Basic Musculoskeletal Considerations

The Chiro.Org Blog

We would all like to thank Dr. Richard C. Schafer, DC, PhD, FICC for his lifetime commitment to the profession. In the future we will continue to add materials from RC’s copyrighted books for your use.

This is Chapter 6 from RC’s bestfselling book:

“Chiropractic Physical and Spinal Diagnosis”

These materials are provided as a service to our profession. There is no charge for individuals to copy and file these materials. However, they cannot be sold or used in any group or commercial venture without written permission from ACAPress.


The skeletal system provides the body framework, shape, articulations, supports, it protects the vital organs, and it furnishes a place for muscle attachment. It provides protection for the internal organs, provides movement when acted upon by muscles, manufactures blood cells, and stores mineral salts. The muscular system moves and propels the body. In order for the skeletal and muscular systems to function properly, the nervous system gives the body awareness of its environment, enables it to react to stimuli from the environment, and allows the body to work as a unit by coordinating its activities.

Inspection, palpation, and mensuration are the three most common techniques used in examination of the musculoskeletal system. As with all systems, a knowledge of anatomy and the pathophysiology involved is essential to make the examination significant.

The Functional Skeleton

The skeletal system includes the bones and their articulations. In addition to providing a bony framework, the skeletal system gives support and shape to the body. It provides protection for the internal organs, provides movement when acted upon by the muscles, manufactures blood cells, and stores mineral salts.

For study purposes, the 206 bones of the adult are divided into the 80 bones of the axial skeleton and the 126 bones of the appendicular skeleton. The axial skeleton includes the skull, vertebral column, ribs, and sternum. The appendicular skeleton includes the bones of the shoulder girdle, upper extremities, pelvic girdle, and lower extremities.

Bone is living tissue containing blood vessels and nerves within the hard bone structure. The osteocytes which form bone have the ability to select calcium and other minerals from blood and tissue fluid and to deposit the salts in the connective tissue fibers between cells. Bones become harder and brittle as age advances because there are higher proportions of minerals and fewer active osteocytes. The osteocytes in periosteum, which is rich in nerves and blood vessels, are active during growth and repair of injuries. The combination of hard and dense compact bone and porous cancellous bone produces maximum strength with minimal weight.

Bones are classified as long, short, flat, and irregular. Long bones in the extremities act as levers to produce motion when acted upon by muscles. Short bones, strong and compact, are in the wrist and ankle. Flat bones form the protective plates and provide broad surfaces for muscle attachments such as the shoulder blades and sternum. Irregular bones have many surfaces and fit into many locations such as the facial bones, vertebral and pelvic bones.

Long bones have a diaphysis and two epiphyseal extremities. The shaft is a heavy cylinder of compact bone with a central medullary cavity containing marrow, blood vessels, and nerves. Cancellous bone is located toward the epiphyses and is covered by a protecting layer of compact bone. Articular cartilage covers the joint surfaces at the ends of a long bone, providing a smooth contact surface in joint formation which gives some resilience for shock absorption. The periosteum, essential for bone nourishment and repair, is anchored to bone by connective tissue fibers. Bone repair is often inhibited when the periosteum is torn away or damaged in severe bone injury.

Projections on bones are often used as points of reference; in function, they serve as sites of muscle, tendon, or ligament attachment or as passageways for blood vessels and nerves. Because surface anatomy plays an important role in physical examination and spinal analysis, bony landmarks must be learned.

Review the complete Chapter (including sketches and Tables) at the ACAPress website