Anatomy Ch 8 - Joints

Explain the function of synovial fluid

Helps to cushion, moisten, and lubricate the smooth cartilaginous surfaces within the joint. It also supplies the articular cartilage with nutrients.

anterior cruciate ligament ACL

originates from the anterior intercondylar area of the tibia and extends to the lateral condyle of the femur

What factors allow an especially wide range of motion in the shoulder?

Due to the looseness of its attachments and the large articular surface of the humerus compared to the shallow depth of the glenoid cavity.

What is the function of the synovial fluid?

It moistens and lubricates the smooth cartilaginous surfaces of the joint. It also helps supply articular cartilage with nutrients obtained from blood vessels of the synovial membrane.

Describe the major ligaments associated with the knee joint

Patellar ligament Oblique popliteal ligament arcuate popliteal ligament tibial collateral ligament fibular collateral ligament anterior cruciate ligament posterior cruciate ligament

Which parts help keep together the articulating surfaces of the shoulder joint?

The coracohumeral ligament is composed of a broad band of connective tissue that connects the coracoid process of the scapula to the greater tubercle of the humerus. The glenohumeral ligament include three bands of fibers that appear as thickenings as in the ventral wall of the joint capsule. The transverse humeral ligament consists of a narrow sheet of connective tissue fibers that runs between the lesser and greater tubercles of the humerus.

Which parts of the elbow permit pronation and supination of the hand?

The head of the radius is free to rotate in the annular ligament. This movement allows pronation and supination.

Name the parts that comprise the hip joint

The hip joint consists of the head of the femur and the cup-shaped acetabulum of the coxal bone

Based upon your knowledge, which do you think could be more satisfactorily replaced by a prosthetic device- a hip joint or a knee joint? Why?

The hip joint could be more satisfactorily replaced. The socket of the hip joint is deeper, its ligaments are larger and stronger, and it is surrounded by muscles. It also does not bear as much weight as the knee joint.

Name the parts that comprise the knee joint

The knee joint consists of the medial and lateral condyles at the distal end of the femur, and the medial and lateral condyles at the proximal end of the tibia. The femur also articulates anteriorly with the patella.

Explain the function of the menisci of the knee

The menisci serve as shock absorbers. They also function to compensate for the differences in shapes between the surfaces of the femur and tibia.

Describe the movements permitted by the elbow joint

The only movements permitted between the humerus and ulna is flexion and extension. The head of the radius, however, is free to rotate in the annular ligament, which allows pronation and supination of the hand.

Explain the function of a synovial membrane

The synovial membrane covers all surfaces within the joint capsule, except the areas the articular cartilage covers. It fills spaces and irregularities within the cavity. It secretes synovial fluid. It may store adipose tissue. It also reabsorbs the synovial fluid.

Describe how joints are classified:

The type of tissue that binds the bones together at each junction can classify joints. They can also be classified according to the degree of movement possible at the bony junctions.

adduction

moving part toward midline

How are joints classified?

They can be classified structurally by the type of tissue that binds the bones at each junction (fibrous, cartilaginous, and synovial). Can also be grouped functionally according to the degree of movement possible at the bony junctions.

Describe how movement occurs at a joint when a muscle contracts.

When the muscle contracts, its fibers pull its movable end (insertion) toward its fixed end (origin), and a movement occurs at the joint.

What are the 6 main parts of a synovial joint?

articular cartilage joint capsule synovial fluid ligaments menisci bursae

tibial collateral ligament (medial collateral ligament)

connects the medial condyle of the femur to the medial condyle of the tibia

posterior cruciate ligament PCL

connects the posterior intercondylar area of the tibia to the medial condyle of the femur

Patellar ligament

continuation of a tendon from the quadriceps muscle group that extends from the margin of the patella to the tibial tuberosity

Name the parts that comprise the elbow joint

trochlea of humerus trochlear notch of the ulna capitulum of the humerus fovea on the head of radius

extension

increasing the angle between parts

Joint movements occur when a muscle contracts and the muscle fibers pull the muscle's more movable end of attachment, the _____, toward its less movable or relatively fixed end, the _____.

insertion, origin

Name the major ligaments associated with the shoulder joint

-Coracohumeral ligament: connects the coracoid process of the scapula to the greater tubercle of the humerus -glenohumeral ligament: three binds of fibers that appear as thickenings in the ventral wall of the joint capsule and extend from the edge of the glenoid fossa to the lesser tubercle and the anatomical neck of the humerus. -transverse humeral ligament: runs between the greater and lesser tubercles of the humerus -glenoidal labrum: attached along the margin of the glenoid fossa and forms a rim with a thick free edge that deepens the fossa.

Describe the movements permitted by each type of synovial joint

1. ball and socket- movement in all planes, as well as rotational movement around a central axis 2. condyloid- variety of movement in different planes, but rotational movement is possible 3. gliding- sliding back and forth motion only 4. hinge- flexion and extension in one plane only 5. pivot- rotation around a central axis only 6. saddle- variety of movements

Describe the structure of a synovial joint.

Articular ends of the bones are covered with a thin layer of hyaline cartilage (articular cartilage). A tubular joint capsule (articular capsule) that has two distinct layers hold together the bones of a synovial joint.

Name the parts that compose the shoulder joint

Consists of the head of the humerus and the glenoid cavity of the scapula

Explain why the shoulder joint permits a wide range of movements

Permits a wide range of movements due to the looseness of its attachments and the relatively large articular surface of the humerus compared to the shallow depth of the glenoid fossa, the movements include flexion, extension, abduction, adduction, rotation, and circumduction.

What is the function of an intervertebral disc?

The disc absorbs shocks and helps equalize pressure between the vertebrae when the body moves.

Compared to the shoulder and hip joints, in what ways is the knee joint especially vulnerable to injuries?

The shoulder and hip joints are ball-and-socket joints which the heads of the humerus and femur respectively fit into and are protected by bony sockets. These sockets, in turn, are surrounded by joint capsules, ligaments, and muscles that protect against injuries. The knee joint is of the condyloid and hinge types, has shallow articular surfaces, and is protected only by ligaments, thus making it more susceptible to injuries.

What is the function of fontanels?

allow the skull to change shape slightly during childbirth.

Fibular collateral ligament (lateral collateral ligament)

connects the lateral condyle of the femur and the head of the fibula

oblique popliteal ligament

connects the lateral condyle of the femur to the margin of the head of the tibia

flexion

decreasing angle between parts

arcuate popliteal ligament

extends from the lateral condyle of the femur to the head of the fibula

What types of movement does the hip joint permit?

flexion, extension, adduction, abduction, rotation, and circumduction

What terms describe movements at synovial joints?

flexion, extension, hyperextension, dorsiflexon, plantar flexion, abduction, adduction, rotation, circumduction, supination, pronation, eversion, inversion, protraction, retraction, elevation, depression

depression

lowering a part

rotation

moving part around an axis

abduction

moving part away from midline

protraction

moving part forward

A _____ is a fibrous joint with bones bound by long connective fibers, whereas a ____ is a fibrous joint where flat bones are united by a thin layer of connective tissue.

syndesmosis, suture

pronation

turning palm downward

eversion

turning the foot so the plantar surface faces laterally

supination

turning the palm upward

Describe how the articular surfaces of the hip joint are held together

-acetabular labrum: horseshoe-shaped ring of fibrocartilage at the rim of the acetabulum deepens the acetabular cavity and encloses the head of the femur -Iliofemoral ligament: connects the anterior inferior iliac spine of the coxal bone to the intertrochanteric line between the greater and elsser trochanters of the femur -pubofemoral ligament: extends between the superior portion of the pubis and the iliofemoral ligament -ischiofemoral ligament: originates on the ischium just posterior to the acetabulum and blends with the fibers of the joint capsule

Name the major ligaments associated with the elbow joint

-radial collateral ligament: connects the lateral epicondyle of the humerus to the annular ligament of the radius -annular ligament: connects the margin of the trochlear notch of the ulna and encircles the head of the radius -ulnar collateral ligament: connects the medial epicondyle of the humerus to the medial margin of the cornoid process. It also connects posteriorly to the medial epicondyle of the humerus and to the olecranon process of the ulna.

Describe the locations of the bursae associated with the knee joint

-suprapatellar bursa: located between the anterior surface of the distal end of the femur and the quadriceps muscle group above it. -prepatellar bursa: located between the patella and the skin -infrapatellar bursa: located between the proximal end of the tibia and the patellar ligament

Name six types of synovial joints and their structure

1. ball and socket (spheroidal): consists of a bone with a globular or egg shaped head that articulates with the cup shaped cavity of another bone 2. condylar (ellipsoidal): the ovoid condyle of one bone fits into the elliptical cavity of another bone 3. plane (gliding): articulating surfaces are nearly flat or slightly curved. 4. hinge: the convex surface of one bone fits into the concave surface of another. 5. pivot (trochoid): cylindrical surface of one bone rotates in a ring formed of bone and a ligament 6. saddle (sellar): forms between bones whose articulating surfaces have both concave and convex regions.

Describe the six types of synovial joints, and name an example of each

1. ball-and-socket- hip joint, shoulder joint 2. condyloid- joints between the metacarpals and phalanges 3. gliding- joints between the various bones of the wrist and ankle 4. hinge- elbow and knee joint 5. pivot- joint between the proximal end of the radius and ulna 6. saddle- joint between the carpal and metacarpal of the thumb

Which structures help keep the articulating surfaces of the hip together?

1. iliofemoral ligament: consists of a Y shaped band of strong fibers that connects the anterior inferior iliac spine of the hip bone to a bony line extending between the greater and lesser trochanters of the femur. Strongest in body. 2. pubofemoral ligament: extends between the superior portion of the pubis and the iliofemoral ligament. 3. ischiofemoral ligament: consists of a band of strong fibers that originates on the ischium just posterior to the acetabulum and blends with the fibers of the joint capsule

Which parts help hold together the articulating surfaces of the knee?

1. patellar ligament 2. oblique popliteal ligament 3. arcuate popliteal ligament 4. tibial collateral ligament 5. fibular collateral ligament

Describe two types of cartilaginous joints

1. synchondrosis: bands of hyaline cartilage unite the bones. Temporary structures. EX: epiphyseal plate. Synarthrotic. EX: between manubrium and first rib 2. symphysis: articular surfaces are covered by a thin layer of hyaline cartilage, and the bones are connected by a pad of fibrocartilage. EX: pubic symphysis, intervertebral disc. amphiarthrotic.

Describe three types of fibrous joints

1. syndesmosis: bones are bound by a sheet (interosseous membrane) or bundle of dense connective tissue (interosseous ligament). Flexible and may be twisted, amphiarthrotic. Between tibia and fibula. 2. Sutures: are only between flat bones of the skull, united by a thin layer of dense connective tissue called a sutural ligament. Synarthrotic. 3. Gomphosis: formed by the union of a cone shaped bony process in a bony socket. Synarthortic.

Define meniscus

A disk of fibrocartilage that occurs in some synovial joints dividing them into two compartments. It serves as a shock absorber and allows bony prominences to fit together easier.

Devine bursa

A fluid filled sac associated with freely moveable joints.

What structures form the hinge joint of the elbow?

A hinge joint between the trochlea of the humerus and the trochlear notch of the ulna and a plane joint between the capitulum of the humerus and a shallow depression (fovea) on the head of the radius. The ulnar collateral ligament, a thick band of dense connective tissue, is located in the medial wall of the capsule. The radial collateral ligament strengthens the lateral wall of the joint capsule, is a fibrous band extending between the lateral epicondyle of the humerus and the annular ligament of the radius.

Describe a gomphosis, and name an example:

A joint formed by the union of a cone-shaped bony process in a bony socket. The peg-like root of a tooth fastened to a jawbone by a periodontal ligament is such a joint.

Compare the structures of a synchondrosis and a symphysis

A synchondrosis uses bands of hyaline cartilage to unite to bones. Many of these joints are temporary structures that disappear during growth. Allows no movement. A symphysis has the articular surfaces of bones covered with hyaline cartilage that is attached to a pad of fibrocartilage. Allows limited movement.

Explain how the joints between vertebrae permit movement

Between each pair of vertebrae there is an intervertebral disk that is composed of a band of fibrocartilage that surrounds a gelatinous core. The disk absorbs shocks and helps equalize pressure between the vertebrae during body movement. As each disk is slightly flexible, the combined movements of many of the joints in the vertebral column allow the back to bend forward, to side, or to twist.

Describe the process of aging as it contributes to the stiffening of fibrous, cartilaginous, and synovial joints

Joint stiffness is often the earliest sign of aging. -Collagen changes cause the feeling of stiffness -Regular exercise can lessen the effects -Fibrous joints are the first to begin to change and strengthen over a lifetime -Synchondroses of the long bones disappear with growth and development. -Changes in symphysis joints of the vertebral column diminish flexibility and decrease height. -Over time, synovial joints lose elasticity.

Describe the loss of function in synovial joints as a progressive process.

Joint stiffness is often the earliest sign of aging. Collagen changes cause the feeling of stiffness. Regular exercise can lessen the effects. Fibrous joints are the first to begin to change and strengthen over a lifetime. Synchondroses of the long bones disappear with growth and development. Changes in symphysis joints of the vertebral column diminish flexibility and decrease height. Over time, synovial joints lose elasticity.

What types of joints are in the knee?

Largest and most complex synovial joint. -Modified hinge joint between the condyles of the femur and tibia -Plane joint between the femur and patella.

How would you explain to an athlete why damaged joint ligaments and cartilages are so slow to heal following an injury?

Ligaments are comprised of dense fibrous connective tissue, which has a poor blood supply. Cartilage is a rigid type of connective tissue that lacks a direct blood supply, resulting in slow cellular respiration and slow healing.

Describe how a joint capsule may be reinforced.

Ligaments are used to bind the articular ends of bones together reinforcing the joint capsule. These can be thickenings in the fibrous layer of the joint capsule or accessory structures that are located outside of the joint capsule.

How would you explain to a person with a dislocated shoulder that the shoulder is likely to become more easily dislocated in the future?

Ligaments holding the articulating surfaces of the shoulder together are rather weak. Dislocating the shoulder would stretch or strain these ligaments, further weakening them, making future dislocations more likely.

Explain why there is less freedom of movement in the hip joint than in the shoulder joint

Muscles surround the joint capsule of the hip. The articulating parts of the hip are held more closely together than those of the shoulder, allowing considerably less freedom of movement.