Questions tagged [human-anatomy]

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

90 questions with no upvoted or accepted answers
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10
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1answer
175 views

Are there certain symmetric-pair muscles that are slightly bigger and NOT due to handedness?

Ok, hear me out, I was just thinking about an article in Nature I read in the past titled "Scrotal asymmetry in man and in ancient sculpture"$^{\dagger}$ and more recently an entire medical textbook ...
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294 views

Anatomical Angle Made by the Fingers of an Extended Palm

Does the angle made by the fingers (excluding the thumb) of an extended palm (as shown in the figure below) have a name (such as the Lovibond or Cobb angle, for instance) ? I have already checked ...
5
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1answer
221 views

What's a “constitutionally small penis”?

I'm reading some urology papers and came across one involving penis growth (Kim & Song, 2008); here's an intro passage that I'm confused about: A total of 58 patients with constitutionally ...
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66 views

Do cells in healing ligaments or tendons have deformation processes? If so, what are they?

I am trying to better understand how non-muscle tissue in the muscuoloskeletal system heals. Specifically, I am interested in how ligaments or tendons heal once torn. I read the following text: ...
5
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539 views

Why are lips covered with specialized skin?

I found out some interesting facts while studying our lips: They are covered in glabrous skin, while most of the skin surface is hairy; The outermost layer (stratum corneum) of the skin is far ...
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880 views

What's so special about Chassaignac tubercle?

1-How does massaging of carotid artery at chassaignac tubercle( anterior tubercle of transverse process of C6 vertebra ) can relieve the symptoms of Supraventricular Tachycardia? My attempt: I think ...
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731 views

Does variation in human gut length vary predictably with diet of ancestors?

Background: Numerous online searches, textbooks and other sources seem to pin the average length of the human gut from mouth to anus (oroanal) between about 5-10m in length. To pick a reputable ...
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681 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 ...
4
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1answer
167 views

Can exercise strengthen tendons and ligaments?

Is is possible to strengthen tendons using exercise to prevent injury, for example preventing shoulder dislocation?
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119 views

In endochondral bone formation, why does only hyaline cartilage get ossified to form bone?

There are three types of cartilage: hyaline, fibrous and elastic cartilage. Fibrous cartilage does not have perichondrium...so it does not take part in ossification because perichondrium needs to ...
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91 views

Is there any evolutionary significance of downward facing nostrils in human beings?

The nostrils in apes and monkeys are almost at the front, but in humans nostrils (external nares) face downwards. Also a lot of non-primate mammals like goats have nostrils at the front. Is it the ...
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395 views

Why do hair on head not get pilo-erected?

Whenever we have "goosebumps", there is a momentary piloerection, due to which hair on our elbows and legs get "erected" and "stand" almost perpendicular to the surface of our skin. But why do our "...
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86 views

Changes in spongy urethra during tumescence

How does the columnar cells of spongy urethra expand during tumescence(erection of penis)? If we assume that the urethra has the length, long enough to sustain tumescence without expansion of cells, ...
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2k views

Do any non-human species have packed abs?

The classic "six-pack abs" in humans is due to tendons stretched across the abdominal muscles and low body fat. Do any other animals have a similar arrangement of tendons that could result in visible "...
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104 views

How do we sneeze?

When a stimulus triggers the sneezing pathway, known as the trigenimal nerve network, how do the droplets from a sneeze get created within the nose? What affects the size of these droplets?
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1k views

Skin extra sensitive to heat after burn

I just got my finger burnt (first degree burn $\Rightarrow$ I didn't even bother to bear the wound). It didn't hurt much, even when I pressed the wound. However, when exposed to heat (hot water, but ...
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203 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. ...
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19 views

Surface perception

I'm looking for research studying: How small and compressed together do particles of a surface need to be to be perceived as solid surface to human touch? E.g. sand still feels grainy. Has there been ...
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0answers
44 views

Is the tendon width determined by genetic predisposition, and if so, is genetics the sole factor?

Tendons' widths vary widely across humans. E.g.: {1}: "the mean patellar tendon width was 26.10mm (SD = 3.31; range 18.33mm-33.33mm)" {2}: "Size of the patellar tendon width, measured at the same ...
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70 views

How can we usually “trust a fart” not to be liquid or solid?

Jack Nicholson's character Edward Cole in the movie The Bucket List said ...and never trust a fart, and a search for Al Roker leakage White House will clear up any doubts what that's all about. How ...
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47 views

Describing the location of the thalamic adhesion in simple English

I'm trying to describe the location of the thalamic adhesion as part of a personal project. I can't reference pictures, and I need to be as precise as possible without using convenient anatomical ...
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0answers
26 views

Exhaustion of skeletal muscle and ligaments

I read somewhere that while doing lifting back should be straight(means normal curve), so that erectors muscle in back do the work but it gets tired easily. Hence we form curve on our back like when ...
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0answers
144 views

Alpha-gamma co-activation

I am having trouble visualizing/grasping the necessity of alpha-gamma co-activation. My understanding is the following: When an external load causes stretching of the sensory muscle spindles, the 1a ...
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0answers
56 views

What causes the blue color seen in baboons?

Based off of this question from Worldbuilding SE. In that question, I talked about how the scrotum and buttocks of various animals have a blue color because of thick deposits of collagen in those ...
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256 views

Why does the clavicle ossify intramembraneously?

The clavicle is the only long bone which ossifies as a membrane bone. I studied this process, but I can't find the reason why it features intramembraneous ossification?
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605 views

Are differing shapes of the acromion congenital or acquired?

In the human body, the acromion is located here: There exist different shapes of acromion, at least 3: The frequency varies according to the acromion type: Some clinicians consider that there exist ...
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0answers
93 views

How to contract sternocleidomastoid muscle by thought?

If I do not turn my head, how can I contract ( or tighten) the sternocleidomastoid muscle ( like we can intensely tighten muscle in limbs)?
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39 views

Does human skeletal muscle fascia grow new additional collagen in response to increases in skeletal muscle size?

For example, if a human skeletal muscle is growing repeatedly due to periodic weightlifting, does the fascia eventually respond to the increasing volume by growing more quantities of collagen or other ...
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0answers
659 views

Does the humeroradial joint move medially/laterally?

The humeroradial joint is a ball-and-socket joint that, if unrestricted, would allow for movement around all possible axes. However (as succinctly stated from Wikipedia): the annular ligament, by ...
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0answers
90 views

Atlas from human brain structures to 3D coordinates?

I would like to visualize specific human brain structures in the three dimensional space and compute specific geometric properties of these brain structures (size, centroid, etc). Therefore, I am ...
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0answers
4k views

Physiologically, how can stress/anxiety cause neuropathy?

According to the Mayo Clinic, stress/anxiety can cause "pins and needles" (neuropathy) sensations all over the body. But how can this be? My understanding of the sensory pathway is that sensory ...
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0answers
149 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 ...
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0answers
339 views

Size of classical liver lobule across species

A classical liver lobule is made up of a central vein and the portal triads. A typical human liver weighs around 3 lbs. , while a typical bovine liver weighs around 12 lbs. I was wondering if anyone ...
2
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1answer
87 views

Why do humans have digestive system present at front and kidneys back?

Outlet of digestive system is present at back of the body but its digestive system at front. Outlet of urinary system is present at front of the body but its system present at back. Why do humans ...
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23 views

Why don't we speak of medial and lateral rotation of the forearm? And pronation and supination of the upper arm?

Why don't we speak of medial and lateral rotation of the forearm? I notice we speak of forearm supination and forearm pronation, but why not medial and lateral rotation. It seems to me that if we ...
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38 views

ATP and Muscle Contraction

I have a question regarding how molecular interactions manifest in physical actions - such as hanging from a bar. To the best of my understanding, when it comes to the contraction of muscles, ATP is ...
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0answers
55 views

Movement of the Thoracic Cage During Movements of the Thoracic Spine

Just for a bit of context: I am trying to create a 3D digital model of the human skeleton as the first step towards computer generated muscle simulation, and as such I want the skeleton to be as ...
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0answers
25 views

For each movement performed by both the gluteus minimus and medius, what percentage of the movement do the gluteus minimus and medius account for?

From what I read on Wikipedia, all functions of the gluteus minimus are mirrored by the gluteus medius. Additionally, the gluteus medius is larger than the gluteus minimus (see comparative images here)...
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0answers
77 views

What are the (statistically) normal pH levels in the most-outer part of human sexual organs?

What are the (statistically) normal pH values of the outer skin/epidermis of human sex organs (groin/crotch) in the male and female? e.g male testes, female vulva, male glans, the enveloping epiderm, ...
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0answers
142 views

What is the average human body density?

Looking for values of the average human body density on the Internet, one often finds the values of 0.98 for male, 0.87 for female. Other values are 0.985 for male and female. However, I can find no ...
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0answers
176 views

Why doesn't peritoneal dialysate leak through the fallopian tubes?

It is my understanding that the female peritoneum does not form a closed (potential) space due to its puncture by the uterine tubes. If that is indeed the case, why is peritoneal dialysis in women not ...
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0answers
504 views

Average width of the male body

I've been looking for the average width (at widest point) of the average American male body but couldn't find it anywhere so far. When I say "widest point", I mean that if you draw a rectangle (that ...
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0answers
27 views

Would preserving your Eyes from Light keep them healhty?

I read about why eyesight diminishes with age. I am aware of the fact that there are different causes that can affect the quality of image received by our eyes and that being vague would not lead to a ...
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0answers
49 views

does being battered build muscle?

My crude understanding of how people normally go about building muscle is something like this following 2 step process: 1) a person can lift weights (for example), which tears muscle and stimulates ...
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0answers
28 views

Muscle layers of pharynx and gi tract

Why does pharynx have an internal longitudinal muscle layer and external circular muscle layer, while oesophagus and the rest of gastrointestinal tract have inner circular and outer longitudinal ...
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0answers
73 views

Tensile strength of collagen?

Really specific question, but what is the average tensile strength of human collagen, type I? I've tried looking for it online, and either my google-fu skills are weak, or I'm just unlucky. Also, is ...
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0answers
41 views

Why do humans lose subcutaneous fat from the extremities with age?

Why does fat tissue die and shrink on the hands, knees, and lower legs of most people as they age, even when they are overweight? In most people, their bone definition becomes much more visible around ...
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0answers
47 views

Why are there sporadic lightly pigmented hairs in facial hair?

My body and scalp hair are entirely black. Until recently, I thought this was the case with my facial hair also, until I noticed a small handful of hairs that were anywhere from light brown to copper-...
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0answers
4k views

What is the occipital bun, precisely (in Neanderthals and Homo Sapiens)?

I've read that the occipital bun is an anatomical feature of the Neanderthals, and only because modern humans (except sub-Saharan Africans) carry a few percent of Neanderthal DNA due to ...
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0answers
99 views

Where does the human brain drain to?

When a brain has a aneurysm and the patient survives untreated then where does that blood drain to or how is it absorbed? How is the pain perceived?