Hyoid Bone Imaging-boon in Asphyxial Deaths Autopsy—A Retrospective Study

Abstract

The X-ray examination of corpses is the most useful tool in the field of medico-legal diagnosis and images allow clear visualization of fractures and radio-opaque foreign bodies within the deceased. In particular, the observations in the neck are quite challenging, as the anterior neck structures have anatomical variations which need differentiation from real pathologic or traumatic findings. Fractures of the hyoid laryngeal complex are commonly regarded as evidence of asphyxia but these can be too subtle to be detected during autopsy. Hyoid fractures in victims of strangulation and hanging are well documented. Plain radiographs of the hyoid laryngeal complex of the neck can be used to determine if fracture is present or if synchondrotic joint explains the apparent discontinuity in the bone or abnormal mobility. We present a study of postmortem radiological assessment of hyoid laryngeal complex of 12 medico-legal cases, which were conducted in the Department of Forensic Medicine & Toxicology, at a tertiary hospital, to find the exact cause and manner of death. Postmortem radiographs were helpful as an aid in the routine autopsy, and documented the signs of trauma to bony structures in the neck.

Introduction

The objectives of a postmortem examination include establishing the identity of the body, to ascertain time since death, cause of death, and whether the death was natural or unnatural. ¹ In postmortem examination of decomposed, charred (Figures 1–3) or highly infectious cadavers and in some countries due to religious practices, there should be a useful alternative way to examine injury in cervical part of cadaver, such as mechanical asphyxia, whiplash injury, vertebra injury, or vascular injury. ² In addition, the charred tissues are difficult to dissect from the bones, and the traumatic fractures could be missed by the macroscopic analysis. ³ Similarly, in decomposed dead bodies where the neck skin is grossly discolored or lost, it is the internal damage to the neck tissue and hyoid bone, which tells the actual cause of death. ⁴ In suspected asphyxial deaths, the hyoid bone becomes the most integral part of internal examination to check whether it is a fracture, ante-mortem or postmortem in nature or just an artifact (Figure 4).

Figure 1.

Swollen, Decomposed, Discolored, Peeling of Skin.

Figure 2.

Charred Body with Neck Structures Charred.

Figure 3.

Decomposed, Maggots, Ligature Material In Situ.

Figure 4.

Oblique Ligature Mark on Neck.

Postmortem forensic radiology deals with the application of modern radiological methods in order to optimize postmortem diagnosis. The use of radiological imaging methods for postmortem purposes is nearly as old as radiology itself. ⁵ Such imaging methods can predict injuries in the internal body before autopsy with minimal or non-invasive techniques to the cadaver. ⁶ Keeping this view in mind, forensic medicine experts have used radiological findings in addition to support the autopsy findings in all gunshot wound cases, deaths of infants and young children, victims of explosions and if a body is decomposed, charred or unidentified. ⁷ Thus, radiology is a valuable tool in the identification of lesions in neck structures, enabling discrimination between strangulation and suicide. ⁸ The hyoid bone follows normal fracture characteristics of bone. A fracture line in the greater horn, dislocation and or angulation can be seen as a radiolucent line, interruption of the cortex or displaced fragments to diagnose a hyoid bone fracture. ⁹

Materials and Methods

During the routine postmortem examination in the Department of Forensic Medicine & Toxicology, cases with suspected asphyxia deaths which were referred, on the basis of either being decomposed/charred/suspicious history of asphyxia deaths or in the interest of justice. During dissection of the neck region, the hyoid laryngeal complex was subjected to radiological examination, to rule out any prior fracture or bony injury.

Results and Observation

The external, internal, and the radiological findings of HLC of 12 cases as and when were subjected to postmortem examination, are recorded, in tabulated format (Table 1).

Table 1.

Chart Showing the Findings and Radiological Images of Asphyxial Deaths.

Case No.	Age/Sex	Reason for Referral	Gross Condition of Neck Tissue	Autopsy Findings of Neck Region	X-ray Findings
1.	16 years/female	Could not differentiate between mobility/fracture of the hyoid bone	Laryngo-tracheal structure with hyoid (Figure 5)	Tissues fixed in formalin	Intact hyoid with intact horns (Figure 6)
2.	30 years/male	Decomposed and in the interest of justice	Swollen, decomposed, discolored with peeling of neck skin (Figure 1)	Putrefied tissue, postmortem blebs, the hyoid showed mobility of cornua	Fracture of hyoid horn (Figure 7)
3.	22 years/male	Asphyxial death in mysterious circumstances	Ligature mark on neck, in upper region which was obliquely placed (Figure 4)	Internally, soft tissue showed hemorrhage, fracture of the hyoid and also thyroid cartilage	Fracture of hyoid horn (Figure 8)
4.	40 years/male	Body burnt in car	Totally charred body, externally the neck structures were not identifiable with signs of burns (Figure 2)	Neck structures burnt off, with outline of hyoid bones	Burnt off pieces of neck bones and cartilages (Figure 9)
5.	22 years/male	Strangulation with decomposed	Swollen, decomposed, discolored, with maggots of size 0.5–1 cm crawling, ligature material in situ (Figure 3)	Soft tissue was decomposed with blebs at places	Intact hyoid with non-fusion of body and horn (Figure 10)
6.	40 years/male	Decomposed	Putrefied and decomposed	Soft tissue was decomposed with blebs at places	Fracture of left hyoidHorn (Figure 11)
7.	42 years/male	Sudden fall and injury to head	Crescent abrasion with multiple injuries on neck	Fracture of the hyoid horn and also cricoid	Fracture of hyoid hornand both cricoid
8.	16 years/female	Alleged history of hanging	Reddish brown ligature mark on upper part of neck	Internally, soft tissue showed hemorrhage and ecchymosis, with mobility of cornua (Figure 12)	Non-fusion of body with cornua
9.	22 years/male	Advanced stage of decomposition	Ligature mark on upper part of neck, which was obliquely placed	Putrefied tissue, postmortem blebs, the hyoid showed mobility of cornua	No fracture, non-fusion of body with cornua (Figure 13)
10.	28 years/female	Hospitalized for four days	Ligature mark on upper part of neck, which was obliquely placed	Internally, soft tissue showed hemorrhage and ecchymosis, with abnormal mobility of cornua	Fracture of right cornua of hyoid (Figure 14)
11.	52 years/female	Alleged history of hanging	Ligature mark on upper part of neck, which was running obliquely	Internally, soft tissue showed hemorrhage and ecchymosis, with abnormal mobility of cornua	Fracture of tip of right cornua of neck (Figure 15)
12.	14 years/male	Strangulation with decomposed	Crescent abrasion with multiple injury on neck	Internally, soft tissue showed ecchymosis	Intact hyoid with non-fusion of body and horn (Figure 16)

Figure 5.

Thyro-Hyoid Complex in Formalin with Radiological View.

Figure 6.

X-ray of Hyoid after Dissection of Soft Tissue.

Figure 7.

X-ray Showing Fracture of Hyoid Bone.

Figure 8.

X-ray of Soft Tissue and Articulated Hyoid Showing Fracture.

Figure 9.

X-ray of Charred Neck Tissue with Bony Structure and Soft.

Figure 10.

X-ray of Neck Soft Tissue with Non Fused Hyoid Bone.

Figure 11.

X-ray with Fracture on Left Side and Soft Tissue.

Figure 12.

Fracture Hyoid with Haemorrhage and Ecchymosis.

Figure 13.

X-ray of Soft Tissue with Non Fused Hyoid.

Figure 14.

X-ray with Soft Tissue and Fracture of Right Cornue of Hyoid.

Figure 15.

X-ray of Soft Tissue with Fracture of Tip on Right.

Figure 16.

Hyoid Intact with Non Fusion of Body and Cornue.

Discussion

Hyoid bone is unique; being a sole bony structure, it is U-shaped and lies at the root of the tongue with a central body, two greater horns which sweep backwards and upwards and has natural joints between the body and the greater horns. In teenagers and young adults, the joints are cartilaginous and mobile, and they calcify irregularly as the age increases in middle and later life. These natural joints may be mistaken as fractures, if dissection is not done meticulously, as in Case No. 1 where mobility of the horns was doubtful, hence the radiography revealed no fractures as seen in Figures 5 and 6. The ante-mortem fractures are usually associated with extravasations of blood at the site ¹⁰ (Figure 16). There is also the possibility of fractures being postmortem, due to incorrect autopsy techniques, inexperienced forensic medicine experts, body transit trauma, improper handling in the mortuary. ¹¹ While conducting autopsy, the hyoid bone fractures are difficult to detect and to avoid such misdiagnosis, a careful dissection, radiological examination, or seeking for evidence of hemorrhage is commonly recommended. ¹²

Isolated hyoid bone fractures are associated with accidental trauma (falls, car accidents), self-inflicted injuries (suicide by hanging) as well as assaulted injuries (manual or ligature strangulation, attack with a blunt instrument), but also artificial postmortem damage as a consequence of removal at autopsies. ¹³ Radiographs are typically taken in a lateral orientation and must reveal a radiolucent line, interruption of the cortex or displaced fragments to diagnose a hyoid bone fracture ¹⁴ (Figures 7, 8, 11, and 15), as was observed in Case No. 2 and 3, 6 and 11 where the radiographs of the neck structures were in coherence with the findings of the autopsy. Fractures are typically seen in the body or the greater horn of the hyoid. ¹⁵ As was observed in Case No. 2, 3, 6, 7, 10, 11, and corresponding Figures 9, 10, 11, 12, 14. Morlid also performed the radiography technique before dissection and found it to be very useful, as very fine bony structures of the small bones were revealed. ¹⁶ According to Polson G. J. (1955), the fractures of the hyoid ’bone in cases of hanging involve the greater horns, which are most likely to break at about the junction of their outer one third and inner two thirds. ¹⁷ It is used to document peri-mortem fractures (those caused at or around the time of death), confirm fractures of the hyoid bone in the neck due to hanging, and is also in identification of individuals by determining the age and sex of human remains. It establishes positive identification by means of comparison of ante-mortem and postmortem films. ¹⁸ A similar study proved that the X-ray assessment of the excised HLC proved to be the most reliable imaging technique for postmortem radiological evaluation of suspected violence to the neck ¹⁹ (Figures 9, 10, 13, and 14). Imaging can yield information about findings for later confirmation during autopsy and guide the forensic pathologist to focus on a structure of interest, but it can also visualize lesions that would be impossible to discover and diagnose via standard autopsy alone. ⁶ In light of the advantages of imaging, no autopsy of a trauma-related death can be complete without it. ²⁰ It has been stressed, in a developing country like India, traditional postmortem cannot be completely replaced, but digital autopsy has also been increasingly prominent and recognized. ²¹ Legally for determining age or to prove and document injuries in victims of crime, radiologists understanding and forensic doctor’s knowledge of postmortem in a corpse must be synergized. ²² Hence application of imaging techniques can be used as the guidance and complimentary for the forensic autopsy in the identification of injury manner. ⁷

Conclusion

The evidence produced by radiologic methods can provide a scientific and documentary basis for the investigation agencies. It endorses precision, objectivity, critical thinking, careful observation and practice, repeatability, uncertainty management, and peer review. This will further encourage the use of multidisciplinary approach in the context of medico-legal evaluation of laryngo-hyoid injuries. At the periphery level it will guide to assess suspected laryngeal trauma.