Human Skeletal System



Human Skeletal System

Skeletal System in Humans

Human skeletal system is an endoskeleton, composed of 206 bones. The main fuctions of skeletal system are as follows:

It provides support t6o the body

It allows movement of the body

It protects the internal organs of body

Bone marrow produces blood cells

It stores lipids and minerals

Types of Skeletal System

The skeletal system is basically divided into two types; axial Skeleton and appendicular skeleton.

Axial Skeletal System

The axial skeleton consists of the central axis of body. It is composed of skull bones, ossicles of ears, hyoid bone of throat, rib cage and vertebral column.

Skull Bones

The skull bones act as brain case. They protect the brain from external harm. They also provide support to the face structures. The skull bones are further classified into two types; cranial bones and facial bones. The cranial bones serve the function of protection of brain, and site for muscle attachment of head and neck.

Ossicles of Middle Ear

The auditory ossicles transfer sound waves from the air to the cochlea, in form of vibrations. The auditory ossicles have two hammer bones, two incus bones and two stirrups. Facial bones give spaces for facial sense organs and provide attachments for facial muscles.

Hyoid Bone of Throat

Hyoid bone is located in front of the neck. It is joined with the muscles of jaw, larynx and tongue. It aids in the movement of tongue. The mandibles also support movement of mouth.

Vertebral Column

It is made up of 26 bones out of which 24 are vertebrae, the sacrum and coccyx. The length of vertebral column in vertebrates is approximately 70cm. The vertebral column serves the following functions in human body:

It gives protection to spinal cord. The vertebral column has a hole in which the spinal cord runs.

It keeps the head in position

It provides attachment sites for the ribs and muscles

Rib Cage

The rib cage is also called thoracic cage. It has four parts, ribs, sternum, vertebra and costal cartilages. The rib cage provides protection to the body organs like heart and lungs. It provides attachment site for the diaphragm, back muscles, chest, neck and shoulders. It also supports shoulder girdles and upper limbs. The anterior bone at the chest is called sternum. It is made up of many bones. The rib cage contains 12 pairs of ribs.

Appendicular Skeleton

It consist of upper and lower limbs bones. It is further divided into two parts; pectoral girdle and pelvic girdle.

Pectoral Girdle

The pectoral or shoulder girdle connects the upper limbs to the body. On the anterior side clavicles or collar bones are present, on the posterior side scapulae or shoulder bone is present. The upper limb contains the bones of arm. The upper limb has largest bone called humerus. The upper limb consists of forearm, and hand. The hand consists of palm, wrist bones and finger bones.

Pelvic Girdle

Pelvic girdle attaches the lower body to the axial ...