Category: Joints

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Anatomy & Physiology: Joints—Synovial Joint Types.

 

Structure.

Plane joints.

• Biaxial diarthroses.
• Flattish or very slightly curved.
• Gliding types of planar movements (e.g. sideways or back and forth).
• May also rotate about.
• E.g. intercarpal (in wrist bones); intertarsal (ankle bones); sternoclavicular joint; acromionclavicular; vertebrocostal joints (ribs and transverse processes of thoracic vertebrae.

Hinge joints.

• Uniaxial diarthrosis.
• Like a hinge (door hinge); the bones “fit together” and “open-close” about a pivot point.
• Usually, one bone is “stationary” (like a door frame) while the other bone is the moving part (like the door).
• Rotational movement is about one axis.
• Flexion and extension.
• E.g. knee, elbow, ankle, interphalangeal joints of fingers and toes.

Pivot joints.

• Uniaxial diarthrosis.
• A rounded/pointy bone articulates with a “ring-like” structure formed by another bone and ligaments.
• Rotates about one axis.
• E.g. atlantoaxial joint (C1-C2); radioulnar joint (supinate-pronate).

Condyloid joints.

• Biaxial diarthrosis.
• Oval shaped end of one bone fits into the oval shaped depression of another.
• Movement about 2 axis: flexion-extension; abduction-adduction; very limited circumduction.
• E.g. wrist; metacarpophalangeal joints (II-V).

Saddle joints.

• Biaxial diarthrosis.
• One end of bone (concave) is shaped like a saddle and the other surface is convex and fits the saddle-shaped depression of the other bone.
• Movement about 3 axis: sideways; up-down; limited circumduction.

Ball and socket joints.

• Triaxial diarthrosis.
• Allows for the most movement.
• Movement about 3 axis: flexion-extension; abductio-adduction; rotations/circumduction.
• E.g. shoulder joint; hip joint.

 

Function.

 

 

Clinical Significance.

 

 

References

Biel, A. (2015). Trail guide to the body: A hands-on guide to locating muscles, bones and more.

Cedars-Sinai. (2018). Vertebrae of the spine. Retrieved from https://www.cedars-sinai.org/health-library/diseases-and-conditions/v/vertebrae-of-the-spine.html

Jenkins, G., & Tortora, G. J. (2012). Anatomy and Physiology: From Science to Life, 3rd Edition International Stu. John Wiley & Sons.

Muscolino, J. E. (2017). The muscular system manual: The skeletal muscles of the human body.

 

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Anatomy & Physiology: Joints—Ligaments.

 

Structure.

 

Shoulder.

• Articular capsule: thin loose sac lining that encompasses all the shoulder joint structures—glenoid cavity to anatomic neck of humerus.
• Coracohumeral ligament: ligament that runs from the coracoid process (scapula) to greater tubercle (humerus). It lies deep to the subacromial bursa, the coracoacromial ligament.
• Glenohumeral ligaments: 3 ligamentous bundles anterior and deep to the subacromial bursa and coracoacromial ligament. They run from the glenoid cavity to the lesser tubercle and anatomical neck of humerus. Stabilize shoulder near endpoints of ROM.
• Glenoid labrum: narrow strip of fibrocartilage around the perimeters of the glenoid cavity that provides a little deeper and more surface area for the socket.
• Bursae: reduce friction. There are 4: subscapular, subdeltoid, subacromial, and subcoracoid bursa.
• Acromioclavicular ligament.
• Coracoacromial ligament.
• Transverse humeral ligament.
• Coracoclavicular ligament.
  • Conoid ligament.
  • Trapezoid ligament.
• Superior transverse scapular ligament.

 

Elbow.

• Articular capsule: from humerus to ulna and anular ligament.
• Anular ligament: around the head of the radius. Posteriorly runs from capitulum, olecranon fossa, and lateral epicondyle of humerus; to anular ligament of radius, olecranon of ulna, and ulnar posterior and radial notch..
• Ulnar collateral ligament: from medial epicondyle of humerus to coronoid proces and olecranon of ulna.
• Radial collateral ligament: runs from lateral epicondyle of humerus to anular ligament of radius and ulnar radial notch.
• Anular ligament of radius: encircles radial head to help hold the radial head to ulnar radial notch.

 

Hip.

• Articular capsule: dense and strong; extending from edge of acetabulum to femoral neck. Articular capsule is strengthened by the bidirectional fibers: circular fibers zona orbicularis (like a collar around the neck); and longitudinal fibers.
• Iliofemoral ligament: runs from ilium of hip to intertrochanteric line of femur.
• Pubofemoral ligament: the part of the articular capsule that runs from the ischial wall of the acetabulum to femoral neck. Slacks: adduction. Tenses: abduction. Reinforces articular capsule.
• Ligament of femoral head: runs from the fossa of acetabulum to fovea capitis of femoral head.
• Acetabular labrum: a fibrocartilage rim around acetabulum to increase the depth and surface area of the hip socket to the head of femur can articulate.
• Transverse ligament of acetabulum: crosses over the inferior acetabulum and connects with ligament of femoral head and articular capsule.

 

Knee.

• Articular capsule.
• Medial and lateral patellar retinacula: fused band of tendons at the quadriceps femoris muscle and fascia lata (deep fascia) of thigh. Reinforces anterior of joint.
• Patellar ligament: from the tendon of quad femoris extending from the patella to tibial tuberosity. The infrapatellar fat pad separates this ligament from the synovial membrane.
• Oblique popliteal ligament: from lateral condyle of femur to head and medial tibial condyles. Reinforces posterior of joint.
• Arcuate popliteal ligament: from lateral condyle of femur to fibular head. Reinforces posterior of joint.
• Tibial collateral ligament: from the femoral medial condyle to tibial medial condyle. Reinforces medial area of joint. Attaches to menisus as well.
• Fibular collateral ligament: runs from femoral lateral condyle to fibular head. Reinforces lateral area of joint.
• Intracapsular ligaments: located within articular capsule; runs from femur to tibia.
• Cruciate ligaments (anterior and posterior): attached to tibia and cross over each other to the femural end.
  • Anterior cruciate ligament: runs from posterior to lateral; from the anterior tibial intercondylar area to the femoral medial surface of the lateral condyle. ACL limits ROM hyperextension and prevents anterior sliding dislocations.
  • Posterior cruciate ligament: runs from tibial posterior intercondylar area to femoral lateral area of medial condyle. Prevents sliding dislocations upon knee flexion.
• Articular discs (menisci): 2 discs made of fibrocartilage to pad out the bones.
  • Medial meniscus.
  • Lateral meniscus.
• Bursae.

 

Function.

 

 

Clinical Significance.

• Rotator cuff injury: usually a strain/tear of the rotator cuff muscles (esp. supraspinatus tendon).
• Dislocated shoulder: usually results from the displacement of the head of the humerus (usually inferiorly).
• Separated shoulder: usually where the scapular acromion is displaced from the clavicular acromial end from some kind of blow to that area or fall.
• Torn glenoid labrum: when the fibrocartilaginous labrum tears away from the glenoid cavity.

 

 

References

Biel, A. (2015). Trail guide to the body: A hands-on guide to locating muscles, bones and more.

Cedars-Sinai. (2018). Vertebrae of the spine. Retrieved from https://www.cedars-sinai.org/health-library/diseases-and-conditions/v/vertebrae-of-the-spine.html

Jenkins, G., & Tortora, G. J. (2012). Anatomy and Physiology: From Science to Life, 3rd Edition International Stu. John Wiley & Sons.

Muscolino, J. E. (2017). The muscular system manual: The skeletal muscles of the human body.

 

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Anatomy & Physiology: Joints—Example Joint List.

 

Structure.

Joint	Structural Classification	Functional Classification
Suture	Fibrous.	Amphiarthrosis & synarthrosis.
Atlanto-occipital	Synovial-condyloid.	Diarthrosis.
Atlanto-axial	Synovial-pivot betw. dens and anterior arch; synovial-planar betw. lateral masses.	Diarthrosis.
Intervertebral	Cartilaginous-symphasis betw. bodies; synovial betw. arches.	Amphiarthrosis; diarthrosis.
Vertebrocostal	Synovial-planar.	Diarthrosis.
Sternocostal	Cartilaginous-synchrondrosis betw. sternum & 1st pair; synovial-planar betw. sternum & 2nd to 7th pair.	Synarthrosis; diarthrosis.
Lumbosacral	Cartilaginous-symphysis betw. body & base; synovial-planar betw. articular facets.	Amphiarthrosis betw. body & base; diarthrosis betw. articular facets.
Sternoclavicular	Synovial planar, pivot.	Diarthrosis.
Acromioclavicular	Synovial-planar.	Diarthrosis.
Radioulnar	Synovial-pivot.	Diarthrosis.
Wrist (radiocarpal)	Synovial-condyloid.	Diarthrosis.
Intercarpal	Synovial-planar except for hamate, scaphoid, and lunate which are synovial-saddle.	Diarthrosis.
Carpometacarpal	Synovial-saddle at thumb; synovial-planar remaining digits.	Diarthrosis.
Metacarpophalangeal & metatarsophalangeal	Synovial-condyloid.	Diarthrosis.
Interphalangeal	Synovial-hinge.	Diarthrosis.
Sacroiliac	Synovial-planar.	Diarthrosis.
Pubic symphasis	Cartilaginous-symphasis.	Amphiarthrosis.
Tibiofibular	Synovial-planar proximally; fibrous-syndesmosis distally.	Diarthrosis proximally; amphiarthrosis distally.
Ankle (talocrural)	Synovial-hinge.	Diarthrosis.
Intertarsal	Synovial-planar at subtalar and calcaneocuboid; synovial-saddle at talocalcaneonavicular.	Diarthrosis.
Tarsometatarsal	Synovial-plane.	Diarthrosis.

Function.

 

 

Clinical Significance.

 

 

References

Biel, A. (2015). Trail guide to the body: A hands-on guide to locating muscles, bones and more.

Cedars-Sinai. (2018). Vertebrae of the spine. Retrieved from https://www.cedars-sinai.org/health-library/diseases-and-conditions/v/vertebrae-of-the-spine.html

Jenkins, G., & Tortora, G. J. (2012). Anatomy and Physiology: From Science to Life, 3rd Edition International Stu. John Wiley & Sons.

Muscolino, J. E. (2017). The muscular system manual: The skeletal muscles of the human body.

 

Download these notes.

Anatomy & Physiology: Joints.

 

Structure.

• Structural classification: based on whether or not there is space tween the articulating bones; type of connective tissue that holds the bones together.
  • Fibrous joints: no synovial cavity; dense collagen-fiber-rich connective tissue.
    • 3 types of fibrous joints: sutures, syndesmoses, & interosseous membranes.
    • Sutures: fibrous joint made of thin layer of dense connective tissue. Only occurs in skull bones. Strength from irregular and interlocking edges. In infants and young children the sutures are amphiarthrotic; in adults the sutures are fused and immoveable (synarthrotic).
      • Synostosis: suture present in infants/children but ossified in adults. Synarthrotic.
      • Frontal/metopic suture: if the suture exists past 6 yrs old.
    • Syndesmoses: fibrous joint with some distance between the two bones. Dense connective tissue arranged in bundles (ligamentous) limiting the joint movement. E.g. distal tibiofibular joint.
      • Gomphosis: peg fitting into a socket. E.g. teeth and teeth sockets (alveoli).
    • Interosseous membrane: sheet-like dense connective tissue between long bones; amphiarthrotic. E.g. between ulna and radius; between tibia and fibula.
  • Cartilaginous joints: no synovial cavity; cartilaginous connective tissue (hyaline or fibrocartilage).
    • Synchondroses: hyaline connective tissue. E.g. epiphyseal plate. Synarthrotic (immoveable).
    • Symphasis: ends of bones covered by hyaline cartilage with a broad flattish fibrocartilage connecting the bones. All symphsis occur in the body’s midline. E.g. pubic symphasis; sternal angle between the manubrium and sternal body; intervertebral joints between vertebral bodies.
  • Synovial joints: presence of synovial cavity; articular capsule with dense connective tissue and often accessory ligaments present. Diarthrotic (freely moving).
    • Bones covered with articular cartilage (a layer of hyaline) to reduce friction.
    • Articular (joint) capsule: sleevelike; encloses the joint cavity where the two bones articulate with each other. Has 2 layers: fibrous membrane (mostly collagen, dense) attaches to periosteum of bones; synovial membrane (inner membrane) of areolar connective tissue.
    • Articular fat pads: fatty pads act as cushioning.
    • Synovial fluid: lubrication and reduce friction. Clear and viscous. Fibroblast-like cells in synovial membrane secrete this hyaluronic acid. Also some fluid from blood plasma. Has phagocytic cells as “clean-up” crew.
    • Accesory ligaments.
    • Articular menisci: pads of fibrocartilage.
  • Functional classification: based on how much movement is allowed in a joint.
    • Synarthrosis: immoveable.
    • Amphiarthrosis: somewhat moveable.
    • Diarthrosis: freely moveable joint.
  • Bursae: fluid-filled sacs between skin-bones, tendons-bones, muscles-bones, or ligaments-bones.
  • Tendon sheaths: reduce friction at joints. Tubelike bursa wrap around tendons.

 

Function.

 

 

Clinical Significance.

 

 

 

References

Biel, A. (2015). Trail guide to the body: A hands-on guide to locating muscles, bones and more.

Cedars-Sinai. (2018). Vertebrae of the spine. Retrieved from https://www.cedars-sinai.org/health-library/diseases-and-conditions/v/vertebrae-of-the-spine.html

Jenkins, G., & Tortora, G. J. (2012). Anatomy and Physiology: From Science to Life, 3rd Edition International Stu. John Wiley & Sons.

Muscolino, J. E. (2017). The muscular system manual: The skeletal muscles of the human body.