Ch-07-axial-skeleton-handout

Axial Skeleton

Consists of 80 bones forming the longitudinal axis of the body.

Function of axial skeleton

Supports and protects the brain, spinal cord, and trunk organs.

Cranial bones

Include 8 bones: Frontal, Parietal (x2), Temporal (x2), Sphenoid, Ethmoid, Occipital.

Facial bones

Include 14 bones: Lacrimal (x2), Nasal (x2), Vomer, Mandible, Zygomatic (x2), Maxillary (x2).

Hyoid bone

Does not articulate with any other bone; supports the larynx.

Major cranial sutures

Coronal, Squamous, Sagittal, Lambdoid sutures.

Temple bone

Includes bones related to the side of the skull.

Vertebral column

Composed of 26 bones: 24 vertebrae, 1 sacrum, and 1 coccyx.

Cervical vertebrae

7 vertebrae in the neck with transverse foramina.

Thoracic vertebrae

12 vertebrae with rib articulation points.

Lumbar vertebrae

5 larger vertebrae in the lower back with massive bodies.

Sacrum

Composed of 5 fused vertebrae.

Coccyx

Composed of 3 to 5 fused vertebrae.

Ribs

12 pairs consisting of true, false, and floating ribs.

Thoracic cage

Consists of the sternum and 12 pairs of ribs.

Sternum

Consists of the manubrium, body, and xiphoid process.

True ribs

Pairs 1-7 that articulate directly with the sternum.

False ribs

Pairs 8-12 that do not articulate directly with the sternum.

Floating ribs

Pairs 11-12; do not have any anterior attachment.

Internal acoustic meatus

Passage for the vestibulocochlear nerve (CN VIII).

Foramen magnum

Opening at the base of the skull for the spinal cord.

Optic canal

Passageway for the optic nerve (CN II).

Coronal suture

Suture between the frontal and parietal bones.

Lambdoid suture

Between the occipital and parietal bones.

Sphenoid bone

Bone that forms part of the base of the skull.

Maxilla

Upper jawbone that holds the upper teeth.

Mandible

Lower jawbone that holds the lower teeth.

Zygomatic bone

Bone that forms the cheek.

Nasal bone

Two small bones that form the bridge of the nose.

Vomer

Bone that forms part of the nasal septum.

Ethmoid bone

Bone that forms part of the nasal cavity and orbits.

Sphenoidal sinus

Sinus located within the sphenoid bone.

Frontal sinus

Sinus located within the frontal bone.

Maxillary sinuses

Sinuses located within the maxilla.

Perpendicular plate

Part of the ethmoid forming part of the nasal septum.

Superior nasal concha

Bone that forms part of the nasal cavity.

Middle nasal concha

Also part of the ethmoid bone in the nasal cavity.

Inferior nasal concha

Separate bone that forms part of the nasal cavity.

Alveolar process

The part of the jaw that contains the tooth sockets.

Mental protuberance

The chin area of the mandible.

Condylar process

Part of the mandible that articulates with the temporal bone.

Coronoid process

Part of the mandible for muscle attachment.

Mastoid process

Bony projection behind the ear on the temporal bone.

TMJ

Temporomandibular joint; joint between the mandible and the temporal bone.

C1 vertebra (Atlas)

First cervical vertebra that supports the skull.

C2 vertebra (Axis)

Second cervical vertebra with an odontoid process.

Vertebral foramen

The opening that houses the spinal cord.

Transverse foramina

Holes in cervical vertebrae for vertebral arteries.

Styloid process

Pointy projection on the temporal bone for muscle attachment.

Occipital condyles

Projections on the occipital bone that articulate with C1.

Vertebral column curvature

Curvatures that develop during fetal and early life.

Costal cartilage

Cartilage that connects ribs to the sternum.

Primary curves

Curvatures present at birth: thoracic and sacral.

Secondary curves

Curvatures that develop after birth: cervical and lumbar.

Sternal angle

The angle between the manubrium and body of the sternum.

Jugular notch

Depression at the top of the manubrium.

Sternoclavicular joint

Joint between the sternum and clavicle.

Costal facets

Articulation points on vertebrae for rib connections.

How many bones in axial skeleton?

80 bones.

How many bones in the skull?

Total of 21 bones (8 cranial, 14 facial, 7 associated).

What type of bones are ribs classified as?

Flat bones.

Function of the thoracic cage

Protects thoracic organs and aids in breathing.

What is the cranial cavity?

The space within the skull that houses the brain.

Functions of the hyoid bone

Supports the larynx, provides attachment for muscles, aids in swallowing.

Name the cranial sutures.

Coronal, Squamous, Sagittal, Lambdoid sutures.

Describe a typical rib.

Has a head, neck, tubercle, angle, and shaft.

What bones make up the skull's orbital complex?

Zygomatic, Sphenoid, Frontal, Palatine, Ethmoid, Lacrimal, Maxilla.

What are fontanels?

Soft spots on the infant skull that allow for growth.

Name the three parts of the sternum.

Manubrium, Body, Xiphoid process.

What's unique about the cervical vertebrae?

They have transverse foramina.

How are floating ribs classified?

Ribs that do not have any anterior attachment.

What is the function of the costal groove on ribs?

Houses nerves and blood vessels.

Transverse process of vertebrae function

Provide attachment for muscles and ligaments.

What articulates at the atlantoaxial joint?

C1 and C2 vertebrae.

What forms the nasal septum?

Vomer and perpendicular plate of ethmoid.