Skeletal System Summary

Skeletal System Functions and Structures

• Bones:

  • Framework, supports, and protects organs.

• Joints:

  • Work with muscles, ligaments, and tendons for body movements.

• Calcium:

  • Stored in bones, needed for nerve and muscle function.

• Red bone marrow:

  • Formation of blood cells in spongy bone.

• Newborn skeleton:

  • Fragile membranes and cartilage that ossify into bone through adolescence.

• Bone remodeling:

  • Osteoclasts break down old bone, osteoblasts rebuild.

  • Repairs damage and fractures.

Bone Structure

• Bone tissue:

  • Connective tissue that grows, heals, and reshapes.

• Compact bone:

  • Dense outer layer.

• Spongy bone:

  • Porous, contains red bone marrow.

• Medullary cavity:

  • In long bones, stores red and yellow marrow, lined with endosteum.

• Red bone marrow:

  • Produces blood cells.

• Yellow bone marrow:

  • Fat storage, replaces red marrow after adolescence.

• Cartilage:

  • Connective tissue, shock absorber.

• Articular cartilage:

  • Covers bone surfaces in joints for smooth movement.

• Meniscus:

  • Fibrous cartilage in some joints (e.g., knee).

• Diaphysis:

  • Shaft of long bone.

• Epiphyses:

  • Wider ends of long bones.

• Foramen:

  • Opening for blood vessels/nerves.

• Process:

  • Projection for muscle/tendon attachment.

Joints

• Joints (articulations):

  • Unions between bones classified by structure and movement.

• Fibrous Joints:

  • Tight joints with inflexible connective tissue; sutures.

• Cartilaginous Joints:

  • Slight movement; bones connected by cartilage (e.g., pubic symphysis).

• Synovial Joints:

  • Wide movement range; e.g., ball-and-socket (hips, shoulders), hinge (knees, elbows).

Skeleton

• Adult Skeleton:

  • Around 206 bones.

  • Axial and appendicular divisions.

• Axial Skeleton:

  • Protects major organs; skull, ossicles, hyoid, rib cage, vertebral column.

• Appendicular Skeleton:

  • Enables movement; upper and lower extremities.

Bones of the Skull

• Cranium:

  • Frontal, parietal, occipital, sphenoid, ethmoid; protect the brain.

• Auditory ossicles:

  • Malleus, incus, stapes; in the middle ear.

• Facial bones:

  • Nasal, zygomatic, maxillary, mandible, etc.

Medical Specialists

• Chiropractor:

  • Spinal alignment focus (DC degree).

• Orthopedic surgeon:

  • Bones, joints, muscles treatment.

• Osteopath:

  • Spinal manipulation plus traditional medicine (DO degree).

• Podiatrist:

  • Foot disorders (DP/DPM degree).

• Rheumatologist:

  • Arthritis, osteoporosis, joint inflammation.

Skeletal System Pathology – Joints

• Ankylosis:

  • Immobility.

• Arthrosclerosis:

  • Joint stiffness.

• Bursitis:

  • Bursa inflammation.

• Chondromalacia:

  • Cartilage softening.

• Hallux valgus:

  • Bunion.

• Hemarthrosis:

  • Joint blood.

• Sprain:

  • Ligament tear.

• Synovitis:

  • Synovial membrane inflammation.

• Dislocation:

  • Luxation.

Spinal Column Pathologies

• Herniated disk:

  • Ruptured disk.

• Lumbago:

  • Low back pain.

• Spondylolisthesis:

  • Vertebrae slipping.

• Spina bifida:

  • Incomplete spinal canal closure.

• Kyphosis, Lordosis, Scoliosis:

  • Spinal curvatures.

Bone Conditions

• Avascular necrosis:

  • Bone tissue death due to poor blood supply.

• Osteitis:

  • Bone inflammation.

• Osteomalacia:

  • Adult rickets; soft bones due to vitamin D deficiency.

• Osteomyelitis:

  • Bone marrow inflammation.

• Osteoporosis:

  • OP; Bone density loss; porosity increase.

• Osteopenia:

  • Lower bone density than normal.

Fractures

• Closed fracture:

  • Complete fracture with no open skin wound.

• Open fracture:

  • Compound fracture with open wound.

• Comminuted fracture:

  • Bone is splintered or crushed.

• Incomplete fracture:

  • Bone not completely separated.

Diagnostic Procedures

• X-ray imaging (radiography):

  • Uses electromagnetic radiation.

• Arthroscopy:

  • Visual joint exam.

• Bone marrow biopsy:

  • For abnormal blood cell counts.

• Magnetic resonance imaging (MRI):

  • Images soft tissues in joints.

• Bone Density Testing:

  • For osteoporosis, etc.

• Dual x-ray absorptiometry (DXA):

  • More accurate bone density measurement.

Treatment Procedures

• Bisphosphonates:

  • Slow bone density loss.

• Bone Marrow Transplants (BMT):

  • For cancers; replace destroyed bone marrow.

• Orthotic:

  • Supports impaired limbs.

• Prosthesis:

  • Replaces missing body part.

• Arthrodesis:

  • Joint fusion.

• Arthroplasty:

  • Joint repair/replacement.

• Spinal fusion:

  • Joins vertebrae.

• Craniotomy:

  • Skull opening.

• Osteotomy:

  • Bone reshaping.