What are the 8 cranial bones
parietal (2), temporal (2), frontal, occipital, ethmoid, sphenoid
What are the 14 facial bones
Maxilla (2), Zygomatic (2), Nasal (2), Palantine (2), Lacrimal (2), Inferior Nasal Concha (2), Vomer, Mandible
What are the 26 bones of the vertebral column
7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 1 sacrum (5 fused segments) 1 coccyx (3-5 fused segments)
What tissue layer do somites form from
mesoderm
Why do different areas of the body associate with different levels of the spinal cord
The formation of somites
What are the 3 parts of a somite
sclerotome, dermatome, and myotome
What structure(s) does the sclerotome form
vertebrae and ribs
What structure(s) does the dermatome form
dermis of the skin
What structure(s) does the myotome form
Muscles of the back and limbs
How do sclerotome cells migrate to form vertebrae
They migrate medially to surround the neural tube and notochord, forming the vertebral foramen and body
What structure do the notochord eventually become
nucleus pulposus
What does the fusion of dense and loose tissues of adjacent somites form
The intersegmental vertebra
What are the 3 steps in endochondral ossification of vertebrae
- Mesoderm differentiates into cartilage models of bones 2. Chondrification around the neural tube 3. endochondral ossification replaces cartilage with bone
What do primary ossification centers form
They form vertebral parts that fuse between ages 3-5 yrs
What do secondary ossification centers form
They form on vertebral periphery in puberty
What permits growth in size of vertebrae
cartilage pates between ossification centers
What is the primary curvature of the spine
The primary curvature of the spine is kyphosis, and is present during the fetal life.
What is the secondary curvature of the spine
The secondary curvature of the spine is lordosis, and develops after birth from sitting, holding the head up, walking, etc
What type of curve does each part of the spine have
Kyphotic: Thoracic, sacral
Lordotic: Cervical, Lumbar
What is the body of a vertebra
anterior part that bears most of the weight
What is the vertebral foramen
space enclosed by the vertebral arch
What is the vertebral canal
column of vertebral foramina which enclose the spinal cord
What forms the spinous processes
fusion of the lamina
What forms the transverse processes
fusion of lamina and pedicle
What are mammillary processes
little bumps on the superior articular processes that serve as an attachment for the multifidus, and are only present in lumbar vertebrae
What do the superior and inferior articular processes form
zygopophyseal joint AKA facet joint
Which vertebral regions have the widest range of motion
In order of decreasing motion: Cervical, lumbar, thoracic
What is the unique feature of each vertebra type
Cervical: transverse foramina, bifid S.P.
Thoracic: costal facets, long pointy S.P.
Lumbar: mammillary processes, stout horizontal SP
Which vertebrae have the largest body
In order of decreasing size: Lumbar, thoracic, cervical
What are the main movements of cervical vertebrae
Flexion/extension, rotation, lateral flexion (abduction)
What are the main movements of thoracic vertebrae
Rotation and lateral flexion (abduction)
What are the main movements of lumbar vertebrae
Flexion and extension
What bones form the sacrum
Fusion of the 5 sacral vertebrae after 20 years
What are the sacral crest
The median sacral crest runs down the center and is formed from by the fusion of SP’s, and the lateral sacral crests are formed by the TSP’s
What is the function of sacral canal
It serves as a passage for spinal nerves and ends at the hiatus
What is the function of the sacral foramina
The anterior and posterior foramina convey the anterior and posterior rami of sacral nerves
What is the coccyx
3-5 small fused vertebrae that serve as origin for pelvic muscles and ligaments
What is the sacrococcygeal symphysis
a fibrocartilaginous joint between the sacrum and coccyx
What is the intervertebral joint
symphysis joint between vertebral bodies
What is the annulus fibrosis
crisscross pattern of collagenous fibers that interconnect the lips of the vertebrae
What is the nucleus pulposus
gelatinous center of intervertebral joint that provides shock absorption
From whence does the nucleus pulposus derive structural stability
Proteoglycans that absorb water. The water can be squeezed out to allow for compression without damaging the tissue.
What is a herniated disc
When the nucleus pulposus pushes through the annulus and pinches the outgoing spinal nerve against the articular processes within the intervertebral foramen.
Do hernias always cause pain
Nope! Even if there is a herniated disc and back pain, the hernia is not necessarily the cause
What is a facet joint
Zygapophyseal joints are synovial joints that connect vertebral arches
What is the supraspinous ligament
ligament that joins the tips of SP’s
What is the interspinous ligament
ligament that spans between the SP’s
What is the ligamentum flavum
elastic CT that connects lamina. It helps extend the vertebral column.
Where are the anterior and posterior longitudinal ligaments located
They are affixed to the anterior and posterior surfaces of the vertebral bodies, respectively
What is the function of the anterior and posterior longitudinal ligaments
They add support to the intervertebral joints
What is the atlas
C1. It has no vertebral body
What is the axis
C2. It has the dens (odontoid process) which is formed by the fusion of the bodies from C1 and C2
What is the atlanto-axial joint
pivot joint formed between the dens and anterior arch of the atlas.
What is the transverse ligament
It holds the dens against the anterior arch
Where are the alar and apical ligaments
They attach the dens to the margin of the magnum foramen and limit rotational movement
What is the atlanto-occipital joint
superior articular processes of C1 articulate with occipital condyles of the skull. It permits flexion and extension
Where is the posterior atlanto-occipital ligament (PAO)
ligament that spans from margin of magnum foramen to the posterior arch of C1.
What is a potential pathology of the PAO?
It could cause cervicogenic headaches
What are the suboccipital muscles
Rectus Capitis posterior Major and Minor, Inferior and Superior Obliques
What muscle attaches to the PAO
Rectus Capitis Posterior Minor
What does the head of the rib do
Articulates with vertebral bodies
What is the tubercle of the rib
It is the constotransverse articular facet
What does the sternal end of the rib do
attaches to costal cartilage
What does the costal groove do
Serves as channel for intercostal vessels and nerve
Where are costovertebral articulations
synovial joints on the body and TVP of thoracic vertebrae with ribs
What is the sternal angle
Where the manubrium attaches to the body of the sternum. It is a great landmark for rib 2
What are the parts of the sternum
Manubrium, sternal body, and xiphoid process
How does the sternum connect to the ribs
Via costal cartilage
What is the hyoid bone
Bone in the anterior neck that is anchored by muscles of speech and swallowing. It is the only bone not attached directly to another bone.
