Human Anatomy: Muscles, Bone Classifications, and Joints

Muscular Functions

• Pectoralis Major: Horizontal shoulder abduction.
• Biceps: Elbow flexion.
• Triceps: Elbow extension.
• Trapezius: Scapular retraction.
• Latissimus Dorsi: Shoulder adduction.
• Gluteus Medius: Hip extension.
• Gastrocnemius: Ankle extension.
• Rectus Abdominis: Spinal flexion.
• Deltoid: Shoulder adduction.

Bone Classifications

Long Bones

These are among the longest bones in the body, such as the femur, humerus, and tibia. Long bones are characterized by having a body that is longer than it is wide.

Short Bones

Defined as being approximately as wide as they are long, their primary function is providing support and stability with limited movement. Examples include the carpals and tarsals.

Flat Bones

These are strong, flat plates of bone. Their main function is providing protection to the body's vital organs and serving as a base for muscular attachment. Examples include the scapula and cranium.

Irregular Bones

These bones do not fall into any other category due to their non-uniform shape. Examples include the vertebrae, sacrum, and mandible.

Sesamoid Bones

Usually short or irregular bones embedded in a tendon. The patella is a primary example, sitting within the quadriceps tendon.

Joint Anatomy and Components

• Joint: The point where two or more bones meet.
• Cartilage: Tissue that covers the surface of a bone at a joint.
• Ligaments: Connective tissue that surrounds the joint to provide support and limit movement.
• Tendons: Connective tissue that attaches muscles to bones to control joint movement.
• Bursae: Fluid-filled sacs between bones, ligaments, or other structures that cushion friction in a joint.
• Synovial Membrane: Lines the joint and seals it into a joint capsule.
• Synovial Fluid: A clear, sticky fluid secreted by the synovial membrane.

Joint Classifications

• Fibrous Joints: Held together only by ligaments.
• Cartilaginous Joints: Occur where the connection between articulating bones is made of cartilage.
• Synovial Joints: The most common classification of joint within the human body.

Knee Anatomy

The knee consists of the femur, bursa, synovial membrane, articular cartilage, tibia, patella, synovial fluid, fat, meniscus, and patellar tendon.