Chapter 8
anular ligament of radius
wraps around head of radius; helps to hold it in place at radial notch of ulna
Cartilage tears (menisci)
occur when a meniscus is subjected to compression and shear stress at the same time
coracohumeral ligament
provides the only strong thickening of the capsule and helps support the weight of the upper limb
Synovial fluid (synovial joint)
thin, lubricating film that covers the surface of a joint; complex mixture of polysaccharides, proteins, fat and cells; Hyaluronic acid - Provides slippery, lubricating effect
arthroscopic surgery
The arthroscope, a small instrument bearing a tiny lens and fiber-optic light source, enables the surgeon to view the joint interior, as in Figure 8.13. The surgeon can then repair a ligament or remove cartilage fragments through one or more tiny slits, minimizing tissue damage and scarring.
elevation/depression
Elevation - moves structure superior Depression - moves structure inferior EX-shrugging shoulders (scapular movement), opening/closing mouth (mandible movement)
Movements allowed by synovial joints
1. angular 2. gliding 3. rotation
Symphyses (Cartilaginous Joint)
A joint where fibrocartilage unites the bones.
Rheumatism
A lay term referring to disease involving muscle or joint pain; may be used to apply to arthritis, bursitis, etc.
Anterior Cruciate Ligament (ACL)
A ligament in the knee that attaches to the anterior aspect of the tibial plateau. restricting anterior movement of the tibia on the femur
Posterior Cruciate Ligament (PCL)
A ligament in the knee that attaches to the posterior aspect of the tibial plateau, restricting posterior movement of the tibia on the femur
Ankylosing Spondylitis (AS)
A variant of rheumatoid arthritis that chiefly affects males; it usually begins in the sacroiliac joints and progresses superiorly along the spine. The vertebrae become interconnected by fibrous tissue, causing the spine to become rigid.
What does the term "arthritis" mean?
Answer: Arthritis means inflammation of the joint.
How do bursae and tendon sheaths improve joint function?
Answer: Bursae and tendon sheaths help to reduce friction during joint movement.
PREDICT Babies are sometimes diagnosed with a condition called craniosynostosis. Using the definition you just learned, describe what you think this condition is and predict what problems it might cause.
Answer: Cranio- refers to the skull bones (see Chapter 7, p. 201) and synostosis refers to ossification of skull bone sutures. Craniosynostosis is a disorder in which the sutures in the skull close prematurely (in babies). Premature closing of sutures prevents the brain from growing normally.
MAKE CONNECTIONS Evan is 25 years old. Would you expect to find synchondroses at the ends of his femur? Explain. (Hint: See Chapter 6, p. 187.)
Answer: Evan would not have synchondroses at the ends of his femur. By age 25, his epiphyseal plates have fused and become synostoses.
How are joint mobility and stability related?
Answer: In general, the more stable a joint, the less mobile it is.
What is the cause of Lyme disease?
Answer: Lyme disease is caused by spirochete bacteria and transmitted by a tick bite.
What functional joint class contains the least-mobile joints?
Answer: The synarthroses are the least mobile of the joint types.
Menisci of the knee
C shaped disks Prevent side to side rocking Medial and Lateral
3 common knee injuries
Collateral ligaments Cruciate ligaments Cartilages (menisci)
ulnar collateral ligament
Connects the medial epicondyle of the humerus to the ulna
chondromalacia patellae (CMP)
Damage and softening of the articular cartilages on the posterior patellar surface and the anterior surface of the distal femur; most often seen in adolescent athletes. Produces a sharp pain in the knee when the leg is extended (in climbing stairs, for example). May result when the quadriceps femoris, the main group of muscles on the anterior thigh, pulls unevenly on the patella, persistently rubbing it against the femur in the knee joint; often corrected by exercises that strengthen weakened parts of the quadriceps muscles.
plantar flexion and dorsiflexion (feet)
Dorsiflexion: Lifting the foot so that its superior surface approaches the shin Plantar Flexion: depressing the foot (pointing the toes)
synostoses
During middle age, the fibrous tissue ossifies and the skull bones fuse into a single unit
articular discs (menisci)
Fibrocartilage separates articular surfaces to improve "fit" of bone ends, stabilize joint, and reduce wear and tear
Autologous chondrocyte implantation
Healthy chondrocytes are removed from the body and seeded onto a supporting matrix of tissue-engineered collagen. When subjected to mechanical pressure in the lab, the cells produce new cartilage, which is then implanted.
Synovitis
Inflammation of the synovial membrane of a joint. Caused by injury, infection, or arthritis. Excess synovial fluid accumulates in the joint cavity, a condition called effusion that causes the joint to swell, limiting joint movement.
Bone marrow stimulation
Small holes poked through to the bone marrow allow mesenchymal stem cells from the bone marrow to migrate into the joint and produce new cartilage.
iliofemoral ligament (Y ligament)
Thick, strong ligament resembling an inverted Y Attaches proximally to anterior-superior aspect of acetabular rim, and distally to intertrochanteric line of femur Limits excessive extension of hip
Mesenchymal stem cell regeneration
Undifferentiated mesenchymal cells are removed from bone marrow and placed in a gel, which is packed into an area of eroded cartilage.
opposition movement
allows thumb to touch the tips of the fingers on the same hand (opposable thumb)
Lyme disease
an inflammatory disease caused by spirochete bacteria transmitted by the bite of ticks that live on mice and deer.
intracapsular ligaments of the knee
anterior cruciate ligament (ACL) posterior cruciate ligament (PCL)
arcuate popliteal ligament
arcs superiorly from the head of the fibula over the popliteus muscle and reinforces the joint capsule posteriorly
reinforcing ligaments of synovial joints
capsular, extracapsular, intracapsular
gliding movement of synovial joints
carpals, tarsals, vertebrae occurs when one flat, or nearly flat, bone surface glides or slips over another without appreciable angulation or rotation
ischiofemoral ligament
connects ischium to femur
Articular Surfaces
determines what movements are possible at a joint (minor role)
glenoid labrum
fibrocartilage ring that deepens glenoid cavity
Bursae
flattened fibrous sacs lined with synovial membrane and containing a thin film of synovial fluid - They occur where ligaments, muscles, skin, tendons, or bones rub together.
structural classification
focuses on the material binding the bones together and whether or not a joint cavity is present: fibrous, cartilaginous, and synovial joints
diarthroses (functional)
freely movable joints
Synchondroses (cartilaginous)
hyaline cartilage unites bones (epiphyseal) Virtually all synchondroses are synarthrotic (immovable).
Synarthroses (functional)
immovable joints
gouty arthritis (gout)
inflammation and painful swelling of joints caused by excessive uric acid in the body
Circumduction
is moving a limb so that it describes a cone in space (circum = around; duco = to draw). The distal end of the limb moves in a circle, while the point of the cone (the shoulder or hip joint) is more or less stationary.
Pannus
rheumatoid arthritis
supination and pronation of forearm
rotational movement, results in the palm facing upward/downward
Amphiarthroses (functional)
slightly movable joints
glenoid cavity
socket in scapular that receives head of humerus
oblique popliteal ligament
stabilizes posterior knee joint
glenohumeral ligaments (superior, middle, inferior)
strengthen the front of the capsule somewhat but are weak and may even be absent
dislocation (luxation)
the total displacement of a bone from its joint
Rheumatoid arthritis (RA)
chronic joint condition with inflammation and pain; caused by an autoimmune reaction against joint tissue, particularly the synovial membrane
Patellar ligament (tendon)
connects patella to tibia
pubofemoral ligament
connects pubis to femur
radial collateral ligament
connects the lateral epicondyle of the humerus to the radius
synovial joints
created where two bones articulate to permit a variety of motions
Prostheses
custom-built artificial limbs
arthritis
inflammation of a joint
The stability of a synovial joint depends chiefly on three factors:
- The shapes of the articular surfaces - The number and positioning of ligaments - Muscle tone
To what functional class do most fibrous joints belong?
Answer: Most fibrous joints are synarthroses (immovable).
APPLY Nick bent over to pick up a dime. What movement was occurring at his hip joint, at his knees, and between his index finger and thumb?
Answer: Nick's hip joint was flexed and his knees extended and his thumb was in opposition (to his index finger).
APPLY From an arthritis patient's history and physical examination, how would you determine if he or she might have OA or RA?
Answer: RA typically produces pain, swelling, and joint deformations that tend to be bilateral and crippling. OA patients tend to have pain, particularly on arising, which is relieved by gentle exercise, and enlarged bone ends (due to spurs) in affected joints. Affected joints may exhibit crepitus.
On the basis of movement allowed, which of the following joints are uniaxial? Hinge, condylar, saddle, pivot.
Answer: The hinge and pivot joints are uniaxial joints.
Of the five joints studied in more detail—hip, shoulder, elbow, knee, and temporomandibular—which two have menisci? Which act mainly as a uniaxial hinge? Which depend mainly on muscles and their tendons for stability?
Answer: The knee and temporomandibular joints have menisci. The elbow and knee each act mainly as a uniaxial hinge. The shoulder depends largely on muscle tendons for stability.
Generally speaking, what factor is most important in stabilizing synovial joints?
Answer: The muscle tendons that cross the joint are typically the most important factor in stabilizing synovial joints.
Name the category (according to its shape and movement allowed) of each of the synovial joints labeled a-d below.
Answer: The synovial joint categories are (a) ball-and-socket, (b) hinge, (c) pivot, and (d) condylar.
mandibular fossa of temporal bone
Articulates with the head of the mandible to form the temporomandibular joint. The mandible (lower jaw) joins with the skull at this site.
Ligaments
Connect bone to bone, the more ligaments a joint has, the stronger it is. a ligament can stretch only about 6% of its length before it snaps
Osteochondral grafting
Healthy bone and cartilage removed from one part of the body and transplanted to the injured joint.
articular cartilage of synovial joint
Glassy-smooth hyaline cartilage covers the opposing bone surfaces as articular cartilage. These thin (1 mm or less) but spongy cushions absorb compression placed on the joint and thereby keep the bone ends from being crushed.
General Structure of Synovial Joints
Have following basic features: 1. Articular cartilage 2. Joint cavity (synovial cavity) 3. Articular capsule 4. Synovial fluid 5. Reinforcing ligaments 6. Nerves and vessels
Inversion and Eversion of foot
Inversion: sole of foot faces medially Eversion: sole of foot faces laterally
temporomadibular joint (TMJ)
Jaw joint, is a modified hinge joint. At this joint, the condylar process of the mandible articulates with the inferior surface of the squamous part of the temporal bone
Nerves and blood vessels of synovial joints
Nerves detect pain; monitor joint position and stretch Capillary beds supply filtrate for synovial fluid
Range of motion allowed by synovial joints
Nonaxial—slipping movements only Uniaxial—movement in one plane Biaxial—movement in two planes Multiaxial—movement in or around all three planes
Muscle origin and insertion
Origin: is attached to the immovable (or less movable) bone Insertion: is attached to the movable bone
protraction and retraction of mandible
Protraction: is going out Retraction: is bringing in
Arthroplasty
Replacing a diseased joint with an artificial joint.
joint (articular) cavity
The joint cavity is a feature that is unique to synovial joints. It contains a small amount of synovial fluid. The joint cavity is a potential space because it is normally almost nonexistent, but can expand if fluid accumulates (as happens during inflammation).
articular capsule of synovial joint
The joint cavity is enclosed by a two-layered articular capsule, or joint capsule. The tough external fibrous layer is composed of dense irregular connective tissue that is continuous with the periostea of the articulating bones. It strengthens the joint so that the bones are not pulled apart. The inner layer of the joint capsule is a synovial membrane composed of loose connective tissue. Besides lining the fibrous layer internally, it covers all internal joint surfaces that are not hyaline cartilage. The synovial membrane's function is to make synovial fluid.
crepitus
a crackling or grating sound usually of bones
autoimmune disease
a disorder in which the body's immune system attacks its own tissues.
acetabular labrum of hip
a fibrocartilaginous rim attached to acetabulum which deepens the cavity. Fills up the inequality of surface bone; protects rim, helps keep head of femur from dislocating
synovial joints (diarthroses)
are those in which the articulating bones are separated by a fluid-containing joint cavity. This arrangement permits substantial freedom of movement, and all synovial joints are freely movable diarthroses. Nearly all joints of the limbs—indeed, most joints of the body—fall into this class.
functional classification
based on the amount of movement allowed at the joint. synarthroses, amphiarthrosis, diarthroses
fibrous joints
bones are joined by the collagen fibers of connective tissue. No joint cavity is present. most fibrous joints are immovable. Sutures, syndesmosis, gomphoses
tendon sheath
elongated bursa that wraps around a tendon
fatty pads of synovial joints
for cushioning between fibrous layer and synovial membrane or bone - this is only in select joints, such as the hip and knee joints
lateral patellar retinacula
one of three ligaments from patella to tibia; continuations of the tendon of the bulky quadriceps muscle of the anterior thigh
articular tubercle of temporal bone
front boundary of mandibular fossa
Sutures
immovable joints of the skull, The wavy articulating bone edges interlock, and the junction is completely filled by a minimal amount of very short connective tissue fibers that are continuous with the peri-osteum.
angular movements of synovial joints
increase or decrease the angle between two bones. These movements may occur in any plane of the body and include flexion, extension, hyperextension, abduction, adduction, and circumduction.
Bursitis
inflammation of a bursa and is usually caused by a blow or friction.
Tendonitis
inflammation of tendon sheaths, typically caused by overuse.
femoropatellar joint
intermediate between patella and inferior end of femur (this is plane joint)
ligament of the head of the femur
intracapsular ligament that runs from the acetabulum of the hip bone to the head of the femur
Tumor necrosis factor (TNF)
involved in the inflammation of autoimmune diseases - this drug can help to dramatically slow the course of RA
Extension
involves movement along the sagittal plane that increases the angle between the articulating bones and typically straightens a flexed limb or body part. Examples include straightening a flexed neck, body trunk, elbow, or knee
Hip (Coxal) Joint
is a ball-and-socket joint. It has a good range of motion, but not nearly as wide as the shoulder's range. Movements occur in all possible planes but are limited by the joint's strong ligaments and its deep socket.
Flexion
is a bending movement, usually along the sagittal plane, that decreases the angle of the joint and brings the articulating bones closer together. Examples: bending the head forward on the chest; bending the body trunk or the knee from a straight to an angled position
Gomphoses (fibrous)
is a peg-in-socket fibrous joint, the only example is the articulation of a tooth with its bony alveolar socket
Abduction
is movement of a limb away from the midline or median plane of the body, along the frontal plane. Raising the arm or thigh laterally is an example of abduction
Adduction
is the opposite of abduction, so it is the movement of a limb toward the body midline or, in the case of the digits, toward the midline of the hand or foot
Rotation
is the turning of a bone around its own long axis. It is the only movement allowed between the first two cervical vertebrae and is common at the hip and shoulder joints.
tibiofemoral joint (knee joint)
lateral and medial joints between condyles of femur and C shaped menisci of tibia (these are hinge joints)
Muscle tone (tonus)
low levels of contractile activity in relaxed muscles that keep the muscles healthy and ready to react to stimulation.
rotator cuff
part of the capsule of the shoulder joint - The Four Muscles of the rotator cuff: subscapularis, supraspinatus, infraspinatus, and teres minor
Subluxation
partial dislocation of a joint
fibular and tibial collateral ligaments
prevent lateral or medial rotation or flexion when knee is extended
lateral ligament of TMJ
prevents posterior displacement of the mandible
lateral excursion of mandible
right or left movement from the zero position. the mandible moves with a side-to-side movement
Arthrology
study of joints
cartilaginous joints
the articulating bones are united by cartilage. Like fibrous joints, they lack a joint cavity and are not highly movable. The two types of cartilaginous joints are synchondroses and symphyses.
syndesmoses (fibrous)
the bones are connected exclusively by ligaments (syndesmos = ligament), cords or bands of fibrous tissue. The amount of movement allowed at a syndesmosis depends on the length of the connecting fibers.
sprain
the ligaments reinforcing a joint are stretched or torn. Common sites of sprains are the ankle, the knee, and the lumbar region of the spine. Partially torn ligaments will repair themselves, but they heal slowly because ligaments are so poorly vascularized. Sprains tend to be painful and immobilizing.
Osteoarthritis (OA)
the most common chronic arthritis. A chronic degenerative condition, OA is often called "wear-and-tear arthritis." OA is most prevalent in the aged and is probably related to the normal aging process (although it is seen occasionally in younger people and some forms have a genetic basis). More women than men are affected, and nearly all of us will develop this condition by the age of 80.