Chapter 9 (3)

• Dorsiflexion is elevating your toes while swinging your foot forward to take a step (heel strike). Plantar flexion is extending the foot so that the toes point downward as in standing on tiptoe (toe-off). Inversion is the movement in which the soles are turned medially. Eversion is the movement in which the soles are turned laterally.
• Supination of the foot is the complex combination of plantar flexion, inversion, and adduction. Pronation of the foot is the complex combination of dorsiflexion, eversion, and abduction.
• Anatomy of Selected Diarthroses; The Jaw Joint. The Shoulder Joint. The Elbow Joint. The Hip Joint. The Knee Joint. The Ankle Joint.
• The temporomandibular (jaw) joint (TMJ) is the articulation of the condyle of the mandible with the mandibular fossa of the temporal bone. It combines elements of condylar, hinge, and plane joints. The synovial cavity of the TMJ is divided into superior and inferior chambers by an articular disc.
• Two ligaments support the jaw joint; (1)Lateral ligament prevents posterior displacement of the mandible. AND (2)the sphenomandibular ligament that is on the medial side. A deep yawn or strenuous depression can dislocate the TMJ as the condyles pop out of the fossa and slip forward. It can be relocated by pressing down on molar teeth while pushing the jaw backward.
• Temporomandibular joint (TMJ) syndrome may affect as many as 75 million Americans. The cause of this syndrome includes a combination of psychological tension and malocclusion (misalignment of teeth). Signs and symptoms include clicking sounds in the jaw, pain radiating from the jaw down the neck, shoulders, and back, moderate intermittent facial pain, severe headaches, vertigo (dizziness), and/or tinnitus (ringing in the ears). The treatment includes Psychological management, physical therapy, analgesic and anti-inflammatory drugs, and corrective dental appliances to align teeth properly.
• With the Shoulder Joint, the Glenohumeral (humeroscapular) joint is the hemispherical head of the humerus that articulates with the glenoid cavity of the scapula. It is the most freely mobile joint in the body. The shallow glenoid cavity and loose shoulder joint capsule sacrifice stability for freedom of movement. The Glenoid labrum is the fibrocartilage ring that deepens the glenoid cavity.
• In The Shoulder Joint, the Shoulders are supported by the biceps brachii tendon anteriorly and also by rotator cuff tendons. The tendons fuse to the joint capsule and strengthen it. Supraspinatus, infraspinatus, teres minor, and subscapularis. Five principal ligaments support the shoulder, the first three are called the glenohumeral ligaments, then there's the coracohumeral ligament and the Transverse humeral ligament. Four bursae occur at the shoulder; the Subdeltoid, subacromial, subcoracoid, and subscapular bursae.
• Shoulder Dislocations are very painful and sometimes cause permanent damage. The downward displacement of the humerus is the most common shoulder dislocation. The rotator cuff protects the joint in all directions but inferiorly, the joint is protected from above by the coracoid process, acromion, and clavicle, and dislocations most often occur when the arm is abducted and then receives a blow from above. Children are especially prone to dislocation.
• The Elbow is a hinge that includes two articulations; (1) the Humeroulnar joint where the trochlea of the humerus joins the trochlear notch of the ulna, AND(2) the Humeroradial joint where the capitulum of the humerus meets the head of the radius. Both articulations are enclosed in one joint capsule. The Olecranon bursa on the posterior side of the elbow eases movements of the tendons. The radial (lateral) collateral ligament and ulnar (medial) collateral ligaments restrict side-to-side motions.
• The elbow region also contains the proximal radioulnar joint. It functions as a pivot, not a hinge. The head of the radius fits into the radial notch of the ulna. It is held in place by an annular ligament encircling the radial head, and it allows for pronation and supination.
• With the coxal (hip) joint the head of the femur inserts into the acetabulum of the hip bone. It bears weight, has deeper sockets, and is more stable than the shoulder.
• With the hip joint, the Acetabular labrum is a horseshoe-shaped ring of fibrocartilage that deepens the socket. Dislocations of this are rare. Ligaments support the hip joint, such as the Iliofemoral and pubofemoral ligaments (which are anterior), the ischiofemoral ligament (which is posterior), and the Transverse acetabular ligament bridges the gap on the inferior margin of the acetabular labrum. Round ligament (ligamentum teres) arises from the fovea capitis and attaches to the lower margin of the acetabulum. It contains an artery that supplies blood to the head of the femur.
• Dislocation of hip is rare. Some infants suffer congenital dislocation because their acetabulum is not deep enough to hold head of femur in place, so a harness is worn for 2 to 4 months which can assist with proper positioning.
• The Tibiofemoral (knee) joint is the body's largest and most complex diarthrosis. It is primarily a hinge joint, capable of slight rotation and lateral gliding when flexing the knee. The Patellofemoral joint is the gliding joint.
• The joint capsule encloses only the lateral and posterior aspects of the knee. The anterior aspect is covered by the patellar ligament as well as the lateral and medial retinacula. All are extensions of the tendon of the quadriceps femoris muscle.
• The knee is stabilized by: The quadriceps tendon in front and the tendon of the semimembranosus muscle on the rear of the thigh.
• The Lateral meniscus and medial meniscus are C-shaped cartilages within the joint capsule. They absorb shock and prevent side-to-side rocking, and they are joined by transverse ligaments.
• The Popliteal (posterior) region of the knee has extracapsular ligaments; the fibular (lateral) collateral ligament and the tibial (medial) collateral ligament. AND Intracapsular ligaments that cross each other to form X-shaped structures; the anterior cruciate ligament (ACL) that prevents hyperextension of the knee when the ACL is pulled tight and is a common site of knee injury, and the posterior cruciate ligament (PCL) that prevents the femur from sliding off the tibia.
• The knee joint has at least 13 bursae. Four anterior; the superficial infrapatellar, the suprapatellar, the prepatellar, and the deep infrapatellar. Two in the popliteal region: the popliteal bursa and the semimembranosus bursa. AND Seven more bursae on the lateral and medial sides of the knee joint.