Info

Cricoid

D.DDD3%

0.6%

1 case

Cervical spine

Rare

1%

1%

1 case

Fig. 27. Radiograph of hyoid bone. Body of hyoid (B). Greater horns or cornua (C). Synchondroses ("joints") not fused (arrows).

patterns, hyoid width/length ratios are distributed across the population and do not fall into discrete categories (136,161). The degree of ossification or fusion of cornual synchondroses or "joints" predisposes to fracture (Fig. 28; ref. 161). Fusion and fracture incidence increases with age (145,153,161). Children have flexible hyoids and fractures of the hyoid-larynx structures are rare (18). Fusion begins in individuals 21 to 30 yr old

Fig. 28. Suicidal hanging; prolonged suspension. Radiograph of hyoid bone. Bilateral fractures of greater horns. Note bilateral fusion of body and greater horns (arrows).

(136). Miller et al. observed an overall incidence of 16.7% bilateral fusion in this age group (136). Bilateral fusion plateaus in the sixth decade, such that 60% of female and 70% of male synchrondroses are ossified (162). Another study showed there were no sex differences in the rate of fusion (136). Notably, a significant percentage of the elderly still have flexible greater cornua; therefore, neck compression cannot be excluded in an older individual who has an unfractured hyoid bone (162). The relatively increased mobility of a nonfused or incompletely fused hyoid synchondrosis must not be mistaken for fracture (149). A radiograph of a dissected hyoid bone can be used to assess the degree of fusion. One study showed that, of 34 hyoid bones of people aged 21 to 30 yr, 12.5% had unilateral fusion (136). About 30% of individuals greater than 70 yr of age showed unilateral fusion or nonfusion (136).

Other factors playing a role in hyoid fracture are the nature, magnitude, and distribution of force applied to the neck and the time interval between the infliction of neck pressure and death (161,163). Knot placement on the side of the neck was thought to increase the likelihood of fracture (8). A greater tendency for fracture was observed when the highest point of the ligature knot was behind the ear (155). Others have found

Fig. 29. Suicidal hanging. Fracture of left greater horn of hyoid. Ligature knot on right side of neck.

that hyoid bone injuries are not reliable in determining knot location (Fig. 29; ref. 154). Hyoid fractures can occur when suspension is not complete (e.g., a fractured hyoid in an elderly person seated and wearing a vest restraint [49,96,152]). One study showed a higher frequency of fracture in complete suspension compared with incomplete suspension (22 vs 10% [16]).

Hyoid fracture is caused by blunt trauma (e.g., motor vehicle collision) and is usually associated with other fractures (e.g., mandible, thyroid/cricoid cartilage; see Fig. 30 and refs. 144,149,159,164, and 165). Isolated hyoid fractures are possible when there is hyperextension of the neck (159). Chronic alcoholics are predisposed to hyoid fracture (149). Fractures of the hyoid and larynx are found in natural deaths, presumably from intense muscle contractions during the agonal stages of a cardiac arrest or following violent coughing (153,165). A hyoid fracture can be associated with pharyngeal lacerations (159). Even without mucosal injury, laryngeal edema can cause airway compromise (159).

Palpation of the hyoid bone in situ may reveal a variably calcified stylohyoid ligament attached to the lesser cornu, which occurs even in children (165). Fractures at this site are rare, and an incompletely ossified ligament should not be confused with a fracture (165).

Fig. 30. Pedestrian run-over. (A) Abrasion (arrow) on left neck. (B) Fracture of left greater cornu of hyoid (arrow) with associated hemorrhage.

Fig. 31. Anatomic variations of superior horn of larynx. (A) The right superior horn is not attached to the superior (S) edge of the thyroid cartilage lamina. A fibrous membrane (M) extends from it to a "floating" superior horn (superior and inferior limits indicated by arrows). (B) Right superior horn of thyroid cartilage composed of three mobile segments (highlighted with ink).

Fig. 31. Anatomic variations of superior horn of larynx. (A) The right superior horn is not attached to the superior (S) edge of the thyroid cartilage lamina. A fibrous membrane (M) extends from it to a "floating" superior horn (superior and inferior limits indicated by arrows). (B) Right superior horn of thyroid cartilage composed of three mobile segments (highlighted with ink).

Any examination of the superior horns of the larynx must consider anatomic variations that should not be confused with fractures (Fig. 31; refs. 142,156,157,165, and 166). A common anatomic variant is a mobile, variably calcified cartilaginous nodule (triticeous cartilage) in the thyrohyoid ligament above the superior horn (165).

Triticeous Cartilage
Fig. 32. Skeletal remains. Irregular ossification of thyroid cartilage lamina. Note prominent superior horns that have completely ossified.

Fracture incidence rises with age as calcification progresses, but this is variable because ossification does not proceed in a constant manner (Fig. 32; refs. 16, 50, 57,142, 145, 153, and 157). Calcification can be absent in older individuals (64,157). Superior horn fractures are seen with partial suspension (in one study, 50% of complete suspension and 31% of incomplete suspension cases [16,49,152]). Laryngeal fractures do occur opposite knot placement (16,154). Narrow furrows had a higher incidence (62%) of laryngeal fracture than broad marks (15%) in one study (16).

Superior horn fractures are not unique to fatal neck compression. Direct blunt trauma (e.g., motor vehicle impact, falls from heights), resuscitation, and poor autopsy technique can lead to this injury (51,142,167). Fractures of the lamina do occur with blunt trauma (64,168). Healed injuries may be identified in the hyoid bone and larynx (Fig. 33). One study, using skeletonized autopsy specimens, showed previous trauma in 17.3% and involvement of two elements in 3.2% of cases (168). Old fractures were identified in the thyroid cartilage (11.4%), cricoid (7.3%), hyoid (1.6%), and trachea (0.2%).

Fractures of the thyroid cartilage lamina can result from long-drop hangings (109). Such a fracture in the setting of a "usual" hanging raises suspicions of a homicidal direct neck blow followed by a staged suicide (64). Cricoid fractures from suicidal hanging are rare (Table 1; Fig. 34; ref. 16).

Autopsy Images Hyoid Bone Fractures
Fig. 33. Healed fracture of right greater horn of hyoid. Previous hanging attempt.

Cervical spine fractures are usually associated with "long drops" and hangings in older individuals with osteoporosis; however, one case report described a C-spine fracture (C1-C2) in a 12-yr-old boy who did not drop a long distance (Fig. 35; refs. 7,16, 50,152, and 154). A 23-yr-old man was suspended 4.6 m (15 ft), and on his waist there was an 11-kg (25-lb) chain (46). He sustained a C3 vertebral fracture. A 10-yr-old boy was jumping on a bed when he became suspended from a bedpost by a lanyard holding a house key (126). He had a C1/C2 dislocation. Extensive associated neck trauma can be observed when the cervical spine is fractured (7). In judicial hangings, the drop length (in the range of 8 ft or 2.44 m) was calculated based on the subject's weight with the objectives being neck dislocation and a humane instantaneous loss of consciousness (169). Although a classical "hangman's fracture"—i.e., fracture-dislocation of C2 through its pedicles—has been described, studies have shown variable damage (i.e., absence of complete fracture, fractures from C1 to C5 including involvement of other bony elements; see Fig. 36 and ref. 169). Basal skull fractures have been observed (169). Rarely, the classical fracture is seen in a seatbelt user involved in a motor vehicle collision (71,170).

Fig. 34. Right cricoid fracture seen in hanging death (circled area adjacent to probe indicates depressed fracture site).

Decapitations are described in large individuals, with application of outside force (e.g., motor vehicle) and in long drops (129,137,169,171,172).

Rare cases of frontocranial suspension, i.e., the suspension point from the center of forehead and the noose around the back of the neck, have been described (173).

In contrast to disruptive injuries of the larynx-trachea and cervical spine, fractures of the hyoid and superior horns of the larynx are not usually a direct cause of death (174). They do indicate that significant forces have been applied to the neck, and asphyxial mechanisms are implicated in the death (174).

Fig. 35. Obese man (>100 kg) with psychiatric history. Hanging in stairwell about 20 min. Exposure of anterior cervical spine. Cervical spine (C6-C7 fracture; arrow). Tracking of hemorrhage in soft tissue below fracture site.

2.1.7.5. Other Trauma and Findings

Tongue injuries are seen in neck compression (175). In hangings, tongue protrusion between clenched teeth is a common finding (Fig. 21). Injuries include bite marks with or without underlying small hemorrhages ("marginal" hemorrhages) and varying degrees of "internal" muscle hemorrhage. In one study of 178 homicidal strangulations, 28% of manual strangulations and 16% of ligature strangulations had bite marks (175). In contrast, of the 20 suicidal strangulations and 255 hangings, 0 and 1%, respectively, had bite marks (175). The frequency of deeper tongue hemorrhages was 53, 42, 50, and 4% of homicidal manual,

Fig. 36. Classical "hangman's fracture." (A) Fracture through pedicle of C2 (axis) by hyperextension. Dislocation of C1 (atlas) and vertebral body of C2 (lined) leading to spinal cord trauma and death. (Reprinted, with permission, from ref. 170 and the Journal of Forensic Sciences, Vol. 34, No. 2, copyright ASTM International, West Conshohocken, PA). (B) Radiograph of a "hangman's fracture" (fracture of pedicle of C2—arrow).

Fig. 36. Classical "hangman's fracture." (A) Fracture through pedicle of C2 (axis) by hyperextension. Dislocation of C1 (atlas) and vertebral body of C2 (lined) leading to spinal cord trauma and death. (Reprinted, with permission, from ref. 170 and the Journal of Forensic Sciences, Vol. 34, No. 2, copyright ASTM International, West Conshohocken, PA). (B) Radiograph of a "hangman's fracture" (fracture of pedicle of C2—arrow).

homicidal ligature, and suicidal ligature strangulations, and hangings, respectively (175). Hemorrhage was found by either transverse or sagittal incisions of the tongue. "Central" hemorrhages are indicative of severe congestion and are more likely in strangulation deaths (175,176). In one series of hangings, 2% had bleeding restricted to the tip of the tongue (175). Some of the hanging cases that showed tongue bleeding in this series were atypical, i.e., the deceased were either sitting or kneeling. Most of the hangings studied had evidence of cranial congestion, i.e., facial petechiae. Another mechanism leading to tongue hemorrhage is direct pressure of the hyoid on the base of the tongue (175).

Tears in the upper respiratory tract can be observed leading to secondary subcutaneous and mediastinal emphysema (Fig. 37; ref. 174).

Carotid intimal tears have been associated with obese victims, long drops, and posteriorly placed knots (7,129,154). Intimal tears of one or more carotid arteries were more common with complete suspension (12%) than incomplete suspension (2%) in one series (16). Carotid injury is also seen in homicidal strangulation (109).

A study of 36 suicidal hangings showed vertebral artery injuries (rupture, intimal tear, subintimal hemorrhage) in one-fourth of cases (177). Subintimal hemorrhage was most frequent. Longitudinal traction was considered the mechanism, but complete suspension was not a prerequisite. There was an association with cervical spine injury.

Craniocerebral trauma raises the possibility of homicidal hanging; however, injuries arise from careless handling of the body (see Subheading 2.1.6.6., Fig. 25, and refs. 68 and 78).

Any genital injuries may mean a sexual assault homicide (7,28).

Fig. 37. Delayed death from hanging. Probe indicates transmural laceration in epiglottic area. (Courtesy of Dr. B. Wehrli, London Health Sciences Centre, London, Ontario, Canada.)

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