Human Skeleton

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Human Skeleton

Human Skeleton

The basic foundation of the body is provided by the bones called the skeleton. Now we shall get a general idea of the skeleton. The human skeleton may be divided into two parts. The first one is the axial skeleton, which contains the bones of the head, neck, and trunk. The second one is the appendicular skeleton which consist of the bones of the limbs.

Human Skull: –

It is the skeleton of the head. The skull contains a large cranial cavity in which the brain is lodged. The skull shows two large depressions just below the forehead, which called the right and left orbit, in which the eyes are lodged. In the region of the nose and mouth there have the apertures which lead into the interior of the skull. The skull is made up of large number of bones and these bones are firmly joined together. The frontal bone is in the region of the forehead. At the back of the head there is the occipital bone . The top of the skull, and the parts of its side walls, are formed mainly by the parietal bones (right and left). TwoTemporal bones are situated just above the both ears. The upper jaw form by the bone is the maxilla which also bears the upper teeth. The Zygomatic bone forms the prominence of the cheek. In the floor of the cranial cavity there is an unpaired bone namely thesphenoid bone. The mandible is bone of the lower jaw and the rest of the scull is separated from it. But, those are not all; several numbers of small bones also take part to structure the scull of the human skeleton.

Vertebral column : –

The central axis of the body, below the skull is formed by the vertebral column which is the backbone of the human body. A large number of irregular shape bones called vertebrae which made up the vertebral column. In the neck there have seven cervical vertebrae. Below these there are twelve thoracic vertebrae which forms the thorax of the human skeleton. Then the lower of the thoracic vertebrae there have five lumbar vertebrae which lie in the posterior wall of the abdomen. Sacrum is the lowest part of the vertebral column, which consist of five sacral vertebrae which are fused together and a small bone named the coccyx. Actually four rudimentary vertebrae fusing together made up the coccyx. So there is total thirty three vertebrae and if we take sacrum and coccyx as a single bone, the vertebral column is consisting of twenty six bones in human skeleton.

Thorax: –

A bony cage that protects the heart, the lungs, and some other organs called the thorax. It is made-up of twelve thoracic vertebrae at behind and a bone called sternum in

Human Thorax

Human Thorax

the front. Upper part of the sternum is the manubrium , lower part is the xiphoid process and the middle part is called the body. twelve ribs on the ether side formed the side wall of the thorax. Each of the ribs is a long curved shape bone attached posteriorly to the vertebral column. Anterior end of it is attached to a bar of costal cartilage through which it attaches the sternum. In the upper seven ribs this arrangement can be seen typically, and the 8th, 9th and 10th costal cartilages do not reach up to sternum and the ends get attach to the next higher cartilage. The 11th and 12th ribs are free in anterior namely the floating ribs.

Upper Limb: –

Each upper limb of human skeleton consists of the bones of the pectoral griddle which lie in close relation to the upper part of the thorax and those of the free limb. The collar bone clavicle and thescapula has made the pectoral griddle. A rod like bone placed in front of the upper part of the thorax is the clavicle. At medial it is attached to the manubrium of the sternum and at lateral to the scapula. Humerus is the bone of the arm. Radius and ulna are the two bones of the forearm, where as the lateral one is radius and the medial is the ulna. In the wrist there are eight small, roughly cuboids carpal bones. Five rod like metacarpal bones made up the palms, where the phalanges made up the fingers of human skeleton. The proximal, middle, and distal are the three phalanges in each finger (digit) except the thumb. The thumb has only proximal and distal. The upper end of humerus is joined to the scapula at the shoulder joints and at the lower end it joins to the radius and ulna and forms the elbow joint. Lower end of radius and ulna meet with the carpal bones is called the wrist joint.

Lower Limb: —

Lower limb of human skeleton consist of the bones of the pelvic griddle and the free limb. One hip bone on either side made up the pelvic griddle. Ilium is the upper extensive part of the bone. The pubis is a small in the front and the lower part of the bone is the ischium. Two pubic bones anteriorly meet in the midline joint which is the pubic symphysis, and the sacrum posteriorly fixed in between the two hip bones. Bony pelvis is formed by the hip bones, the sacrum and the coccyx. The bone of the thigh is called the femur which is the longest bone of the body. The leg consists of two bones. The tibia is the midial bone and the fibula is the outer bone of the leg. The three bones of the lower limb, the femur, the tibia and the fibula have the cylindrical shafts and expanded to upper and lower ends. Seven roughly cuboidal tarsal bones are in the region of the ankle, which is the posterior part of the foot. In the anterior part of the foot there are five metatarsal bones. Except the greet toe each toe has three phalanges, namely the proximal, middle and distal, where as the greet toe has no middle one. Into a deep socket in the hip bone called theacetabulum the upper end of the femur is fitted which is the hip joint. The lower end of the femur meets the tibia and form the knee joint. A small bone is situated in front of the knee, which is called the patella.The tibia and fibula are joined to each other at the both end and the upper joint is called the superior tibiofibular joint and the lower end is the inferior tibiofibular joint.

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