Chapter 8: Joints of the Skeletal
are also called articulations.
bind parts of the skeletal system, make possible bone growth, permit parts of the skeleton to change shape during childbirth
and enable the body to move in response to skeletal muscle contractions.
1. Three general groups
of joints are fibrous, cartilaginous, and synovial.
can also be grouped according to the degree of movement possible at the bony junctions.
joints are called synarthrotic.
movable joints are called amphiarthrotic.
movable joints are called diarthrotic.
joints are so named because the dense connective tissue holding them together contains many collagenous fibers.
three types of fibrous joints are syndesmosis, suture, and gomphosis.
3. In syndesmois,
bones are bound together by long fibers of connective tissue that form an interosseous ligament.
4. An example
of a syndesmosis is at the distal ends of the tibia and fibula, where they join to form the tibiofibular articulation.
a syndesmosis permits slight movement, it is called amphiarthrotic.
are only between flat bones of the skull.
7. A sutural
ligament is thin layer of dense connective tissue that joins flat bones of the skull together.
allow the skull to change shape slightly during childbirth.
9. An example
of a suture is the parietal suture.
sutures are immovable, they are called synarthrotic.
11. A gomphosis
is a joint formed by the union of a cone-shaped bony process in a bony socket.
12. A periodontal
ligament is a structure that firmly attaches a tooth to the jaw.
example of a gomphosis is a tooth in a socket.
of cartilaginous joints are joined by hyaline cartilage or fibrocartilage.
types of cartilaginous joints are synchondroses, and symphyses.
3. In a
synchondrosis, bands of hyaline cartilage unite bones.
synchondroses are temporary structures and disappear during growth.
examples of synchondroses are epiphyseal plates and the joint between the first rib and manubrium.
do not permit movement and are therefore synarthrotic.
7. In a
symphysis, the articular surfaces of bones are covered with a thin layer of hyaline cartilage and the cartilage is attached
to a pad of springy fibrocartilage.
examples of symphyses are the symphysis pubis and intervertebral joints.
joints are synovial.
joints allow free movement and are called diarthrotic.
joints consist of articular cartilage, a joint capsule, and a synovial membrane
Structure of a Synovial Joint
cartilage is a thin layer of hyaline cartilage that covers the ends of bones.
joint capsule is a tubular structure that holds together the bones of a synovial joint.
outer layer of the joint capsule consists of dense connective tissue.
inner layer of the joint capsule consists of a synovial membrane.
reinforce the joint capsule.
synovial membrane is a shiny, vascular layer of loose connective tissue.
fluid comes from the synovial membrane.
secreting synovial fluid, the synovial membrane may also store adipose tissue and form movable fatty pads with the joint.
fluid has a consistency of uncooked egg white and functions to moisten and lubricate the smooth cartilaginous surfaces within
are discs of fibrocartilage.
function to cushion articulating surfaces.
are fluid filled sacs associated with synovial joints.
are located between the skin and underlying bony prominences.
function to cushion and aid the movement of tendons that glide ofver bony parts of over other tendons.
names of bursae reflect locations.
IV. Types of
six major types of synovial joints are ball-and-socket, condyloid, gliding, hinge, pivot, and saddle.
ball-and-socket joint consists of a bone with a globular head that articulates with a cup-shaped cavity of another bone.
ball-and-socket joint allows a wider range of motion than any other type of joint.
of ball-and-socket joints are the hip joint and shoulder joint.
structure of a condyloid joint is an ovoid condyle of one bone fitting into the elliptical cavity of another bone.
example of a condyloid joint is between the metacarpals and phalanges.
articulating surfaces of gliding joints are nearly flat or slightly curved.
of gliding joints are joints within the wrists and ankles.
structure of a hinge joint is a convex surface of one bone fitting into the concave surface of another bone.
example of a hinge joint is the elbow joint.
structure of a pivot joint is a cylindrical surface of one bone rotating within a ring formed of bone and fibrous tissue of
of pivot joints are the joint formed between the proximal ends of the radius and ulna, and the joint between the dens of the
axis and ring of the atlas.
structure of a saddle joint is a convex surface of one bone articulating with a concave surface of another bone.
example of a saddle joint is the joint between the trapezium and the metacarpal of the thumb.
V. Types of Joint
insertion of a muscle is its movable end.
origin of a muscle is its fixed end.
is bending of a body part.
is straightening of a body part.
is excess extension of a body part beyond the anatomical position.
is bending of the foot at the ankle upward.
flexion is the bending of the foot downward at the ankle.
is moving a part away from the midline of the body.
is moving a part toward the midline of the body.
is moving a body part around an axis; also known as twisting.
is moving a body part in a circular path.
is turning the palm of the hand up.
is turning the palm of the down.
is turning the sole of the foot laterally.
is turning the sole of the foot medially.
is moving a body part forward.
is moving a body part backward.
is raising a body part.
is lowering a body part.
of Synovial Joints
shoulder joint is a ball-and-socket joint that consists of the rounded head of the humerus and the shallow glenoid cavity
of the scapula.
shoulder joint capsule is very loose.
and tendons reinforce the shoulder joint capsule.
four ligaments that help prevent displacement of the shoulder joint are coracohumerual, glenohumeral, transverse humeral,
and the glenoid labrum.
coracohumeral ligament strengthens the superior portion of the joint capsule.
glenohumeral ligament extends from the edge of the glenoid cavity to the lesser tubercle and the anatomical neck of the humerus.
transverse humeral ligament runs between the lesser and the greater tubercles of the humerus.
glenoid labrum functions to deepen the glenoid cavity.
four major bursae associated with each shoulder joint are subscapular, subdeltoid, subacromial, and subcoracoid.
shoulder joint is capable of a wide range of movement due to the looseness of its attachments and the relatively large atricular
surface of the humeurs compared to the shallow depth of the glenoid cavity.
articulations of the elbow joint are a hinge joint between the trochlea of the humerus and the trochlear notch of the ulna
and a gliding joint between the capitulum of the humerus and a shallow depression on the head of the radius.
ulnar collateral ligament is located on the medial wall of the capsule.
ulnar collateral ligament attaches the medial epicondyle of the humerus to the medial margin of the coronoid process of the
ulna; it also attaches the medial epicondyle of the humerus to the olecranon process of the ulna.
radial collateral ligament is located between the lateral epidondyle of the humerus and the annular ligament of the radius.
radial collateral ligament strengthens the lateral wall of the joint capsule.
pads of the elbow joint protect nonarticular bony areas during joint movements.
only movements that occur at the elbow joint are flexion and extension.
1. The hip joint is
a ball-and-socket joint.
hip joint consists of the head of the femur and the cup-shaped acetabulum.
acetabular labrum is a ring of fibrocartilage and functions to deepen
the cavity of the acetabulum.
major ligaments of the hip joint are iliofemoral, pubofemoral, and ischiofemoral.
iliofemoral ligament attaches the anterior inferior iliac spine to the intertrochanteric line.
pubofemoral ligament extends between the superior portion of the pubis and the iliofemoral ligament.
ischiofemoral ligament connects the ischium to the joint capsule.
hip joint has less freedom of movement than the shoulder joint.
surround the capsule of the hip joint.
largest and most complex of the synovial joints is the knee joint.
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.
femur articulates with the patella anteriorly.
knee functions as a modified hinge joint.
articulation between the femur and tibia is a condyloid joint.
articulation between the femur and patella is a gliding joint.
knee joint is greatly strengthened by ligaments and tendons of several large muscles.
5 ligaments of the knee joint are patellar, oblique popliteal, arcuate, tibial collateral, and fibular collateral.
patellar joint extends from the margin of the patella to the tibial tuberosity.
oblique popliteal ligament connects the lateral condyle of the femur to the margin of the head of the tibia.
arcuate popliteal ligament connects the lateral condyle of the femur to the head of the fibula.
12. The tibial collateral ligament connects the medial condyle of the femur to the medial
condyle of the tibia.
fibular collateral ligament connects the lateral condyle of the femur to the head of the fibula.
ligaments within the knee joint are called cruciate ligaments.
anterior cruciate ligament connects the anterior intercondylar area of the tibia to the lateral condyle of the femur.
posterior cruciate ligament connects the posterior intercondylar area of the tibia to the medial condyle of the femur.
menisci separate the articulating surfaces of the femur and tibia.
bursae associated with the knee joint are suprapatellar, prepatellar, and infrapatellar.
in collagen lie behind joint stiffness.
fibrous joints are the first to change.
that connect epiphyses to diaphyses in long bones disappear as the skeleton grows.
lose their elasticity as collagen fibers become more tightly cross-linked.
the intervertebral discs, less water diminishes the flexibility of the vertebral column and impairs the ability of the discs
to absorb shocks.
of function of synovial joints begins in the third decade of life.
capillaries serving the synovial membrane slow the circulation of synovial fluid, and the membrane may become infiltrated
with fibrous material and cartilage.