The Skeleton

Underneath the human body is a skeleton. The word skeleton comes form the Greek word meaning "dried up body" or "mummy."This skeleton is made up of 206 bones. At birth, the baby may have from 300-350 bones that later on end up fusing together. About 20% of body mass is in the skeleton, which is made up of bones, cartilages, joints, and ligaments.

The Skull

The skull is formed by 22 cranial and facial bones.Most of the skull bones are flat, except for the mandible (jawbone). The purpose for the cranium is to protect the brain and to provide a place for the head and neck muscles to attach. The facial bones serve for five purposes;

• they form the framework for the face
• house the cavities for the organs of sight, taste, and smell
• provide a place for passage of air and food
• provide a place for teeth to attach
• provide a place for the muscles of expression

Most of the skull bones are flat, with the exception of the mandible.

The Cranium

The cranium is made up of eight boines. These bones form a protective helmet to protect the brain. The cranium is made up of the following bones:

• 2 temporal bones- The bones above the ears on each side of the skull.
• 2 parietal bones- The curved bones that form most of the superior and lateral aspects of the skull
• 1 frontal bone- The anterior part of the skull. It is also known as the forehead.
• 1 occipital bone- The bone at the back of the head above the neck.
• 1 sphenoid bone- A butterfly shaped bone that forms the central wedge to articulate with the other bones.
• 1 ethmoid bone- Positioned between the sphenoid and the nasal bones of the face.

The Facial Bones

The facial skeleton is made up 14 bones.

• mandible- the strongest bone of the face (jawbone)
• vomer- the bone that forms part of the nasal septum
• 2 maxillary bones-the upper jaw and the center of the facial skeleton
• 2 Zygomatics- the cheekbones
• 2 nasals-form the bridge of the nose
• 2 lacrimals-fit in the middle of both orbits (eye sockets)
• 2 palatines-from the back part of the nasal cavity and a small tip of the orbits
• inferior nasal conchae-form the lateral walls of the nasal cavity

The vertebral column is known as the spine. It is made up of 26 bones and serves as a support trunk for the skull to the pelvis. The pelvis is the point in which the weight is transferred to the lower limbs.It also protects the delicate spinal cord and gives a place for the ribs and muscles in the back of the neck to attach.

The vertebral column is 28 inches long in the average adult. It is made up of the five following divisions:

• 7 cervical vertebrae-known as C1-C7-the smallest and lightest vertebrae
• 12 thoracic verterbae-known as T1-T12-these articulate with the ribs
• Lumbar Vertebrae-known as the small of the back
• Sacrum-shapes the posterior wall of the pelvis
• Coccyx-tailbone

The Bony Thorax

The thorax is known as the chest. The purpose of the thorax is to provide protection around the vital organs of the thoracic cavity. These organs are the heart, lungs, and great blood vessels. It also supports the shoulders and upper limbs, and provides a place for the muscles of the neck, back, chest and shoulders to attach.

The Sternum

The sternum is in the center of the thorax. It looks like a dagger and is about 6 inches long. The sternum is made up from the fusion of the manubrium, the body, and the xiphoid process. The sternum is also known as the breastbone.

Ribs

There are 12 pair of ribs in the human body. All of thee ribs attach to the thoracic vertebrae. The upper ribs from the back side of the body (posteriorly). The upper seven pair of ribs attach to the sternum. These are known as the true ribs. The last five ribs are known as false ribs. They attach indirectly to the sternum.

The appendicular skeleton is the part of the skeleton that forms the longitudial part of the body. The appendicular skeleton allows us to carry things and be able to move freely.

The Shoulder

The shoulder is made up of the clavicle and the scapulae. The two clavicles(collarbone) extends horizontally across the upper thorax. It's purpose is to provide a place for muscles to attach, and to hold the scapulae and arms out laterally. The clavicles are not very strong and can break very easily.

The Scapulae (shoulder blades) are above the ribcage. Both of the scapuleas form part of the shoulder and articulates with the humerus and the clavicle.

The Upper Limbs

The sole bone of the arm is the humerous. It is the longest and largest bone in the body. It connects to the scapula and the ulna at the elbow. The ulna nerve runs behind the bone and is the reason you experience a painful sensation when you hit your (funny bone) or humerous.

The forearm is made up of two bones; the ulna and the radius. The ulna is slightly longer than the radius. It forms the elbow joint along woth the humerous. the end of this bone looks like a monkey wrentch. This bone is like a hinge and allows flexibility in the arm.

The radius looks like the head of a nail. This bone contributes most to the wrist joint. It allows hand movement.

The Hand

The hand is made up of the carpus (wrist); the metacarpus(palm); and the phalanges (bones of the fingers).

The carpus is the part of the hand. it consist of eight short bones called carpals. It is very flexible.The carpals are arranged in two rows of four bones:

• scaphoid
• lunate
• triquetral
• pistiform
• trapezium
• trapeziod
• capitate
• hamate

The Metacarpus is also known as the palm. The small bones of the palm are not named but are numbered 1-5 from thumb to pinky.

The Phalanges are also known as the fingers or digits. they are also numbered from 1-5 beggining with the thumb. The thumb is called the pollex. Each hand has 14 phalanges.

The Pelvic Girdle

The plevic girdle is known as the hip. The purpose for this bone is to attach the lower limbs to the axial skeleton, transmit the weight to the lower limbs, and support the viceral organs of the pelvis. The pelvic girdle is formed by a pair of hip bones. The structure formed by the hip bones and the sacrum is called the bony pelvis. The point of the hip bone where the ilium, ischium, and pubis fusion is called the acetabulum.

• The ilium is the large bone that forms the upper part of the coxal bone.
• The Ischium forms the postoinferior part of the hip bone.
• The pubis or pubic bone forms the anterior part of the hip bone.

The Lower Limbs

The lower limbs are strong and thick to hold up the upper body. The three parts to the lower limbs are the thigh, the leg, and the foot.

The femur or thigh is the strongest bone in the body. It can endure alot of stress and allows a person to jump and bounce. The femer is covered in alot of muscle. The length of the femer is one quater of a person's size.

Two parallel bones form the leg. They are the fibula and the tibia. The tibia or shinbone takes the weight from the femur and gives it to the foot. The fibula does not bear any weight and is alot thicker than the fibula.

The Foot

The foot is made up of the tarus, metatarsus, and the phalanges.

The Tarus is made3 up of seven tarsal bones. The human body weight is carried mostly by the two longest, outside tarsals.

The metatarsus is made up of 5 small long bones called metatarsals. The metatarsals are numbered from 1-5 starting with the planter.

There are 14 phalanges in the toes. they are alot smaller than those in the fingers. The great toe is known as the hallux.