This tag is for questions about the general anatomical features of human beings as opposed to the anatomy of non-human animals.

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4
votes
1answer
39 views

Why does the sacrum fuse together?

Everywhere I look describes how the 5 sacral vertebrae start fusing together during adolescence and are totally fused by the time you're 30 or so. But nobody seems to explain why this happens. It ...
4
votes
1answer
113 views

Accurate Human Skull Model for Educational Purpose

I want to buy a model of Human skull for education purpose. However, I really want a very accurate model and at a decent price. I got the info that many of the available skulls in the market are not ...
2
votes
1answer
42 views

Is the human collarbone supposed to break?

I've read it in a book and have heard people mention it, but I can't find any documentation about it. But the point being made is this: The human collarbone acts as a shock absorber for impact on ...
2
votes
0answers
38 views

Where do the 31 spinal nerves start/meet?

Which part of the brain is the first place (from top to bottom) where all 31 pairs of spinal nerves (on each side) meet? Or if they all start at one place - where is that? Nominally, the beginning of ...
1
vote
1answer
311 views

If penis reconstruction from a clitoris is possible why isn't penis enlargement possible?

I don't understand why, if a penis can be reconstructed from a clitoris for sex change, surgical penis enlargement is not possible.
1
vote
1answer
40 views

People say the cardiac cycle depends on blood pressure? How so?

I know what the cardiac cycle is. There are two phases diastole and systole. One is the relaxed, and the other is the contracted form of the heart. The diastole is where blood is pumped to the ...
5
votes
1answer
201 views

Would a spinal injury decrease human height?

A woman I know has been losing height at a rate of few cm a year following a severe spinal injury. How is this possible? What kind of injury could cause such progressive loss of height? Could this be ...
13
votes
4answers
963 views

Could we transmit smells electronically?

We can encode sound and images in radio waves and send them, but presumably there's some physiological reason that we can't easily make a picture or video of a smell. Could we realistically break ...
15
votes
1answer
3k views

Is humans' height ideal?

More or less we humans are around 1.70 meters tall. My question is, would it be possible to scale us? that is, is it in principle possible having humans 1 cm tall, or 10 meters tall or is there some ...
2
votes
1answer
61 views

Development of vitreous humor

I have tried reading about development of vitreous humor but it is all very confusing. When does it first developed ? Does it renew itself ? Please provide reliable sources..
-2
votes
0answers
20 views

Twisted Toe Pain [closed]

Occasionally, when curling and stretching my toes in an attempt to pop them, either my 2nd toe will get caught behind my 3rd toe, or my 3rd toe will get caught behind my 4th. Then there is an intense ...
2
votes
1answer
52 views

Biology Analogy

In my book are given several paired analogies with me being asked to give reason for them. I could solve all of them except this: liver = thrifty house-keeper I mean, I do not understand why the ...
2
votes
1answer
130 views

Function of the Auricle in heart

What is the function of the auricles (conical appendages through the atria) present in the heart? Do they have any other function than increasing the volume of blood the heart can hold?
2
votes
1answer
112 views

Difference between flexion and contraction?

i asked this to my anatomy teacher and he said there is no difference but when it comes to specialy in body building when you say to flex their bicep they freeze their upper limb in order to do that ...
1
vote
0answers
57 views

Can human change its morphology or anatomy due to ecological changes?

According to Charles Darwin, as the surrounding environment changes, so changes the anatomy or morphology of a specific organism. But nowadays, humans have become very advanced in the technology and ...
2
votes
0answers
37 views

What causes headaches (biologically)? What does it mean directly? [closed]

Even though your brain can't feel pain, thingies in your head are installed to compensate for that. Once I thought your head starts to hurt when your brain is tired. I can't believe this any more. ...
2
votes
0answers
23 views

Questions regarding Scapulohumeral Rhythm

I'm actually an artist, but I wanted to ask this because it will help a lot in my figure drawings. My artistic anatomy teacher taught me about the Scapulohumeral Rhythm. He said that in during the ...
2
votes
1answer
98 views

Are Asian people shorter than Europeans?

People in different countries have different average heights. For example, Wikipedia's article on human height states that Australian men have an average height of 177.8 cm, and Australian women 163.8 ...
2
votes
1answer
31 views

What are the criteria for determining the origin and end of muscle anatomically?

For example the pectoralis muscle starts from sternum region and ends on the acromion or coracoid process. Why you can't say that it starts acromion process and ends on the sternum?
1
vote
1answer
39 views

Anatomy suffixes?

Here are some suffixes I want to know their meaning: -ium: trapezium (carpal bone) -ius: trapezius (column muscle) -ous: Talous and calcanous (tarsal bone) -alis: Acromialis, Ulnaris (shoulder ...
1
vote
0answers
30 views

zygomatic fracture and orbital [closed]

Might a zygomatic fracture create problems in eyes orbit ?
2
votes
0answers
87 views

Human female chest model or data representation?

I am looking for professionally used representation of female chest (I know how it sounds ;). Generally - a model comprehensive enough to effectively represent human chest, with focus on breasts. ...
3
votes
4answers
103 views

Bad Eyesight and Evolution

Why do many humans have bad eyesight, such as near-sightedness, which hampers performance in a wide variety of tasks? Shouldn't there be evolutionary pressure towards better eyesight?
1
vote
1answer
60 views

Why do we suffer abdominal pain after we get very angry or stress?

You also realize probably, when we get so much anger or high levels of stress, after some point we have terrible stomach ache, like really heavy pain. Why is that? How stress or anger can effect our ...
3
votes
2answers
89 views

Could humans theoretically see infrared better than regular light?

I have noticed that in infrared film, people's eyes reflect that light within their eyes much like nocturnal animals (and many other animals for that matter) do with regular light. I know that this is ...
2
votes
1answer
78 views

What is the evolutionary cause for various finger lengths?

Why are the lengths the way they are with middle finger the longest?
2
votes
0answers
221 views

What is a lip? (upper lip and lower lip)

Everyone knows what a lip is but I'm asking from a technical and anatomical standpoint. Actually what we call "lip" is "vermilion" in medical terminology. But I want to ask if my understanding is ...
2
votes
1answer
28 views

Does digit 1 have an extensor sheath?

Extensor digitorum and extensor digiti minimi both insert into the extensor hoods of digits 2-5 (or just 5 in the case of e. digiti minimi). In every source that I can find, extensor pollicis longus ...
1
vote
0answers
61 views

In-Ear headphones increasing nasal breathing resistance

I figure this is a rather strange question, however, I noticed this quite some time ago and wanted to make sure that this is in fact a permanent condition before posting. The situation is as follows: ...
4
votes
2answers
6k views

Why do toenails grow much slower than fingernails?

As the title suggests, I've noticed that my fingernail grow much faster than my toenails. For instance, I usually trim my fingernails every two week or so, but for toenails the number would be about 6 ...
3
votes
1answer
193 views

what are the mechanics of sweating?

The causes of sweating aside, i.e. I'm not interested in which and how nerve signals are transmitted to sweat glands. But I would like to read a detailed account on what a sweat gland consists of, ...
1
vote
1answer
30 views

Are bronchioles and alveoli covered by respiratory epithelium?

Which parts of respiratory apparatus are covered by respiratory epithelium and which are covered by other kinds of epithelium?
2
votes
0answers
67 views

How to maximize lung oxygen intake?

What method of breathing provides a sudden surge of oxygen into the lungs filling it as full as possible in volume and density. Deep breaths? Shallow breaths? Breaths taken while bent over? Deep ...
1
vote
1answer
22 views

Specifics of decussation

Beginner question here: The definition of decussation I see is the crossing through the midline of a bunch of neurons. But I was wondering if there was a little more to it than this, because I'm ...
2
votes
1answer
65 views

Average face shape

I am doing face detection application where every face detected is inside a rectangle. The rectangle always contains some background behind the face and now I need to extract as much of the face as ...
1
vote
1answer
136 views

Near point and far point of myopic eye

Suppose a person wears the specs of power -6D, the far point for that person is 16cm. But the near point of normal eye is 25cm. So, is the near point of a person with myopia (having far point less ...
3
votes
1answer
34 views

Is there a way to measure ATP usage in the brain similarly to fMRI?

Is there a way to measure ATP usage in the brain (or anywhere else) similarly to how fMRI works (measuring changes in iron resonance in oxygenated/deoxygenated blood)? Is there some sort of similar ...
18
votes
3answers
17k views

If the brain has no pain receptors, how come you can get a headache?

I've read many years ago in books, that the brain has no nerves on it, and if someone was touching your brain, you couldn't feel a thing. Just two days before now, I had a very bad migraine, due to a ...
1
vote
0answers
12 views

What causes human hair to go gray? [duplicate]

What causes the graying of human hair? Additionally, why does extreme stress bring it on faster?
1
vote
1answer
51 views

Why are new vessels more permeable in microvasculature?

I know for microvasculature New microvasculature (arterioles, venules) are always more permeable as they lack pericytes. and then I have this sentence about new blood vessels (not specific) ...
3
votes
2answers
73 views

What is the evolutionary purpose of the topology of the human ear?

What is the evolutionary purpose of the topology of human ears? I understand why the ears may have a funnel-like shape but if the various "hills and valleys" do not amplify incoming sound, what ...
4
votes
2answers
144 views

How would constantly growing nails have aided early human?

Nails grow rapidly and constantly, such that without constant artificial trimming they would reach lengths difficult to manage. How did this benefit early humans, say 200kya? Were they used like ...
2
votes
1answer
105 views

Why don't we have more cone cells (bigger fovea)?

Background Apart from being able to sense color, cone cells are able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods. ...
6
votes
1answer
47 views

Healing rate of cut while suffering from a cold

I recently cut my finger fairly deeply with a box cutter and had to have it stitched. During the healing process I contracted a strong cold/mild flu (a sore throat and runny nose with a high fever, ...
3
votes
0answers
46 views

How do duplicate brain regions (ex: left/right amygdaloid body) operate together?

I frequently hear talk about parts of the brain like "Amygdala" or "Hypothalamus", so I looked them up in an app called "essential anatomy". What I see is that there's mirror symmetry, and most of ...
0
votes
0answers
26 views

How to predict the position of the femoral head center given surface anthropometric data?

Given surface measurements such as hip breadth and hip depth, how would you predict the location of the femoral head center?
3
votes
2answers
4k views

What could cause hairs to gray at the tips but not the roots?

I have noticed that some of my sporadic gray hairs are gray at the tip side but oddly, not near the roots. Some are even only gray in the middle. I find all of this very counter intuitive, and I ...
1
vote
1answer
78 views

Breathing in and out

I was reading my textbook and it says that breathing involves inhaling and exhaling but it doesn't say whether they happen simultaneously or sequentially. Also is my overall understanding of ...
0
votes
0answers
47 views

Stomach sagittal section

Can anyone please tell me where is exactly the stomach in this image? This is a sagittal section from the University of Michigan Visible Human Browsers. Thank you.
6
votes
1answer
138 views

Why don't we have hair on palms?

We have hair all over the body except palms. What is the biological reason behind this? Thanks