Joints of the Skeletal System

Joints Functions Childbirth Movement Bone growth possible

Classification of Joints - Function **How much movement they allow** Synarthrotic joints Immovable Amphiarthrotic joints Slightly movable Diarthrotic joints Freely movable

Classification of Joints – Structure (1) Fibrous joints Dense connective tissues Between bones in close contact (2) Cartilaginous joints Hyaline or fibrocartilage (3) Synovial joints Most complex Allow free movement

(1) Fibrous Joints 1. Suture synarthrotic flat bones thin layer of CT 3 types 1. Suture Parietal bone Margin of suture Sutural bones (a) Suture Occipital bone synarthrotic flat bones thin layer of CT Skull * Synostoses

(1) Fibrous Joints 2. Syndesmosis: Amphiarthrotic Interosseus membrane of leg 2. Syndesmosis: Amphiarthrotic Fibrous tissue connection Interosseous membrane Tibia/Fibula Radius/Ulna Fibula Tibia

(1) Fibrous Joints 3. Gomphosis: Synarthroses Tooth in jawbone Crown of tooth Root of tooth Alveolar process of mandible Periodontal ligament

(2) Cartilaginous Joints 2 types 1. Synchondrosis Synarthrotic Hyaline cartilage Sternum & first rib Epiphyseal line Thoracic vertebra First rib Costal cartilage Manubrium

(2) Cartilaginous Joints 2. Symphysis: Amphiarthrotic Fibrocartilage + Hyaline Pubic Symphysis and Intervertebral Discs Gelatinous core Spinous process Band of fibrocartilage Body of vertebra Pubis Intervertebral discs Fibrocartilage disc of symphysis pubis (a) (b)

(3) Synovial Joints Diarthrotic 5 distinguishing features: Articular cartilage (hyaline) Joint (articular) capsule Joint cavity Synovial fluid Ligaments Spongy bone Joint capsule Joint cavity filled with synovial fluid Articular cartilage Synovial membrane

(3) Synovial Joint (3) Synovial Joint Tendon attaches muscle to bone Ligament attaches bone to bone Odds and Ends: - Bursae - Tendon sheaths Figure 5.28

Synovial Joints: Movement Factors that affect synovial joint stability (3) 1. Articular Surfaces 2. Ligaments 3. Muscle Tone Types of synovial joint movement 1. Non-axial 2. Uniaxial 3. Biaxial 4. Multiaxial

Types of Synovial Joints Gliding (Plane) Non-axial Between carpals Between tarsals Hinge Uniaxial Elbow joint Femur and tibia (**modified) Between phalanges Humerus Radius Ulna Carpals

Types of Synovial Joints Pivot Joint Uniaxial Between atlas (C1) & axis (C2) Condylar Joint Biaxial Between metacarpals and phalanges Between radius and carpals Dens Transverse ligament Atlas Metacarpal Axis (e) Pivot joint Phalanx

Types of Synovial Joints Saddle Joint Biaxial Between carpal and 1st metacarpal (of thumb) Ball-and-Socket Joint Multiaxial Hip joint Shoulder joint Hip bone Head of femur in acetabulum First metacarpal Femur Trapezium

A closer look at the Synovial Joints of the…

Shoulder Joint Head of humerus + glenoid cavity of scapula Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Head of humerus + glenoid cavity of scapula Loose joint capsule Ligaments prevent displacement Very wide range of movement circumduction Acromion process Clavicle Coracoid process Coracoid process Joint capsule Clavicle Coracohumeral ligament Acromion process Transverse humeral ligament Subscapular bursa Tendon of biceps brachii (long head) Glenohumeral ligaments Glenoid labrum Glenoid cavity Humerus Articular capsule (glenohumeral ligaments hidden) Scapula Triceps brachii (long head) Scapula (a) (b)

Shoulder Joint Clavicle Acromion process Subdeltoid bursa Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Clavicle Acromion process Subdeltoid bursa Joint capsule Synovial membrane Joint cavity Joint capsule Joint cavity Head of humerus Articular cartilage Scapula Humerus Humerus Articular cartilage Scapula (a)

Hip Joint Ball-and-socket joint Heavy joint capsule Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ball-and-socket joint Heavy joint capsule Many reinforcing ligaments Less freedom of movement than shoulder joint Circumduction Hip bone Joint cavity Articular cartilage Synovial membrane Ligamentum capitis Joint capsule Femur (a)

Hip Joint (b) Hip bone Ilium Ilium Articular cartilage Joint cavity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hip bone Ilium Ilium Articular cartilage Joint cavity Pubofemoral ligament Head of femur Iliofemoral ligament Pubis Joint capsule Greater trochanter Iliofemoral ligament Ischiofemoral ligament Femur Ischium Lesser trochanter Femur Femur (a) (b) (b) © Paul Reimann

Ulnar collateral ligament Radial collateral ligament Elbow Joint Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Humerus Humerus Medial epicondyle Tendon of biceps brachii muscle Lateral epicondyle Anular ligament Radius Anular ligament Radius Ulna Coronoid process Ulnar collateral ligament Olecranon process Radial collateral ligament Ulna (a) (b)

Elbow Joint Many reinforcing ligaments Stable joint Hinge joint (a) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Humerus Hinge joint Many reinforcing ligaments Stable joint Joint capsule Synovial membrane Joint cavity Articular cartilage Coronoid process Anular ligament Radius Ulna Olecranon process Trochlea (a)

Knee Joint Largest joint Most complex Strengthened by many ligaments Femur Synovial membrane Suprapatellar bursa Largest joint Most complex Strengthened by many ligaments & tendons Menisci separate femur and tibia Bursae Quadriceps femoris tendon (patellar tendon) Patella Prepatellar bursa Joint cavity Articular cartilage Patellar ligament Menisci Infrapatellar bursa Joint capsule Tibia

Knee Joint (b) Femur Tendon of adductor magnus (cut) Femur Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Femur Tendon of adductor magnus (cut) Femur Anterior cruciate ligament Joint capsule Posterior cruciate ligament Femur Gastroc- nemius muscle (cut) Lateral condyle Plantaris muscle (cut) Medial condyle Lateral condyle Lateral meniscus Anterior cruciate ligament Tendon of semimembranosus (cut) Oblique popliteal ligament Lateral meniscus Articular cartilage Medial meniscus Tibial collateral ligament Fibular collateral ligament Lateral condyle Medial condyle Lateral condyle Popliteus muscle cut) Fibular collateral ligament Arcuate popliteal ligament Tibial collateral ligament Head of fibula Tibia Fibula Patellar ligament (cut) Tibia Fibula Fibula Tibia (b) (a) (b) © Paul Reimann

Anterolateral Ligament (ALL) 1) Two knee surgeons at University Hospitals Leuven have provided the first full anatomical description of a previously enigmatic ligament in the human knee. The ligament appears to play an important role in patients with anterior cruciate ligament (ACL) tears. Despite successful ACL repair surgery and rehabilitation, some patients with ACL-repaired knees continue to experience so-called 'pivot shift', or episodes where the knee 'gives way' during activity. For the last four years, orthopaedic surgeons Dr Steven Claes and Professor Dr Johan Bellemans have been conducting research into serious ACL injuries in an effort to find out why. Their starting point: an 1879 article by a French surgeon that postulated the existence of an additional ligament located on the anterior of the human knee. That postulation turned out to be correct: the Belgian doctors are the first to provide a full anatomical description of the ligament after a broad cadaver study using macroscopic dissection techniques. Their research shows that the ligament, called the anterolateral ligament (ALL), was noted to be present in all but one of the 41 cadaveric knees studied. Subsequent research shows that pivot shift, the giving way of the knee in patients with an ACL tear, is caused by an injury in the ALL ligament. KU Leuven. (2013, November 5). Surgeons describe new ligament in the human knee. ScienceDaily. Retrieved February 27, 2014 from www.sciencedaily.com/releases/2013/11/131105081352.htm 2) They propose, given its structure and location in the knee, that the ALL controls the rotation of the tibia, one of the two bones in the lower leg, and that pivot shift may be caused by an injury to the ALL. They have since carried out some research that appears to confirm this.

Types of Joint Movements 4 general movements 1. Gliding

Types of Joint Movements 2. Angular - Increase or decrease angle between 2 bones - Flexion (˅) - Extension (˄) - Hyperextension

Flexion, Extension and Hyperextension

Abduction and Adduction Abduction (away from the midline) Adduction (towards the midline)

Circumduction Movement in which one end of an appendage remains stationary while the other end makes a circular motion

3. Rotation Turning around long axis Medial (inwards) rotation of trunk, thigh, head or arm Medial (inwards) Lateral (outwards)

4. Special Supination and Pronation Forearm Supination palm faces anterior Pronation palm faces posterior

Movements of the Foot Dorsiflexion - raising of the toes Plantarflexion -toes point downward Inversion - soles are turned medially Eversion - soles face laterally

Protraction and Retraction Protraction - movement anteriorly on transverse plane thrusting the jaw forward shoulders or pelvis forward Retraction - movement posteriorly

Elevation and Depression Elevation – upward vertical movement mandibles are elevated during biting clavicles during a shrug Depression – downward vertical movement

Opposition When you touch your finger to your thumb Grasping Manipulation of objects

Movements of Head and Trunk Flexion, hyperextension and lateral flexion of vertebral column

Rotation of Trunk and Head Right rotation of trunk; rotation of head

Movements of Mandible Lateral excursion = sideways movement Medial excursion = movement back to the midline side-to-side grinding during chewing Protraction – retraction of mandible

Movement of Hand and Digits Radial and ulnar flexion Abduction of fingers and thumb Opposition is movement of the thumb to approach or touch the fingertips Reposition is movement back to the anatomical position

Cracking your knuckles Bones pulling apart Stretching synovial joint capsule = increasing volume Increase volume = decrease pressure Decrease in volume means gasses lose solubility and form bubbles Cavitation When pressure gets low enough, bubbles pop and that is the cracking sound Takes about 25-30 minutes for gas to redissolve into joint. During this time you cannot crack that joint (it won’t make the sound) Only 1 study done Results – does not cause arthritis, may cause soft tissue damage and decreased grip strength Due to repeated stretching of ligaments around joint Does show increased mobility

Benign joint hypermobility syndrome Girls Genetic Disease Issues SIGNS OF HYPERMOBILITY Can you touch the floor with the palms of your hands flat while the knees are straight? Can your elbows go beyond straight? Can your knees move beyond Can you move your thumb to touch your forearm as shown? Can your little fingers be moved so they are perpendicular to the upper arm as shown? http://www.rheumatology.org/Practice/Clinical/Patients/Diseases_And_Conditions/Hypermobility_(Pediatric)/

Injuries Sprains Cartilage Dislocation

Arthritis Musculoskeletal disorders 3 main types Osteoarthritis Rheumatoid Juvenile