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40 Cards in this Set
- Front
- Back
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The temporomandibular joint is an articulation between what two bones?
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The Mandible and the Temporal Bone
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What does the condyle of the mandible articulate with?
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The condyle of the mandible articulates with a meniscus that interposes itself between the condyle and the articulating surface of the temporal bone.
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The ligaments of the temporomandibular are separated into what two categories?
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Functional and Accessory
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What are the functional ligaments of the TMJ?
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Temporomandibular ligament
Collateral ligament Capsular ligament |
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What are the accessory ligaments of the TMJ?
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Sphenomandibular ligament
Stylomandibular ligament |
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1. What is another name for the capsular ligament?
2. What is the function of the capsular ligament? |
1. Articular capsule
2. Encloses the entire temporomandibular joint, it extends anterior to include the articular eminence and encompasses the entire articular surface of the joint. By doing so it retains the synovial fluid within the joint. |
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What are the attachments of the capsular ligament/articular capsule?
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Superior - periphery of the mandibular fossa
Posterior - behind the squamotympanic fissure Anterior - anterior slope of the articular eminence Inferior - periphery of the neck of the condyle |
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Where are both fibrous and elastic tissue found in the capsule?
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Upper part
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1. Where are collateral ligaments found and what are they made of?
2. What are the two collateral ligaments? 3. Where do the medial collateral ligaments attach and what are their function? |
1. Collateral ligaments are pieces of connective tissue found just on the outside of the bone and deep to the capsule.
2. The two collateral ligaments are the lateral and medial collateral ligament. 3. The medial ligaments attach the medial and lateral borders of the articular disc to the medial and lateral poles of the mandibular condyle. Their function is to restrict movement of the disc AWAY from the condyle. They facilitate the hinge movement associated with the TMJ. |
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What are the functions of the medial and lateral collateral ligaments of the TMJ?
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Their function is to restrict movement of the disc away from the condyle. They facilitate the hinge movement associated with the TMJ. Although the ligaments allow anterior movement of the condyle they prevent posterior and inferior displacement of the condyle.
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What are the two portions of the temporomandibular ligament and what are their functions?
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1. Outer oblique portion - extends from the articular tubercle and zygomatic process to the outer surface of the neck of the mandibular condyle. Functions in limiting the extent of the opening of the oral cavity.
2. Inner horizontal portion - extends from the articular tubercle of the zygomatic process to the lateral pole of the mandibular condyle and the posterior portion of the articular disc. It function in limiting hte posterior movement of the mandibular condyle and the articular disc. |
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What are the two accessory ligaments of the TMJ?
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1. Sphenomandibular ligament
2. Stylomandibular ligament |
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What is the sphenomandibular ligament a remnant of and where does it run?
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The sphenomandibular ligament is a developmental remnant of Meckel's cartilage and runs from the spine of the sphenoid bone to the lingula of the mandible.
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Where does the stylomandibular ligament run and what does it serve as?
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The stylomandibular ligament runs from the styloid process of the occipital bone to the angle of the mandible. It serves as a thickened anterior portion of the parotid capsule that separates the parotid gland from the infratemporal fossa.
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What is the function of the accessory ligaments?
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The function of the accessory ligament is speculative. It is though that the sphenomandibular ligament plays a small role in limiting lateral mandibular movement and the stylomandibular ligament might limit protrusion of the mandible.
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What is the vascular supply to the TMJ?
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-Branches of the superficial temporal artery
-Maxillary artery As branches of these arteries pass by the joint capsule. |
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What supplies sensory to the TMJ?
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-Via branches of the mandibular nerve with the primary supply being via the auriculotemporal nerve
-Other sensory fibers travel with the deep temporal nerve and masseteric nerve |
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The TMJ is the only joint in the body in which...
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the meniscus separates the internal aspect of the joint so that there is an upper joint space and lower joint space
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What are the 3 areas of the meniscus of the TMJ and where does it fit into?
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- The three zones of the meniscus are:
1. anterior lump or band 2. flattened intermediate zone 3. Posterior disk band -The meniscus fits neatly into the glenoid fossa |
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What covers the articular surfaces of both the mandibular and temporal portions of the TMJ?
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The articulations, both mandibular and temporal, of the TMJ are covered by fibrous connective tissue and not by hyaline (articular) cartilage.
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What are the other two synovial joints covered by fibrous connective tissue instead of hyaline (articular) cartilage?
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1. Acromioclavicular joint
2. Sternoclavicular joint |
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What is the fibrous layer of connective tissue found along the articulations of the TMJ composed of?
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The fibrous layer consists of fibroblasts scattered throughout a dense layer of Type I collagen. Deep to this layer is a layer of fibrocartilage. Thus, although fibrocartilage is found on the bones it does not play a part in the articulation.
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What is the articular disc composed of?
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It is generally composed of Type I collagen bundles loosely arranged and randomly oriented except in the central region where they are bound in organized bundles.
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What does the anterior portion of the articular disc fuse and attach to?
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The anterior portion of the disk fuses with the anterior and medial walls of the capsule.
It is also attached to the lateral pterygoid muscle, |
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What are other names of the posterior region of the articular disc and why are they named so?
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The posterior region is the bilaminar zone of the disk, also known as the retrodiscal area or retrodiscal pad. The area is known as the bilaminar zone as it is notable for the division of the meniscus into an upper and lower portion.
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Is the majority of the articular disc vascular or avascular?
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Avascular
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How do nutrients get to the articular disc?
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Nutrients diffuse into it from synovial fluid and blood vessels located on its periphery.
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What makes the superior portion of the bilaminar zone different from the posterior portion of the bilaminar zone?
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The superior portion of the bilaminar zone possesses numerous blood vessels and is quite flexible.
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How does the inferior portion of the bilaminar zone differ from the superior portion?
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The inferior portion of this area is avascular and quite inelastic.
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What type is the majority of collagen in the articular disc made up of and what type is a small amount made up of?
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The majority of collagen in the articular disc is Type I. However, there is also a very small amount of type III collagen present.
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What % in dry weight do glycosaminoglycans in the disk comprise?
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5%
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What percentage of glycosaminoglycans are chondroitin sulfate and what percent of those are dermatan sulfate?
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80% are chondroitin sulfate
15% are dermatan sulfate |
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What two distinct motions are involved in opening of the mouth?
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1. The mandibular condyle rotates just the slightest bit
2. The condyle translates forward. But, not only does the condyle travel forward so does the disk (meniscus). |
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What kind of joint is the TMJ?
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Ginglymoarthroidial joint.
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Where does the mandibular condyle site when the mouth is closed?
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Sits directly inferior to the posterior band of the meniscus.
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Where does the condyle move to as the mouth begins to open?
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The condyle moves forward and lies under the intermediate zone of the meniscus.
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Where does the condyle lie when the mouth is fully opne?
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The condyle often, but not always, lies inferior to the anterior band of the mensicus.
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What muscle is primarily responsible for the action of mandibular protursion?
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Lateral pterygoid muscle
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What does the superior head of the lateral pterygoid do when the mandible closes?
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Contracts on mandibular closing (elevation)
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What does contraction of the superior head of the lateral pterygoid help prevent?
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Helps to prevent the condyle from slamming into the retrodiscal pad during mandibular elevation and retrusion.
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