Download Bone Diversity

Bone Diversity
Dr. Anderson
GCIT
Bone Diversity
• There are normally 206
bones in the adult
human body
• Each bone is derived
from connective tissue
and grows to articulate
with other bones to
form the functional
human skeleton
The Axial Skeleton
• Composed of the
skull, vertebrae, ribs
(thoracic cage) and
coccyx
The Skull
• Cranium
– Made of
multiple bones
that are
immovable (as
adult) and
connect in
sutures, houses
the brain
Cranium – Frontal Bone (#1)
• Shell-shaped frontal
bone, anterior to
parietal (coronal)
sutures
• Makes up superior
wall of orbits
Cranium – Parietal Bone (#2)
• Form most of the superior and lateral aspects
of the skull and articulate with other skull
bones
Cranium - Occipital Bone (#4)
• Forms most of the
skull’s posterior walls
and base
• Foramen magnum
occurs in the inferior
surface of this bone,
allowing the spinal
cord to pass through
Cranium - Temporal Bone (#3)
• Inferior to parietal bones (3 regions)
– Squamous region
• Produces the zygomatic process anteriorly to meet the
zygomatic bone (makes up the “cheekbone”) and
contains the mandibular fossa (meets the mandible to
articulate the lower jaw)
– Tympanic Region
• Contains acoustic meatus and styloid process
– Mastoid region
• Exhibits mastoid process (anchors some neck
musculature) and has the stylomastoid foramen (allows
cranial nerve VII to exit the skull)
Cranium - Temporal Bone (#3) (con’d)
Cranium - Sphenoid Bone (#5)
• Very complex, but
articulates with almost all
other bones
– Spans the width of the
middle cranial fossa
Cranium - Sphenoid Bone (#5) (con’d)
Cranium - Sphenoid Bone (#5) - con’d
• Openings in sphenoid
include
– Optic canals – anterior to
the sella turcica, allow
cranial nerves to pass to
the eyes
– Superior Orbital Fissure
• Allows cranial nerves that
control eye movements to
exit
Facial Bones - Mandible
• Lower Jawbone –
articulates with
mandibular fossa (on
temporal bone)
• Two main parts
– Body (chin)
– Ramus (vertical part)
Maxillary Bones
• Bilateral maxillary
bones are fused
medially – form the
upper jaw and the
central part of the face
Smaller Facial Bones
(pg 213)
•
•
•
•
•
Zygomatic bones – form cheek bones
Nasal Bones – forms bridge of nose
Lacrimal Bones – medial orbit walls
Palatine Bones – posterior part of hard palate
Inferior nasal conchae – lateral walls of nasal
cavity
All of the Aforementioned Bones are
Summarized on pp. 214-215
The Vertebral Column
• Consists of 33 irregular
(in shape) bones
• Segmentation =
flexibility!
• Prone to damage
under heavy and/or
chronic forces
Vertebral Function
• Transmits force from upper body to legs
• Houses and protects the spinal cord
• Attachment points for ribs, and for muscles/
ligaments of the back and neck
Spinal Divisions
• 7 cervical (neck)
vertebrae
• 12 Thoracic
vertebrae
• 5 Lumbar vertebrae
• 5 Sacral (fused)
vertebrae
• 4 Vertebrae in Coccyx
Scoliosis
• Abnormal curvature of
the spine
• Leads to gait problems,
pain and disability,
breathing difficulties
• Can be corrected early
by bracing, in extreme
cases- surgery
Spinal Arrangement
• Alternating
arrangement of
vertebrae and discs
• Peripheral nerves
from spinal cord
extend from each
vertebral “level”
Intervertebral Discs
• Serves as a shock
absorber between
vertebrae- composed of
collagen and
fibrocartilage
• Composed of 2 layers
– Inner, gel-like layer
(nucleus pulposus)
– Annulus fibrosus – tough
outer covering that
resists compression
Herniated Discs
• Injury leads to
rupture of the anulus
fibrosis leading to a
“bulge” which may
press on the spinal
nerves causing
intense pain,
numbness or loss of
motor fuction
Vertebra (Dorsal View)
• Centrum bears the
weight of the body
(interspersed by discs)
• Spinal cord passes
through the vertebral
foramen
• Spinous process and
transverse process are
for muscle attachment
Vertebral Names
• Cervical Vertebrae
(C1-C7)
• Thoracic Vertebrae
(T1-T12)
• Lumbar Vertebrae
(L1-L5)
• Sacral Vertebrae
(S1-S5)
Superior-Inferior Changes
• Centra of each
vertebrae tend to
thicken inferiorly
• Vertebral foramen
narrows inferiorly
• No rib articulation
past T12
The Thoracic (Rib) Cage
• Roughly cone-shaped
• Protects the heart,
lungs
• Provides a solid
foundation for muscles
to pull and push
against for inhalation
and exhalation
Sternum
• Articulates with the
costal cartilages of
the ribs (anteriorly)
Ribs
• Serve to protect the
organs of the thoracic
cavity (heart, lungs)
• 12 pairs (in both
genders)
– 7 pairs are “true” ribs
that articulate directly
with sternum
– 5 pairs are “false” ribs
that articulate
indirectly with the
sternum
Posterior Rib Articulation
Appendicular Skeleton
• Peripheral to axial
skeleton
• Includes limb bones
(arms and legs) and
pelvic a shoulder
girdles
Shoulder (Pectoral) Girdle
• Attach upper limbs to
the axial skeleton
• Major bones
– Scapula (shoulder
blade)
• Posterior aspect
– Clavicle (collar bone)
• Anterior aspect
Scapula
• Bilateral and
posterior
• Does NOT articulate
directly with the axial
skeleton – held in
place by muscles
– This articulation
allows for flexibility at
the cost of stability
Scapula - Anatomy
• Triangular bone
• Notable features
– Glenoid cavity (fossa)
articulates with the
humerus on lateral
border
Upper Limb (Arm) Bones
• Humerus – Upper
Arm
• Radius, Ulna –
Forearm
• Carpal bones –
wrists
• Metacarpals – palm
• Phalanges - Fingers
Ulna
• Forms elbow joint with humerus
• Longer forearm bone (on pinky side), thicker
proximally
• Notable features
– Olecranon (elbow)
– Coronoid Process
– Trochlear notch
Grips trochlea of
humerus, forming
articulation proximally
– Distal head (forms articulation with wrist)
Radius
• Thicker distally
• Notable features
– Proximal head – articulates with
capitulum of humerus
– Radial tuberosity – provides
attachment for bicep
– Styloid process – provides
attachment for wrist ligament
Proximal
Distal
Ulna – Detailed Structure
The Hand
• Carpals – (8 bones total)
• Metacarpals (5 bones) labeled 1-5 (thumb to
pinky)
• Phalanges – multiple bones each
– Two in thumb
– Three in all other fingers
• Distal, middle, proximal
The Hand
The Pelvic (Hip) Girdle
• Attaches lower limbs
to the axial skeleton
• More stable but less
flexible than
shoulder girdle
• “Pelvis” is actually
three separate bones
Pelvic Function
• Attaches lower
appendicular
skeleton to the axial
skeleton
• Firmly attached with
ligaments
• Provides a strong
foundation for femur
articulation and
muscle attachment
Pelvic Bones
• 3 main parts
– Ilium (superior)
– Ischium (inferior and
posterior)
– Pubis (inferior and
anterior)
• The acetabulum (hip
socket) is where all
three hip bones fuse
and where the femur
articulates
Medial view
Lateral view
Ischium and Pubis
• Ischium
– Ischial tuberosity
• Bears all weight
when sitting
• Pubis
– Forms anterior part
of hip bone
– Pubic symphysis
(cartilaginous disc
connects pubic
bones medially)
Gender Differences in Pelvic Anatomy
• What are the major
differences in hip
morphology between
men and women?
The Lower Limb (Leg) Bones
•
•
•
•
•
•
Femur – thigh bone
Tibia – shin bone 1
Fibula – shin bone 2
Tarsals – ankle bones
Metatarsals – foot bones
Phalanges - toes
Femur
• Largest and strongest
bone in the body
• Transfers all weight
from the pelvis to the
legs
Tibia
• Tibia transmits
weight of femur to
the foot
– Lateral and medial
condyle articulate
with femur (proximal
end)
• Medial malleolus
(distal end) – “bulge”
on inside of ankle
Fibula
• Primarily for muscle
attachment
– Does not bear weight
• Lateral Malleolus
– “Outside” bump of
ankle
Ankle and Foot Bones
• Tarsals – ankle bones
• Metatarsals –
proximal foot bones
– Calcaneus – heel
bone
• Phalanges - Toes