What was the topic of Dr Tulp’s lecture?
There are many reasons to believe that the painting shows praelector Tulp giving a lesson on the hand’s muscle function. Tulp is lifting a muscle belly by use of the artery forceps. If you look at the distal end of the tendons, you see the flexor digitorum superficialis (FDS) muscle joined to the middle phalanges of the fingers. The division into the two terminal tendon spindles is clearly seen around the profundus tendons just before the insertion (fig 3).
Rembrandt is said to have misplaced the origin of the muscle at the lateral epicondyle (3) – (12), when it is commonly known to be at the medial epicondyle of the elbow. This has been challenged by others who maintain that Dr Tulp has already loosened the origin in order to demonstrate the effect of the muscle in flexing the finger’s middle joint (PIP joint). This can be seen from certain of the white fibres at the far proximal end, which may indicate that the muscle belly has been loosened from its attachment and Tulp is lifting it up (10). From contemporary anatomy drawings, we can see that this was normal. This is probably also a separate dissected upper arm, which accounts for the somewhat distorted perspective.
In connection with the 400th anniversary of Rembrandt’s birth in 2006, a group of Dutch colleagues dissected an upper arm in order to establish once and for all whether there were anatomical errors in the painting. After this dissection they concluded that Rembrandt really had made anatomical errors (11). But we do not agree with their interpretation. We think Dr Tulp has loosened several of the structures of the forearm (e.g. m. Palmaris longus) in order to free the superficial flexor muscle (m. flexor digitorum superficialis), which he wanted to demonstrate. Rembrandt would surely have made a special effort with his first group portrait and his commissioner, the famous anatomist Dr Tulp, would hardly have allowed him to portray the anatomy wrongly. Several of the other observations made by the Dutch group have also recently been refuted (12).
The fact that Dr Tulp demonstrates the muscle function of the flexor digitorum superficialis can also be seen from the odd way he is holding his left hand. This is no typical gesture of speech, which was often portrayed at the time. His left wrist is fully extended and, with his base joints straight (MCP: metacarpophalangeal joints), he is showing flexion in his middle joints (PIP). He is probably about to pull the muscle belly with his forceps to show the same action on the corpse. In support of this interpretation, we see that the surgeon Matthijs Calkoen, just to the right of Dr Tulp, is also flexing the PIP joints in the same way with his own left hand (fig 1). Rembrandt has also created the illusion of movement in the painting. For whereas Jacob de Wit is bending forward and watching what Dr Tulp is doing with the corpse, Calkoen, to his right, is staring just as intensely at the hand of his master. We know what is about to happen in the next second when Dr Tulp pulls on the tendons. This gives a dynamic climax to Rembrandt’s presentation of functional anatomy, as opposed to the descriptive anatomy common at the time. However, the painting does not show a normal anatomy lecture for the year 1632. This is seen from the fact that the abdomen and chest have not been opened (3, 18). In the 1600s, the perishable inner organs were usually dissected first, and then the extremities. Has Dr Tulp chosen to go directly to the arms? Or have the surgeons positioned themselves in such a way that Rembrandt could draw them before the dissection started and then add in the anatomical details relevant to the lecture later?
In 1543, Andreas Vesalius (1513 – 64) issued (as previously mentioned) history’s most famous anatomical work De Fabrica Humani Corporis – with 700 folio pages and 300 illustrations. The work in seven volumes was printed in Basel and is perhaps the most splendid medical textbook that has ever been published. On the title page, Vesalius is portrayed with a dissected forearm and hand – and, at the same time, holding up a freed m. flexor digitorum superficialis in his right hand (fig 4). The background for Dr Tulp’s dissection may be that he wanted to appear as Vesalius had done a hundred years earlier, and be seen as his successor (3, 5, 6). It is also probable that Rembrandt used Vesalius’ work himself to describe certain details.