Anatomy Chapter 7

Vertebral body enlarges

caudally

Coronal suture

frontal and parietals

Squamous suture

parietal and temporal

Passing inferiorly through the sacrum is a bony tunnel called the

sacral canal, which terminates at the sacral hiatus near the inferior tip of the sacrum.

Crossing the middle of the parietal bone in an arched direction are two curved lines

the superior and inferior temporal lines; the former gives attachment to the temporal fascia, and the latter indicates the upper limit of the muscular origin of the Temporal muscle (muscle of mastication).

Ethmoid bone

Cranial floor, orbital wall, roof of nasal cavity, nasal septum. cribiform plate and olfactory foramina. has perpendicular plate which separates left from right nasal cavity. Also has superior and middle nasal conchae.

Vomer

Inferior part of nasal septum

Palatine bone

L-shaped, dorsal end of hard palate, also part of orbit

Foramen magnum

Spinal cord passes through here

sacral and coccygeal fusions do not start until age

20 and are not completed until middle age.

The vertebral column originally develops as a series of

33 vertebrae, but this number is eventually reduced to 24 vertebrae, plus the sacrum and coccyx.

transverse foramen

An important artery that supplies the brain ascends up the neck by passing through these openings.

Typical cervical vertebrae, such as C4 or C5, have several characteristic features that differentiate them from thoracic or lumbar vertebrae

Cervical vertebrae have a small body, usually have a bifid (Y-shaped) spinous process. The spinous processes of the C3-C6 vertebrae are short, but the spine of C7 is much longer. Costal processes - reduced ribs form transverse foramina.

Vertebral column composed of

1. 24 vertebrae (7 cervical, 12 thoracic, 5 lumbar) 2. Sacrum and coccyx

Roles of skull

1. Protection - cranium has multiple ossification centers 2. Sensory in the face 3. mastication mouth 4. breathing in nose

Looking at the posterior surface, the curvatures are:

1. Thoracic and sacrococcygeal curves are convex. 2. Cervical and lumbar curves are concave.

Articulation of rib

1. head articulates with costal facet on vertebral body. 2. Tubercle of rib articulates with transverse costal facet, but is lacking in floating ribs.

Sternum consists of

1. manubrium, joins clavicles separated by jugular notch. 2. body, receives costal cartilages 3. Xiphoid process - attachment site of rectus abdominis muscle

Temporal bone has 3 parts

1. squamous part (zygomatic process, and mandibular fossa) 2. Tympanic part (external acoustic meatus) (internal meatus allows passage of nerve to brain (inner ear)) 3. Petrous part ( internal acoustic meatus, auditory ossicles, mastoid process and styloid process)

The ribs are classified as

1. true ribs (1-7) connected by their own costal cartilage. 2. false ribs (8-12) connected by cartilage to costal cartilage of rib 7. 3. The last two pairs of false ribs are also known as floating ribs (11-12).

Bones of face (14)

2 nasal, 2 lacrimal, 2 inferior nasal conchae. 2 maxillary, 2 zygomatic, 2 palatine, 1 mandible 1 vomer.

The second cervical (C2) vertebra is called the axis,

because it serves as the axis for rotation when turning the head toward the right or left. The axis resembles typical cervical vertebrae in most respects, but is easily distinguished by the dens (odontoid process), a bony projection that extends upward from the vertebral body. The dens joins with the inner aspect of the anterior arch of the atlas, where it is held in place by transverse ligament.

secondary curve develops gradually after

birth as the child learns to sit upright, stand, and walk. Secondary curves are concave posteriorly, opposite in direction to the original fetal curvature.

A typical vertebra will consist of a

body, a vertebral arch, and seven processes

Mandible

condylar for attachment and coronoid process for articulation Has alveolar process has mental and mandibular foramina

Vertebral foramen enlarges

cranially relative to size of body

Pedicle and lamina will

create an arch around vertebral column. This arch is protection for the neural tissue. Same way brain case protects the brain.

The axial skeleton (80 bones)

forms the vertical, central axis of the body and includes all bones of the head, neck, chest, and back (Figure 7.2). It serves to protect the brain, spinal cord, heart, and lungs.

the coccyx, or tailbone, results from the fusion of

four small coccygeal vertebrae.

The coccyx, or tailbone, is derived from the fusion of

four very small coccygeal vertebrae. Starts fusing at 26 and ends at ?

Sinuses

frontal, ethmoid, sphenoid, maxillary. Used for thermal insulation and resonating chamber for voice.

Sacrum

fusion of 5 vertebrae which starts at puberty and ends at age 25-30

Structure of rib contains

head (connects to vertebrae), neck tubercle and body. Tubercle articulates with transverse process of vertebra.

Sella turcica (in sphenoid)

holds pituitary gland

Pterygoid process (in sphenoid)

insertion of jaw muslces (allows for complex movements of jaw)

The single sacrum, which is also part of the pelvis,

is formed by the fusion of five sacral vertebrae.

sacral promontory

is the anterior lip of the superior base of the sacrum. Lateral to this is the roughened auricular surface, which joins with the ilium portion of the hipbone to form the immobile sacroiliac joints of the pelvis.

The body is the anterior portion of each vertebra and

is the part that supports the body weight.

Vertebral foramen

lodges spinal cord

C7 vertebra prominence

long, round spinous process. Ligamentum nuchae attaches to external occipital protuberance.

Intervertebral foramen

nerves pass through here. formed by the superior and inferior vertebral notches on pedicle.

the C1 vertebra articulates (forms a joint) with the

occipital condyles of the skull.

Inferior nasal conchae

only most inferior sworls are apart of the "facial bones"

Optic canal (in sphenoid)

optic nerve passes through here. visual sensory infomration passes through here.

Seven processes arise from the vertebral arch.

paired transverse process, single spinous process (vertebral spine), A superior articular process, an inferior articular process

Sagittal suture

right and left parietals

Frontal bone has

squamous part (Frontal suture and supra-orbital margin and foramen); oribtal part (lacrimal fossa and notch for ethmoid)

The first cervical (C1) vertebra is also called

the atlas, does not have a body or spinous process. Instead, it is ring-shaped, consisting of an anterior arch and a posterior arch. Also has oval superior articular surfaces

lateral sacral crest

the fused transverse processes of the sacral vertebrae

Auricular surface articulates with

the hip bone. Tuberosity allows for a lot of fiber attachment between the two

The thoracic cage (rib cage) forms the

thorax (chest) portion of the body. It consists of the 12 pairs of ribs with their costal cartilages and the sternum

External occipital protuberance

which serves as an attachment site for a ligament of the posterior neck. (attachment of ligamentum nuchae)

vertebral arch forms the posterior portion of each vertebra.

It consists of four parts, the right and left pedicles and the right and left laminae.

Lambdoid Suture

Parietal and occipital

Bones of cranium (8)

Parietal, occipital, frontal, temporal, sphenoid, ethmoid

The four adult curvatures are classified as either primary or secondary curvatures.

Primary curves are retained from the original fetal curvature, while secondary curvatures develop after birth.

Cranial bones articulate through

Sutures

Thoracic vertebrae (12)

The characteristic feature for a typical midthoracic vertebra is the spinous process, which is long and has a pronounced downward angle that causes it to overlap the next inferior vertebra. costal facets connect to ribs

Sacrum has

apex, base, sacral promontory, and superior articular processes.

The 4 articular processes

are added stability, form an X, have superior and inferior portions. Also have facets, for articulation.

Lumbar vertebrae (5)

are characterized by having a large, thick body and a short, rounded spinous process.

fontanelle

As the brain case bones grow in the fetal skull, they remain separated from each other by large areas of dense connective tissue, each of which is called a fontanelle

Accessory bones of the skull

Auditory ossicles (malleus, incus, stapes) - all found in petrous part of temporal bone. Hyoid - no articulation, suspended by muscles of tongue, neck, and pharynx.

The anterior and posterior surfaces of the sacrum have a series of paired openings called sacral foramina (singular = foramen) that connect to the sacral canal.

Each of these openings is called a posterior (dorsal) sacral foramen or anterior (ventral) sacral foramen. These openings allow for the anterior and posterior branches of the sacral spinal nerves to exit the sacrum.

Thoracic vertebrae have several additional articulation sites, each of which is called a facet, where a rib is attached.

Most thoracic vertebrae have two facets located on the lateral sides of the body, each of which is called a costal facet (costal = "rib"). These are for articulation with the head (end) of a rib. An additional facet is located on the transverse process for articulation with the tubercle of a rib.

Intervertebral Disc

The disc consists of a fibrous outer layer called the anulus fibrosus and a gel-like center called the nucleus pulposus.

Superior and inferior nuchal lines

The nuchal lines represent the most superior point at which muscles of the neck attach to the skull, with only the scalp covering the skull above these lines.

Occipital condyles

These condyles form joints with the first cervical vertebra and thus support the skull on top of the vertebral column. (Articulation with vertebral column (helps you say yes))

Curvatures of the Vertebral Column

These curves increase the vertebral column's strength, flexibility, and ability to absorb shock.

Rectus abdominas

allows us to bend our vertebral column forward.

scoliosis

an abnormal, lateral curvature, accompanied by twisting of the vertebral column

lordosis

an excessive anterior curvature of the lumbar region

kyphosis

an excessive posterior curvature of the thoracic region

Thoracic vertebrae have superior and inferior articular facets on the vertebral body for articulation with the head of a rib,

and a transverse process facet for articulation with the rib tubercle.

median sacral crest

a bumpy ridge that is the remnant of the fused spinous processes, on the posterior side of sacrum.