Suicidal head impalement with a hydraulic press machine

Serbia. A 63-year-old mechanic, diagnosed with schizophrenia, was released from a psychiatric clinic to spend a weekend with his family. According to the police report, his son heard a noise from the workshop and when he went to investigate he found him dead next to the hydraulic press machine.

The decedent was in a sitting position, bent towards the machine, with his head between the piston and the pressing plate. As his left cheek was placed on the pressing plate, his body was turned slightly to the left, and his flexed left arm was on the lever beneath the machine pedestal (Fig.1). On the right side of the machine pedestal there was a power switch, which was still in the “on” position. His right arm was beside his body, but away from the machine (Fig.2).

When the body was removed, a piece of blood soaked cloth was found on the pressing plate (Fig.4). The upper parts of his clothes were soaked with blood, while blood spatters were present on his left hand and left trouser leg (Fig.5). There was no suicide note, or any known previous suicide attempts.

An autopsy was performed within 12 h. The body was of average physique (height 190 cm (6’3″), weight 79 kg (174 lbs)), and the most important finding on external examination was the deformed, flattened head. In the right temporal area there was a gaping laceration, which had an arched shape upon reconstruction (Figs.6-7). The wound extended to the right ear lobe, where a small piece of helix was missing. In the left preauricular area there was a longitudinal laceration, the edges of which were inverted slightly outwards and displayed surrounding desiccation (Fig.8). Between these wounds, a canal extended through the head from the right to the left. Along the canals trajectory the temporal lobes and brain-stem were destroyed (Fig.9), but no brain contusions were present. There was a depressed fracture of the right temporal and parietal bone, radiating to the anterior and middle cranial fossae as well as to the facial bones (Fig.10). A piece of skin and cartilage originating from the right ear lobe were found on the inner surface of the left temporal bone (Fig.11). Besides blood aspiration in both lungs, all other findings were unremarkable.

Toxicological analysis (gas chromatography with head-space technique and flame ionization detector, gas chromatog-raphy–mass spectrometry, liquid chromatography tandem mass spectrometry) showed therapeutic concentrations of psychiatric medications and their metabolites (olanzapine, halo-peridol, levomepromazine, mirtazapine), whilst there was no alcohol in the blood or urine. Death was attributed to the fatal head injury that resulted from the low-velocity penetration of the hydraulic press piston.

Whilst the cause of death in this case was self-evident and undoubted, the manner of death required medico-legal investigation. The cloth that was placed on the pressing plate, a medical history of schizophrenia, and the absence of any defensive injuries, all led to the conclusion that this was a case of a rather unusual suicide. Self-inflicted, low-velocity, non-missile head injuries are not uncommon, although victims often tend to choose sharp objects (pens, sticks, knives etc.) and natural orifices (orbit, nose, mouth) to attempt suicide, which in many cases does not lead to a fatal outcome.

A hydraulic press is a device that uses a hydraulic cylinder to generate a compressive force. Also known as the Bramah press, it was invented by an English man, Joseph Bramah, in 1795. There are many models and countless uses for a hydraulic press (the one in this case was used for removing car wheel bearings), and they are often homemade, like in the presented case. Its function is based on Pascal’s principle: the pressure throughout a closed system is constant. In non-industrial presses pulling the lever creates a small force that acts upon a small piston. This creates pressure that is transferred through a hydraulic fluid (usually oil) to a larger piston, where a correspondingly large mechanical force is produced. The pressure that is produced is usually between 1 to 30 tons. An electric motor circulates the hydraulic fluid; thus the machine has to be switched “on” when the machine is working.

When the skull receives a focal impact (the extent may be surprisingly large, even if the impact is transient), there is momentary distortion of the shape of the cranium. The mechanical input can be dynamic (<200 ms; in most cases <20 ms) or static, e.g. when the head is slowly (>200 ms) squeezed or crushed, like in this case. The piston of the hydraulic press was moving slowly, but steadily, transmitting great pressure to the skin of the right temple in the first instance, ripping the right ear lobe (which was transferred and imprinted onto the contralateral side of the skull). Objects penetrating the brain at low velocity do not create temporary cavitation; the extent of the injury is usually limited to the path of the impaled object.

In this case the wound canal was much larger than the piston diameter because the crushed and detached skull bones also became impaling objects, increasing the extent of the brain injury. Because this machine press was designed for removing wheel bearings, the piston was not set to make contact with the plate; thus, it did not transfix the victim’s head. This could explain why the opposite, left temporal bone was not entirely crushed (Fig.11), although the pressure still exceeded the elasticity of the skin in the left preauricular area, resulting in the laceration of skin and surrounding desiccation (Figs.6-7).

Although it placed an enormous pressure on the head, the motion of the piston alone did not deliver a substantial transfer of force to the head. This could explain the absence of brain contusions. Nevertheless, lung aspirations are sufficient and definitive vital reactions in the presented case.

The position of the body during the fatal event resulted in the spattering of arterial blood on the left hand and leg. This confirms the theory that the victim himself pulled the left-sided machine lever and did not move much during this slow and painful process. Although this could be observed as a form of an occupation-related suicide, it remains unclear why such a peculiar and bizarre method for committing suicide was chosen.