Model 6 Mizzou Anatomy

how many bones does the skull have

28 bones

Skull bone are unites by

Sutures (interlocking, immoveable joints)

Flat bones are formed

Intramembranous ossification

Infant skull bones connected by

Flexible connective tissue to allow head to deform during birth, and allow rapid brain growth (soft spot)

Craniosynostosis

A premature of the skull bones. Leads to unusual cranial vault shape

Cranial bone functions

Protects brain

Provide attachments sites for some head/neck muscles

Fascial bone functions

Form the framework of face

Openings for passage of air and food

Hold teeth

anchor muscle of the face

Cranium can be subdivides into the

Vault

Vault =

Superior , lateral and posterior bones of the skull (includes forehead)

Base =

Inferior part of the cranium

Craniums is made up of

8 bones

Parietal bone make up most of

The superior part of the skull, extend posteriorly and laterally

Sagittal suture is

between two parietal bones

Lambdoid suture is

Between parietal and occipital bones

Foramen magnum has

a large opening in occipital bone that allows the spinal cord to pass and connect with brain

The occipital condyles are

the region where skull articulates with the vertebral column

How many bones does the face has

14 bones

Lacrimal bones

Allows tears drain into nasal cavity

Zygomatic bones

Cheekbones

Nasal bones

From bridge of nose attach to cartilages

Orbit

supports the eyes and muscles that move the eye, contains fat and lacrimal glands

Maxillae

Forms upper jaw

Alveolar processes contains teeth

Frontal processes extend upward to reach frontal bone

Zygomatic processes of maxilla articulate with zygomatic bone

Vomer

midline of the nasal

Paired Temporal bone

House opening to ear, forms the base of cheekbone

Temporal bone regions

Petrous, tympanic and squamous

Petrous is

Hard, contains middle and inner ear cavities

Squamous portion is

The vertical portion (part of cranial vault )

The external meatus (EAM):

Opening in the tympanic region leading to the middle inner ear

Temporomandibular Joint (jaw)

The condyle of the mandible articulates with temporal bone at the mandibular fossa

Middle ear cavity (temporal)

3 ear ossicles in the middle ear: malleus, incus and stapes. Bones are really small (sound waves causes vibration)

Sphenoid

Sella tunica - bony depression that holds the pituitary gland, cranial bone

Ethmoid Bone (inside brain nose)

Take up area between nasal cavity and orbits, forms boundaries of the nasal, and separates nasal form the brain. Anterior to the sphenoid

Crista Galli (ethmoid)

Attaches to cribriform plate; nasal cavity from brain, site of attachment for dura mater (covers brain)

Cribriform plate (ethmoid)

Helps form the roof of nasal cavities; foramina allow passage of olfactory nerves into brain

Lateral walls of nasal cavity:

Nasal conchae, bones, maxillae, palatine (superior, middle, inferior)

Floor of nasal cavity -

Hard palate, formed by palatine process of maxillae, horizontal plate of palatine

Palate and inferiro nasal septum

Composed of maxillary bones and the palatine bone (bottom tough bone) inferior of nasal septum

Cleft palate

failure of 2 sides of the palate to join during development leads to…

Mandibular symphysis

Where two halves of the body join to form the chin (mental protuberance)

Vessels and nerves enter via ____ foramen and exit via mental foramen inferior

Mandible

Strongest bone ins face, tooth is on the superior border (alveolar processes)

Condyle of the mandible

Articulates with the temporal bone to form the temporomandibular join (both side jaws)

By the age of 2 the cranium is

¾ the sizes of an adult (6-13 is when they catch up)

The Hyoid

Is in the neck inferior to mandible (Only bone that doe snot articulate with any other bone)

Acts as a base for tough, that moves the larynx

The thoracic Cage includes (ribs)

Thoracic vertebrae, ribs, sternum and costal cartilages

What does the thoracic cage protect (ribs)

Heart, lunges and supports pectoral girdle and provides attachment points

I)thoracic Cage intercostal spaces

Hold muscles that aid in breathing

Sternum articulates with

Clavicles and ribs and costal cartilages

Sternum angle is

Landmark for thoracic anatomy

Sternum has 3 bones which are

Manubrium

Body

Xiphoid Process

Rib Cage function:

Protect internal organs, aid in respiration

How many bone in a Rib Cage

12 bones

All ribs attached..

Posteriorly to thoracic vertebrae

Rib Cage: 1-7 (true ribs)

Attach to sternum by costal cartilages

Rib Cage 8-10 (false Ribs)

Do not have direct attachment to the sternum. They attach to shared costal cartilage (1-7)

Rib Cage 11-12 (floating ribs)

Do not have attach anteriorly to the sternum

Main part of rib is the

Shaft (body)

Rib articulates with the

Vertebra at the head an tubercle

“Neck’ is a

Thinner region between the head and tubercle

Head has 2 facets

One facet articulates with the body or its vertebra and one articulates of the vertebra superior to it

The vertebral column functions

Protects spinal cord, support body axis, attachment points for ribs and muscles of neck and back and anchor pectoral and pelvic girdle

Vertebrae become larger as

Move inferiorly to support weight

Scrum articulates

With hip bones or pelvis, passes weight to appendicular skeleton

Curves in the spine increase

Flexibility; also position center of gravity over axis of body

Scoliosis

Lateral curvature of the spine (abnormal)

Kyphosis is

Excessive curvature of thoracic spine caused by osteoporosis (hump)

Osteoporosis - imbalanced and degradation

Calcium and osteoclast break bone down to release the calcium into the bloodstream

Lordosis (beer belly)

Excessive curvature of the lumbar spine

Vertebral

Arch made of lamina and pedicles

• Creates vertebral foramen (surround spinal cord )

• Stacked vertebrae results in vertebral canal

Spinous and transverse process are

Ligament & muscle attachment sites

Spinal cord passes through and protected within

The Vertebral (spinal) canal

Spinal nerves exits between

The body of the vertebra and the vertebral arch intervertebral foramina

Cervical vertebrae features (C1-C7)

Have transverse foramina

Articular facets face superior/inferior

Bifid (split) spinous processes

Atlas (C1)

Occipital condyles, allows flexion/extension of head (nodding yes)

Axis (C2)

Den with atlas, allows rotation movement (shaking no). apart of atlas not axis

12 Thoracic Vertebrae

Costal facets for ribs, located on each body of the thoracic vertebrae

Articular facets face

Spinous processes are long and project inferiorly

5 Lumbar Vertebrae

• Large bodies

• Articular facets face medial/lateral

• Short, flat spinous processes

Sacrum (5 fuse vertebrae)

Forms posterior wall of pelvis

Ala on lateral scrum articulate with hip bones to form sacroiliac joints

Coccyx

3-5 fused Vertebrae (tail bone)