4.1 Overview of Joints

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of joint is characterized by having no movement?

Diarthrosis

Amphiarthrosis

Synovial joint

Synarthrosis (correct)

Which of the following statements best describes the function of synovial fluid?

It forms a protective barrier against infections.

It connects muscle to bone for joint stability.

It serves to protect joints from excessive movement.

It absorbs shock and provides nutrients to joint cartilage. (correct)

Which anatomical structure covers the bony surfaces in a synovial joint?

Ligament

Joint capsule (correct)

Articular cartilage

Synovial membrane

What type of joint allows the greatest range of motion?

Diarthrosis Signup and view all the answers

In which movement do you decrease the angle between two body parts?

Flexion Signup and view all the answers

Which movement involves moving a limb away from the midline of the body?

Abduction Signup and view all the answers

What is the primary purpose of ligaments in synovial joints?

To stabilize bone-to-bone connections. Signup and view all the answers

Which type of joint permits little movement?

Amphiarthrosis Signup and view all the answers

What type of movement is characterized by a circular motion involving several joints?

Circumduction Signup and view all the answers

Which accessory structure in joints provides friction relief?

Bursa Signup and view all the answers

What movement is described by the action of moving the forearm with the palm facing forward?

Supination Signup and view all the answers

Which of the following joints is classified as a ball and socket joint?

Shoulder joint Signup and view all the answers

What type of joint is the elbow primarily classified as?

Complex hinge joint Signup and view all the answers

During which movement does the forearm move such that the palm is facing backward?

Pronation Signup and view all the answers

Which of these movements is NOT associated with the hip joint?

Opposition Signup and view all the answers

Which ligaments are associated with the stability of the elbow joint?

All of the above Signup and view all the answers

What type of movement is allowed by the knee joint apart from flexion and extension?

Limited rotation Signup and view all the answers

Which movement refers to the circular motion at joints like the shoulder and hip?

Circumduction Signup and view all the answers

What is the primary function of the annular ligament in the elbow?

To cover the head of the radius Signup and view all the answers

Which movements are primarily facilitated by the shoulder joint?

Flexion, extension, adduction, rotation Signup and view all the answers

Study Notes

Joints

Joints are also known as articulations and allow movement of the appendicular skeleton
The strength and stability of a joint is inversely proportional to its range of motion
Joints can be classified based on their range of motion and structure
Joints with no movement are classified as synarthrosis
Joints with little movement are classified as amphiarthrosis
Joints with free movement are classified as diarthrosis
Structurally, joints are classified as bony, cartilaginous, or fibrous

Synovial Joints

Freely movable joints
Have a joint capsule (or articular capsule) that covers the bony surfaces
Contain synovial fluid which lubricates, provides nutrients, and absorbs shocks
Have accessory structures such as fat pads, ligaments, tendons, and bursae
Fat pads provide padding
Ligaments connect bone to bone, providing stability
Tendons connect muscle to bone
Bursae are fluid-filled sacs that reduce friction

Joint Motion

Flexion is movement in the anterior plane that decreases the angle between bones
Extension is movement in the anterior plane that increases the angle between bones
Hyperextension is extension beyond the anatomical position
Abduction is movement away from the midline of the body
Adduction is movement towards the midline of the body
Circumduction is a circular motion
Rotations are movements around a longitudinal axis
Lateral (external) rotation moves the anterior surface of the limb away from the midline
Medial (internal) rotation moves the anterior surface of the limb towards the midline
Supination is the movement of the forearm so that the palm faces anteriorly
Pronation is the movement of the forearm so hat the palm faces posteriorly

Special Movements

Elevation is movement in a superior direction
Depression is movement in an inferior direction
Protraction is movement in an anterior direction
Retraction is movement in a posterior direction
Inversion is movement of the sole of the foot medially
Eversion is movement of the sole of the foot laterally
Dorsiflexion is movement of the foot that decreases the angle between the foot and the leg
Plantar flexion is movement of the foot that increases the angle between the foot and the leg
Opposition is the movement of the thumb to touch the tips of the other fingers on the same hand

Elbow Joint

A complex hinge joint
Allows for flexion and extension, as well as limited rotation of the forearm
Stabilized by ligaments, including the ulnar collateral ligament, the radial collateral ligament, and the annular ligament

Knee Joint

A hinge joint
Allows for flexion and extension
Contains menisci, which act as shock absorbers and improve joint stability
Stabilized by the anterior cruciate ligament (ACL), the posterior cruciate ligament (PCL), and the medial and lateral collateral ligaments (MCL and LCL)

Shoulder Joint

A ball and socket joint, allowing for a wide range of motion
Allows for flexion, extension, abduction, adduction, circumduction, and rotation
Stabilized by the glenohumeral ligaments, the coracohumeral ligament, and the rotator cuff muscles
The rotator cuff muscles are important for stabilizing the shoulder joint and allow for precise movements

Hip Joint

A ball and socket joint
Allows for a wide range of motion similar to the shoulder joint
Stabilized by ligaments such as the iliofemoral ligament, the pubofemoral ligament, and the ischiofemoral ligament.
Also stabilized by the muscles surrounding the joint

Joint Types

Plane joint - allows for sliding or gliding motions (example: intercarpal joints)
Hinge joint - allows for flexion and extension movements (example: elbow joint)
Pivot joint - allows for rotation around a central axis (example: proximal radioulnar joint)
Condyloid joint - allows for flexion, extension, abduction, and adduction movements (example: metacarpophalangeal joints)
Saddle joint - allows for flexion, extension, abduction, adduction, and circumduction, but limited rotation (example: carpometacarpal joint of the thumb)
Ball and Socket joint - allows for a wide range of movement (example: shoulder and hip joints)