Chapter 8, Section 1. Joints. Joints, also called articulations , are functional junctions between two bones. The science of joints is called arthrology . Functions of joints Bind skeleton together Enable body movements Makes growth possible
between two bones
The science of joints is called arthrology.
Functions of joints
Bind skeleton together
Enable body movements
Makes growth possible
Permit changes in skeleton for childbirth
Classifications based on amount of movement
Synarthrotic = immovable
Amphiarthrotic = slightly moveable
Diarthrotic = fully movable
Classifications by types of tissue:
Fibrous joint = dense connective tissue
Cartilaginous joint = bones connected by cartilage
Synovial joint = contains a synovial membrane
Interosseous membrane between tibia and fibula is a syndesmosis joint.
Synovial Joints are Freely movable (Diarthrotic)
Figure 8.7 The generalized structure of a synovial joint.
Figure 8.8 Menisci separate the articulating surfaces of the femur and tibia. Several bursae are associated with the knee joint.
End of Chapter 8, Section 1
Types of Joint Movements
Movement at a joint occurs when a muscle contracts and its fibers pull its moveable end (insertion) towards its fixed end (origin).
Abduction = movement away from the midline
(think of someone being abducted, or taken away)
Adduction = movement towards the midline
(think of adding together)
Supination = turning the hand so the palm faces upward or anteriorly
Example: turning a doorknob clockwise with your right hand.
Pronation = turning the hand so the palm faces downward or posteriorly
Dorsiflexion = movement at the ankles that points toes towards the sky
Plantar flexion = movement at the ankles that points toes towards the ground
Eversion = turning the foot so the planter surface faces laterally
Inversion = turning the foot so the plantar surface faces medially
End of Chapter 8, Section 2
The Knee Joint and Joint Disorders
The knee joint is the largest and most complex synovial joint in body.
Two distal condyles of the femur articulate with two proximal condyles of the tibia. This is a condylar joint.
The femur also articulates anteriorly with the patella. This is a plane joint.
General structures of a synovial joint in the knee
Several ligaments and tendons strengthen the knee joint.
Patellar tendon - The patella is partially enclosed in tendons fused together from the thigh muscle.
Patellar ligament – continuation of patellar tendon. Extends from patella to the tibialtuberosity.
Tibial collateral ligament – connects medial condyle of femur with medial condyle of tibia.
Fibular collateral ligament – connects lateral condyle of femur with head of fibula.
Anterior & Posterior Cruciate ligaments – provide additional support to medial surface of tibia and femur
Figure 8.21a Anterior right knee with patella removed.
Two menisci (medial & lateral meniscus) separate the femur and tibia, and align them.
Figure 8.20 (a) sagittal section of the knee joint.
(b) Photograph of the left knee joint (frontal section)
Three major bursae surround the knee joint.
Sprain = overstretching or tearing of connective tissue (tendons, ligaments, or cartilage) associated with a joint.
However, the bones are not disarticulated.
Arthritis = inflamed, swollen, and painful joints.
Osteoarthritic fingers often take on a gnarled appearance.
Knuckles may swell as a result of rheumatoid arthritis.
End of Chapter 8, Section 3