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The adult human body is made up of 206 bones. They range in size from the smallest in the middle ear to the largest in our thigh. The human body contains many bones, many of which can be found on yourself or a skeleton. There are about 270 bones at the time of birth, which later decreased to 206, with 80 bones in the axial skeleton and 126 bones in the appendicular skeleton. Of the 206 bones, 172 are part of a pair, and the remaining 34 are unpaired. Many small accessory bones, such as sesamoid bones, are not included in this.
The human skeleton is the internal framework of the human body. The skeleton’s bone mass accounts for approximately 14% of total body weight (ca. 10-11 kg for an average person) and reaches maximum mass between the ages of 25 and 30.
The human skeleton performs major functions, which include giving support, providing movement, protection, production of blood cells, storage of minerals, and endocrine regulation.
The human skeleton is not differentiated on the basis of sex, but subtle differences between sexes in the morphology of the skull, dentition, long bones, and pelvis exist.
List of Human Bone
The axial skeleton, comprising the spine, chest, and head, contains 80 bones. The appendicular skeleton, comprising legs and arms, including the shoulders and pelvic girdles, contains 126 bones, bringing the total for the skeleton to 206 bones.
The different bones that make up the human skeleton include,
- Spine (Vertebral Column)
The spine, also known as the vertebral column or backbone, is a crucial part of the human body’s skeletal system. It is a flexible, bony structure that extends from the base of the skull to the pelvis. The spine serves several important functions, such as providing support, protection, flexibility, and movement.
The spine is divided into five different regions:
- Cervical spine: The neck region, consisting of seven vertebrae (C1 to C7)
- Thoracic spine: the upper and middle back region, with twelve vertebrae (T1 to T12).
- Lumbar spine: the lower back region, composed of five vertebrae (L1 to L5)
- Sacrum: A triangular bone at the base of the spine, formed by the fusion of five sacral vertebrae.
- Coccyx: The tailbone is formed by the fusion of four coccygeal vertebrae.
- Chest (Thorax)
The thorax, or chest, is made up of several bones that form the rib cage and protect vital organs like the heart and lungs. The human rib cage contains 12 pairs of ribs. These ribs are attached to the spine’s thoracic vertebrae and wrap around to connect to the sternum directly or indirectly via cartilage.
The upper seven pairs of ribs are called true ribs because they connect directly to the sternum through cartilage, while the lower five pairs are called false ribs, some of them connect indirectly to the sternum or not at all. They are generally categorized as true and false ribs. False ribs are also considered floating ribs.
The bony structure that forms the head is known as the human skull. It is a complex bone framework that encases and protects the brain as well as supports the structures of the face. The main bones of the human skull consist of the cranium, mandible, maxilla, zygomatic bones, nasal bones, and ethmoid bones.
These bones work together to support the body, protect the brain, and house sensory organs such as the eyes and ears. These bones’ specific arrangement and fusion result in a rigid yet protective structure that allows for the complex functions of the head and face.
- Pelvis (Pelvic Girdle)
The pelvic bone, also known as the pelvic girdle or hip bone, is a set of bones that forms the skeletal structure of the pelvis in the human body. The pelvis is the basin-like structure at the base of the spine, and it plays a crucial role in supporting the weight of the upper body and protecting the internal organs in the pelvic cavity.
The pelvic bone is made up of three main bones on each side that fuse together as we age. These three bones are the ilium, ischium, and pubis. The fusion of these three bones creates a sturdy, ring-like structure known as the pelvic ring.
The pelvic ring encloses an opening called the pelvic inlet, through which the baby passes during childbirth. The pelvic bone also provides attachment points for muscles, supports the weight of the upper body, and contributes to maintaining balance and stability.
- Lower and Upper Limbs
The human limbs are divided into the upper limbs (arms) and lower limbs (legs). Each limb consists of several bones that contribute to the structure and function of the limb. Here are the main bones of the upper and lower limbs:
- Upper Limb Bones
- Humerus: The humerus is the bone of the upper arm, extending from the shoulder to the elbow.
- Radius and Ulna: These are the two bones of the forearm. The radius is on the thumb side, and the ulna is on the pinky side. They extend from the elbow to the wrist.
- Carpal Bones: The carpal bones are the small bones that make up the wrist. There are eight carpal bones, arranged in two rows.
- Metacarpal Bones: These are the long bones of the palm of the hand. There are five metacarpal bones, one for each finger.
- Phalanges: The phalanges are the bones of the fingers. Each finger has three phalanges (proximal, middle, and distal), except for the thumb, which has two.
- Lower Limb Bones
- Femur: The femur is the thigh bone and is the longest bone in the human body. It extends from the hip to the knee.
- Patella: The patella, commonly known as the kneecap, is a small, flat bone located in front of the knee joint.
- Tibia and fibula: These are the two bones of the lower leg. The tibia is the larger, weight-bearing bone on the inner side, and the fibula is the smaller bone on the outer side. They extend from the knee to the ankle.
- Tarsal Bones: The tarsal bones are the small bones that make up the ankle. There are seven tarsal bones.
- Metatarsal Bones: These are the long bones of the sole of the foot. There are five metatarsal bones, one for each toe.
- Phalanges: Similar to the fingers, the toes also have phalanges. Each toe has three phalanges, except for the big toe, which has two.
Human Bone Marrow
Bone marrow is a soft, spongy tissue found within the cavities of certain bones, most notably the femur (thigh bone), tibia (shin bone), and humerus (upper arm bone).
The process of blood cell formation in the bone marrow is called hematopoiesis. It involves the differentiation and maturation of blood cell precursors into mature blood cells. Bone marrow is a vital component of the human body’s hematopoietic system, ensuring the continuous production of blood cells essential for various physiological functions.
FAQ’s on Human Bones
How many major bones does the adult human body have?
The adult human skeleton usually consists of 206 named bones. These bones are divided into two categories: the axial skeleton and the appendicular skeleton. The vertical axis of the body is formed by the 80 bones of the axial skeleton. They consist of the skull, vertebral column, ribs, and breastbone or sternum.
How many bones are in the human body, female vs male?
The human skeleton contains 206 bones; male and female skeletons are common, but there are some differences based on size, shape, and so on. The size difference between the male and female skeletons is significant; the male skeleton is typically larger in size.
How many bones do we have in our body?
There are a total of 206 bones in an adult human body. This total decreases in infancy, and the average newborn has around 300 bones. The difference between the number of bones in an adult and an infant has to do with bone development.