Joints and Muscles Overview

Joints and Muscles

• Muscles are related to movement
• Myology is the study of muscles
• Musculus refers to muscle
• Myocytus is a muscle fiber (cell)
• Bones and muscles are part of the locomotor system

Joint Classification

• Joints are classified based on their movement abilities
• Fibrous joints have no movement; bones are connected directly
• Cartilaginous joints allow limited movement; bones are connected by cartilage
• Synovial joints permit full movement; bones are separated by a fluid-filled joint cavity

Fibrous Joints

• Fibrous joints offer no movement between bones
• Examples include the sutures of the skull and the distal tibiofibular syndesmosis

Cartilaginous Joints

• Cartilage connects bones in these joints, enabling limited movement
• An example is the sternocostal joints

Synovial Joints

• Synovial joints have full movement potential.
• An articular capsule surrounds the joint
• Synovial membrane lining the inner joint surface secretes synovial fluid
• Articular cartilage covers the bone surfaces
• Ligaments strengthen the joint

Types of Synovial Joints

• Synovial joints are categorized by shape (e.g., ball-and-socket, hinge)

Anatomical Axes

• Sagittal axis: Extends from front to back
• Vertical axis: Extends from top to bottom
• Frontal axis: Extends from right to left (parallel to the ground)

Angular Movements

• Flexion decreases the angle between bones
• Extension increases the angle between bones
• Hyper-extension extends beyond the normal anatomical position

Abduction and Adduction

• Abduction moves a limb away from the body's midline
• Adduction moves a limb toward the body's midline

Rotational Movements

• Rotation is movement around a longitudinal axis
• Lateral rotation moves away from the body's midline
• Medial rotation moves toward the body's midline

Supination and Pronation

• Supination externally rotates the forearm, palm facing forward
• Pronation internally rotates the forearm, palm facing backward

Inversion and Eversion

• Inversion turns the sole of the foot inward
• Eversion turns the sole of the foot outward

Skeletal Muscle Function

• Produce movement
• Generate heat
• Stabilize posture

Terminology

• Tendon: Connects muscle to bone
• Aponeurosis: Flattend muscle sheet connecting muscle to bone
• Contraction: Muscle shortening
• Isometric contraction: No change in muscle length
• Isotonic contraction: Change in muscle length

Motor Unit

• A motor unit includes a motor neuron and all the muscle fibers it innervates

Naming Muscles

• Muscles are named based on location, shape, size, action, origin, insertion

Muscle Contraction Mechanism

• Origin is the muscle's starting point
• Insertion is where the muscle attaches to its insertion point
• Function of a muscle depends on location

Shoulder Girdle

• M. deltoideus is a shoulder muscle responsible for abduction and rotation

Brachial Region

• M. biceps brachii is a muscle responsible for flexion and supination of the forearm

Brachial Region M. triceps brachii

• Is responsible for extension of arm and forearm

Hip Region M. iliopsoas

• Is the strongest flexor for thigh

Hip Region M. gluteus maximus

• Is the strongest extensor of the thigh
• Is the largest gluteal muscle

Femoral Region M. quadriceps femoris

• It is a muscle that extends the knee

Hamstring Muscle Group

• Located on the posterior side of the thigh
• These muscles cause flexion of the knee and hip extension

Crural Region M. tibialis anterior

• Dorsiflexes the ankle

Crural Region M. triceps surae

• Plantar flexes the ankle

Thoracic Region M. pectoralis major

• Adducts the arm

Thoracic Region M. serratus anterior

• It pulls the scapula forward and upward

Respiratory System M. diaphragm

• It is responsible for breathing and breathing mechanisms

Dorsal Region M. trapezius

• Prevents shoulder from collapsing
• M. latissimus dorsi is responsible for pulling the arm down and back

Abdominal Region

• Help micturition, defecation, vomiting, forced expiration
• It helps to keep the abdominal contents in place

Facial Muscles

• Originate from bone or fascia, Insert to facial skin

Explore the fascinating world of joints and muscles in this quiz. Learn about the types of joints, their classifications, and the essential role muscles play in movement. Test your knowledge on myology and the locomotor system today!