Axial and Appendicular
Skeleton
Chapters 7 & 8
• Axial and Appendicular Skeleton
• The skeleton (greek=dried up body) has
206 bones. The axial skeleton is
composed of the skull, vertebral column,
and rib cage. The appendicular skeleton
is composed of the upper and lower limbs
and the shoulder and pelvic girdle.
• *** see page 147 for the definition of
certain bone land marks.
• I. The skull-contains cranial bones that protect the brain, these are
joined at sutures. The facial bones make up the rest of the skull and
serve several functions. See the section on the fetal skull pg173-174
and learn the regions.
• A. The skull is composed of many cavities and openings which allow
nerves, blood vessels, and organs to function.
• B. Cranium- composed of eight bones, two are paired
•
1. parietal (2) 3. frontal
5. ethimoid
•
2. temporal (3) 4. occipital
6. sphenoid
• C. Facial bones- there are 14 facial bones
•
1. mandible
4. nasal (2)
7. zygomatics
•
2. maxillae (2) 5. vomer
8. lacrimal (2)
•
3. palantine(2) 6. inferior nasal conchae (2)
(2)
Supracilliary Arch
Orbital Part
Anterior Cranial Fossa
Parietal Bone and Sutures
Occipital Bone
Occipital Bone
Occipital Bone
Groove for
sigmoid sinus
Groove for transverse dural sinus
Temporal Bone and Zygomatic bone
Temporal Bone
Petrous Part
Temporal Bone
Groove for
sigmoid sinus
Groove for transverse dural sinus
Cranial Fossa
SPHENOID BONE
Sphenoid Bone
Sphenoid Bone
Ethmiod bone
Superior
Nasal
Conchae
Facial Bones
Alveolar Margin
Alveolar sockets (where
teeth insert)
Mandible and Maxillae
Facial Bones
Cleft Palate is a
congenital condition
in which the two
halves of the
maxillary and
palate bone fuse.
The opening affects
the roof of the
mouth and the
nasal cavity and
upper lip. It is
treated with surgery
and can be easily
prevented by taking
folic acid during
pregnancy.
• D. Special parts of the skull
• 1. Orbits- cavities that hold the eye and all tissues related to
the eye. It is formed by the union of seven bones which also
form the lacrimal fossa, optic foramen, and orbital fissures.
• 2. Nasal Cavity- made up of bone and cartilage the top is
made by the cibriform plate and the bottom by the palantine.
There are three conchae (shelfs) two made by the ethmoid
bone and one by the inferior conchae bone. The nasal
septum divides the nose down the middle.
• 3. Paranasal sinuses- air filled cavities around the nasal area
that connect to the nasal cavity and help in treating the air as
well as in voice resonance.
• 4. Hoyd bone- inferior to mandible, only bone that does not
have a joint, it is an attachment site for the tongue and other
neck muscles.
Bones of the nasal cavity
Bone of the Eye Orbit
Sinuses
Hyoid Bone
Vertebral Column
• II. The vertebral column- made up of 26
(33 technically but 9 are fused) bones,
forms the body’s axis, it protects the spinal
cord. It articulates with the ribs and
provides attachment for dorsal muscles
and rib muscles. Anterior and posterior
longitudinal ligaments, the supraspinous
and interspinous ligaments, and the
ligamentum flavum stabilize the vertebral
column.
Intervertebral Disc
•A. Intervertebral discs- composed of fibrocartilage it endures compression and
shock absorption. It has two regions the annulus fibrosus and the nucleus
pulpusus. They make up 25% of the height of the column and flatten
throughout the day.
Vertebral sections and curves
•B. Regions and normal
curvatures- The spinal
column in made up of the
cervical (7), throracic (12),
lumbar (5), sacrum (5
fused), and coccyx (4
fused). Each region has a
curve: concave for cervical
and lumbar and convex for
thoracic and sacral.
Ligaments of the vertebrae
Common vertebral landmarks
C. General structure of
vertebrae- All vertebrae
except the first two cervical
vertebrae (atlas and axis)
share common
characteristics that differ
slightly according to region.
All vertebrae have a centrum
(body), vertebral arch,
vertebral foramen, pedicles,
laminae, spinous process,
tansverse process, and
inferior/superior articulating
facets.
Axis and Cervical Vertebrae
D. Regional vertebral
characteristics- each region has
vertebrae that serve different
functions thus they vary slightly:
1. Cervical vertebrae- rectangle
like, bifid spinous process,
triangular vertebral foramen, has
transverse foramen,
superior/anterior facets are
located in slightly opposite
positions.
Thoracic and Lumbar Vertebrae
2. Thoracic vertebrae- body is slightly heart shape, has demifacets (for ribs),
long spinous process, circular vertebral foramen, transverse processes
articulate with ribs, provides most of the rotation.
3. Lumbar vertebrae-bears most of the weight so it has a massive body, short
thick pedicles and laminae, triangular vertebral foramen, articulating facets
prevent rotation, and short thick spinous process.
Anterior and Posterior Sacrum
4. Sacrum-five fused vertebrae, articulates with the bones of pelvis,
center of gravity for the human is within this region
5. .
5. Coccyx- 4 (or 3-5) fused vertebrae, also known as the tail bone.
Spinal Abnormalities
• E. Abnormalities of the spinal column- These present themselves
when the curvatures of the spinal column are exaggerated.
• 1. Scoliosis- lateral curvature, most often in thoracic region. The
cause is sometimes unknown. Sometimes the vertebrae are
deformed and or the one side of muscles is stronger pulling the
vertebral column to that side. In some cases scoliosis can cause
compression of the lung.
• 2. Kyphosis- a bent on a saggital plane along the thoracic region
causing a hunchback. Happens most often in women as a result of
vertebral fractures due to osteoporosis.
• 3. Lordosis – an over curvature of the lumbar region causing a
swayed back. This often occurs in people carrying a large long
infront or spinal tuberculosis or osteomalacia (boen softening)
Bones of the Anterior Thorax
• III. The bony thorax- the rib cage is also part of
the axial skeleton and assist in breathing as well
as protect internal organs.
• A. Sternum- has three sections: manubrium,
body, xyphoid process (cartilage)
• B. Ribs- there are twelve pairs of ribs, the first 7
are true ribs (attach to sternum) and the last 5
are false ribs (floating).
Bone of the upper appendicular
Skeleton
• IV. The pectoral girdle- consist of the
scapula and clavicle, attaches upper limbs
to axial skeleton, and provides attachment
sites for muscles
• A. Clavicles-also called the collarbone,
they are long bones.
• B. Scapulae-also called shoulder-blades,
they are flat bones with three borders.
• V. The upper limb- 30 bones make up these three
sections
• A. Arm- applies to area between shoulder and elbow: the
humerus.
• B. Forearm- applies to area from elbow to writst: radius
and ulna. These bones articulate with the humerus, the
wrist, and each other. They are attached to each other
by the interosseous membrane.
• C. Hand- includes the carpals (wrist bones) metacarpals
(palm) and phalanges (finger digits). Phalanges are
numbered 1-5 beginning with the thumb (pollex)
• VI. The pelvic girdle- consists of two coxal bones (os coxae) that
attach to the axial skeleton by very strong ligaments, they bear the
body’s weight and have deep joint sockets for the lower limbs. The
two coxal bones are made up of three fused bones.
• A. Ilium- large lateral flaring bones
• B. Ischium-located posterior inferior to ilium, also known as the sit
bones
• C. Pubis-anterior bones of the pelvis
• D. True and false pelvis- false pelvis refers to the greater pelvis that
is superior to pelvic brim, forms part of the abdomen, and contains
abdominal organs. The true pelvis is inferior to pelvic brim and
holds pelvic organs.
• E. Pelvic structure and childbearing- womens’ pelvic girdles are
designed for child bearing. They have a true pelvis that is broad and
shallow, bones are lighter and thinner, the acetabula are smaller and
further apart and the pubic arch is more rounded.
• VII. The lower limbs- they carry the entire weight of the body, it
includes the thigh (femur) the leg (tibia and fibia) and the foot
(tarsals, metatarsals, and phalanges).
Disorders of the appendicular
skeleton
• Hip dysplasia- common birth defect in which the
acetabulum is incompletely formed or the ligatments are
lose allowing the femur to slip out of its socket. The
treatment involves properly positioning the head of the
femur so cause the acetabulum to deepen.
• Club foot-a congenital disorder that is caused by heredity
or malpositioning of the fetus in the womb. The soles of
the feet point medially and the toes point inferiorly. It is
treated with casts that reposition the foot or with surgery.
Growth of body and proportions of
limbs to trunk-. After birth limbs
grow faster than the trunk.