Musculoskeletal System
This system consists of muscles, bones, joints, bursae, tendons, and ligaments. There are three types of muscles:
Muscular System
- Smooth Muscles: non-striated, involuntary muscle (controlled by the ANS), forming muscle layers in the walls of the digestive tract, bladder, various ducts, arteries and veins, and other internal organs.
- Cardiac Muscles: striated, involuntary muscle (controlled by the ANS), comprising heart tissue.
- Skeletal Muscles: striated, voluntary muscle (controlled by the SNS). This is the most abundant tissue in the human body.
Skeletal System
Humans are born with ~270 bones that merge down to 206 bones. There are two main parts
- Axial Portion comprising of 80 bones, containing the skull, ribs, sternum, and spine.
- Appendicular Portion comprising of 126 bones, with 64 in the shoulders and upper limbs, and 62 in the pelvis and lower limbs.
Bones can be classified according to:
- Shape:
- Long Bones: rounded ends and often bear weight; these are longer as they are wide e.g. clavicle, humerus, radius, ulna, femur, tibia, fibula.
- Short Bones: small and bear little or no weight. These are the carpals, tarsals, metacarpals, and metatarsals.
- Flat bones: ribs, sternum, and scapula
- Irregular Bones: with unique shape, skull, pelvis, and vertebrae.
- Sesamoid Bone: A short bone embedded within a tendon e.g. the patella (kee cap)
- Structure/Composition:
- Periosteum
- Cortex (Compact Bone: compact suggests a hard part of the bone. This gives strength to the bone.
- Medullary Cavity: the space inside the diaphysis contains the yellow bone marrow
- Hyaline Cartilage: cartilage covers the ends of the bones.
- Epiphysis: extremity of the bones
- Cancellous bone: spongy part of the bone, storing red bone marrow where blood cells are manufactures.
- Epiphyseal Seal
Bones have various functions:
- Provides a framework for the body and allows the body to be weight-bearing and upright.
- Supports the surrounding tissues as attachments of muscle, tendons, and ligaments
- Assists in the movement through muscle attachments and joint formation
- Protects vital organs, such as the heart and lungs.
- Manufactures blood cells in red bone marrow (hematopoiesis)
- Provides a storage for mineral salts (Ca and Phosphorus)
- Joints provide movement and flexibility in the body.
- Synarthrodial/Synarthrosis Joints
- Amphiarthrodial/Amphiarthrosis Joints
- Diarthrodial/Diarthrosis Joints
- Tendons (muscle to bone) and ligaments (bone to bone)
- Cartilage is a type of connective tissue
- Hyaline cartilage
- Elastic cartilage
- Fibrocartilage
- Bursae are fluid-filled sacs that cushion aras of friction between or within the layers of moving parts e.g. between two muscles, bones, joints, etc.
Traumatic Conditions
- Contusions: “bruise”; a soft tissue injury produced by a blunt force (blow, kick, fall)
- Pain, swelling, discoloration
- Resolves in 1 to 2 weeks
- Subcutaneous
- Intramuscular
- Periosteal (bone bruise), the most severe form
- Strain: a “pulled muscle” due to overuse, stretching, or stress of a muscle.
- Soreness, sudden pain, local tenderness upon muscle use.
- Sprain: a torn ligament due to a twisting motion. Blood vessels rupture and edema occurs.
- Tender joint, painful movement, pain increases during the first 2 to 3 hours due to swelling and bleeding.
- X-ray is required to R/O bone injury.
- Typed between 1, 2, and 3 from slight tears to complete tearing.
- Management: RICE (rest, ice, compression, and elevation)
- Rest: prevent additional injury, promote healing
- Ice: moist/dry cold applied intermittently for 20 to 30 minutes during the first 24 to 48 hours to relieve bleeding, edema, and discomfort.
- Compression: elastic compression bandage controls bleeding, reduces edema, and provides support for the injured tissues.
- Elevation: controls swelling.
- After 48 hours, heat may be applied intermittently for 15 to 30 minutes qid to relieve muscle spasm and to promote vasodilation, absorption, and repair.
- Dislocation: a condition in which the articular surfaces of the bones forming the joint are no longer in anatomic contact. These are orthopedic emergencies if caused by trauma.
- Avascular necrosis and nerve palsy may occur if not immediately treated
- Pain, change in joint contour, change in extremity length, and loss of normal mobility.
- X-ray confirms the diagnosis and any associated fractures.
- Fracture: a disruption in the continuity of a bone.
- Complete: complete cross-sectional break across the bone.
- Incomplete: only through a part of the cross-section
- Closed/Simple
- Open/Compound
- The orientation of the fracture may also classify as normal, transverse, oblique, spiral, compression, etc.
- Pain (increasing severity until immobilized), loss of function, deformity, shortening, crepitus, swelling, and discoloration
- 4 Rs of Management
- Recognition
- Reduction: procedure by which the bone fragments are realigned with their original position, either externally (closed) or through surgery (internal)
- Retention
- Rehabilitation