Mwili wako ni mbali na kamilifu. Wewe ni bidhaa ya mamilioni ya miaka ya mageuzi, lakini utaratibu huu haina kujitahidi kuelekea "ukamilifu". Kwa kweli, haina kujitahidi kuelekea chochote. Ni hutokea tu: kwa sababu kuna tofauti kati ya watu binafsi katika aina, na baadhi kuwa na nafasi nzuri ya aliyebaki na reproducing kuliko wengine. Kuna kamwe lengo katika akili. Ya muhimu ni wale nafasi ya kuishi na uzazi: mchezo unachezwa nje katika wakati, kati ya viumbe na mazingira yao.
Kuangalia kwa undani katika anatomy ya binadamu, Mimi daima kushoto na mawazo mawili kivitendo irreconcilable: miili yetu ni ya ajabu, masterpieces intricate; na kisha - wao ni cobbled-pamoja, rag-mfuko, wakati mwingine clunking mashine. Kuna bits hivyo, wengi wa anatomy ambayo inaweza kuwa bora zaidi iliyoundwa. Kama mimi nilikuwa mbuni mwenye akili ya binadamu, Ningependa kubadili retina karibu kuondokana doa kipofu ambapo mishipa ya kuondoka nyuma ya jicho; Ningependa kuweka pampu kidogo katika mishipa ya mguu kusaidia damu nyuma moyo na kupunguza hatari ya kupata thrombosi ya kina venous; Ningependa fimbo katika kiungo mzuri kati ya mishipa wawili ugonjwa, Ili ikiwa mmoja akawa imefungwa, mengine inaweza kwa urahisi kuchukua juu ya; na ningependa kutatua mgongo ili kupunguza uwezekano wa matatizo ya nyuma. Baadhi ya hizi ni matatizo niggling, baadhi inaweza kuwa kutishia maisha. Lakini hawana wanaonekana kuwa walioathirika sana nafasi za mababu zetu ya kuishi na uzazi, hivyo uteuzi wa asili hana "niliona" yao - na sisi ni kukwama kwa wao.
mgongo ni mfano mkubwa wa kitu ambacho straddles hii perceptual mgawanyiko: inaonekana kama kipande msiazimie ya uhandisi fikra, lakini inaonekana karibu imeundwa ili kushindwa. Angalau, inaonekana kuwa iliyoundwa na kushindwa kwa umri; inakuja na kujengwa katika obsolescence.
safu ya uti wa mgongo imeundwa na 33 vertebrae. wale wa chini ni fused: tano na kuunda sakramu, na mwisho nne kama coccyx. The 24 vertebrae juu sakramu ni vitengo tofauti. Kila vertebra ni alijiunga na majirani zake, juu na chini, na viungo ndogo synovial kuelekea nyuma. Hizi kibali kiasi fulani ya harakati kati ya kila jozi ya vertebrae. Lakini kuu uzito kuzaa viungo wa mgongo ni mito ya cartilage - rekodi intervertebral - kati ya miili ya vertebrae. discs Hawa wajumbe wa pete fibrous nje, ambayo yenyewe lina tabaka annular, kama kitunguu. katikati ya disc ni tofauti: gel-kama, kitu kama msimamo wa dawa za meno - uliofanyika katika mahali na pete kwamba fibrous nje. gel husaidia kueneza mzigo hela nyuso za vertebrae kupinga. Angalau, hiyo ni jinsi vijana disc kazi.
Kama wewe kupata zaidi, rekodi yako kupata zaidi na wewe. Na, haki inevitably, wanaanza degenerate. kiini dries nje na badala ya kueneza mzigo hivyo sawasawa, inaruhusu peaks ya shinikizo kuendeleza katika disc. Dakika fractures inaweza kuonekana katika uso wa vertebrae, na hatimaye kusababisha mashimo madogo, na kiini kusukuma juu katika vertebra yenyewe. mashimo hizi zinaitwa nodes Schmorl ya. Nyufa katika nje fibrous pete kuruhusu kiini cha ndani ili kusongea kupitia, kujenga nini inajulikana kama "disc slipped". protrusions kama unaweza waandishi kwenye mishipa ya uti wa mgongo, na hivyo si ajabu kwamba hii inaweza kuwa chungu.
Wakati mimi nina kuangalia Archaeological inabakia binadamu, Siwezi kuchukua baadhi ya ishara ya aina hii ya ugonjwa neurodegenerativa. Mimi hutaweza kujua kama mtu mateso kutoka disc slipped - kwamba ni yote tishu laini. Lakini naona ambapo viungo ni mapya ya kupoteza yake, and extra bone builds up around the edges of the vertebra – “marginal osteophyte” – as if in an attempt to stabilise a failing joint. And I can certainly pick up Schmorl’s nodes, punching into the end-plates of vertebrae. These are relatively common lesions in older skeletons.
A couple of weeks ago, I had the chance to look at my own spine in a way I’d never done before. Early one Saturday morning, I headed to Cheltenham, to the Cobalt Imaging Centre, for a hot date with their 1.5 Tesla MRI scanner. I was going to have what amounted to almost a full body scan – from my neck to my pelvis, missing out my head, arms and legs. This was all for a talk about anatomy – my anatomy – for the Cheltenham science festival, juu ya 5 Juni.
I was really intrigued to get this opportunity to look inside my body – and to see bits of myself for the first time. Na bado, as I drove up to Cheltenham that Saturday, I approached my appointment with the massively powerful magnetic machine with trepidation. The people at Cobalt were going to see right through me – what would they find? Ndani ya recent study ya 666 apparently healthy people, 659 of them had some kind of incidental finding – some very minor, others very serious.
I lay in the open-sided scanner, listening to the clanking of the machine around me, and wondering what it was seeing. The scans of my lower body seemed to take a long time. hatimaye, after about two hours, I met up with radiologist Iain Lyburn to look at my scans. There was something wrong. We were looking at a sagittal slice through my body, right through the middle of my spine. I could see the plump intervertebral discs, each with a juicy, pale grey centre – right down to the last but one. This disc, L4/5, lying between the fourth and fifth lumbar vertebrae, was black. It had also punched up into the body of L4, the fourth lumbar vertebra, above it. And it was herniated – I could clearly see a bubble of black pushing out beyond the vertebrae at the back, uncomfortably close to the lumbar nerve roots.
Iain was very kind. I was quite sanguine. I’ve had back pain on and off for years. Having children and then carrying them around certainly hasn’t helped. I knew I had a bad back. Now I was seeing it.
The scan has made me more careful of my back. I tended to dismiss it as just muscular before, and to carry on doing things that were a little bit painful. So I won’t push my back in stretches now. I won’t do high impact aerobics – there’s plenty of other exercise I can do without hurting my back or making it worse – and, with some reluctance, instead of carrying my toddler to his bed and lying him gently down, I ask him to climb in himself.
It’s interesting, this completely degenerate L4/5 disc, ink-black on the MRI. It will never not be degenerate. I just have to live with it. It’s part of my body’s built-in obsolescence. When I was in my 20s, and even though I was studying medicine, I didn’t ever really think that my body would fail. Now I’m in my 40s, I have to face a different reality – I, like everyone else, am slowly falling apart. There are plenty of things I can do to reduce the rate of decline, but I can’t stop it. As far as evolution is concerned, I’m not perfect at all. I’m just about good enough. And I’m mortal.
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