Chapter 8 (Axial skeleton)

Axial Skeleton

Division of the skeleton that is made up of the central bones

Appendicular Skeleton

Division of the skeleton that is made up of the bones that "hang" on the axial skeleton

Orthopedics

The branch of medical science that is conceded with the prevention or correction of disorders of the musculoskeletal system

Musculoskeletal System

The bones, muscles, and joints together form an integrated system called \____________________ \____________________

Upper limbs/extremities and lower limbs/extremities, and the girdles

These make up the appendicular system

Long bones

greater length than width, consist of a diaphyses (body) and a variable number of extremities or epiphyses (ends), and are slightly curved for strength

Short bones

Cube-shaped bones, consist of spongy bone and compact bone. Examples: Carpal bones and Tarsal bones

Flat bones

Generally thin and composed of two nearly parallel plates of compact bone tissue enclosing a layer of spongy bone tissue. Examples: Cranial bones, sternum, and ribs

Irregular bones

Complex shapes and cannot be grouped into any of the other categories. They may vary in the amount of compact and spongy bone that they contain. Example: vertebrae, hip bones, some facial bones, and calcaneus

Seasmoid bones

Develop in certain tendons where there is a lot of friction, tension, and physical stress such as the palms and soles. They vary in amount from person to person and are not always completely ossified and are small. Ex: Patellae (these have exceptions b/c most ppl have them)

Sutural bones

Small bones that are classified by location instead of shape. These are found in sutures and can vary between people.

Surface Markings

Structural features of bones that have been adapted for specific functions

Two major types of surface markings:

1. Depressions and openings 2. Processes

Fissure

Narrow slit between adjacent parts of bones through which blood vessels or nerves pass

Foramen

Opening through which blood vessels, nerves, or ligaments pass

Fossa

Shallow depression

Sulcus

Furrow along bone surface that accommodates blood vessel, nerve, or tendon

Meatus

Tubelike opening

Condyle

Large, round protuberance with a smooth articular surface at the end of bone

Facet

Smooth, flat, slightly concave or convex articular surface

Head

Usually rounded articular projection supported on neck

Crest

Prominent ridge or elongated projection

Epicondyle

Typically roughened projection above condyle

Line

Long, narrow ridge or border (less prominent than crest)

Spinous process

Sharp, slender projection

Trochanter

Very large projection

Tubercle

Variably sized rounded projection

Tuberosity

Variable sized projection that has a rough, bumpy surface

Skull

The bony framework of the head that contains 22 bones and rests on the superior end of the vertebral column.

Categories of Skull bones

1. Cranial bones 2. facial bones

Cranial bones

These form the cranial cavity, which encloses and protects the brain. There are 8 of these bones (frontal, 2 parietal, 2 temporal, occipital bones, sphenoid bone, and ethmoid bone

Facial bones

These form the face and consist of 14 bones ( 2 nasal, 2 maxillae, 2 zygomatic bones, mandible, 2 lacrimal bones, 2 palatine bones, 2 inferior nasal conchae, and the Vomer

Frontal bone

Forms the forehead and most of the anterior part of the cranial floor

Metopic suture

Unites the left and right sides of the frontal bone, disappears at the age of six and eigth

Frontal squama

a scalelike plate that forms the forehead of the skull; Frontal bone

Frontal bone

Supraorbital margin

Black Eye

Bruising around the eye due to an injury to the face

Parietal bones

Form the greater portion of the sides and roof of the cranial cavity

Temporal bones

Form the inferior lateral aspects of the cranium and part of the cranial floor

temporal squama

Thin, flat part of the temporal bone that forms the anterior and superior part of the temple

temporal bone

Zygomatic process

Mastoid process

Rounded projection in the temporal bone that serves as a point of attachment for several neck muscles

Styloid process

Projects inferiorly from the inferior surface of the temporal bone and serves as a point of attachment for muscles and ligaments of the tongue and neck

mandibular fossa

Socket located on the inferior posterior surface of the zygomatic process

Petrous portion

located at the base of the skull between the sphenoid and occipital bones, houses the internal ear and the middle ear, structures involved in hearing and equilibrium

Mastoiditis

Painful inflammation of the mastoid air cells due to a middle ear infection is this

Occipital bone

Forms the back part and most of the base of the cranium

Foramen magnum

large opening inferior of the occipital bone

Medulla oblongata

connects with the spinal cord within this foramen, and the vertebral and spinal arteries also pass through it along with the accessory (XI) nerve

occipital condyles

oval processes with convex surfaces on either side of the foramen magnum

Hypoglossal canal

superior to occipital condyles

External occipital protuberance

most prominent midline projection on the posterior surface of the bone

Sphenoid bone

Lies at the middle part of the base of the skull

pterygoid processes

Sphenoid bone; project inferiorly from the points where the body and greater wings of the sphenoid bone unite

Sphenoid bone

foramen lacerum

Ethmoid bone

A delicate bone located in the anterior part of the cranial floor medial to the orbits and is spongelike in appearance. It is anterior to the sphenoid and posterior to the nasal bones

crista galli

a small upward bony projection located at the midline that functions as anterior attachment point for one of the covering layers of the brain

cribriform plate

small, flattened area with numerous small openings termed olfactory foramina

Nasal septum

A partition that divides the nasal cavity into right and left sides

Nasal bones

Small, flattened, rectangular-shaped bones that form the bridge of the nose

Lacrimal bones

Thin and roughly resemble a fingernail in size and shape near. These form the medial all of each orbit

lacrimal fossa

vertical tunnel formed with the maxilla, that houses the lacrimal sac

Lacrimal sac

a structure that gathers tears and passes them into the nasal cavity

Palatine bones

These form the posterior portion of the hard palate, part of the floor and lateral wall of the nasal cavity, and a small portion of the floors of the orbits

Inferior nasal conchae

Inferior to the middle nasal conchae of the ethmoid bone, are separate bones, but not part of the ethmoid bone

Cleft palate

When the maxillary bones or palatine bones don't unite during development

Cleft lip

When there is a split in the lip occurring with a cleft palate

Vomer

Roughly triangular bone on the floor of the nasal cavity that articulates superiorly with the perpendicular plate of the ethmoid bone and sphenoid bone and inferiorly with the maxillae and palatine bones

Maxillae

These bones unite to form the upper jaw bone

Hard palate

The bony roof of the mouth and is formed by the palatine processes of the maxillae and horizontal plates of the palatine bones

palatine process

horizontal projection of the maxilla that forms the anterior three-quarters of the hard palate

infraorbital foramen

opening in the maxilla inferior to the orbit, allows passage of the infraorbital blood vessels and nerve

Maxilla

inferior orbital fissure

Maxilla

alveolar process

Maxilla

incisive foramen

Zygomatic bones

Commonly called the cheek bones. They articulate with the frontal, maxilla, sphenoid, and temporal bones

Zygomatic bones

temporal process

Mandible

Lower jawbone, largest and strongest facial bone

Temporomandibular joint (TMJ) syndrome

Where the mandibular fossa and articular tubercle of the temporal bone articulate. When this is characterized by dull pain around the ear, tenderness of the jaw muscles, clicking or popping noise when opening or closing the mouth, etc

Mandible

Condylar process

mandibular notch

depression between the coronoid and condylar processes

Orbit

Eye socket that is made up of the frontal, sphenoid, ethmoid bones, palatine, zygomatic, lacrimal, and maxilla

Foramina

Openings for blood vessels, nerves, or ligaments

Suture

An immovable joint that holds most skull bones together

Coronal Suture

Holds the frontal bone and both parietal bones together

Sagittal suture

Unites the two parietal bones on the superior midline of the skull.

Lambdoid suture

Unites the two parietal bones to the occipital bone

Squamous suture

Unites the parietal and temporal bones on the lateral aspects of the skull

Paranasal sinuses

Cavities with certain cranial and facial bones near the nasal cavity. Lined with mucous membrane and allow the skull to change in size without changing the mass, help with voice resonance, and keeps it light weight

Sinusitis

The inflammation of the mucous membrane of two or more paranasal sinuses

Fontanels

Soft spots where unossified mesenchyme develops into the dense connective tissues of the skull. Seen in infants.

Anterior fontanel

The largest fontanel that is located at the midline among the two parietal bones and the frontal bone and is roughly diamond-shaped; Closes 18 to 24 months

Posterior fontanel

Fontanel located at the midline among the two parietal bones and the occipital bone. Generally closes 2 months after birth

Anterolateral fontanels

Fontanels located laterally among the frontal, parietal, temporal, and sphenoid bones, are small and irregular in shape. Usually close 3 months after birth.

Posterolateral fontanels

Fontanels located laterally among the parietal, occipital, and temporal bones, are irregularly shaped. close after 1-2 months after birth although not complete until 12 months.

Hyoid Bone

unique component of the axial skeleton that suspends from the styloid processes of the temporal bones by ligaments and muscles

Hyoid Bone

supports the tongue, providing attachment sites for muscles of the tongue, neck, and pharynx.

Vertebral column

also called the spine, backbone, or spinal column,

Vertebrae

Series of bones in the vertebral column

Vertebral column

7 cervical

12 thoracic vertebrae

5 lumbar vertebrae

1 sacrum

1 coccyx