Posts tagged spine
Brown-throated sloth - Bradypus variegatus
The brown-throated sloth is one of the three-toed sloths, and lives in the neotropical regions of South America. Though the species as a whole eats a wide variety of leaves, each individual sloth tends to specialize in one to three species, and preferentially eats from those particular trees.
As sloth babies begin to eat leaf particles from their mother’s fur as early as the fourth day of life, they tend to develop the same leaf preferences as her.
That said, sloths aren’t so picky that they won’t eat any other leaves. You may like pizza a whole lot, but would you really JUST eat pizza your whole life? Sloths tend to slow their eating habits significantly when they’re allowed to eat only the species they appeared to be most preferential of initially.
Brehm’s Tierleben: Allgemeine Kunde des Tierreichs. Prof. Otto zur Strassen, 1912.
Plaster model of executed Chinese pirate
The neck stump of this executed Yangzee River pirate is surprisingly accurate for what was probably a sideshow prop. The cervical spine, blood vessels, muscles, trachea, and esophagus are all visible.
The muscular nature of the esophagus is highly visible here. You can also see the hardness of the trachea.
The donation of this model to the Science Museum London came with little accompanying information, but it is known that it was produced in England, between 1910 and 1922. The braid is real human hair, and the plaster and finish is of a high quality. Given its “blood-splattered” carrying case, it was most likely a prop in a traveling sideshow.
Extreme case of kyphotic lordosis.
Kyphosis: Greek kyphos, ”a hump” - the over-curvature of the thoracic vertebrae in the upper back.
Lordosis: Greek lordos, ”bent backwards” - the inward curvature of a portion of the lumbar and cervical vertebral column. All spines should be lordotic to an extent, but an excessive inward curvature (often caused by anterior pelvic tilt) can cause many orthopedic problems.
Orthopadische Chirurgie. Dr. August Schreiber, 1888.
Position of the spinal cord in the vertebral canal
The spinal cord proper does not extend the entire length of the vertebral canal. It ends between the first and second lumbar vertebra (two vertebra below the last set of ribs - just below the middle of the back), and a bundle of nerves that extend from it, called the cauda equina (“horse’s tail”), extends the rest of the way down the back, and into the sacrum.
In adults, the spinal cord is usually between 17-18 inches long (43-45 cm).
Atlas of Applied (Topographical) Anatomy for Students and Practitioners. Dr. Karl von Bardeleben and Dr. Heinrich Haeckel, 1906.
Corrective orthopedic apparatuses for antero-posterior curvature of the spine (Pott’s disease)
From the Charles Lentz & Sons Illustrated Catalog of Surgical Instruments. 1915.
Tuberculous spondylitis - Historically known as “Pott’s Disease”
Pott (or Pott’s) disease was named after Percivall Pott, who wrote several lectures on the nature and treatment of this condition.
The name “tuberculous spondylitis” comes from the disease tuberculosis, and the Greek “spondylos”, meaning spine, and “-itis”, meaning swelling. This is actually a form of chronic osteomyelitis, generally found in the lower thoracic or upper lumbar spine of adults. It’s also one of the oldest chronic conditions for which we have archaeological evidence.
Before tuberculosis had effective treatment modalities, this was one of the most common bone afflictions in adults. There were often internal abscesses that the infection drained into, which, while generally not the primary concern, could rupture and cause peritonitis or generalized infection of the thoracic cavity.
As the condition advanced, the degeneration of the bone often caused spinal cord compression and so-called “Pott’s paralysis” - a form of paraplegia that was actually reversible if the pressure was taken off the spinal cord soon after it started. This was usually done by stiff metal or (later) plastic braces or medical corsets. Once the infection advanced to the point that paralysis was caused, it often caused a complete collapse of the affected vertebrae, and could result in thoracic kyphosis, or “hunchback”.
The images above show a mummified priest of Ammon, from the XXIst dynasty (1000 BCE) of Egypt, with the characteristic lateral protrusion of the spine (left image) that hasn’t yet advanced to a collapse of the spinal discs. There is also a large sac in the abdomen (right image) that was soft when mummification occurred, and which would have been the abscess where the infection drained. There was evidence that the priest lived for over a decade with this condition, and it was probably not what killed him in the end.
Studies in the Paleopathology of Egypt. Sir Marc Armand Ruffer, 1921.
![Hero or Armored Shrew (Scutisorex somireni)
This curious creature is very cool, and not nearly well-known enough! Its unique characteristics make it almost as fascinating as the tuatara, but I have seen so very few articles or papers published regarding the species - though the fact that it only lives in central Africa in the deep jungle, in a land of rebel fighters and landmines, probably doesn’t make it very conducive to making researchers desire to go out there and find out more about them.
From what we already know, the armored shrew is unique among mammals, as it has an incredibly strong interlocking spinal column. Early vertebrates had a spine that was interlocking, and today the trait is carried on in many reptiles, amphibians, and the gar fish. However, mammals lost the interlocking spine when they no longer had to carry a disproportionate amount of weight in their thorax and abdomen, and the armored shrew is a callback to the days when we were first differentiating from lizards. From what we know about mole and shrew evolution, it’s presumed that the interlocking spine re-emerged in this species, after millenia of having “normal”, non-interlocking bones for the spinal column.
Thanks to their incredibly strong spine, they are able to withstand incredible weights compared to other similarly-sized mammals. A paper written in 1917 regarding the strength of the interlocking spine noted that “the column can withstand the weight of a 160 lb human without harm”. I really have to wonder about how they found that out - a 160 lb human is different than 160 lbs of pressure, due to weight distribution. I have to assume there was, at least at some point, a researcher literally standing on top of their shrew.
The Congo Expedition of the American Museum of Natural History. Published Aug 1, 1919.
[p.s. Thanks to octoberwaffle for bringing this slice of awesome to my attention - it’s been a long time since I was completely clueless about the existence of such a cool creature!]](http://24.media.tumblr.com/tumblr_md7h87i4A01qk931ho1_400.jpg)
Hero or Armored Shrew (Scutisorex somireni)
This curious creature is very cool, and not nearly well-known enough! Its unique characteristics make it almost as fascinating as the tuatara, but I have seen so very few articles or papers published regarding the species - though the fact that it only lives in central Africa in the deep jungle, in a land of rebel fighters and landmines, probably doesn’t make it very conducive to making researchers desire to go out there and find out more about them.
From what we already know, the armored shrew is unique among mammals, as it has an incredibly strong interlocking spinal column. Early vertebrates had a spine that was interlocking, and today the trait is carried on in many reptiles, amphibians, and the gar fish. However, mammals lost the interlocking spine when they no longer had to carry a disproportionate amount of weight in their thorax and abdomen, and the armored shrew is a callback to the days when we were first differentiating from lizards. From what we know about mole and shrew evolution, it’s presumed that the interlocking spine re-emerged in this species, after millenia of having “normal”, non-interlocking bones for the spinal column.
Thanks to their incredibly strong spine, they are able to withstand incredible weights compared to other similarly-sized mammals. A paper written in 1917 regarding the strength of the interlocking spine noted that “the column can withstand the weight of a 160 lb human without harm”. I really have to wonder about how they found that out - a 160 lb human is different than 160 lbs of pressure, due to weight distribution. I have to assume there was, at least at some point, a researcher literally standing on top of their shrew.
The Congo Expedition of the American Museum of Natural History. Published Aug 1, 1919.
[p.s. Thanks to octoberwaffle for bringing this slice of awesome to my attention - it’s been a long time since I was completely clueless about the existence of such a cool creature!]
Thorax and shoulder girdle
The shoulder girdle is also known as the pectoral girdle. It consists of the clavicle and scapula, and connects the upper limbs of the body to the axial skeleton (the parts that aren’t in the chest or abdomen).
Unlike the pelvic girdle, the pectoral girdle in humans is almost completely non-weight-bearing, and fairly fragile - anyone who has landed hard on their arms (which have very strong bones), but broken their clavicle (with its weak structure), can tell you this in graphic detail.
Gray’s Anatomy. Henry Gray et al, 1911.
Internal View of Lumbar Region
Thanks to the thick, protective mesentery and sheer mass of the intestines (not to mention the consequences if they’re damaged), many surgeries of the pelvic and lumbar organs are performed by opening the back, instead of the abdomen.
You can clearly see both the ascending and descending colon and the kidneys in this dissection.
Anatomy, Descriptive and Surgical. Henry Gray, 1911.
Anatomy of the coccyx and sacrum
In reference to this question, here is the anatomy of the coccyx and sacrum. As can be seen, the sacral portion of the spinal column is still significantly important, in terms of both structural importance and nervous integration/protection. However, the coccygeal spine does little more than anchor two pelvic muscle pairs, and a few ligaments.
In terms of “having a tail”, the closest humans tend to come to that is being born with a tiny, flesh-covered tail (when the coccyx is malformed), which is almost always removed straight after birth, or being born with spina bifida occulta, which can often present with a birthmark over the site of the malformed vertebrae, which has a tendency to grow hair. This hair has occasionally grown long enough to warrant a person inclusion in a “freak show” as a “tailed man/woman” in the recent past.
Lewis Sayre and his suspension device for the treatment of scoliosis (1877)
Study of ancient bones reveal current day infectious disease brucellosis has existed since at least medieval times. (via Scientists crack medieval bone code)
Extreme case of kyphotic lordosis.
Kyphosis: Greek kyphos, ”a hump” - the over-curvature of the thoracic vertebrae in the upper back.
Lordosis: Greek lordos, ”bent backwards” - the inward curvature of a portion of the lumbar and cervical vertebral column. All spines should be lordotic to an extent, but an excessive inward curvature (often caused by anterior pelvic tilt) can cause many orthopedic problems.
Orthopadische Chirurgie. Dr. August Schreiber, 1888.
A French device for attempting to use tension and recumbency to correct curvature of the spine. The author of “Orthopraxy” notes that the mechanics of the device are meticulously made and very impressive, but ineffective. To correct lateral curvature of the spine, pressure must be applied to either side of the deformed area, to encourage the body to grow into a more correct form.
Orthopraxy: the Mechanical Treatment of Deformities, Debilities, and Deficiencies of the Human Frame. Henry Heather Bigg, 1877.
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