Musculoskeletal System Notes

Support: The musculoskeletal system provides a framework for the body, enabling it to maintain its shape and posture.
Protection: Protects vital organs such as the heart, lungs, and spleen, particularly through structures like the ribcage.
Stability: Essential for maintaining balance and stability during movement and at rest.
Hematopoiesis: Involved in the production of red blood cells through red bone marrow.
Healing: Facilitates healing of the structural components of the body.

Terminology:
- Bone: Root word osteo.
- Muscle: Root word myo.
- Joint/Articulation: Related to ligaments associated with flexibility and movement.
- Ligaments: Connect bones together and provide joint stability.
Types of Movement: Refers to movements allowed by different joints (e.g., ball and socket joints, hinge joints).

Bone Types:
- Long Bones: E.g., femur, humerus.
- Short Bones: E.g., carpals, tarsals.
- Flat Bones: E.g., sternum, ribs.
- Irregular Bones: E.g., vertebrae.
- Sesamoid Bones: Small, pebble-like bones found within tendons (e.g., patella).

Total Bones: Adult skeleton typically has 206 bones. An infant is born with approximately 306 bones due to the presence of more separated bones that later fuse.
Sutures: Areas in the skull where bones fuse as a child grows, these remain throughout life.
Ossification: Process by which bone tissue is formed, involving the fusion of separate bony structures.

Cellular Composition:
- Osteocytes: Bone cells.
- Osteoblasts: Cells that build bone.
- Osteoclasts: Cells that break down bone tissue.
Bone Matrix: Composed of compact and cancellous (spongy) bone.
Medullary Cavity: Contains bone marrow, which produces blood cells.

Bone Depressions: Areas that form pits, grooves, or cavities in bones.
- Fossa: A shallow depression.
- Sinuses: Hollow spaces within bones that lighten their weight and provide resonance to the voice.

Axial Skeleton: Includes the skull, vertebral column, and rib cage. Responsible for to protect central nervous system and thoracic organs.
Appendicular Skeleton: Comprises limbs and girdles (shoulders and pelvis).
- Major Bones:
- Upper Limb: Scapula, clavicle, humerus, radius, ulna, carpals, metacarpals, phalanges.
- Lower Limb: Pelvis (ilium, ischium, pubis), femur, patella, tibia, fibula, tarsals, metatarsals, phalanges.

Range of Motion Terminology:
- Flexion: Decreasing the angle between body parts (e.g., bending arm).
- Extension: Increasing the angle between body parts (e.g., straightening arm).
- Abduction: Movement away from the midline.
- Adduction: Movement towards the midline.
- Supination: Rotation bringing the palm up.
- Pronation: Rotation bringing the palm down.
- Dorsiflexion: Upward movement of the foot.
- Plantar Flexion: Downward movement of the foot.
Rotation & Circumduction:
- Rotation: Pivoting around an axis.
- Circumduction: Circular movement.

Types of Muscles:
- Skeletal Muscle: Voluntary muscles attached to bones.
- Smooth Muscle: Involuntary muscles found in walls of hollow organs.
- Cardiac Muscle: Involuntary muscle found in the heart.
Muscle Interaction:
- Antagonistic Muscles: Opposing muscle pairs that work against each other (e.g., bicep and tricep).
- Synergistic Muscles: Muscles that work together to perform a movement.
Tendons: Connect muscles to bones.
- Origin: Attachment point of a muscle that remains stationary.
- Insertion: Attachment point that moves during muscle contraction.

Importance of Bone Health: The ability of bones to carry weight effectively decreases as conditions change (e.g., obesity leading to spine issues).
Surgical Considerations: Patient weight can affect surgical outcomes and recovery (e.g. bariatric surgery).
Common Problems: Issues such as bursitis (inflammation of bursa) and joint replacements may arise from degenerative conditions affecting bone and muscle function.

Further exploration of the musculoskeletal system will continue with a detailed discussion on musculoskeletal pathology.