BIO120 Anatomy and Physiology Essentials
Phase 4 Individual Project
3 May 2015
Features of synovial joints
There are 5 distinct feature of the synovial joint:
Encloses the joint cavity. The capsule is composed of dense irregular connective tissue and loose connective tissue
This is the space where a small amount of synovial fluid is kept.
Hyaline cartilage that covers the opposing bone surface. Spongy cartilage is placed on the joint and keeps the bone ends from being crushed
Lubricating fluid that reduces friction between the articular cartilage during movement.
Surrounds the joint to give it extra strength. There are 3 types of these ligaments: intrinsic, extrinsic and intracapsular ligaments.
(Marieb & Hoehn, 2007)
Images of ligaments that support the
Image of ligaments (cont)
Anterior cruciate ligament (ACL)
The function of the ACL is to provide stability to the
knee and minimize stress to the knee joint.
It is one of the most important ligament of the knee that
connects the bones together.
It restrains excessive forward movement of the tibia in
relation to the femur.
It also limits rotational movement of the knee.
This ligament is often the one injured during knee
Posterior cruciate ligament (PLC)
This ligament is the strongest of the 4 ligaments.
The PCL’s primary function is to prevent forward
displacement of the femur and backwards displacement
of the tibia.
It also prevents hyper-flexion of the knee.
Injuries can occur many different way. One can be by
backwards force applied to the front of the lower leg
just below the knee while the knee is flex, sever
hyperextension of the knee and forced hyper-flexion.
Injuries to the PCL are far less common than those to
Medial collateral ligament (MLC) &
Lateral collateral ligament (LCL)
These ligaments are found on the sides of the joint.
They provide side to side stability of the joint.
The MCL is a broader ligament where as the LCL is a
cord like ligament.
MCL tears are common but fortunately are more often
Grade I (slight stretching) or II (partial disruption. They
usually result from a twist or any mechanism that forces
the foot out and the knee in.
Isolated LCL injuries are infrequent with the
mechanism of injury being the opposite of an MCL
(Centers for Orthopedics, 2014)
Difference between an ankle joint and a knee
The ankle joint is a plane joint. It allows the joint to
move up and down as well as side to side.
The knee joint is a hinge joint. This joint only moves
back and forth.
Most common ligament injury in your ankle
The most frequent injury involves the anterior
talofibular ligament, posterior talofibular ligament and
the calcaneofibular ligament.
These ligaments are usually involved in ankle sprains
(Massachusetts General Hospital, 2003)
Centers for Orthopaedics. (2014). Knee Ligament Anatomy. Retrieved from: http://www.orthoassociates.com/SP11B41/
EhealthMD. (2014, Oct 23). What is the Anterior Cruciate Ligament. Retrieved from: http://ehealthmd.com/acl-tears/what-anterior-cruciate-ligament#axzz3Z0Hp4wI9 HowStuffWorks. (2014). Types of Joints. Retrieved from:
http://health.howstuffworks.com/human-body/systems/musculoskeletal/bone11.htm Marieb, E. N., & Hoehn, K. (2007). Human Anatomy & Physiology (7th ed., p. 255-256). San Francisco: Pearson Benjamin Cummings.
Massachusetts General Hospital(2013, July). Ankle Sprains. Retrieved from: http://www2.massgeneral.org/ortho/Pediatric_Ankle_Sprains.htm UW Health. (2015, April 30). About the Posterior Cruciate Ligament. Retrieved from:...
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