Friday, 12 April 2013

Forensic Fridays Part 2: Anatomy of Murder

Meet Ed. He's a skeleton assembled by the Archaeology Department at the University of Calgary for learning purposes. The fun part is that he's made out of real bones instead of plastic like all of the other skeletons. He's going to be your friend for today's lesson.
Hello my precious darlings, I'm back with part two of the Forensic Series. Today I'm going to be breaking down some basic skeletal structure for you. These are the technical terms your Medical Examiner would use - and a lot of these terms will be useful down the road when we get into the darker, murder-y stuff like hangings and drownings and such.

Of course these aren't all the bones because frankly 206 is a lot to go through so this is just the basic stuff.

Again I want to thank El, my best friend in the world for helping me out with this project.
Now without further ado, let us begin.

I might talk about muscles in a later post but for now I’ll just say that bones are the structure for the body and act as levers for muscles. The points where the muscles attach to the bone are the origin (proximal end) and insertion (distal end).

Now, let’s start from the top.

The skull (or cranium) protects the brain. It sits on the first vertebra (atlas) and the jaw bone is called the mandible. If it were a solid bone, humans would need enormous neck muscles and huge muscle attachments. To combat this, there are pockets of air within the skull known as sinuses.

The hyoid bone is found just underneath the jaw bone to stabilize muscles like the tongue – it is the only bone that is not attached to another bone. The clavicle or collar bone consists of two bones joining the top of the breast bone (sternum) to the shoulder blade (scapula).

The humerus is attached to the scapula by a ball and socket joint (shoulder) and connects to the bones of the forearm. It is this bone and the scapula that are involved when the shoulder is dislocated. The bones of the forearm are the ulna and radius. The bones run parallel. If the arm is held palm up, the radius is attached to the base of the thumb. The ulnar nerve runs along the outside of the elbow and is colloquially known as the “funny bone”, due to the nerve firings experienced when it is hit.

The wrist is made up of carpals and the hand (palm) is made up of metacarpals. The head of each metacarpal forms the knuckles.  The fingers are made up of three phalanges each while the thumb has two.

The torso is made up of the ribs which are attached to the sternum by cartilage – there are seven true ribs while the other ribs are called floating or false ribs. The false ribs are attached vertically to the seventh rib.

The Spine consists of thirty-three “vertebrae”: the first seven from the top are called the Cervical Vertebrae (often referred to as C1-7), the next twelve are the Thoracic Vertebrae (T1-12), the next five are the Lumbar Vertebrae (L1-5).  The sacrum is made up of 5 vertebrae fused together and forms the back of the pelvis. Between the vertebrae are Intervertebral Disks which cushion the force of meeting bones while the body is moving. At the bottom of the spine is  the Coccyx or tail bone.

The pelvic bone is one of the more reliable ways to distinguish a male from a female skeleton. A female’s pelvic bone is more open – looks kind of like a butterfly – while the male is much more narrow.

The Femur is the longest bone in the body, running from the pelvis, forming the hip joint, down to the Tibia (lower leg) to form the knee joint. It is also a point of weakness and prone to fracture. The Tibia is the front of the leg and is the thicker of the two bones of the lower leg. It supports the lower body and runs parallel to the Fibula, the smaller and thinner bone. It can easily be felt near the knee cap (Patella) were the bone is just below the skin. The patella is held in place by important ligaments that affect knee integrity when damaged. The Fibula is not as important for strength or support which is why it can safely be used for grafting onto other bones in the body.

The ankle is made up of seven tarsals while the foot is made up of five metatarsals. The Metatarsal Bones are five long bones in the foot that make up the central skeleton of the foot and are held in an arch formation by surrounding ligaments. The toes are made up of phalanges .

And there you have it.
Next month we're going to get started with the murder portion of the program with blood spatter patterns. Lots of pictures so be aware that I'm going to be talking about BLOOD next month. Ahhh! Okay, thanks for stopping by, my darlings.

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