Forensic Anthropology The vertebral column

The Vertebral Column Cervical (5) Thoracic (12) Lumbar (5) Sacral (5) Coccygeal (4) Functions: support, movement of trunk Total of 33 (usually) individual vertebra 5 types of vertebrae (plural)

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General morphology – need to know Vertebral body (ant) Vertebral arch (post) On each arch…. 2 pedicles – attach arch to body 2 transverse processes – lateral projections 2 lamina – posterior surface of arch Spinous process – points postero-inferiorly 2 articulations for each adjacent vertebra 2 superior 2 inferior Encircle vert foramen (form vert canal)

How to orient vertebrae Superior facets face posteriorly Inferior facets face anteriorly Spinous process points postero-inferiorly

Articulations Each vertebra articulates with 2 other vertebrae (superior and inferior) Other articulations in…. The cervical vertebra: C1 articulates with the occipital The thoracic vertebra: 2 ribs with EACH vert Lumbar (NONE) Sacrum: ilium of the innominate (x2)

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Vertebral growth areas 3 growth centers for each vertebra Centrum (body) and 2 arches Arches fuse first T spine <1 year old C spine 2 years old L spine 5 years old Arches (at the pedicles) fuse to the centrum between 2 – 5 years of age 5 secondary growth centers at the transverse processes, spinous process, and superior and inferior vertebral bodies appear in teens, fuse in early adulthood

The C spine – unique characters C1 – call the atlas Occipital articulation surface Articular surface for dens (p/i) NO VERT BODY C2 – called the axis Dens (odontoid process) Greek mythology – ATLAS holds up the world Axis – turning point – rotational axis for C1/ skull Functions stability and mobility of the head http://www.med.howard.edu/anatomy/gas/wk7/20-4_Spec_Cerv_vert.jpg

Typical C spine C3 – C7 Bifid spinous process “Square-shaped” bodies C7 has the longest spinous process and forms the vertebral prominence http://www.clinicalexams.co.uk/images/Cervical_vertebrae.jpg

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The T spine Rib facets/costal pits – articular area of each 12 vertebrae (pair with 12 pairs of ribs) Rib facets/costal pits – articular area of each T2-T8 typically have 2 rib demi-facets on each lateral side of the vertebral body (4 total) T1-T10 typically have 1 rib facet on each transverse process (2 total) http://www.frca.co.uk/images/epidural-anatomy1.gif

1 demi facet (inferior) on each side The T spine T1 1 full facet (superior) on each side 1 demi facet (inferior) on each side 1 facet on each transverse process T2-T8 2 demi facets on each side 1 facet on transverse process T10 1 facet on each side of body T11 1 facet on each side of the body T12 same as T11, but with widened inferior body to meet with L1

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The L spine Notice it for what it is missing – No transverse foramena OR rib facets Typically large bodied Short stunted spinous process S/I articular facets curved in (U-shaped) in order to increase stability

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http://www. maitrise-orthop http://www.maitrise-orthop.com/corpusmaitri/orthopaedic/mo70_maigne_thoracolumbar/fig2.GIF

Sorting the vertebrae There should be a logical progression as the descend Body size increases Spinous process size changes Increase in C spine Decreases through T and L spine Articular surface shape and position should match

Sorting the vertebrae Make three piles Orient each with spinous process away, superior surface up Begin at top and work way down matching inferior surface of upper with superior surface of next one down

The sacrum Large, wedge-shaped Composed of 5 sacral vertebrae – fused Articulates with L5, both innominates Characteristics Large bodies Reduced spinous processes

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The sacrum – need to know Superiorly Sacral promontory (sup/ant): central, superior border of S1 Superior articular facets: articulation of L5-S1 Spinal canal Ala (wings) Laterally Auricular surface Spinous processes Posteriorly – Posterior sacral foramina Anteriorly Anterior sacral foramina Transverse line of fusion

The sacrum – uses in forensics Male vs female Males sacrum curved Females sacrum straight (WHY?) Age Transverse line between S1 – S2 closes mid twenties

The coccyx Coccyx – group of fused bones vs coccygeal vertebra (individual bone) Usually 4 segments fused – variation 3-5 CV1 had transverse processes and horns (cornua) CV2+ are variable, small, frequently lost Typically all fuse together and frequently to sacrum

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THE PELVIS The many names for this region Pelvis: composed of 2 innominate bones and the sacrum Innominate (or Os Coxae): each half of the “pelvic bowl” formed by the fusion of Ilium Ischium Pubis USE INNOMINATE WHEN COMPLETE USE INDIVIDUAL BONE NAMES WHEN SEPARATE OR TO REFERENCE A SPECIFIC BONE OR FEATURE

THE INNOMINATE ILIUM – most superior of the 3 the blade ISCHIUM - most inferior of the 3 the ‘sit bone’ PUBIS – most anterior of the 3 forms the symphysis

THE INNOMINATE FUNCTIONS: Support internal organs Changes in the human pelvis allow for bipedal locomotion

THE INNOMINATE Each innominate articulates with *sacrum (at the auricular surface) *one femur (at the acetabulum) *the other innominate (at pubic symph)

THE INNOMINATE – what to know The ilium: medially - Iliac crest – superior rim Iliac fossa – superior depression under rim ASIS and AIIS Arcuate line – midline inferior ridge Iliac tuberosity – posterior rugosity Auricular surface - posterior (art.w/ sacrum) Preauricular sulcus

THE INNOMINATE – what to know The ilium: laterally – Iliac crest Iliac pillar – ridge on midline of blade PSIS and PIIS Greater sciatic notch Acetabulum (actually the point where all three bones fuse together, art. w/femur)

THE INNOMINATE – what to know The ischium and pubis – medially Pubic ramus: anterior/superior, twists Pubic symphysis: most anterior point Ischiopubic ramus: flat Obturator foramen: big hole The ischium and pubis – laterally Ischial spine: most inferior/posterior Lesser sciatic notch: inferior Ischial tuberosity: very thick Pubic tubercle: anterior, above symph

THE INNOMINATE – L from R Orient ilium (crest and blade) superior Orient the pubic symphysis anteriorly and medially, ischium posterior and inferior The acetabulum is on the side of origin (lateral)

THE INNOMINATE – fusion ages Ischiopubic ramus; 5-8 years Acetabululm; 11-17 years Ischial tuberosity; 16-20 years Iliac crest; 17-23 years

THE INNOMINATE uses in forensics The pelvis is best for sex – due to changes in the pelvis for childbirth, there are numerous, easy to distinguish features that help differentiate males from females in both the PUBIS and the ILIUM ALSO, well developed methods for aging adults based on changes in the PUBIC SYMPHYSIS

THE INNOMINATE uses in forensics TO RECAP: SEX: PUBIS AND ILIUM AGE: FUSIONS, AURICULAR SURFACES, PUBIC SYMPHYSIS