Human skeleton

Page semi-protected
Source: Wikipedia, the free encyclopedia.

Human skeleton
Oklahoma City, Oklahoma
Details
Identifiers
Greekσκελετός
TA98A02.0.00.000
TA2352
FMA23881
Anatomical terminology]

The human skeleton is the internal framework of the

pelvic girdle
and the bones of the upper and lower limbs.

The human skeleton performs six major functions: support, movement, protection, production of

blood cells
, storage of minerals, and endocrine regulation.

The human skeleton is not as

penile bones.[4]

Divisions

Axial

The axial skeleton (80 bones) is formed by the

skull
(22 bones and 7 associated bones).

The upright posture of humans is maintained by the axial skeleton, which transmits the weight from the head, the trunk, and the upper extremities down to the lower extremities at the

hip joints. The bones of the spine are supported by many ligaments. The erector spinae muscles
are also supporting and are useful for balance.

Appendicular

The appendicular skeleton (126 bones) is formed by the pectoral girdles, the upper limbs, the pelvic girdle or pelvis, and the lower limbs. Their functions are to make locomotion possible and to protect the major organs of digestion, excretion and reproduction.

Functions

The skeleton serves six major functions: support, movement, protection, production of blood cells, storage of minerals and endocrine regulation.

Support

The skeleton provides the framework which supports the body and maintains its shape. The pelvis, associated ligaments and muscles provide a floor for the pelvic structures. Without the

lungs
would collapse.

Movement

The joints between bones allow movement, some allowing a wider range of movement than others, e.g. the ball and socket joint allows a greater range of movement than the pivot joint at the neck. Movement is powered by skeletal muscles, which are attached to the skeleton at various sites on bones. Muscles, bones, and joints provide the principal mechanics for movement, all coordinated by the nervous system.

It is believed that the reduction of human bone density in prehistoric times reduced the agility and dexterity of human movement. Shifting from hunting to agriculture has caused human bone density to reduce significantly.[5][6][7]

Protection

The skeleton helps to protect many vital internal

organs
from being damaged.

Blood cell production

The skeleton is the site of

blood cells that takes place in the bone marrow. In children, haematopoiesis occurs primarily in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum.[8]

Storage

The

hydroxyapatite
, the latter making up 70% of a bone. Hydroxyapatite is in turn composed of 39.8% of calcium, 41.4% of oxygen, 18.5% of phosphorus, and 0.2% of hydrogen by mass. Chondroitin sulfate is a sugar made up primarily of oxygen and carbon.

Endocrine regulation

Bone cells release a

fat deposition. Osteocalcin increases both insulin secretion and sensitivity, in addition to boosting the number of insulin-producing cells and reducing stores of fat.[9]

Sex differences

Scarborough Railway Bridge in 1901, workmen discovered a large stone coffin, close to the River Ouse. Inside was a skeleton, accompanied by an array of unusual and expensive objects. This chance find represents one of the most significant discoveries ever made from Roman York
. Study of the skeleton has revealed that it belonged to a woman.

Anatomical differences between human males and females are highly pronounced in some soft tissue areas, but tend to be limited in the skeleton. The human skeleton is not as

skull, dentition, long bones, and pelvis are exhibited across human populations. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within a given population.[citation needed
] It is not known whether or to what extent those differences are genetic or environmental.

Skull

A variety of gross morphological traits of the

Dentition

Human inter-sex dental dimorphism centers on the canine teeth, but it is not nearly as pronounced as in the other great apes.

Long bones

Long bones are generally larger in males than in females within a given population. Muscle attachment sites on long bones are often more robust in males than in females, reflecting a difference in overall muscle mass and development between sexes. Sexual dimorphism in the long bones is commonly characterized by morphometric or gross morphological analyses.

Pelvis

The human pelvis exhibits greater sexual dimorphism than other bones, specifically in the size and shape of the pelvic cavity, ilia, greater sciatic notches, and the sub-pubic angle. The Phenice method is commonly used to determine the sex of an unidentified human skeleton by anthropologists with 96% to 100% accuracy in some populations.[11]

Women's pelvises are wider in the pelvic inlet and are wider throughout the pelvis to allow for child birth. The sacrum in the women's pelvis is curved inwards to allow the child to have a "funnel" to assist in the child's pathway from the uterus to the birth canal.

Clinical significance

There are many classified skeletal disorders. One of the most common is osteoporosis. Also common is scoliosis, a side-to-side curve in the back or spine, often creating a pronounced "C" or "S" shape when viewed on an x-ray of the spine. This condition is most apparent during adolescence, and is most common with females.

Arthritis

Arthritis is a disorder of the joints. It involves inflammation of one or more joints. When affected by arthritis, the joint or joints affected may be painful to move, may move in unusual directions or may be immobile completely. The symptoms of arthritis will vary differently between types of arthritis. The most common form of arthritis, osteoarthritis, can affect both the larger and smaller joints of the human skeleton. The cartilage in the affected joints will degrade, soften and wear away. This decreases the mobility of the joints and decreases the space between bones where cartilage should be.

Osteoporosis

Osteoporosis is a disease of bone where there is reduced

medications, specifically glucocorticoids.[12] Osteoporosis usually has no symptoms until a fracture occurs.[12] For this reason, DEXA scans are often done in people with one or more risk factors, who have developed osteoporosis and be at risk of fracture.[12]

Osteoporosis treatment includes advice to stop smoking, decrease alcohol consumption, exercise regularly, and have a healthy diet. Calcium supplements may also be advised, as may vitamin D. When medication is used, it may include bisphosphonates, strontium ranelate, and osteoporosis may be one factor considered when commencing hormone replacement therapy.[12]

History

India

Suśruta-saṃhitā, composed between 6th century BCE and 5th century CE speaks of 360 bones. Books on Salya-Shastra (surgical science) know of only 300. The text then lists the total of 300 as follows: 120 in the extremities (e.g. hands, legs), 117 in the pelvic area, sides, back, abdomen and breast, and 63 in the neck and upwards.[14] The text then explains how these subtotals were empirically verified.[15] The discussion shows that the Indian tradition nurtured diversity of thought, with Sushruta school reaching its own conclusions and differing from the Atreya-Caraka tradition.[15] The differences in the count of bones in the two schools is partly because Charaka Samhita includes thirty two teeth sockets in its count, and their difference of opinions on how and when to count a cartilage as bone (both count cartilages as bones, unlike current medical practice).[16]

Hellenistic world

The study of bones in ancient Greece started under

Ptolemaic kings due to their link to Egypt. Herophilos, through his work by studying dissected human corpses in Alexandria, is credited to be the pioneer of the field. His works are lost but are often cited by notable persons in the field such as Galen and Rufus of Ephesus. Galen himself did little dissection though and relied on the work of others like Marinus of Alexandria,[17] as well as his own observations of gladiator cadavers and animals.[18] According to Katherine Park, in medieval Europe dissection continued to be practiced, contrary to the popular understanding that such practices were taboo and thus completely banned.[19] The practice of holy autopsy, such as in the case of Clare of Montefalco further supports the claim.[20] Alexandria continued as a center of anatomy under Islamic rule, with Ibn Zuhr a notable figure. Chinese understandings are divergent, as the closest corresponding concept in the medicinal system seems to be the meridians, although given that Hua Tuo
regularly performed surgery, there may be some distance between medical theory and actual understanding.

Renaissance

De humani corporis fabrica, which contained many illustrations of the skeleton and other body parts, correcting some theories dating from Galen, such as the lower jaw being a single bone instead of two.[23] Various other figures like Alessandro Achillini
also contributed to the further understanding of the skeleton.

18th century

As early as 1797, the death goddess or folk saint known as Santa Muerte has been represented as a skeleton.[24][25]

See also

References

  1. .
  2. ^ "Healthy Bones at Every Age". OrthoInfo. American Academy of Orthopaedic Surgeons. Archived from the original on 18 November 2022. Retrieved 6 January 2023.
  3. ^ Thieme Atlas of Anatomy, (2006), p 113
  4. ^ "Switching Farming Made Human Bone Skeleton Joint Lighter". Smithsonian Magazine. 23 December 2014.
  5. ^ "Light human skeleton may have come after agriculture". Retrieved 4 March 2017.
  6. ^ "With the Advent of Agriculture, Human Bones Dramatically Weakened". 22 December 2014. Archived from the original on 13 March 2017. Retrieved 4 March 2017.
  7. PMID 24237971
    .
  8. .
  9. ^ Buikstra, J.E.; D.H. Ubelaker (1994). Standards for data collection from human skeletal remains. Arkansas Archaeological Survey. p. 208.
  10. PMID 5772048
    .
  11. ^
    ISBN 978-0-7020-3085-7. {{cite book}}: |first= has generic name (help)CS1 maint: multiple names: authors list (link
    )
  12. .
  13. ^ Hoernle 1907, p. 70.
  14. ^ a b Hoernle 1907, pp. 70–72.
  15. ^ Hoernle 1907, pp. 73–74.
  16. S2CID 37476347
    .
  17. .
  18. ^ "Debunking a myth". Harvard Gazette. 7 April 2011. Retrieved 12 November 2016.
  19. .
  20. ^ Sooke, Alastair. "Leonardo da Vinci: Anatomy of an artist". Telegraph.co.uk. Retrieved 9 December 2016.
  21. ^ Bambach, Carmen. "Anatomy in the Renaissance". The Met’s Heilbrunn Timeline of Art History.
  22. ^ "Vesalius's Renaissance anatomy lessons". www.bl.uk. Retrieved 18 December 2016.
  23. . Retrieved 2021-11-30.
  24. ^ Livia Gershon (October 5, 2020). "Who is Santa Muerte?". JSTOR Daily. Retrieved 2021-11-30.

Bibliography