Skeletal Anatomy Flashcards
How does the study of skeletal anatomy help a forensic scientist?
- To recognize the presence of human remains and differentiate them from animals remains
-To calculate the minimum number of individuals in a mass grave or mass fatality
-Human identification
-To identify age, sex and population ancestry
-To calculate probable stature, mass and handedness
-for clues into probable occupation/routine activity
-To look at perimortem injuries to reconstruct cause of death
-To reconstuct an individuals history of antemortem injury and healing
-To reconstruct an individual’s history of disease, health and lifestyle
Why do forensic scientists need to tell the difference between human and animal bones?
To determine whether their is a forensic case
What is MNI ?
Minimum number of individuals
What is the first question a forensic anthropologist asked ?
Are these animal or human remains ?
What does perimortem mean ?
Injury at death
What does antemortem mean?
Injury before death
Why would a forensic anthropologist want to know an individuals history of antemortem injury?
To match injury to medical records
Which bones would be the best to estimate sex in a human skeleton ?
Pelvic or cranium
Which bones could be used to estimate stature in the human skeleton ?
Femur
What is handedness and which bones would reveal this feature?
If an individual is right or left handed, this can be seen by musculature in the arm
How might we calculate MNI at a mass fatality ?
- Count all the bones
-Categorize
-Put them in pairs if they come in pairs
-Whichever bone is accounted for the most
What is the anatomical position of a cadaver or skeleton ?
- body erect
-feet slightly apart
-palms facing forward - thumbs pointing away from body
Superior
Towards the head
Inferior
Away from the head
Anterior
Towards the front of the body
Posterior
Towards the back of the body
Medial
Towards the midline of the body
Lateral
Away from the midline
proximal
Closer to the origin of the body part
Distal
Farther from the origin of the body part
Superficial
Toward the body surface
Deep
Away from the body surface
What are the 3 types of cartilage
-Hyaline, elastic and fibrocartilage
What type of cartilage is the most prominent ?
Hyaline
What is the role of hyaline cartilage ?
provides support, flexibility and resilience
Where is hyaline cartilage present ?
- Articular- covers the ends of long bones
-Costal- connects the ribs to the sternum
-respiratory- makes up larynx, reinforces air passages
-Nasal- supports the nose and makes its appearance
Where is elastic cartilage found ?
Found in the external ear and epiglottis
Where is fibrocartilage found ?
Found in menisci of the knee and intervertebral discs
What is the structure of fibrocartilage ?
Highly compressed with great tensile strength and contains collagen fibers
How many bones are in the human body ?
206 bones
How many bones are in the cranium ?
29
How many bones are in the axial skeleton ?
27 single bones
how many ribs are in a skeleton ?
24
How many paired bones are in the upper and lower body ?
10 paired bones in the upper body and 10 paired bones in the lower body
How many hand and wrist bones are there ?
54
How many foot and ankle bones are there ?
52
What is the axial skeleton ?
Bones of the skull, vertebral column and rib cage
What is the appendicular skeleton ?
Bones of the upper and lower limbs, shoulder and hip
How are bones classified?
By shape
How are long bones classified ?
They are longer than they are wide. (Humerus)
How are short bones classified?
-cube shaped bones of the wrist and ankle
-Bones that form within tendons (e.g. patella)
How are flat bones classified ?
they are thin, flattened and a bit curved. (E.g sternum and most skull bones )
How are irregular bones classified ?
they have complicated shapes (e.g vertebrae and hip bones)
What are the functions of bones ?
-support
-protection
-movement
-mineral storage
-blood cell formation
What is used as the primary way of estimating age ?
Teeth
Where is the hyoid bone ?
Not actually part of the skull but lies just inferior to the mandible in the anterior neck
What is the role of the hyoid bone
Attachment point for neck muscles that raise and lower larynx’s during swallowing and speech
What does damage to the hyoid mean ?
fracture of the hyoid is associated with manual strangulation as it is results from extreme pressure placed on the anterior of the neck
Why is hyoid damage associated with strangulation
The hyoids location makes it unlikely to break in most circumstances and it would be hard to break in any accidental cause of death
What are the different parts of the vertebrae ?
- cervical vertebrae - 7 bones of the neck
-thoracic vertebrae - 12 bones of the torso - lumbar vertebrae - 5 bones of the lower back
-sacrum - bone inferior to the lumbar vertebrae that articulates with the hip bones
What are intervertebral discs ?
Cushion-like pad composed of two parts
- nucleus pulposus and annulus fibrosus
What is the general structure of the vertebrae
- body/ centrum- disc-shaped, weight-bearing region
-vertebral arch- composed of pedicles and laminae that along with the centrum, enclose the vertebral foramen
-vertebral foramina- make up the vertebral canal through which the spinal cord passes
-spinous processes project posteriorly and transverse processes project laterally
-superior and inferior articular processes- protrude superiority and inferiorly from the pedicle-laminated junctions
-intervertebral foramina - lateral openings formed from notched areas on the superior and inferior borders of adjacent pedicles
What is the arrangement of the cervical vertebrae ?
Seven vertebrae (C1-C7) which are the smallest, lightest vertebrae
C3-C7 are distinguished with an oval body, short spinous processes and large, triangular vertebral foramina
What is the role of the atlas (C1)
support the entire weight of the skull
What is the structure of the atlas (C1)
-The atlas has no body and no spinous process.
-It consists of anterior and posterior arches, and two lateral masses
-The superior surfaces of lateral masses articulate with the occipital condyles
What is the role of the axis (C2)
Movement of the skull
What is the structure of the axis
-The axis has a body, spine and vertebral arches as do other cervical vertebrae
-unique to the axis is the dens or odontology process which projects superiority from the body and is cradled in the anterior arch of the atlas
What is the arrangement of the thoracic vertebrae ?
-There are twelve vertebrae (T1-T12)
-Major marking include 2 facets and 2 demifacets on the heart shaped body, the circular vertebral foramen, transverse processes and a long spinous process
-The location of the articulate facets prevents flexi on and extension but allows rotation of this area of the spine
What is the arrangement of the lumbar vertebrae ?
-The five lumbar vertebrae (L1-L5) are located in the small of the back and have an enhanced weight-bearing function
-They have short, thick pedicles and laminae, flat hatched-shaped spinous processes and a triangular shaped vertebral foramen
-orientation of articulate facets locks the lumbar vertebrae together to provide stability
What is the arrangement of the sacrum ?
-Consists of 5 fused vertebrae (S1-S5) which shape the posterior wall of the pelvis
- It articulates the L5 superiority and with the articular surfaces of the hip bones
-Major markings include the sacral promontory, transverse lines, algae, dorsal sacral foramina, sacral canal and sacral hiatus
What is the arrangement of the coccyx ?
Made up of four (3-5) fused vertebrae that articulate superiorly with the sacrum
What unique feature is possessed by all cervical vertebrae ?
It has transverse foramen
What 2 bones articulate with the superior and inferior surfaces of the sacrum ?
Lumbar 5 and Coccyx
What is the technical description of a true rib ?
It runs vertebrosternal
What are the three parts of the sternum ?
Manubrium, body and xiphoid
What are the identifiable features of the first couple of ribs ?
-horizontal
-flat
-C shaped profile
What is the identifiable feature of false ribs ?
They have a round sternal end
What is an identifiable feature of floating ribs ?
They have no cartilage attachment
How does the cervical vertebrae change as the number progresses ?
-spinous process gets longer
-vertebrae get larger as they go down
What are unique features that identify thoracic vertebrae ?
-transverse facets
-heart shaped body
-spinous process overlap
How does the thoracic vertebrae change as the number progresses ?
-overlapping of the spinous process
-first few thoracic vertebrae mimic the shape of the C7
what are identifying features of the lumbar vertebrae ?
-axe shaped spinous process
-largest body
-kidney shaped body
How does the lumbar vertebrae change as the number progresses ?
-vertebrae increases in size as it goes down
-T12 mimics the start of lumbar vertebrae
What is the appendicular skeleton made up of ?
The bones of the limbs and their girdles
What are pectoral and pelvic girdles ?
pectoral girdles attach the upper limbs to the body trunk and pelvic girdles secures the lower limbs
What do the pectoral girdles consist of ?
Anterior clavicles and posterior scapulae
What do pectoral girdles allow for ?
Maximum movement
What do the pectoral girdles provide attachment points for ?
Muscles that move the upper limbs
How are clavicles described?
Slender, doubly curved long bones lying across the superior thorax
What 2 bones does the clavicle articulate with ?
The acromial end articulates with the scapula and the sternal end articulates with the sternum
What does the clavicle do?
provide attachment points for numerous muscles and acts as braces to hold the scapulae and arms out laterally away from the body
How is the scapulae described ?
triangular, flat bones lying on the dorsal surface of the rib cage between the second and seventh ribs
What are the major markings of the scapulae ?
Suprascapular notch, the supraspinous and infraspinous fossae, the spine, the acromion and the coracoid process
What is the sole bone of the upper arm ?
Humerus
What two bones does the humerus articulate with ?
Scapula at the shoulder and the radius and ulna at the elbow
What does the proximal humerus include ?
Head, anatomical and surgical necks, greater and lesser tubercles and the intertubercular groove
what does the distal humerus include ?
The capitulation, trochlea, medial and lateral epicondyles and the coronoid and olecranon fossae
What are the bones of the forearm ?
radius and ulna
What two bones do the radius and ulna articulate with ?
-proximal with the humerus and distally with the wrist bones
What joins the two bones along their entire length ?
Interosseous membrane
where is the ulna located in the forearm ?
medically in the forearm and is slightly longer than the radius
What are the major markings of the ulna ?
Olecranon, coronoid process, trochlear notch, radial notch and the styloid process
what two bones does the radius articulate with ?
Radial notch of the ulna and the capitulum of the humerus
What are the major markings of the radius ?
radial tuberosity, ulnar notch and styloid process
What bones are in the hand ?
-wrist bones (carpals)
-bones of the palm (metacarpals)
-bones of the fingers (phalanges)
What are the 8 bones of the carpus ?
-scaphoid
-lunate
-triquetral
-pisiform
-trapezium
-trapezoid
-capitate
-hamate
How many metacarpal bones are there ?
5
What two bones do the metacarpal bones articulate with ？
Bases articulate with the carpals and heads articulate with the phalanges
How many finger bones are in each hand ?
14
How many phalanges are in each finger ?
3
How many phalanges are in each thumb ?
2
How can the health and condition of the vertebral column help forensic scientists ?
Indication of physical strain experienced during life
What damage becomes common to the vertebrae in old age ?
Compression fractures or microfractures
What is the thoracic cage made up of ?
The thoracic vertebrae, the ribs, sternum and costal cartilages
What is the role of the thoracic cage ?
-forms a protective cage around the heart, lungs and great blood vessels
-supports the shoulder girdles and upper limbs
-provides attachments for many neck, back and chest muscles
-uses intercostal muscles to lift and depress the thorax during breathing
How is the sternum described ？
A dagger shaped, flat bone that lies in the anterior middle of the thorax
What are the major markings of the sternum ?
- jugular notch
-sternal angle
-xiphisternal joint
What are the three types of ribs ?
-true
-false
-floating
How do the ribs attach ?
Attach posteriorly to the thoracic vertebrae
What is the structure of a true rib ?
bowed, flat bone consisting of a head, neck, tubercle and shaft
What do long bones consist of ?
Diaphysis and epiphysis
How is the Diaphysis described ?
-Tubular shaft that forms the axis of long bones
-Composed of compact bone that surrounds the medullary cavity
-yellow bone marrow (fat) is contained in the medullary cavity
How is the epiphyses described ?
-expanded ends of long bones
-Exterior is compact bone and the integrity is spongy bone
-joint surface is covered with articulate cartilage
-Epiphyseal line separates the diaphysis from the epiphyses
What is the epiphyseal line ?
Allows active growth and fuses when growth stops
what is periosteum ?
Double layered protective membrane
How is the periosteum described ?
-ouster fibrous layer is dense regular connective tissue
-inner osteogenic layer is composed of osteoblasts and osteoclasts
-richly supplied with nerve fibers, blood and lymphatic vessels which enter the bone vials nutrient foramina
What is the structure of flat bones ?
Compact bones surround the inner spongy bone allowing for maximum strength and minimum weight
How are shor, irregular and flat bones described ?
-Thin plates of periosteum covered compact bone on the outside with endosperm covered spongy bone on the inside
-have no diaphysis or epiphyses
-contain bone marrow between the trabeculae
Where are hematopoietic tissues in infants ?
Found in the medullary cavity and all areas of spongy bone
Where are hematopoietic tissues in adults ?
Found in the dipoe of flat bones and the head of the femur and humerus
What is the structure of compact bone ?
-lamella- column like matrix, tubes composed mainly of collagen
-central canal, containing blood vessels or nerves
-volkmann’s canals-channels lying at right angels to the central canal connecting blood and nerve supply of the periosteum to that of the Haversian canal
What are osteocytes
Mature bone cells
What are lacunae ?
Small cavities in bone that contain osteocytes
What are canaliculi
Hairlike canals that connect lacunae to each other and the central canal
What are osteoblasts
Bone-forming cells
What are osteoclasts
Large cells that resort or break down bone matrix
What is osteoid
Unmineralised bone matrix composed of proteoglycans, glycoproteins and collagen
What is the chemical compostitons of bones
65% hydroxyapatities
Mainly calcium phosphates
35% protein (collagen)
What is osteogenesis and ossification
The process of bone tissue formation
What does osteogenesis and ossification lead to ?
-the formation of the bony skeleton in embryos
-bone growth until early adulthood
-bone thickness, remodeling and repair
What are the 3 steps to identify the side of the scapula ?
-the glenoid surface is lateral
-spine is posterior
-the inferior angle is inferior
What are the 4 steps to identify the side of the clavicle ?
-smooth surface is anterior and superior
-rugid surface is posterior
-conoid tubercle is posterior and inferior
-sternal end articulates with the sternum and is medial
What are the 4 steps to identify the side of the humerus ?
-trochlea is inferior
-deltoid tuberosity is lateral
-elecronon fossa is posterior
-capitulum is lateral to trochlea
What are the 4 steps to identify the side of the radius ?
-styloid process aligns with your thumb
-radial tuberosity is anterior
-interosseous crest points to the midline of the arm
-head of radius is superior to the rest of the bone
What are the 4 steps to identify the side of ulna ?
-trochlea notch is superior to your 5th finger
-styloid process aligns with 5th finger
-interosseous crest points to the midline of the arm
-trochlea notch articulates with the trochlea of the humerus
What bones make up the pelvic girdle (coxal)
a pair of hip bones, sacrum and coccyx
What is the role of the pelvic girdle ?
-attaches the lower limbs to the axial skeleton with the strongest ligaments of the body
-transmits weight of the upper body to the lower limbs
-supports the visceral organs of the pelvis
What 3 parts make up the pelvic girdle ?
Ilium, ischium and pubis
How is the ilium described ?
A large flaring bone that forms the superior region of the coxal bone.
-it consists of a body and superior winglike portion called the ala
-the broad posterolateral surface is called the gluteal surface
What are the major marking of the ilium ?
Iliac crests, four spines, greater sciatic notch, iliac fossa, accurate line and the pelvic brim
How is the ischium described ?
forms the posteroinferior part of the hip bone
What does the ilium articulate with ?
The auricular surface articulates with the sacrum (sacroiliac joint)
What does the ischium articulate with ?
The thick body articulates with the ilium and the thinner ramus articulates with the pubis
What are the major markings of the ischium ?
Ischial spine, lesser sciatic notch and the ischial tuberosity
What does the pubis form ?
Anterior portion of the hip bone
What does the pubis articulate with ?
Ischium and the ilium
What are the major markings of the pubis ?
Superior and inferior rami, the pubic crest, pubic tubercle, pubic arch, pubic symphysis and obturator foramen
What are the characteristics of a female pelvis ?
Tilted forward- adapted for childbearing, cavity of the pelvis is broad, shallow and has greater capacity, bone thickness is less, bones are lighter and thinner, pubic arch is broach (80 degrees)
What are the characteristics of a male pelvis ?
Tilted less far forward, adapted for support of males heavier build and stronger muscles, cavity of the true pelvis is narrow and deep, bones are heavier and thicker and markings are more prominent. Pubic arch is more acute (50 degrees)
What are the segments of the lower limb ?
Thigh, leg and foot
What do the lower limbs do ?
Carry the wight of the erect body, and are subjected to exceptional forces when one jumps or runs
What is the sole bone of the thigh ?
Femur
What bones does the femur articulate with ?
Articulates proximally with the hip and distally with the tibia and fibula
What are the major markings of the femur ?
Head, fovea capitis, greater and lesser trochanters, gluteal tuberosity, lateral and medial condyles and epicondyles, linear aspersions, patella surface and intercondylar notch
Where does the patella bone sit ?
The patella surface of femur
How are the tibia and fibula connected ?
Interosseous membrane
What bones form the skeleton of the leg ?
Tibia and fibula
What do the tibia and fibula articulate with ?
Femur proximally and with the ankle bones distally
What are the major marking of the tibia ?
Medial and lateral condyles, intercondylar eminence, the tibial tuberosity, anterior crest, medial malleolus and fibula notch
What is the role of the tibia ?
Receives the weight of the body from the femur and transmits it to the foot
how is the fibula described ?
Sticklike bone with slightly expanded ends located laterally to the tibia
What are the major markings of the fibula ?
The head and lateral malleolus
What are the 3 steps to identify the side of the patella ?
-apex is inferior
-patella always falls to the side it belongs
-lateral facet of patella is larger and is lateral feature
What are the 4 steps to identifying the side of the femur
-the head of the femur is superior to the patella surface
-greater and lesser trochanter are posterior
-epicondyles are posterior and inferior
-patella surface is anterior
What are the 4 steps to identifying the side of the coxal bone ?
-ischium is always inferior to ilium
-iliac crest is the most superior and lateral
-auricular surface articulates with sacrum
-pubic arch is medial
What are the 4 steps to identify the side of the tibia ?
-medial malleolus is medial
-anterior crest is anterior
-intercondylar eminence is the most superior
-tibral tuberosity Is anterior
What are the 3 steps to identifying the side of the fibula ?
-lateral malleolus is lateral and posterior
-interosseous crest is medial
-head of fibula is superior
