Download Lecture 1 – Anatomy Basics

Biology 218 – Human Anatomy
Clemens
Joints (Articulations)
Text: Chapter 9
Learning Objectives
1.
2.
3.
4.
Characterize the major structural types of joints.
Describe the structure of a synovial joint.
Identify different types of synovial joints and movements at these joints.
Compare the structures of the shoulder, hip, and knee joints and discuss features
that help to stabilize these joints.
A. Structural Types of Joints
1. Fibrous joints
a. suture
b. syndesmosis
2. Cartilaginous joints
a. symphysis
b. synchondrosis
3. Synovial joints
Functional classification of joints:
1. synarthrosis - immovable or slightly movable
(fibrous and cartilaginous joints)
2. diarthrosis - freely movable
(most synovial joints)
B. Structure of a Synovial Joint
1.articular capsule
a. fibrous membrane (dense reg. CT)
b. synovial membrane (areolar CT)
2. synovial cavity
contains synovial fluid
3. articular cartilage (hyaline cartilage)
:
Supporting structures:
ligaments
tendons
bursae
tendon sheaths
C. Types of Synovial Joints
planar
(carpals, tarsals, articular facets of vertebrae)
hinge
(ulna-humerus, interphalangeal joints)
pivot
(radius-ulna, atlas-axis)
condyloid
(metacarpal-phalangeal joints, radius-carpal joint)
saddle
(trapezium-1st metacarpal)
ball & socket (shoulder joint, hip joint)
D. Movements at Joints
flexion / extension
abduction / adduction
circumduction
medial rotation / lateral rotation
elevation / depression
protraction / retraction
pronation / supination
dorsiflexion / plantar flexion
Biology 218 – Human Anatomy
Clemens
E. Examples of Major Joints
1. Shoulder Joint
glenohumeral joint: head of humerus ↔ glenoid cavity of scapula
- shallow ball and socket - high mobility, less stability
- muscular stabilizers:
rotator cuff muscles: subscapularis, supraspinatus, infraspinatus, teres minor
act as “dynamic ligaments” to stabilize shoulder joint in different positions
long head of biceps brachii muscle - holds head of humerus in glenoid cavity
subacromial bursa - cushions narrow space containing tendons under acromion
2. Hip Joint
coxal joint: head of femur ↔ acetabulum of hip bone
- deep ball and socket - more stable than shoulder joint
- reinforcing ligaments: iliofemoral, pubofemoral, ischiofemoral ligaments
3. Knee Joint
tibiofemoral joint: medial & lateral condyles of femur ↔ proximal end (condyles) of tibia
- functions as a hinge joint
- fit between articular surfaces is somewhat unstable
- many supporting structures help to stabilize and cushion the knee
patella and patellar ligament - insertion of quadriceps muscles; stabilizes anteriorly
tibial (medial) collateral ligament
} stabilize medial-lateral motion
fibular (lateral) collateral ligament
medial meniscus
} stabilize articular surfaces, absorb shock
lateral meniscus
anterior cruciate ligament (ACL)
} stabilize anterior-posterior motion
posterior cruciate ligament (PCL)
bursae (several)
Study Questions
1. What are the three main structural types of joints? Give an example of a specific
location for each type in the body.
2. Describe and diagram the structure of a synovial joint. Label the components of
the synovial joint and know the specific tissues that form each structure.
3. Know the general structure and at least one specific location for each of the
following types of synovial joints: planar, hinge, pivot, condyloid, ball and socket.
4. Describe accessory structures associated with synovial joints including ligaments,
bursae, tendon sheaths, and menisci. Know the general functions of these
structures and identify a specific example of each of these structures in the body.
5. Describe the major structures that stabilize the shoulder joint and the knee joint.
Know examples of common shoulder and knee injuries that pertain to these
structures (for example, dislocated shoulder, torn meniscus, torn ACL).