Orthopedics: Medical Specialty

Definition and Scope

Orthopedics is the medical specialty focused on the anatomy, physiology, and diseases of the skeletal and muscular systems. Orthopedists use diagnostic tests, medical and surgical procedures, and drugs to treat conditions affecting bones and muscles.

• Orth/o: means straight

• Ped/o: means child

• -ics: means knowledge; practice

Skeletal System Overview

Structure and Function

The skeletal system is a widespread, connected body system consisting of 206 bones and other structures. It extends from the top of the head to the tips of the fingers and toes, providing support, protection, and movement.

• Key Functions: Support, protection of organs, movement, mineral storage, blood cell production

• Major Divisions: Axial skeleton and appendicular skeleton

Anatomy of the Skeleton

Axial Skeleton

The axial skeleton forms the central structure around which other parts move. It includes the head, neck, chest, and spinal bones.

• Cranial Bones: Form the cranium and protect the brain

• Facial Bones: Support the nose, cheeks, and lips

• Ossicles: Three tiny bones in each middle ear (malleus, incus, stapes)

• Hyoid Bone: Located in the neck, not connected to other bones

• Rib Cage: Sternum and 12 pairs of ribs (true, false, floating)

• Spine: Five regions: cervical, thoracic, lumbar, sacrum, coccyx

Cranial Bones

• Frontal bone: Forehead

• Parietal bones: Upper sides and posterior

• Occipital bone: Base

• Temporal bones: Sides

• Sphenoid bone: Central base

• Ethmoid bone: Nasal septum

Fontanels

Fontanels are soft spots on an infant's skull where bones have not yet fused. The anterior and posterior fontanels are covered by fibrous connective tissue.

Chest and Rib Cage

• Sternum: Manubrium, body, xiphoid process

• Ribs: 12 pairs (1-7 true, 8-10 false, 11-12 floating)

Spine

• Cervical vertebrae (C1-C7): Neck

• Thoracic vertebrae (T1-T12): Thorax

• Lumbar vertebrae (L1-L5): Lower back

• Sacrum: Five fused vertebrae

• Coccyx: Fused vertebrae forming the tailbone

Appendicular Skeleton

The appendicular skeleton consists of the limbs and their girdles, including the shoulder, arm, hip, and leg bones.

Shoulder

• Clavicle (collarbone)

• Scapula (shoulder blade)

Upper Extremity

• Humerus: Upper arm bone

• Radius and Ulna: Forearm bones

• Carpal bones: Wrist

• Metacarpal bones: Hand

• Phalanges: Fingers (three per finger, two in thumb)

Hip

• Ilium: Most superior

• Ischium: Most inferior

• Pubis: Most anterior

• Acetabulum: Hip socket

Lower Extremity

• Femur: Thigh bone

• Tibia: Shin bone

• Fibula: Thin bone of lower leg

• Patella: Kneecap

Ankle and Foot

• Tarsal bones: Ankle

• Metatarsal bones: Midfoot

• Phalanges: Toes (three per toe, two in hallux/great toe)

Structure of Bone

Osseous Tissue and Bone Anatomy

Bone is a type of connective tissue called osseous tissue. The surface is covered by periosteum, a thick, fibrous membrane. Long bones have a shaft (diaphysis) and ends (epiphyses), with cortical (compact) bone and cancellous (spongy) bone.

• Medullary cavity: Contains yellow bone marrow

• Epiphyseal plates: Sites of bone growth

• Red bone marrow: Produces blood cells

Joints, Cartilage, and Ligaments

Types of Joints

Joints (articulations) are formed where two bones meet. They are classified by their movement:

• Suture joints: Immovable (cranial and facial bones)

• Symphysis joints: Slightly movable (pubis, vertebrae)

• Synovial joints: Fully movable; hinge and ball-and-socket types

Joint Structure

• Cartilage: Dense collagen fibers, covers bone ends

• Meniscus: Cartilage pad in some synovial joints

• Ligaments: Strong connective tissue bands

• Joint capsule: Contains synovial membrane and fluid

*Additional info: Synovial fluid lubricates and nourishes the joint.*

Physiology of Bone Growth

Bone Cells and Remodeling

Bone growth and maintenance involve several cell types:

• Osteocytes: Mature bone cells, monitor mineral content

• Osteoclasts: Break down bone tissue

• Osteoblasts: Build new bone tissue

Bone is composed of calcium salts and collagen fibers. Calcium is released as needed for muscle function and bone repair.

Bone Remodeling

• 10% of skeleton is remodeled annually

• Osteoclasts dissolve old bone; osteoblasts form new bone (osteogenesis)

• In children, bone formation exceeds breakdown; in adults, rates are equal; in older adults, breakdown exceeds formation

Ossification and Growth

• Cartilage is replaced by bone at epiphyseal plates

• Growth occurs until adulthood

Bone and Cartilage Diseases

Fractures

Fractures are breaks in bone, classified by their pattern and severity.

Osteoporosis

Osteoporosis is a disease characterized by decreased bone density and increased risk of fractures. It is common in older adults, especially postmenopausal women.

Chest and Spine Diseases

Scoliosis

Scoliosis is a lateral curvature of the spine, which can cause uneven shoulders, hips, and arm lengths. Diagnosis and treatment planning involve physical examination and imaging.

Hallux Valgus and Clubfoot

• Hallux Valgus: Lateral deviation of the great toe, often with bunion formation

• Clubfoot: Congenital deformity with inwardly rotated foot

Joints, Cartilage, and Ligaments Diseases

Osteoarthritis

Osteoarthritis is a degenerative joint disease characterized by loss of articular cartilage, narrowing of joint space, and malalignment of bone ends.

Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune disease causing severe joint deformities, especially in the hands.

Laboratory, Diagnostic, and Radiologic Procedures

Bone Densitometry

Bone mineral density tests (such as DXA scans) assess bone health and risk of osteoporosis. The hip and spine are common sites for measurement.

Medical Procedures

Cast Application and Crutches

Casts are applied to immobilize fractured bones. Patients may use crutches and require physical therapy after healing.

Goniometer

A goniometer is used by physical therapists to measure the range of motion in joints.

Prosthesis

Prosthetic limbs are custom-built for patients after amputation, allowing for rehabilitation and mobility.

Surgical Procedures

Arthroscopic Surgery

Arthroscopy is a minimally invasive surgical procedure used to examine and treat joint conditions. A fiberoptic scope and instruments are inserted through small portals.

Hip Prostheses

Total hip replacement involves removing the head of the femur and replacing it with a prosthesis. The acetabulum is also replaced with a cup, and the ball is inserted into the cup.

Orthopedic Plate and Screws

Fractures may be stabilized using metal plates and screws.

Appendix: Key Abbreviations and Terms

• RUE: Right Upper Extremity

• LUE: Left Upper Extremity

• RLE: Right Lower Extremity

• LLE: Left Lower Extremity

• BMI: Body Mass Index

Example Calculation: BMI for Children

For children and teenagers, BMI is calculated as:

*Additional info: Percentiles are used to assess growth and nutrition in pediatric patients.*