ANT 201: Week 4

Osteology 09/15/23

[ Skelatal Anatomy ] x

SKELETON Basics + Functions

• Support
• Movement
• Protection (ribcage)
• Mineral and fat storage (calcium stored in bones)
• Blood cell formation (BC’s formed in bones)

BONE

• Made of both organic & inorganic parts

Organic: proteins (collagen)

Inorganic: hydroxyapatite (minerals-calcium + phosphate)

• Strength + elasticity
• Osteocytes -> osteoclasts vs osteoblasts

Osteoclasts → cells that absorb borne

Osteoblasts → cells deposit bone

• Over the course of your life, your bone is constantly being turned over

(happens over the course of 10 years)

• An infant has around 300 bones when first born

→ by the time we’re adults we only have about 260 bones

Long Bone Structure

• Found in the legs
• Main length: diaphysis
• Where a lot of cell production occurs
• Ends: epiphysis (end of a long bone)
• Cortical (compact bone on the outside) & Trabecular (spongey)
• Cortical tends to be thickest at the diaphysis

Standard Anatomical Position

• Palms are always facing forward

WHY: because when you twist your arm your bones cross over

Ex: my tattoo shifting on my arm

Axial Skeleton: skull, ribcage, spine

Appendicular Skeleton: limbs/appendages

*** all append. have pairs (one on each side)

Skull

Cranium: area that surrounds your brain

Mandible: jaw

Frontal bone:

• Orbits (eye sockets)
• Supraorbital margin (very outside of orbit [top of eye socket])
• Supraorbital ridge (brow ridge [unibrow area])
• Temporal line
• Coronal suture (line that runs between the frontal & parietal)

Parietal bone: [paired with occipital]

• Temporal line
• Coronal suture
• Sagittal suture
• Lamboidal suture

Occipital bone:

• Nuchal line (runs up your spine into your brain)
• Foramen magnum (spine cord gets into the cranium)
• Lambdoidal suture
• Occipital condyles

Temporal bone:

• Mastoid process
• Extend auditory meatus (external opening to the ear canal)

Maxilla [paired

• Upper jaw
• Holds your top teeth

Mandible

• Lower jaw
• Hold your lower teeth

*** NOT PART OF THE CRANIUM***

→ when referring to both maxilla and mandible you say SKULL

• Mental eminence

***: when you think you touch your chin

Nasal

• One part of your nose made of bone
• Where your glasses lay

Zygomatic

• Cheekbones
• Lateral to our maxilla

POSTCRANIUM

Hyoid

• Upper part of your esophagus
• related to speech
• Attachment point to the muscles that allow us to talk

+ Only bone in the body that doesn’t articulate with any other bone

Sternum

• Also referred to as the breastbone
• Composed of 3 parts

Ribs

• Articulate through the sternum
• 12 pairs [24 T]
• True pairs [1-7] → articulate individually w/ the sternum
• False ribs [8-10] → share cartilage but aren’t indiv.
• Floating ribs [11-12] → don’t articulate at all

FUN FACT: Some people are born without a 12th rib + if they are it can be really small

Vertebra

• What the spinal column is made of
• Each individual ridge is a vertebra
• Cervical [7] → part of the neck
• Thoracic [12] → stabilizes the ribcage
• Lumbar [5] → bigger and robust b/c they make the lower back
• Sacrum [ 5, fused]
• Coccyx [4, fused]
• Atlas (C1) + Axis (C2)
• First and second vertebrae that allow us to move our head

Sacrum + Coccyx

• Inferior to the vertebra is the Sacrum
• Right under the sacrum is the coccyx

Clavicle

• Also known as the collarbone
• Has an ‘S’ shape
• Makes up part of our shoulder joint

Scapula

• Also known as the shoulder blade
• Glenoid fossa → part of the shoulder joint

Humerus [arm]

• Head

→ is joined with the glenoid fossa + give arm motion range

• Olecranon fossa

Ulna [forearms]

• Medial part
• Olecranon process

→ fits into the olecranon fossa and creates our elbow joint

• Lateral part is the radius

*** when you give a thumbs up it's the radius side

Hand

• Carpals [palm]
• Metacrapals [5 of them → lead into the fingers]
• Hand phalanges [in the fingers]

Singular: phalanx

- 4 fingers have 4 phalanges

- thumb only has 2 phalanges

Innominate [hips]

- innominate: means “no name”

- Also known as oscoxa

• Made up of 3 sections which fuse together as you develop
• Illium [hands on your hips]
• Ischium
• Pubis [important for sex estimation]
• Pubic symphysis [where they fuse→ looked at for aging]
• Acetabulum [connects hip to the femur (ball + socket joint)]

** it does’t connect the same in your shoulder which is why its easier to dislocate

Femur

• Strongest bone in the body
• head

Patella

• Sits at the knee

Foot

Teeth

• Made of dentition and enamel

***NOT made of bone [enamel doesn’t regenerate like bones]***

4 types of teeth:

• Incisor
• Canine
• Premolar
• Molar

Dental Formula = 2-1-2-3

If you were to break the jaw into 4 quads [corner] this is the number of each type of tooth you’ll find in each corner

FUN FACT: humans don’t have as many teeth as other species

Forensic Anthro 09/21/23

What is it?

the application of anthropological principles to medico-legal investigations, typically through specialized knowledge of human osteology

Common Analyses

Questions we have to ask ourselves when investigating

• Identify what is bone and what is not bone
• Is it a human bone?

ex: in wildfire cases, what are human or dog remains

• Are they modern bones [recent] or archaeological?

General rule: 50+ years makes it archaeological → flexible

• Inventory of elements present

- Fragmentary osteology

- minimum number of individuals (MNI)

- individuation of commingled remains

• Biological profile
• Skeletal trauma
• Pathological or taphonomic alterations

Pathology= anything that happens after death

Taphonomic example: body being moved, animals eating the carcass…

Comparative Osteolgy:

• Used to identify whether a bone is human or not by comparing it to other bones

Biological Profile:

• Biological particulars of an indiv. are estimated from remains including the person’s sex, age at death, stature, and population affinity
• Seeks to aid in the positive ID of victims in forensic settings

*** CANNOT assign positive ID, just narrows it down***

Sex Estimation

Non-metric: [morphological]

• On average, males have more robust muscle attachment and narrow pelvis

+ pelvis is the most accurate measure along w/ the skull

↳ females have a wider pelvis in order to give birth

Metric: [measurements] taking metric of certain features

• Postcranial elements
• On average, males are taller w/ more muscle

Sex Estimation: innominate

Works on a scale: 1-5

- Females closer to 1, males closer to 5

Females <—--------------------> Males

• Used when measuring things like the contour [curve] of the innominate (pelvis hip)

→ males have more of a ‘V’ shape while females have a ‘U’ shape

Sex Estimation: Skull

• Although the pelvis is much more accurate, the skull is also used to identify sex

*** Also works on a 1-5 scale

• Males have a more robust skull

→ eyebrow ridge protrudes

→ as well as the back the head sticks out more w/ a slight hook

• Females are more gracile

→ smoother eyebrow ridge, and compacted skull

• Also used when looking at jaws

Age Estimation in subadults: Dental formation & Eruption

Eruption: teeth growing in

Pubic Symphysis:

• Babies have something called billows which wear down to nothing as an adult
• Younger individuals don’t have rims on the surface

Adult Age Estimation

• Sternal rib end phases
• Auricular surface phases

Stature Estimation

• Use certain tools [osteometric boars and calipers] for precise measurements
• Input long bone lengths into regression formulae
• Optimally use all long bones

Trauma (injury)

• Indicates injuries suffered [whether or not associated with death]
• May reflect day-to-day life or interpersonal injury

*** Foresencis anthropologists DO NOT state cause of death***

Blunt force Trauma

Caused by force with an object with a wide area of impact

Ex: hammer or a car accident

• Features: radiating fracture [grow out from area of impact]

Sharp Force Trauma

Caused by force with an object with a more focused/small area of impact

Ex: cutting, stabbing, incision

• Can examine cut marks

Projectile Trauma

• Trauma from an object that was moving in the air

Ex; gunshots, arrows, spears, shrapnel atc.

Gunshot Wounds (GSW)

• Directionality of GSW is determined based on beveling, size, and irregularity of edges

Intern wound: internal beveling Extern wound: external beveling

• Often radiating fractures

Antemortem Trauma

• Trauma before death
• Identified through signs of healing

difficult task: differentiate between perimortem vs. postmortem trauma

Ex: breaking off a wet stick vs. dry

→ → → Slow velocity: bend High velocity: break