Human Skeletal System: Anatomy and its Functions

The human skeletal system consists of bones, cartilage, and tendons, and human adults have 206 bones. On the contrary, children’s skeletons contain more bones since some of them, including those of the skull, fuse together when they grow up. 

Parts of the Skeletal System

The human skeletal system is divided into two parts: The axial skeleton and the Appendicular skeleton.

1. Axial Skeleton System

The axial skeleton system is made up of 80 bones. It includes skull bones, auditory ossicles, hyoid, vertebral column, and thoracic cage.

a. Skull 

The human skull comprises 22 bones. The skull bones can be further classified into:

Cranial bones: the cranial bone forms the bulk of the human skull, which further protects the human brain.

Facial bones: there are in total 14 facial bones which makes up the front of the human skull and face.

b. Auditory ossicles

The auditory ossicles are the small bones located within the inner ear canal in the human skull. There are three auditory ossicles on each side of the head, which makes it total six in number. They are the malleus (hammer), incus (anvil) and stapes (stirrup). The ossicles work together to transmit sound waves to the inner ear structures.

c. Hyoid

The hyoid is a U-shaped bone found at the base of the human jaw. It acts as a link between the muscles and ligaments in the neck.

d. Vertebral column

The vertebral column consists of 26 bones. The first 24 bones are all vertebrae, and the rest two are sacrum and coccyx (tailbone).

e. Thoracic cage

The thoracic cage consists of the breastbone and 12 pairs of ribs. The bones form a protective cage around the upper torso, including the heart and lungs.

2. Appendicular Skeleton System

The appendicular skeleton system is made up of 126 bones. It includes the pectoral gilder, upper limbs, pelvic gilder, and lower limbs.

a. Pectoral gilder

It is a place where arms attach to the axial skeleton. The pectoral gilder consists of the collarbone and shoulder blade, one for each arm.

b. Upper limbs

Upper limbs consist of 30 bones in total. These are humerus, radius, ulna, carpals, metacarpals and phalanges.

c. Pelvic gilder

The pelvic girdle is commonly known as hips where legs attach to the axial skeleton. It consists of two hipbones, one for each leg.

d. Lower limbs

The lower limbs comprise of 30 bones namely, femur, tibia, fibula, patella, tarsals, metatarsal and phalanges. 

Conditions affecting the Skeletal System

The conditions which affect the skeletal system include fractures, arthritis, metabolic bone diseases, cancer, and spinal curvatures.

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