Joints

Question 1

Structures of human knee

Answer 1

1. quadriceps femoris tendon: Connects the quadriceps femoris to the patellar ligament
2. patellar ligament: Connects the quadriceps femoris tendon to the tibial tuberosity.
3. tibial (medial) collateral ligament: Originates from the medial epicondyle of the femur and attaches to the medial surface of the tibia.
4. fibular (lateral) collateral ligament: Originates from lateral epicondyle of the femur and inserts into the head of the fibula.
5. Anterior cruciate ligament: Attaches posteriorly in the intercondylar fossa of the femur to the anterior of the intercondylar area of the tibia.
6. Posterior cruciate ligament: Is posterior, runs from the medial condyle of the femur and the intercondylar area of the tibia. Posteriorly attaches to the surface of medial condyle of femur and
7. Lateral meniscus: Lateral “pad” between tibia and fibia
8. Medial Meniscus: Medial “pad” between tibia and fibia

Question 2

Name the three ligaments (we need to know) on the hip

Answer 2

1. iliofemoral ligament: Large ligament shaped like an inverted y. Anterior and superior to the hip joint. Large ligament “on top” of hip joint
2. pubofemoral ligament: Is anterior to hip joint, deep to iliofemoral joint. Attaches to the pubis anteriorly
3. ischiofemoral ligament: Is posterior to the hip joint. Attaches to ischia posteriorly.

Question 3

Structure of the shoulder

Answer 3

1. coracoacromial ligament: attaches acromion to coracoid process.
2. coracohumeral ligament: Runs from posterior / inferior border of coracoid process to the greater and lesser tubercles of the humerus.
3. glenohumeral ligament: anterior, three ligaments, inferior, middle and superior.
4. subscapularis: subscapular fossa
5. teres minor: Inferior to infraspinatus muscle
6. supraspinatus: covers supraspinous fossa
7. infraspinatus: covers infraspinous fossa

teres major is not part of rotator cuff

Question 4

What are articulations (joints)

Answer 4

A point of contact between, two bones, between bone and cartilage, or between bone and teeth.

• joint structure determines the direction and distance of movement (range of motion). As joint strength increases mobility decreases.

Range of motion (ROM) is the measurement of the movement around a specific joint or body part. It refers to the distance and direction a joint can move to its full potential. ROM is typically measured in degrees and is used to assess the flexibility, strength, and overall function of the joint.

Question 5

Describe two manners to classify joints

Answer 5

1. Functional classification: Based on the range of motion of the joint. Synarthrosis (immovable), Amphiarthrosis (slightly movable), diarthrosis (freely movable)
2. Structural classification: relies on the anatomical organization of the joint. Fibrous, cartilaginous, synovial.

Question 6

What are the structural classifications of joints?

Answer 6

1. fibrous
2. cartilaginous
3. synovial: includes ball-and-socket, hinge, plane, condylar, saddle

Question 7

What are the functional classifications of joints?

Answer 7

1. Synarthrosis: immovable joints. Fibrous or cartilaginous connections, may fuse over time.
2. Amphiarthrosis: slightly movable. Little movment. Fibrous or cartilaginous connections.
3. Diarthrosis: freely movable joint / synovial joints. More movement and subdivided by movement type.

Question 8

Name 4 types of Synarthrotic Joints

Answer 8

1. Suture: Only found in the skull, bones interlocked and bound by a dense fibrous connective tissue.
2. Gomphosis: Fibrous connection via periodontal ligament, binds teeth to sockets. Tooth anchored into socket in the alveolar process.
3. Synchondrosis: A rigid cartilaginous bridge between two bones. Epiphyseal plate of long bones, joint between rib 1 and sternum.
4. Synostosis: Fused bones, immovable. Frontal suture of the skull, epiphyseal line of long bones.

suture joints of the skull can become synostosis joints. During early development and childhood, the bones of the skull are connected by suture joints, which are fibrous joints that allow for slight movement and growth. As a person matures, these suture joints gradually ossify and fuse, transforming into synostosis joints, resulting in a rigid and immovable connection between the skull bones.

Question 9

Name two types of Amphiarthrotic Joints

Answer 9

1. Syndesmosis: Bones connected by ligaments (connection between the tibia and fibula and radius and ulna.
2. symphysis Bones separated by fibrocartilage (pubic symphysis, intervertebral joint)

Question 10

Names types of synovial joints

Answer 10

1. Plane: nonaxial (multiaxial): Gliding / sliding
2. Hinge: monoaxial: flexion / extension
3. Pivot: monoaxial: rotation around a single axis
4. condylar: biaxial: flexion, extension, abduction, adduction, circumduction
5. saddle: biaxial: flexion, extension, abduction, adduction, cirucmduction (greater range than condylar)
6. ball and socket: triaxial: flexion, extension, abduction, adduction, circumduction, rotation

freely moveable joint, typically at ends of long bones, lined with synovial membrane

Question 11

Describe Plane joints

Answer 11

Occurs at flat articular surfaces
Examples: intercarpal, intertarsal, articular process of vertebrae (facet joints).
Movement type: Allows short nonaxial / multiaxial gliding movements. Abduction/adduction of the wrist,

Question 12

Describe Hing joints

Answer 12

Occurs at cylindrical end of one bone which fits into the trough-shaped end of another bone
Examples: elbow, knee joints, and interphalangeal joints.
Movement Type: monaxial -> flexion and extension

Question 13

Describe Pivot Joints

Answer 13

Occurs at rounded process of one bone, which conform nicely to ring of bone on second bone
Examples: Atlantoaxial articulation (no with head), proximal radioulnar joint).
Movement Type: Allows monaxial movements, rotation of the head pronation / supination of the forearm.

Question 14

Describe Condylar Joints

Answer 14

Occurs where condyles articulate with fossa
Examples: Metacarpals with respective phalanges, atlanto-occipital joint
Movement Type: Allows Biaxial movements (flexion / extension; abuction / adduction, circumduction

abduction of fingers spreading them out

Question 15

Describe Saddle Joints

Answer 15

Occurs where bones come together like a rider in a saddle or two kidney beans touching.
Examples: Trapeziometacarpal joint (thumb), sternoclavicular joint
Movement Type: Allows biaxial movements (flexion and extension / abduction and adduction), circumduction, and opposition (JUST at trapeziometacarpal joint moving thumb to touch fingertips)

Question 16

Describe Ball-and-Socket joint

Answer 16

Occurs where round head of bone rests in cup-like depressions of articulating bone.
Examples: shoulder and hip joints
Movement Type: triaxial: extension and flexion, abduction and abduction, rotation

Question 17

Describe the components of a synovial joint

Answer 17

1. Joint capsule: inner synovial membrane, outer fibrous capsule (dense irregular CT).
2. The Joint cavity contains synovial fluid (proteoglycans secreted by fibroblasts) produced by the synovial membrane. The fluid lubricates, distributes nutrients, and absorbs shock.
3. Accessory structures (vary in different joints):

• meniscus (fibrous cartilage pad) cushion the joint.
• fat pads protect articular cartilages
• ligaments support and strengthen joints
• tendons help support joint and attach muscles
• bursae are pockets of synovial fluid that cushion areas where tendons or ligaments rub

synovial membranes DO NOT cover articular cartilage. But synovial fluid lubricates the articular cartilage during movement.

Question 18

Describe Flexion, Extension and Hyperextension

Answer 18

Flexion: This movement decreases the angle between two bones at a joint, effectively bending the joint. For example, bending the elbow or knee.

Extension: Increases the angle between two bones at a joint, straightening the joint back to the anatomical position, straightening the elbow / knee.

Hyperextension: Extends the joint beyond the anatomical position, increasing the angle. Bending the head backward beyond the upright position

Question 19

Describe abduction and adduction

Answer 19

Abduction: This movement takes a limb or other part of the body away from the midline of the body or from the midline of a limb. For example, raising the arm or leg sideways away from the body.

Adduction: This movement brings a limb or other part of the body toward the midline of the body or towards the midline of a limb. For example, lowering the arm or leg back towards the body.

• raising arm laterally, moving leg laterally, spreading fingers or toes

Question 20

Describe circumduction

Answer 20

is a circular movement of a limb or extremity that combines flexion, extension, abduction, and adduction in such a way that the distal end of the limb describes a circle while the proximal end remains relatively stable

From should joint, moving arm in a circle
From hip joint, moving leg is circle,
From metacarpophalngeal joint, moving fingers in a circle

Question 21

Describe rotation and supination and pronation

Answer 21

Rotation: the movement of a bone around its longitudinal axis. It can be either medial (internal) rotation, where the anterior surface of the limb moves toward the midline of the body, or lateral (external) rotation, where the anterior surface moves away from the midline.

• turning head side to side. Rotating the medially or laterally at the shoulder.

supination: This movement involves rotating the forearm so that the palm faces upward or forward (anatomical position). In this position, the radius and ulna are parallel.

pronation: This movement involves rotating the forearm so that the palm faces downward or backward

Question 22

Describe Eversion and Inversion dorsi flexion and plantar flexion

Answer 22

Eversion
Eversion is the movement of the sole of the foot away from the midline of the body, resulting in the sole facing outward.

Inversion
Inversion is the movement of the sole of the foot towards the midline of the body, resulting in the sole facing inward.

Dorsiflexion is the movement that decreases the angle between the dorsum (top) of the foot and the shin. It involves lifting the foot upwards towards the shin.

Plantar flexion is the movement that increases the angle between the dorsum of the foot and the shin. It involves pointing the toes downward, away from the shin.*

Question 23

Describe retraction, protraction, opposition, depression, elevation, and lateral flexion

Answer 23

Retraction the movement of a body part in the posterior direction (toward the back of the body).
- Pulling the shoulders backward or pulling the jaw back

Protraction is the movement of a body part in the anterior direction (toward the front of the body).
- Pushing the shoulders forward, pushing the jaw forward

opposition is the movement that brings the thumb and a finger together, allowing for the grasping of objects

depression the downward movement of a body part.
- lowering the shoulders from the shoulder girdle, lowering the jaw when the mouth opens.

elevation the upward movement of a body part
- raising the shoulders at the shoulder girdle, raising the jaw when the moth closes

lateral flexion bending of the body or a body part to the side
- bending the spine or neck to the left or right.

Question 24

Describe intervertebral articulations

Answer 24

symphysis at vertebral bodies: These are cartilaginous joints that include the intervertebral discs, which are composed of an outer fibrous ring called the annulus fibrosus and a gel-like center called the nucleus pulposus. These structures connect adjacent vertebral bodies, providing shock absorption and slight movement.

synovial at articular processes: These are synovial joints, specifically plane joints, located between the superior and inferior articulating facets of adjacent vertebrae. These joints allow for gliding movements and contribute to the spine’s flexibility

slipped disc -> bulge in annulus fibrosus
herniated disc -> nucleus pulposus breaks through annulus fibrosus -> presses on spinal cord or nerves

Question 25

Describe the Elbow Joint

Answer 25

The elbow joint is composed of three distinct joints. 1. **humeroulnar joint**: true hinge joint -> It is where the trochlea of the humerus articulates with the trochlear notch of the ulna. It allows for flexion and extension of the elbow 2. **humeroradial joint**: modified hinge joint -> It is where the capitulum of the humerus articulates with the head of the radius. It allows for flexion and extension of the elbow. Plays a supportive role in supination / pronation. 3. **proximal radioulnar joint**: pivot joint -> allows rotation movement allowing supination and pronation.

Question 26

Describe the knee joint

Answer 26

- Largest and most complex joint of the body. Transfers weight from femur to tibia, allows flexion, extension and some rotation. - Three joints surrounded by single joint cavity 1. **femoropatellar**: plane joint that allows the patella to glide up and down along the femur during knee flexion and extension. 2. **lateral tibiofemoral**: hinge joint with some rotational component, allowing flexion and extension of the knee, along with slight rotation when the knee is flexed 3. **medial tibiofemoral**: hinge joint with some rotational component, permitting flexion and extension of the knee, as well as some rotation when the knee is flexed. - The knee joint has a medial and lateral minisci, fibrous cartilage pads which cushion and stabilize the joint and provide lateral support. Locking your knees jams the lateral meniscus between the tibia and femur.

Question 27

Describe the shoulder joint

Answer 27

- very mobile (weak) **ball-and-socket diarthrosis joint**. Most mobile joint - formed between the head of the humerus and the glenoid cavity of the scapula. This joint allows for a wide range of movements, including flexion, extension, abduction, adduction, circumduction, and both medial and lateral rotation. Its ball-and-socket structure provides a high degree of mobility, making it one of the most flexible joints in the body. - shoulder joint is stabilized by ligaments that bind to acromion and coracoid process. - the rotator cuff stabilizes the shoulder joint: supraspinatus, infraspinatus, teres minor, and subscapularis

Question 28

Describe the glenoid cavity

Answer 28

The glenoid cavity is a shallow depression in the scapula that articulates with the head of the humerus to form the shoulder joint. The **glenoid labrum** is a ring of fibrocartilage that surrounds the glenoid cavity, deepening the socket and providing additional stability to the shoulder joint

Question 29

Describe the hip joint (coxal joint)

Answer 29

- strong **ball-and-socket diarthrosis joint** with a decent range of motion - Head of the femur fits into the socket of the **acetabulum** (meeting point of the ilium, ischium, and pubis. - The **acetabular labrum**, a ring fibrocartilage that surrounds the acetabulum, deepens the socket, enhances the stability of the hip joint, and helps to distribute pressure more evenly during weight-bearing activities - **ligamentum teres** (ligament of the femoral head) connects the fovea capitis on the femoral head. Supplies blood to the femoral head.

Question 30

Describe the Temporomandibular joint (TMJ)

Answer 30

- Mandibular condyle articulates with mandibular fossa of temporal bone. - Fibrocartilage articular disc (meniscus) seperates joint cavity into superior / inferior compartments (synovial cavities). - The temporomandibular joint (TMJ) is a synovial **hinge and gliding joint** that allows for complex movements. Functionally, it is classified as a diarthrosis joint, permitting a wide range of motion. Structurally, it is a combination of a hinge and a plane joint. The TMJ involves the articulation between the condylar process of the mandible (lower jaw) and the mandibular fossa of the temporal bone. Movements allowed by the TMJ include elevation and depression (closing and opening the mouth), protrusion and retraction (moving the jaw forward and backward), and lateral movements (side-to-side). The joint also contains an articular disc (or meniscus) made of fibrocartilage, which divides the joint cavity into two compartments, enhancing the joint's stability and allowing for smooth movement between the articulating bones

Question 31

Aging related joint issues

Answer 31

- **rheumatism** a broad term referring to various painful conditions of the muscles, tendons, joints, and connective tissues, often involving inflammation - **arthritis** condition characterized by inflammation, pain, and stiffness (rheumatism) in the joints, primarily affecting the cartilage, synovial membrane, and surrounding tissues such as ligaments and tendons of synovial joints - **gouty arthritis** -> caused by the accumulation of uric acid crystals in the joint, leading to intense inflammation. This can damage the cartilage, synovial membrane, and surrounding tissues, and may result in bone fusion. It is often hereditary. - **infectious arthritis**, caused by bacteria, viruses and fungi. The joint is damaged due to lysosomal release. Can be reversed if promptly treated. - **osteoarthritis** progressive degenerative synovial joint disease caused by wear and tear of joint surfaces or genetic factors affecting collagen formation. It involves the degeneration of articular cartilage and primarily affects major weight-bearing joints first. - **rheumatoid arthritis**: autoimmune disorder where immune cells gather in joint capsules and produce enzymes that destroy chondrocytes and cartilage matrix. This process forms granulation tissue, which can ossify, reducing mobility and potentially deforming joints.

Question 32

Injuries to Synovial joints

Answer 32

- **dislocation** articulating surfaces forced out of position, damages articular cartilage, ligaments, joint capsules. - **sprain**: collagen fibers in ligaments tear - **adhesions**: fibrous bands between surfaces where bones join - **spurs**: extra bone tissue along joint edges.