Fractures

This blog post is the 3^rd in its series on bone fractures. To view the first blog post on the basic fracture types and information, including open and closed fractures, click here.

This blog post will highlight some of the common ‘named’ fractures you will often find in archaeological and anthropological settings. It is important to know their characteristics and common causes to help establish what happened – whether the fracture was received by defensive or offensive action, or purely accidental. This blog post will examine the first five common fractures associated with the hand and forearm bones.

Common ‘Named’ Fractures of the forearms and hands: A) Boxer’s fracture, B) Bennett’s fractures, C) Parry’s or Monteggia’s fracture, D) Colles’ fractures, and E) Smith’s fractures.

The first two fractures we will look at affect the metacarpal bones;

A) Boxer’s fracture: This fracture occurs due to the axial loading, meaning a force was applied along/parallel to the axis of the bone, on the transverse neck of the 4^th and 5^th metacarpal, secondary to an indirect force. A Boxer’s fracture often happens due to punching an object/person with a closed fist, hence the name ‘Boxer’ being associated to it.

B) Bennett’s fracture: This fracture affects the 1^st metacarpal (thumb) and extends into the carpometacarpal (CMC) joint which is complicated by subluxation (dislocation of a joint). A Bennett’s fracture is an oblique (See 1^st blog post for meaning, click here) intra-articular metacarpal fracture caused by an axial force directed against the partially flexed metacarpal. This injury is also common when someone punches a hard object, but its most common cause is falling onto the thumb. An example of this is falling off a bike, as the thumb is extended around the handle bars.

The last three fractures affect the longbones of the forearm, the ulna and radius;

C) Parry’s/Monteggia’s fracture: This fracture occurs on the proximal third of the ulna with subluxation of the radius/ulna. The most common cause of this fracture is by blunt force trauma caused by lifting the forearm up to protect the head or body in defence from an oncoming attack/striking object.

These two fractures affect the distal radius but cause displacement in two directions;

D) Colles’ fracture: A Colles’ fracture, also known as a “dinner fork” or “bayonet” fracture, occurs when the distal radius is broken with dorsal displacement of the wrist and hand. This fracture is common when the person falls forwards and uses their outstretched hand to cushion the fall, which causes the force to displace and break the head of the radius.

E) Smith’s fracture: A Smith’s fracture is the same as the Colles’ fracture but with ventral displacement of the broken radius head. The cause of a Smith’s fracture is the same as the Colles’ fracture, but it is less common.

Fractures: D) Colles’ fracture, and E) Smith’s fracture.

The next Quick Tips post will discuss other ‘named fractures’ in archaeological/anthropological situations and their causes and characteristics.

This is the third post of a set on fractures, so keep your eyes open for the other posts, and the new ones to come. To view all the other Quick Tips posts click here!

There is a relatively easy way to see whether a fracture to a skeleton is ante, peri or even post mortem. It is essential to detail and deduce which category a fracture falls into, as this is very important to see whether the fracture had played a part in the person’s death.

To first classify a fracture, we need to understand what the different categories mean. Some of you will already know these terminology, but here’s a quick reminder;

If a fracture is ante-mortem, it means that the fracture was made before death of the persons.
With peri-mortem fractures, it means that the fracture was received at or near the time of death of the persons – so could have been the fatal strike.
Post-mortem fractures are fractures that have been received after death, so during the time from death to the time of recovery. These fractures are usually from excavation processes, dismemberment, or even natural processes (soil, animal and plant activity).

You will be able to determine if a bone fracture was ante-mortem due to there being signs of healing which is shown by cell regrowth and repair.

With peri-mortem fractures, the person died before the healing started to take place, but the fractures will still contain the biomechanics that are present in ante-mortem fractures.

Post-mortem breaks tend to shatter compared to peri-mortem breaks which splinter, this is because bones which are in the post-mortem stage tend to be dry and rather brittle. Another big indicator of a fracture being post-mortem is the difference in colour.

The ‘Quick Tip’ that my applied anthropology lecturer taught me on how to easily distinguish between peri-mortem and post-mortem is to look at the fracture and decide; is it a clean break, as if you were breaking in half a bar of chocolate? If it is, then the fracture is most likely to be a peri-mortem fracture. If the break looks crumbly, like breaking a biscuit in half, it’s post-mortem fracture. Obviously this tip is not the most scientific, but it’s an easy way to begin your distinguishing process.

Skull with signs of post-mortem fractures. This photo is from a practical lab session.

If you look at the photo above it illustrates a post-mortem fracture. You can determine this easily due to the colour difference on the edge of the fracture, where it is a much lighter colour compared to the rest of the skull and the crumbly nature of the cut.

References:

Most of this is my own knowledge that I learnt during my degree in my anthropology lectures/lab practical sessions. But if you’re looking for a published journal check the one below. It is very informative and easy to understand if you’re a beginner in the world of anthropology/archaeology! It also highlights some problems that can arise when distinguishing trauma, it’s really interesting!

Smith, A.C. 2010. Distinguishing Between Antemortem, Perimortem, and Postmortem Trauma. Academia.edu. Available from here in .pdf form!