Anatomy - Musculoskeletal System

Skeletal System

The skeletal system is divided into two major parts:

1. Axial skeleton – which are the bones of the skull, vertebral column, hyoid bone, the ribs, and the sternum (breastbone).
2. Appendicular skeleton – which is the shoulder bones, the arms, the hip bones and the legs.

Structure of Bones

A bone is enclosed in a protective sheath known as the periosteum which contains blood vessels that help supply nutrients to the bone. Bones are classified into four general categories according to their shape and size as follows:

1. Long bones (such as the bones of the arms and legs)
2. Short bones (such as the wrist and ankle)
3. Flat bones (such as the bone that protects the brain, rib bones)
4. Irregular bones (such as facial bones)

Another part of the musculoskeletal system includes the joints of the body. There are six major joints as follows:

1. Hinge joint (knee)
2. Ball-and-socket joint (hip and shoulder)
3. Pivot joint (elbow)
4. Ellipsoid joint (fingers and toes)
5. Gliding joint (wrist and ankle)
6. Saddle joint (thumb)

Muscles

All muscles perform their work by contracting. Connective tissue covering a muscle tapers into a tough cord called a tendon. Most skeletal muscles are attached to bones by means of tendons. All skeletal muscles are attached at both ends.

The deltoid muscles form the curves of your shoulders and allow you to raise your arms out to the side. Your bicep brachii muscles allow you to bend your arms at the elbow. Your tricep brachii muscle lets you straighten your arms.

The hamstrings are a group of three muscles in the back of your thigh and work together to bend the leg at the knee.

When learning and coming to understand the musculoskeletal system, like many other things in science, there comes a vocabulary list that helps to identify the different parts of the system. Among those vocabulary words, and their meanings, are the following (see below).

If you are thinking of entering into the medical field one day, knowing this information will be invaluable to giving you a head start into your field of study. Even if you do not enter into that field, understanding the skeleton and muscle structure will help you to make wiser choices about what you do to your body and how to keep it healthy.

Building upon your understanding of the human body, below are ten questions on the musculoskeletal system. See if you can challenge yourself to get all the answers correct!