Bones of the Body

Bones of the Body

How many bones in the human body?

The human body encompasses the entire structure of what it means to call oneself a human being; including your thorax, head, neck, and accompanying appendages, such as your hands and feet. This extraordinary biological product was created through billions of years of biological evolution; as described by Charles Darwin in On the Origin of Species (1859). This is the theory that through incremental changes, through the mechanism of natural selection, species divert and evolve along their own evolutionary path. Human beings or, Homo sapiens, did not evolve from apes but, rather, share a common ancestor with apes. These changes are brought about by alterations in the genetic code, known as mutations.

Bones in Human Body

The wonderful thing about biological evolution is that it leaves behind some of these legacies. This is evident in one of the existing bones of the body – the tailbone. Known anatomically as the coccyx, this bone once formed part of a structure that supported a tail. As humans stopped clinging to the trees and began walking upright, the need for this tail declined – after all, it requires energy to maintain any part of your body, so why expend energy on a tail that’s never used any more? It’s this intrinsic logic of evolution that ultimately sacrificed our tail in favor of growth for other areas of our body, such as our enlarging brain.

Some might argue, but why does the tailbone still exist to some extent? This is because parts of the body that lose their function can still retain a minor function, in this case, serving as an attachment point for various muscles. The original purpose of a tail is to provide balance, but as one walks upright, we need not have an unnecessary hanging tail to aid us in this function. Some defunct organs can even develop new functions, something that has happened with the appendix. This organ was once required to aid in digestive processes, in the same way many species today use it to digest plant materials, such as cellulose.

Bone
Facts

Ossification is the name given to the formation of new bone in the body. For example, when bones become solid, the bones are said to ossify.

The end of a bone is known as its epiphysis while the shaft of a bone is known as its diaphysis.

The strength of bone comes from its high concentration of calcium phosphate – arranged in crystals known as hydroxylapatite. Bones also contain collagen which improved resistance to fractures.

Scrimshaw is the name given to engravings, artwork, and carvings performed on bones or ivory. The designer of scrimshaw is known as a scrimshander!

The study of bones and teeth is known as osteology – a subject that has wide application in subjects as diverse as archaeology, anatomy, and forensic science.

Bone Structure

Research has shown that the appendix lives on in humans in part because it developed a new function – to retain good bacteria in our gut that aid these digestive processes. These defunct parts of the body, such as the tailbone and the appendix, are known as vestigial organs, organs that once played a significant role in the past but which play a small or no role in the present. Many other bones of the body demonstrate this vestigiality; such as our wisdom teeth. These teeth were required by our ancestors to break down robust plant tissue and, moreover, our ancestors had larger jaws than us. As our diets changed so, too, has the size of our jaws, meaning we’re left with useless extra teeth that only cause harm.

So, how does understanding vestigial and evolutionary processes help us understand how many bones are in the human body? Quite simply as it’s these mechanisms that lead to an ever changing quantity of bones and muscles in our body. The dynamism of the human body means it’s constantly subject to genetic alterations, meaning the quantity of bones and muscles change over time. Humans, for instance, are born with approximately 270 bones – a significantly higher number that we have at adulthood – namely 206. This 64 bone difference arises out of the fact many of these bones fuse together as the child develops, forming sturdier, full-bodied bones – bones able to withstand falls and the stresses of everyday life.

Human Skeleton

The word skeleton comes from the Greek skeletosmeaning “dried body” or “mummy”. Mummy it isn’t, as the vitality of the body lives on in the movement and protection that the skeleton provides our internal organs. The human skeleton, though, is usually divided into two main types, depending on its overall structure and function:

  • The Axial Skeleton [80 Bones]
  • The Appendicular Skeleton [126 Bones]

The axial skeleton comprises your vertebral column, rib cage, and skull. This is in contrast with the appendicular skeleton that comprises all other limbs and appendages, such as arms, legs, and pelvic girdles. The axial skeleton provides protection for the most important organs of our body – the brain, spinal column, and heart – whereas the appendicular skeleton merely attaches appendages and limbs to this axial skeleton. Another way of thinking about it is that the appendicular skeleton allows movement whereas the axial skeleton provides the central structure to allow that movement to happen in the first place.

Did you know?

Our bones are constantly remodelling and being remade every day, to the point where we more-or-less possess new bones every seven years!

As well as providing movement and support, bones of the body are also used in blood cell production. This process, known as hematopoeisis, occurs due to the presence of flexible bone marrow tissue found inside the bone structure. A breathtaking 500 billion blood cells are produced each and every day in the bone marrow, manufacturing red blood cells (erythrocytes), white blood cells (leucocytes), and platelets (thrombocytes). Red blood cells are required to collect oxygen from our lungs and distribute it around the body to every cell which requires it for their metabolism. White blood cells are involved in maintaining the immune system while platelets function to stop bleeding; by forming plugs, as in scabs.

The axial skeleton is composed of all the familiar bones that make up this foundation structure, bones such as:

Bones of the Body Anatomical Name Other Axial Bones
Shoulder Blade Scapula Ribs
Collar Bone Clavicle Vertebrae
Breastbone Sternum Hipbone
Thigh Femur Hyoid Bone
Kneecap Patella
Shinbone Tibia
Calf Bone Fibula
Tailbone Coccyx

The vertebrae themselves are split into several distinct sections depending on their location along the column. The top seven vertebrae are called the cervical vertebrae; the next twelve are known as the thoracic vertebrate, while the lower five are known as the lumbar vertebrae. Beneath the lumbar vertebrae, we’ll find the sacrum – a large bone at the base of the spine. This sacrum is composed of five distinct and un-fused vertebrae, however these five bones begin to fuse around the age of 16 and remain completed fused by the age of 35. The medical condition, Spina bifida, often results in sacral and lower spinal malformations.

The first vertebra of the spine is known as the Atlas Bone, so named because of the Atlas of Greek Mythology who supported the world on the back of his head.

The only remaining part of the axial skeleton we haven’t yet looked at is the skull. Also known as the cranium, the skull is composed of eight different bones, each of which is fused with one another to give the appearance of one distinct skull. These bones include the frontal bone, parietal bone, temporal bone, occipital bone, sphenoid bone, and ethmoid bone. Such is the fascination with the human skull, that German physician Franz Joseph Gall developed his theory of Phrenology in 1796, the idea that you can determine one’s psychological attributes by analyzing the shape of the skull. No surprise, however, that it’s unanimously regarded as pseudoscience by the entire academic community.

We mustn’t forget the facial bones – all fourteen of them that comprise the jigsaw puzzle of our facial shape, bones of the body such as:

  • Mandible (Jawbone)
  • Maxilla
  • Palatine Bone
  • Zygomatic Bone (Cheekbone)
  • Nasal Bone/Inferior Nasal Conchae
  • Lacrimal Bone
  • Vomer

Hidden within our skull, we find the middle ear bones, including the smallest bone in the body – the stapes! Surrounding the stapes we have two other middle ear bones, the malleus and the incus. These bones take their Latin name for what they look like. So, for instance, the malleus bone takes its name as it’s shaped like a hammer, the incus as it’s shaped like an anvil, and the stapes as it’s shaped like a stirrup. These bones of the body are integral to the transmission of vibrations into the ear, with these vibrations ultimately rendered into meaningful sounds by the inner ear.

Bones of the Hand

Bones of the Hand

The anatomical wonder that is the human hand has bore many biological fruits. Some of these fruits bear out as the 27 bones that comprise each hand – meaning both of your hands hold 54 bones – over a quarter of the entire amount of bones of the body! And, if you think about it, this makes sense, particularly if you reflect on the type and amount of movement your hands and wrists engage in on a daily basis. From an evolutionary standpoint, hands play a crucial role in the management and acquisition of food, not appendages that would function well if they were only to host one bone each!

The bones from your knuckles to your fingertips are known as the phalanges, named depending on their location: proximal (near the knuckle), middle, and distal phalanges. Just before your knuckles, we find the metacarpal bones. The hand bones, therefore, comprise 40 of the 54 bones – with the remaining 14 bones within the wrist. These wrist bones are known as the carpal bones – locked like nuts and bolts into your wrist to aid overall movement and flexibility. These carpal bones include:

Scaphoid Bone Triquetrum Bone Trapezium Bone Capitate Bone
Lunate Bone Pisiform Bone Trapezoid Bone Hamate Bone

These wrist bones are, in turn, connected to the radius and ulna bones of the arm which are, in turn, connected with the humerus bone of the upper arm.

Bones of the Foot

Foot Bones

Probably just as anatomically complex as the hand, the bones of your foot are as numerous as they are flexible. The weight and pressure we exert on these bones day-to-day means it’s got to have some tough foundation in order to work effectively. And, this is precisely what we see – take a look at the sturdiness of the ankle bone (talus) and the heel bone (calcaneous), powerful bones that can take a lot of damage. Just like your hand, you possess phalanges (distal, intermediate and proximal), the toe bones which permit you flexibility while walking and balance in your aim to remain upright.

Unlike the metacarpals of the hand, we have the metatarsals of the foot. The simplest way to recall the difference is that metatarsals (with the ‘t’) are for toes – knowing this makes it impossible to forget metacarpals are in the hand. And, similar to the wrist, we’ve got a network of bones between the heel and your toes, ultimately facilitating movement, while providing support for the heel and ankle bones together. These bones of the foot include:

Cuboid Bone Navicular Bone Cuneiform Bone(s)
Calcaneous (Heel Bone) Phalanges Metatarsals
Talus (Ankle Bone)

The 206 bones of the human body have proven to be much more interesting than one might otherwise have imagined. It’s deceptively easy to think of the bones as somehow dead, lifeless, and inactive; there only to support the central organs of our body. To think this would be to miss out on the wide spectra of functions and capabilities of our bones, constantly being renewed in ways that profoundly influence how our body behaves – the bones of our body even secrete hormones, such as osteocalcin, into the body! So, in the end, we hold a greater gratitude of biological debt to our bones – a debt that continues to be paid in the form of the vestigial appendages we described above.

Quiz

The Olecranon is a bone found in which part of the body?

Which bones are the most commonly broken bones, accounting for over half of broken bones?

What is the only bone in the body which is not connected to any other bone?

What’s the name of the tissue that joins bone to bone in the formation of a joint?

Humans and which other animal have the same number of bones in their neck?

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