Praise be to Allaah.

Firstly: 

What the verse means is a reminder to man of his origin and that he was created from a water gushing forth, and that the One Who created him by means of His power and might is able to recreate him for the Reckoning. Az-Zamakhshari said: If you say: what is the connection between the words “So let man see…” [v. 5] and the verse that comes before it (“There is no human being but has a watcher over him”--  v. 4)? I would say: The connection is that when He said that over every human being there is a watcher, He followed that by advising man to think of his starting point in the first creation, so that he may know that the One Who created him is able to recreate him and recompense him, so let him strive for the Day of resurrection and recompense, and let him not cause his watcher to record anything but that which will make him happy in the Hereafter.

End quote from Tafseer al-Kashshaaf. 

The sulb (translated above as backbone) is the back, according to the consensus of the commentators. As for the taraa’ib (translated above as ribs), the scholars differed as to what it is and where it is located. 

Imam at-Tabari (may Allah have mercy on him) said: The commentators differed as to what is meant by at-taraa’ib and where they are located. Some said that the word at-taraa’ib refers to the place where the necklace goes on a woman’s chest. This was narrated from Ibn ‘Abbaas, ‘Ikrimah and others. 

Others said that the taraa’ib is the area between the shoulders and the chest. This was narrated from Mujaahid and others among the early generation. 

Yet others said that what is meant is that it emerges from between a man’s back and upper chest. This was narrated from Qataadah. 

And there were other opinions which suggested that it refers to the arms, legs or eyes, or that it refers to the ribs that are below the back, or that it refers to the essence of the heart. 

Then he – i.e., at-Tabari (may Allah have mercy on him) – said: The correct view concerning that, in our opinion, is the view of those who said that it is the place where the necklace goes on a woman’s chest, because that is the well-known usage in the Arabic language and in Arabic poetry. 

This view that was favoured by the imam of the mufassireen (Qur’an commentators), that what is meant is a man’s backbone and the taraa’ib of a woman, which is the place where her necklace goes, is also the view that was favoured by Imam al-Qurtubi in his Tafseer (16/343, 5/20) and by al-Haafiz Ibn Katheer in his Tafseer (8/375). It was also favoured by al-‘Allaamah Muhammad al-Ameen ash-Shanqeeti (may Allah have mercy on him) who said: 

It should be noted that Allah has explained that some this water, which is the nutfah (sperm drop), comes from the sulb, i.e., it is the man’s water, and some of it comes from the taraa’ib, i.e., it is the woman’s water. This is what is referred to in these verses in which Allah says (interpretation of the meaning):

“So let man see from what he is created!

He is created from a water gushing forth

Proceeding from between the back-bone (as-sulb) and the ribs (at-taraa’ib)”

[at-Taariq 86:5-7].

Because what is meant by as-sulb is the man’s back and what is meant by at-taraa’ib is the woman’s taraa’ib, which is the place where her necklace goes. 

Adwa’ al-Bayaan, 3/194 

Ibn al-Qayyim (may Allah have mercy on him) favoured the view that what is meant is the sulb and taraa’ib of the man. He said: 

There is no difference of opinion concerning the fact that what is meant by as-sulb is the back of the man. However there was a difference of opinion concerning at-taraa’ib. 

It was said that what is meant is the man’s taraa’ib too, that is the bones of the chest, the area between the collar bone and the breast. And it was said that what is meant is the taraa’ib of the woman. 

The former view is more likely to be correct, for the following reasons: 

1.

Because Allah, may He be glorified, says (interpretation of the meaning): “Proceeding from between the back-bone (as-sulb) and the ribs (at-taraa’ib)”, and He did not say that it proceeds from the back-bone (as-sulb) and the ribs (at-taraa’ib). So the man’s water must necessarily come from between these two different places, as He said concerning milk (interpretation of the meaning): “from between excretions and blood” [an-Nahl 16:66].  

2.

Moreover, Allah has told us that He created man from a nutfah (sperm drop) in more than one place, and the nutfah is the water of the man. This was also stated by the linguists. Al-Jawhari said: The nutfah is pure water, whether it is a small amount or a large amount, and the nutfah is the water of the man… 

3.

That which is described as gushing forth or being emitted forcefully is the water of the man; the water of the woman is not described in these terms. End quote. 

I‘laam al-Muwaqqi‘een, 1/145-146 

This is the view favoured by Shaykh Ibn ‘Ashoor, Ibn Sa‘di and Ibn ‘Uthaymeen, as it says in Liqa’ al-Baab al-Maftooh, no. 45. See similar comments in al-Liqa’ ash-Shahri, no. 45 

Al-Qurtubi narrated from al-Hasan al-Basri (may Allah have mercy on him) that what is meant is: it comes forth from the sulb of the man and the taraa’ib of the man, and from the sulb of the woman and the taraa’ib of the woman. End quote. 

Tafseer at-Tabari, 20/4 

This view was also favoured by Imam Ibn Juziy (may Allah have mercy on him, in his Tafseer. See: Tafseer at-Tasheel by Ibn Juziy, 785 

Secondly: 

The second question is that scientific facts that have been discovered today say that the man’s semen is produced in the testes that contain cells that are made for that purpose, not in the area of the back or chest. So how come the Qur’an describes the emission of gushing water as coming from between the back and the ribs? 

The answer is that this is one of the scientific miracles of this great Book. Modern medicine has discovered that this place -- between the backbone and the ribs -- is the place where the cells that will form the testes first grow, and at a later stage of embryonic development they descend to the scrotum below the abdomen. 

Dr. Muhammad Dawdah says:  

The scientific fact is that the primordial cells of the testes in the male or the ovaries in the female accumulate in the backs of the parents during the embryonic stage, then they come out of the back from the area between the start of the spinal column and the start of the ribs, then the ovaries migrate towards the pelvis in the vicinity of the uterus, and the testes migrate to the scrotum where the temperature is lower, otherwise they will fail to produce sperm and become subject to the risk of developing into cancerous tumours if the journey is not completed. 

The phrase “Proceeding from between the back-bone (as-sulb) and the ribs (at-taraa’ib)” is sufficient to describe the history of how offspring develop; it includes all the events that point to the existence of a prior blueprint and perfect design in creation, from their initial formation in the backs of their parents and their migration behind the intestines, starting from the area between the backbone and the ribs, until they reach their final destinations and until the parents are born, reach puberty and get married, and the offspring are created from something like a drop of water in which no human characteristics or features appear, namely the sperm which is alive and moves by itself until it is mixed with its counterpart, then the nutfah is formed, which is “drops of mixed semen (discharge of man and woman)” (cf. al-Insaan 76:2). 

“He is created from a water gushing forth, Proceeding from between the back-bone (as-sulb) and the ribs (at-taraa’ib)”[at-Taariq 86:5-7]. These are scientific facts that science has only recently discovered, although they were proven thirteen hundred years ago. The fact is that the sulb of the man is his spinal column and his taraa’ib are the bones of his chest … If we turn to embryology we will find in the development of the man’s testes and the woman’s ovaries that which will explain these verses that have been unclear to many people…  

Both the testes and the ovaries, in the initial stages of their development, are near the kidneys, in a location between the backbone and the ribs, that is, between the midpoint of the spine and opposite the lowest ribs. Then when the testes and ovaries have migrated to their final locations in the body, they are supplied with arterial blood and controlled by nerves that are connected to a place in the body that is located between the backbone and the ribs. Thus the truth of what the Holy Qur’aan said has become clear, but science has only discovered it recently, thirteen hundred years after this Book was revealed. After developing, the testes and ovaries both descend to their places in the body. The testes descend to their place in the scrotum and the ovaries descend to their place in the pelvis, near the fallopian tubes. In some cases this descent is not complete and the testes stop partway, failing to go all the way to the scrotum; in this case surgery is required. End quote. 

Taken from

http://islamtoday.net/questions/show_question_content.cfm?id=10335 

Dr. Muhammad ‘Ali al-Baarr (may Allah preserve him) says: 

The verse says that the gushing water comes from between the backbone and the ribs, and we say that this water (semen) is formed rather in the testes as the egg is formed in the ovary in the woman. So how can we reconcile the scientific fact with the Qur’anic fact? 

The testes and ovary are formed from the genital tubercle between the sulb and taraa’ib of the foetus. The sulb is the spinal column and the taraa’ib are the ribs. The testes and ovaries are formed in this exact region, i.e., between the backbone and the ribs, then the testes descend gradually until they reach the scrotum (outside the abdomen) at the end of the seventh month of gestation; the ovaries descend to the female’s pelvis. … However, nourishment continues to reach the testes or ovaries via the circulatory, nervous and lymphatic systems from the point where they originated, i.e., from between the backbone and ribs. The arteries that supply the testes or ovaries come from the aorta, from between the backbone and the ribs, and the veins coming from the testes end in the same region, i.e., between the backbone and the ribs. The nerves to the testes and ovaries come from a group of nerves that exist beneath the stomach, between the backbone and the ribs. The lymphatic vessels also end in the same area, i.e., between the backbone and the ribs. 

Can there be any doubt, after all this, that the testes and ovaries receive nourishment and blood from, and are connected to nerves that come from, between the backbone and the ribs? 

The material for formation of the sperm in the man and the eggs in the woman comes from an area between the backbone and the ribs, in addition to the fact that the sperm and eggs develop from cells that originate between the backbone and the ribs. So this verse is a complete miracle, as it says “from between the back-bone (as-sulb) and the ribs (at-taraa’ib)” and it does not say “from the backbone and the ribs”. The word “between” is not only eloquent; it is also scientifically precise. 

Modern science affirms that the water that does not gush, and only flows, is secretions from the vagina and Bartholin’s glands that are connected to it. These secretions play no role in the formation of the foetus; rather their function is to lubricate the vagina. But modern science has discovered something amazing: the sperm is carried by gushing water, which is the semen, but the egg in the ovary forms in the Graafian follicle surrounded by water. When the follicle ruptures, the water gushes forth and is caught by the fimbriae of the fallopian tube, where it meets the sperm to form the “Nutfah drops of mixed semen (discharge of man and woman)” (cf. al-Isnaad 76:2). This water carries the egg just as the man’s water carries the sperm. In both cases the water gushes, and both emerge from between the backbone and the ribs, from the reproductive organs, the testes and ovaries. 

Once again the miraculous scientific meaning of the Qur’anic verses has become clear: gushing water from the testes, carrying the sperm, and gushing water from the Graafian follicle carrying the egg.

End quote 

Khalq al-Insaan bayna at-Tibb wa’l-Qur’aan, p. 114-124 

And Allah knows best.