Who would have ever realised that something so seemingly simple and intuitive as the High Five is in fact a marvel of biomechanics.

  What follows is a guide to the functional anatomy of the High Five for anyone devoted to understanding the art form in its full glory.

  Merely lifting the arm into the receiving position requires the use of virtually all of the muscles of the anterior upper arm and rotator cuff. Supraspinatus, supplied by the Suprascapular nerve initiates the abduction of the arm, when, after 15°, the middle part of the more powerful Deltoid, innervated by the Axillary nerve, takes over.

  Flexing the arm at the elbow uses the showy Biceps Brachii but the main effort comes from the oft-overlooked Brachialis muscle. Both flexor muscles are supplied by the Musculocutaneous nerve, with some of the more lateral parts of Brachailis being supplied by the Radial nerve - it's that special it has to have two. Brachioradialis, supplied by the radial nerve, also plays its part in flexing the elbow, but it is grouped with the muscles of the forearm - more on those later.

  The arm must also be pronated to ensure the palm is facing forward before the Five can be delivered. The power for this comes from Pronator Teres (which also does a little bit towards flexing the elbow, it's good like that) and Pronator Quadratus, supplied by the Median nerve and the Anterior Interosseous branch of the Median nerve respectively.

  Finally, before the arm is fully in position, it needs to be laterally rotated. Infraspiatus, supplied by the Suprascapular nerve, does more than it's fair share with the Posterior part of Deltoid chipping in. The same nerve that supplied Deltoid also innervates Teres Minor to finish off the job.

  The arm itself is now in position, but if that were all that was going on, the wrist and fingers would just be flopping - limp and useless. The wrist and fingers all need to be held upright which takes us into the murky depths of the extensor compartment of the forearm.

  To hold the hand up against gravity, Extensor Carpi Radialis Longus and Brevis, supplied by the Radial nerve and its deep branch respectively come in very useful and with names like those, you'd hope so. The Deep branch of the Radial nerve goes on to become the Posterior Interosseous nerve, which supplies Extensor Carpi Ulnaris. Together, these muscles keep the wrist in line with the arm, or, with a bit of extra effort, cock the wrist back should you wish to indicate to your buddy your desire to receive rather than give the Five. Just a quick mention at this point of the Extensor Retinaculum, under which all of the extensor tendons pass, snug within their sheaths, without which, none of this would even be possible.

  All that remains is to straighten the fingers out. Extensor Digitorum, Extensor Digiti Minimi and Extensor Indicis sort the fingers, while Extensor Pollicis Longus and Brevis take care of the thumb. Moving the thumb away from the fingers in the work of Abductor Pollicis Longus. These muscles are all supplied by the Posterior Interosseous nerve, which is certainly earning its keep, but really we have the Radial nerve to thank for that.

  Usually, the fingers are all held together and this is done through the work of a group of muscles in the hand known as the Palmar Interossei. In the case of the Air Five, the fingers need to be splayed out away from each other. This is done through the Dorsal Interossei, all of which are supplied by the Ulnar nerve.

  So after all of the hard work, all that's happened is that the arm's been lifted up and is now primed to deliver (or receive) the blessed Five. A lot has been spoken of nerve supply, and the Axillary, Musculocutaneous, Ulnar and Radial (including it's continuation, Posterior Interosseous) nerves have featured highly. In order to further marvel in wonderment at the sheer level of complexity behind the High Five, it seems only fitting to bring in the dreaded Brachial Plexus.

  The Brachial Plexus is formed in the neck by Roots from C5 to T1 and continues down into the armpit. Roots C5 and C6 join to create the Superior Trunk, C8 and T1 join into the Inferior Trunk and lonely C7 just carries on to become the Middle Trunk. Each Trunk splits into Anterior and Posterior Divisions, which supply the Flexor and Extensor compartments respectively, with the Superior Trunk throwing off the Suprascapular nerve for good measure. The Divisions recombine form three Chords, the Lateral (Anterior Divisions of the Superior and Middle Trunks), the Medial (a continuation of the Anterior Division of the Inferior Trunk) and the Posterior (Posterior Divisions of the Superior, Middle and Inferior Trunks). In case this is becoming confusing, take heart in the fact that if you ever saw it, the names of the Chords refer to their relationship to the second part of the Axillary Artery (!) The Chords go on to become Infraclavicular Terminal Branches, which are in effect the main nerves of the arm. The Lateral Chord becomes the Musculocutaneous nerve and the Medial Chord becomes the Ulnar nerve. A combination of Lateral and Medial Chords makes up the Median nerve, while the Posterior Chord splits into the Axillary and Radial nerves. Other smaller nerves come off at various points, but we wouldn't want to make it too complicated now would we?!

  So, poised to deliver what could potentially be the Ultimate Five, all that's left is to move the arm forward (in a straight line of course!) to meet your buddy's. Fiving involves a combination of elbow extension, shoulder flexion and medial rotation along with increasing the level of wrist extension and arm pronation to keep your palm parallel to your buddy's.

  Elbow extension is primarily the domain of Triceps Brachii, but Anconeus assists and plays a part in stabilising the elbow joint. Both are supplied by the Radial nerve. Shoulder flexion comes from the ever-dependable Anterior part of Deltoid and the Clavicular part of Pectoralis Major, innervated by the Pectoral nerves. Biceps Brachii, jealous of Deltoid and not content with just flexing the elbow, joins with Coracobrachialis, another one supplied by Musculocutaneous, to help with flexing the shoulder.

  Subscapularis, supplied by the Upper and Lower Subscapular Nerves and aided by the muscles Pectoralis Major, Teres Major, the Anterior part of Deltoid and the mighty Latissimus Dorsi polish off a sharp, crisp High Five with just the right amount of medial rotation to bring the palms together with a stinging, yet satisfying slap.

  For those desperate to know, Teres Major is innervated by the Lower Subscapular nerve and Latissimus Dorsi by non-other than the Thoracodorsal nerve, which, along with the Upper Subscapular nerve are some of the other nerves arising from the Brachial Plexus that were mentioned earlier. To be precise, those three all come from the Posterior Chord before it splits into the Axillary and Radial nerves - now doesn't that just round everything off beautifully!