ALL NOTES

Muscle Descriptions and Basic Actions

• Orbicularis Oris: surrounds the lips, responsible for pursing, closing, protruding, and compressing lips.
• Orbicularis Oculi: surrounds the eye, responsible for closing eyelids and facial expressions.
• Sternocleidomastoid (SCM): connects the sternum, clavicle, and mastoid process, responsible for flexing the neck forward and tilting/rotating the head.
• Trapezius: located in the upper back and neck, responsible for elevating the shoulder girdle, retracting the scapula, and depressing the shoulder girdle.
• Serratus Anterior: located in the lateral aspect of the thorax, responsible for protracting the scapula and stabilizing the scapula.
• Pectoralis Major: located in the chest, responsible for adduction, medial rotation, and flexion of the shoulder.
• Latissimus Dorsi: located in the lower and middle back, responsible for adduction, extension of the shoulder, and medial rotation.
• Deltoid: located in the shoulder, responsible for flexing, abducting, and extending the shoulder joint.
• Biceps Brachii: located in the front of the upper arm, responsible for flexing the elbow and supinating the forearm.
• Triceps Brachii: located in the back of the upper arm, responsible for extending the elbow and assisting in shoulder extension.
• Flexor Carpi Muscles: located in the anterior forearm, responsible for flexing the wrist and assisting in flexing the elbow.
• Extensor Carpi Muscles: located in the posterior forearm, responsible for extending the wrist and assisting in extending the fingers.
• Rectus Abdominis: located in the anterior abdominal wall, responsible for flexing the trunk and assisting in stabilization.
• External Oblique: located in the lateral abdominal wall, responsible for flexing and rotating the trunk, and compressing the abdomen.
• Gluteus Maximus: located in the buttocks, responsible for extending the hip, externally rotating the hip, and assisting in stabilization.
• Hamstrings: located in the back of the thigh, responsible for flexing the knee and extending the hip.
• Adductor Muscles: located in the medial thigh, responsible for adducting the hip, and assisting in flexion and extension of the hip.
• Tibialis Anterior: located in the anterior lower leg, responsible for dorsiflexion of the ankle and inversion of the foot.
• Gastrocnemius: located in the back of the lower leg, responsible for plantar flexion of the ankle and flexion of the knee.

Characteristics of Muscles

• Smooth Muscle: makes up walls of hollow organs, has no striations, moves involuntarily, and contracts slowly.
• Cardiac Muscle: makes up walls of the heart, has striated cells, and generates electrical impulses to contract.
• Skeletal Muscle: makes up the largest amount of body muscle tissue, has striated cells, and is stimulated by the nervous system to contract voluntarily.

Common Diseases and Conditions of the Muscles

• Strain: injury to a muscle and its surrounding tendons, causing pain, limited motion, muscle spasms, and inflammation.
• Treatment: RICE (rest, ice, compression, elevation)

Functions of the Skeletal System

• Serves as framework for body: protects brain, spinal cord, and other structures.
• Works with muscles to produce movement: stores calcium and produces blood cells.
• Types of Joints: fibrous, cartilaginous, and synovial.
• Types of Synovial Joints: gliding, hinge, pivot, condyloid, saddle, and ball-and-socket.

Movement and Actions

• Flexion and Extension: flexion bends the elbow, extension straightens the knee.
• Abduction and Adduction: abduction raises the arm sideways, adduction brings the leg towards the body.
• Rotation: medial rotation rotates the leg inward, lateral rotation rotates the arm outward.
• Circumduction: moving the arm in a circular motion.
• Pronation and Supination: pronation rotates the forearm to face the palm downward, supination rotates the forearm to face the palm upward.
• Dorsiflexion and Plantar Flexion: dorsiflexion bends the foot upward, plantar flexion points the toes downward.
• Inversion and Eversion: inversion turns the sole of the foot inward, eversion turns the sole of the foot outward.

Effects of Aging on the Skeletal System

• Slower pace of bone remodeling: weaker, more fragile bones.
• Osteoporosis: extreme loss of bone mass.
• Decreased ability to form proteins: fractures heal slowly.
• Reduction in collagen in tendons, ligaments, and skin: stiffness.
• Thinning of disks between bodies of vertebrae: height loss.