsTissues which may be remodeled include: The uvula The soft palate The pharynx UPPP involves removal of the tonsils, the posterior surface of the soft palate, the uvula; the uvula is folded toward the soft palate and sutured together as demonstrated in the figures. In the US, UPPP is the most performed procedure for obstructive sleep apnea with 33,000 procedures performed per year; the surgery is more successful in patients who are not obese, there is a limited role in morbidly obese individuals. Standard UPPP procedure UPPP is administered to patients with obstructive sleep apnea in isolation, it is administered as a stand-alone procedure in the hope that the tissue which obstructs the patient's airway is localized in the back of the throat. The rationale is that, by removing the tissue, the patient's airway will be wider and breathing will become easier.
The Role of UPPP in the "Stanford Protocol" operation UPPP is offered to sleep apnea patients who opt for a more comprehensive surgical procedure known as the "Stanford Protocol", first attempted by Doctors Nelson Powell and Robert Riley of Stanford University. The Stanford Protocol consists of two phases; the first involves surgery of the soft tissue and the second involves skeletal surgeries. First, Phase 1 or soft tissue surgery is performed and after re-testing with a new sleep study, if there is residual sleep apnea Phase 2 surgery would consist of jaw surgery; the goal is to thereby treat sleep apnea. It has been found that obstructive sleep apnea involves multiple sites where tissue obstructs the airway; the Protocol successively addresses these multiple sites of obstruction. Note that genioglossus advancement can be performed either during Phase 1 or Phase 2 surgeries. Phase 2 involves maxillomandibular advancement, a surgery which moves the jaw top and bottom forward; the tongue muscle is anchored to the chin, translation of the mandible forward pulls the tongue forward as well.
If the procedure achieves the desired results, when the patient sleeps and the tongue relaxes, it will no longer be able to block the airway. Success is much better for Phase 2 than for Phase 1 - 90 percent benefit from the second phase, the success of the Stanford Protocol Operation therefore is due in large part to this second phase. There is debate among surgeons as to the role of Phase 1 surgery. In 2002, an Atlanta-based surgical team, led by Dr. Jeffrey Prinsell, published results which have approximated those of the Stanford team when UPPP was not included in their mix of surgeries; when UPPP has been administered in isolation, the results are variable. As explained above, sleep apnea is caused by multiple co-existing obstructions at various locations of the airway such as the nasal cavity, the base of the tongue; the contributing factors in the variability of success include the pre-surgical size of the tonsils, palate and tongue base. Patients who are morbidly obese are less to have success from this surgery.
Over one thousand people have undergone The Stanford Protocol operation and received follow-up sleep study testing. 60 to 70 percent of patients have been cured. In ninety percent of patients, a significant improvement can be expected. In the recent years, many surgeons have tried to address the multiple levels of obstruction by performing multiple procedures on the same surgical day, called the "multi-level approach". Typical surgeries in a multi-level approach may include: Nasal-level surgeries turbinoplasty, septorhinoplastySoft palate-level surgeries uvulectomy, uvulopalatopharyngoplasty, tonsillectomyHypopharyngeal-level surgeries hyoid suspension tongue suspension tongue base reduction genioglossus advancementThis approach improves postoperative results in well-selected patients. See Uvulopalatoplasty One of the risks is that by cutting the tissues, excess scar tissue can "tighten" the airway and make it smaller than it was before UPPP; some individuals who have undergone UPPP as a stand-alone procedure have written on internet forums that they experienced a worsening of their breathing following UPPP.
Others have spoken of severe acid reflux. After surgery, complications may include these: Sleepiness and sleep apnea related to post-surgery medication Swelling and bleeding A sore throat and/or difficulty swallowing Drainage of secretions into the nose and a nasal quality to the voice. English language speech does not seem to be affected by this surgery. Narrowing of the airway in the nose and throat snoring and iatrogenically caused sleep apnea. Patients who have had the uvula removed will become unable to pronounce uvular consonants, found in French, German and others. Long term complications with pain, feeling sick and lesser sleep quality than before the LAUP. In 2008, Dr. Labra, et al. from Mexico, published a variation of UP3, by adding a uvulopalatal flap, in order to avoid such complications, with a good rate of success. WebMDHealth. Uvulopalatopharyngoplasty for snoring Retrieved August 26, 2005. Royal College of Surgeons Audit Symposium March 8th 2002 Retrieved April 22, 2006. University of Maryland Medical Center Patient Education - UPPP Retrieved April
Orthognathic surgery. Coined by Harold Hargis, this surgery is used to treat congenital conditions such as cleft palate. During oral surgery, bone is cut, moved and realigned to correct a dentofacial deformity; the word "osteotomy" means the excision of bone. The dental osteotomy allows surgeons to visualize the jawbone, work accordingly; the operation is used to correct jaw problems in about 5% of general population presenting with dentofacial deformities like maxillary prognathisms, mandibular prognathisms, open bites, difficulty chewing, difficulty swallowing, temporomandibular joint dysfunction pains, excessive wear of the teeth, receding chins. Many surgeons prefer this procedure for the correction of a dentofacial deformity due to its effectiveness, it is estimated that nearly 5% of the UK or USA population present with dentofacial deformities that are not amenable to orthodontic treatment requiring orthognathic surgery as a part of their definitive treatment. Orthognathic surgery can be used to correct: Gross jaw discrepancies Skeletofacial discrepancies associated with documented sleep apnea, airway defects, soft tissue discrepancies Skeletofacial discrepancies associated with documented temporomandibular joint pathologyA disproportionately grown upper or lower jaw causes dentofacial deformities.
Chewing becomes problematic, may cause pain due to straining of the jaw muscle and bone. Deformities range from micrognathia, when the mandible doesn't grow far forward enough, when the mandible grows too much, causing an under bite. A total maxilla osteotomy is used to treat the "long face syndrome," known as the skeptical open bite, idiopathic long face, hyper divergent face, total maxillary alveolar hyperplasia, vertical maxillary excess. Prior to surgery, surgeons should take x-rays of the patient's jaw to determine the deformity, to make a plan of procedures. Mandible osteotomies, or corrective jaw surgeries, benefit individuals who suffer from difficulty chewing, swallowing, TMJ pains, excessive wear of the teeth, open bites, underbites, or a receding chin; the deformities listed above can be perfected by an osteotomy surgery of either the maxilla or mandible, performed by an oral surgeon, specialized in the working with both the upper and lower jaws. Orthognathic surgery is available as a successful treatment for obstructive sleep apnea.
Cleft lip and palateOrthognathic surgery is a well established and used treatment option for insufficient growth of the maxilla in patients with an orofacial cleft. There is some debate regarding the timing of orthognathic procedures, to maximise the potential for natural growth of the facial skeleton. Patient reported aesthetic outcomes of orthognathic surgery for cleft lip and palate appear to be of overall satisfaction, despite complications that may arise. A significant long-term outcome of orthognathic surgery is impaired maxillary growth, due to scar tissue formation. A 2013 systematic review comparing traditional orthognathic surgery with maxillary distraction osteogenesis found that the evidence was of low quality. Although infrequent, there can be complications such as bleeding, infection and vomiting. Infection rates of up to 7% are reported after orthognathic surgery. There can be some post operative facial numbness due to nerve damage. Diagnostics for nerve damage consist of: brush-stroke directional discrimination, touch detection threshold, warm/cold and sharp/blunt discrimination, electrophysiological tests (mental nerve blink reflex, nerve conduction study, cold and warm detection thresholds.
The inferior alveolar nerve, a branch of the mandibular nerve, must be identified during surgery and worked around in order to minimize nerve damage. The numbness may be either temporary, or more permanent. Recovery from the nerve damage occurs within 3 months after repair. Orthognathic surgery is performed by an oral and maxillofacial surgeon in collaboration with an orthodontist, it includes braces before and after surgery, retainers after the final removal of braces. Orthognathic surgery is needed after reconstruction of cleft palate or other major craniofacial anomalies. Careful coordination between the surgeon and orthodontist is essential to ensure that the teeth will fit after the surgery. Planning for the surgery involves input from a multidisciplinary team, including oral and maxillofacial surgeons, a speech and language therapist. Although it depends on the reason for surgery, working with a speech and language therapist in advance can help minimize potential relapse; the surgery results in a noticeable change in the patient's face.
Radiographs and photographs are taken to help in the planning. There is advanced sof