Bones of the Human Skeleton

Bones of the Human skeleton:

The adult human skeleton is composed of 206 bones. At birth, a baby initially has 300 bones. As the baby grows and develops, some of these bones fuses or joins together, giving a total of 206 bones afterwards.

Together, these 206 bones form a framework on which the body take its shape. This bony bodily framework that make up the body is termed skeleton.

The human skeleton is upright, thus giving them their unique upright appearance. In humans, it performs six main functions.

Please read on the functions of the human skeleton here.

 

Below are all the bones that make up the human skeleton:

1. The bones of the head and face, also referred to as the skull. It is made up of 22 bones. These are:

(A) The cranium or brain box which houses the brain. It is made up of 8 bones. The bones are:

• One frontal bone: Bone of the forehead
• Two parietal bones
• Two temporal bones
• One occipital bone: This bone is present at the posterior and lower part of the cranium. Think of it as the bone located at the back of the head.
• One sphenoid bone: This bone has the shape of a butterfly.
• One ethmoid bone: It lies between the two orbits just at the roof of the nasal cavity. For now, relate the orbits to the eye sockets.

(B) The bones of the face which is made up of 14 bones. These are:

• One mandible: This is the lower jaw bone. The lower 16 teeth are attached on the mandible.
• Two maxilla: This is the upper jaw bone. The upper 16 teeth are present on the maxilla. The maxilla contributes to the roof of the upper cavity. You can actually feel it by opening your mouth and touching its roof.
• Two palatine bones.
• Two zygomatic bones: They are the cheekbone on both sides of the face. This bone can be quite prominent in some people.
• Two nasal bones: These bones contribute to the length and size of the nose.
• Two lacrimal bones: They are the smallest bones of the face.
• One vomer
• Two inferior nasal conchae bones

Please read on Types of Bones here.

 

2. The Ears has 6 small Bones, 3 on each ear. All of these bones are present in the middle ear. They are:

• Two malleus or hammer: It is shaped like a hammer and is attached to the tympanic membrane or eardrum.
• Two incus or anvil: It has the shape of an anvil and connects the malleus bone to the stapes.
• Two stapes or stirrup: It is shaped like a stirrup.

 

3. The Throat has one bone named the hyiod bone

• Hyiod bone

Please read on the differences between bones and cartilages here.

 

4. The shoulder has 4 bones, two on each side. These bones attach the arm or upper limbs to the body. They include:

• Two clavicle bones or collar bones: These are a pair of long bones that is attached to the scapular at the lateral side and to the sternum (manubrium) at the medial side.
• Two scapula or shoulder blade bones: These are flat triangular bones found at the shoulder.

Note: Medial is an anatomical term that refers to any bodily part closer to the body's midline while the term lateral refers to the bodily part located away from the body's midline. Both terms will be used throughout this article.

The manubrium is the upper part of the sternum. The sternum is the bone at the center of your chest. The sternum holds the ribs anteriorly.

The glenoid cavity of the scapular attaches to the round head of the humerus to form the glenohumeral joint; and this is the most flexible (and weakest) joint in the human body, permitting movement in 360^o. This joint is a typical example of a ball and socket joint.

Together, the scapular, lateral side of the clavicle and the upper part of the humerus forms the pectoral girdle.

Please read on some Amazing Facts in Biology here.

 

5. The Thorax or Chest has 25 bones

The thorax extends between the neck and the abdomen. A muscular sheet called the diaphragm separates the thorax from the abdomen.

The bones of the thorax protect the heart and the lungs.

The thoracic bones are:

• 24 rib bones: They include 12 on each sides attached to the sternum anteriorly and each thoracic vertebrae posteriorly. The thoracic vertebrae are 12 in number.
• Sternum: The sternum is the bone at the center of your chest. The sternum holds the first 10 ribs anteriorly while the vertebral column attaches to the 12 ribs posteriorly. The last 2 ribs are unattached anteriorly and are thus referred to as floating ribs.

The sternum also holds the clavicle (collar bone) in its upper part called the manubrium.

The sternum can be divided into 3 parts. These are:

1. Manubrium

2. Body of the sternum

3. Xiphoid process

The ribs and sternum are important in the breathing process. Meanwhile, certain people may have an extra rib (13^th rib).

Please read on the Basic Characteristics of Life here.

Understand that the term anterior means 'in front' while posterior means 'behind' or 'at the back'.

 

6. The vertebral bones or vertebral column or spinal column are group of small bones found posteriorly and in the mid-line region of our body (back region).

Each vertebrae is joined together via a fibro elastic joint to form the vertebral column or spinal column.

These bones making up the vertebral column are 33 in numbers. They protect the spinal cord and serve as an attachment to the ribs posteriorly.

The vertebral bones include:

• Seven cervical vertebrae found in the neck region.
• Twelve thoracic vertebrae present in the thorax posteriorly.
• Five lumbar vertebrae present in the lumbar region of the body.
• One sacral vertebral bone present at the hip or pelvic region. The sacral vertebral bones are actually 5 separate bones that are fused to form the sacrum.
• One coccygeal vertebra: These bones are 4 in humans but are fused together as one. They are the tailbones in animals. In human and some primates, no tail is seen due to the fusion of these bones.

You can read on the uniqueness of man here.

 

7. The arm is the region extending from the shoulder joint to the elbow. It has 2 bones. These are:

• Two humerus, one for each arm: This is the single long bone of each arm. It commences from the shoulder joint and terminates at the elbow joint.

You can read on bone and bone cells here.

 

8. The forearm is the region between the elbow and the wrist. It has 4 bones. The bones are:

• Two ulna bones, one for each forearm: It is present at the medial side of the arm.
• Two radius bones, one for each forearm. It is present on the lateral side of forearm bones.

The ulna and radius are both prismatic in shape.

Please read on the classification of bones based on shape here.

 

9. The hand is the region between the wrist and the tip of the fingers. It is made up of 54 bones.

(A) 16 carpal bones, also called the wrist bones; 8 for each hand.

The 16 carpal bones are small irregularly shaped bones found in the wrist and arranged in two rows of four bones each. They are:

• 2 scaphoid bones

• 2 lunate bones

• 2 triquetral bones

• 2 pisiform bones

• 2 trapezium bones

• 2 trapezoid bones

• 2 capitate bones

• 2 hamate bones

(B) 10 Metacarpal Bones, 5 on each hand.

The metacarpals are the bones of the palms and they lie between the wrist and anterior end of the finger bones; (or between the tarsal bones and the phalanges)

(C) 28 finger bones or phalanges. You can observe these bones by looking at your fingers.

Understand that three phalangeal bones are present in each finger except for the thumb which has only two.

Each of these bones is separated by joints. You can observe these joints by making a fist.

The phalanges include:

• 10 proximal phalanges: The finger bones closest to the palm. They have a joint with the metacarpals.
• 8 intermediate phalanges: The thumb has no intermediate phalanges while other fingers have one each.
• 10 distal phalanges: The distal phalanges are closest to the fingers.

 

10. The pelvic or hip has 2 bones

The pelvis comprise of 2 coxal or innominate or hip bones. Both hip bones fuse at the middle to form the pelvis or pelvic girdle.

Each pelvic bone can be divided into 3 parts. These are:

1. Ilium

2. Ischium

3. Pubis

Please read on the Male Reproductive System here.

 

11. The thigh is the region between the hip and the knee. It is made up of 2 bones.

Two femur bones (one for each thigh). The femur is the longest and strongest bone in the human body. It’s also referred to as the thigh bone.

 

12. The leg is the region between the knee and the ankle. It comprises of 4 bones, two for each leg. These are:

• Two tibia bones: This is the second longest bone in the human body. Footballers wear shin guard to protect this bone. It is the bigger and longer of the leg bones.
• Two fibula bones: This is the thinner of the leg bones. It’s located lateral to the body and is also referred to as the calf bone.

 

13. Present in the knee joint are 2 patella bones.

• Two patella bones: It is a triangular shaped bone, forming a protective cap over the knee joint. People also refer to both bones as the Kneecaps.

 

14. The bones that make up the foot. They are 52 in numbers. They include:

(A) The tarsal bones also called the ankle bones: It comprises of 14 small bones. These are:

• 2 calcaneus bones: Bones of the heel

• 2 navicular bones

• 2 talus bones

• 2 medial cunieform bones

• 2 intermedite cunieform bones

• 2 lateral cunieform bones

• 2 cuboid bones

(B) 10 metatarsal bones, 5 on each foot.

The metatarsal bones lie between the ankle and the anterior end of the toe bones.

(C) 28 Phalanges or toe bones. These bones are put into the followings:

• 10 proximal phalanges, 5 for each foot.

• 8 intermediate phalanges. It is noteworthy to state that the big toe has no intermediate phalanges.

• 10 distal phalanges, 5 for each foot.