Mastering A&P Chapter 8 - Joints

Review the types you have studied, and select a true statement or characteristic of uniaxial movement in a representative joint. A person curls his or her fingers, and the phalanges flex at the interphalangeal joints. The dancer's leg is lifted to a ballet bar. A person bends over, and his or her vertebral processes move past one another. A golfer swings at the ball on the tee.

A person curls his or her fingers, and the phalanges flex at the interphalangeal joints. Uniaxial hinge-type joints include those that are interphalangeal (between the fingers or toes), as well as that of the elbow. These exhibit flexion and extension. Another uniaxial joint is a cylindrical bone rotating along one axis in a sleeve-type opening, the pivot joint, as in atlas-axis (also known as atlantoaxial) rotation or the proximal radioulnar joints. Biaxial joints include the condylar joint, as found in the metacarpophalangeal joint, and the saddle joint, as found in the carpometacarpal joints of the thumbs. Congratulations on expanding your knowledge of joint classification by recognizing both movements permitted and the shapes of the articulating bones!

A joint held together by fibrocartilage would be classified as a __________ joint. cartilaginous synovial fibrous amphiarthrosis

Cartilaginous Cartilaginous joints are held together by cartilage. Fibrocartilage holds together symphyses.

What element of intervertebral disc fibrocartilage gives it its ability to resist stretching? elastic fibers collagen fibers articular cartilage calcium

Collagen fibers

The atlas to axis joint would exhibit

rotation

A cylinder-shaped bone articulating with a trough-shaped bone would exhibit

flexion and extension

In uniaxial movement at the elbow joint, the movement allowed is

flexion and extension.

If a torn anterior cruciate ligament (ACL) is not properly repaired, the consequences could include the inability to prevent ________. medial rotation of an extended knee lateral rotation of an extended knee forward sliding of the tibia on the femur forward sliding of the femur

Forward sliding of the tibia on the femur The ACL extends from the anterior intercondylar notch of the femur to the anterior intercondylar eminence of the tibia. This ligament prevents the tibia from being pushed too far anterior relative to the femur.

Which of the following represents a correct statement about multiaxial joints? Focus your attention on the section called Multiaxial movement in part (f) in Focus Figure 8.1. The ball-and-socket joint permits only one angular motion. Movement in more than two axes is permitted in a multiaxial joint. The articulating surfaces in the multiaxial joint are a cylindrical bone and a trough-shaped bone. The rounded end of the proximal metacarpal fitting into the distal surface of the carpal bone of the wrist is a classic ball-and-socket joint.

Movement in more than two axes is permitted in a multiaxial joint. The multiaxial joint has movement in three directions, around all three axes in space, permitting the most movement of any joint type. Think of your body and the two specific joint locations in which the most movement can be displayed. The articulating surfaces will be shaped like a ball-and-socket Examine your shoulder and move your humerus in different directions. List the specific types of angular movement permitted.

Which joint has sacrificed stability to provide great freedom of movement? knee shoulder ankle elbow

Shoulder In the shoulder joint, stability has been sacrificed to provide the most freely moving joint in the body. The articulating bones provide minimal joint stability because of the size and "fit" of the articulating surfaces. The major stabilizing forces are soft tissue, in particular the tendons of the rotator cuff muscles (via muscle tone).

What factor would account for a strong synovial joint? low muscle tone the deepest articular surface synovial fluid small reinforcing ligaments

The deepest articular surface The deepest articular surface would likely lead to a strong synovial joint.

Description of nonaxial movement

Vertebral processes gliding past one another Flat bones sliding past one another Movement between adjacent carpal bones

Examples of uniaxial movement permitted at the surfaces of bones can be found at these two articulations,

proximal ulna to radius and distal humerus to proximal ulna.