The SkeletonCh. 7

With the lower jaw removed, the skull resembles a lopsided, hollow, bony sphere. The facial bones form its anterior aspect , and the cranium forms the rest of the skull. The cranium can be divided into a vault and a base. The cranial vault, also called the calvaria, forms the superior, lateral, and posterior aspects of the skull, as well as the forehead.

The skull has about 85 named openings (foramina, canals, fissures, etc.) the most important of these provide passageways for the spinal cord, the major blood vessels serving the brain, and the 12 pairs of cranial nerves ( #’s 1-12), which transmit impulses to and from the brain.

Overview of Skull Geography

Appendicular Skeleton Axial Skeleton

The Axial SkeletonStructured from 80

bones segregated into 3 major regions:

SkullVertebral

ColumnsBony Thorax

This part of the skeleton supports the head, neck, and trunk, and it protects the brain, spinal cord, and the organs in the thorax

The SkullThe skull is the body’s

most complex bony structure. It’s formed by cranial and facial bones, 22 in all.

Most skull bones are flat bones. Except for the mandible (jaw) which is connected to the rest of the skull by a freely movable joint

Inside the CraniumFrontal Bone

Shell-shaped frontal bone forms the anterior cranium. It articulates posteriorly w/ the paired parietal bones via the prominent coronal suture.

The most anterior part of the frontal bone is the vertical frontal squama, commonly called the forehead.

Parietal Bones and the Major SuturesThe two large parietal bones are curved,

rectangular bones that form most of the superior and lateral aspects of the skull; hence they form the bulk of the cranial vault.

Inside the Cranium contd…..

The Facial SkeletonCameron Braddy

Facial BonesThe facial skeleton is

made up of 14 different bones. Men’s faces are more elongated than women, meaning women’s faces tend to be less angular.

VomerPlow shaped vomer,

lies in the nasal cavity.

Forms part of the nasal septum.

Discussed below in connection with the nasal cavity.

Inferior Nasal ConchaeInferior nasal

conchae are two paired bones that are thin, curved and in the nasal cavity.

Project medially from the lateral walls of the nasal cavity.

Largest of the three pairs of conchae.

The Coccyx Commonly referred

to as our tailbone.Triangular boneConsists of four

vertebrae fused together.

Affords the pelvic organs.

Nearly useless.Often snipped off by a

physician.

Bony ThoraxBony underpinnings of

the thorax.Roughly cone shaped.Forms a protective cage

around the vital organs.Supports shoulders, and

upper limbs.Provides attachment

points for many muscles of the neck, back, chest, and shoulders.

The Upper Limb, ArmThirty separate bones

form each upper limb.The humerus is the

sole bone of the arm.At the proximal end of

each humerus is smooth hemispherical head, and at the distal end are two chondyles are medial trochlea.

The SternumThe Sternum is a flat

bone located in the middle of the bony thorax.

Means breastbone.The fusion of three

bones, the manubrium, the body, and the xiphoid.

Manubrium at the top, the body in the middle and the xiphoid at the bottom.

Anatomy and Physiology Chapter 7

By: Caroline Baker

Special Characteristics of orbits and nasal cavity: the orbits,

naval cavity, paranasal sinuses, and hyoid bone.

Page: 213- 216

The Orbits•The orbits are bony cavities in which the eyes are firmly encased and cushioned by fatty tissue

•The orbits are formed by seven bones – frontal, sphemoid, zygomatic, maxilla, palatine, lacrimal, and ethmoid bones.

Nasal CavityThe nasal

cavity is constructed of bone and hyaline cartilage. The roof of the nasal cavity is formed by the cribriform plate of the ethmoid.

Paranasal SinusesYou can see

this sinuses in an x-ray image

Paranasal sinuses cluster around the nasal cavity

Hyoid BoneU / horseshoe

shapedThe hyoid bone

lies just inferior to the mandible in the anterior neck.

Neck muscles that raise and lower the larynx durning swallowing and speech.

Sternum, Homeostatic imbalance

Page: 226

SternumThe sternum

(breastbone) lies in the anterior midline of the thorax.

The sternum is a flat bone and it is approximately 15 cm( 6 inches) long.

Homeostatic imbalanceAn inability to maintain homeostasis may lead

to death or a disease, a condition known as homeostatic imbalance.( Wikipedia)

Of the sternum- in some people the xiphoid process projects dorsally

Forearm, Ulna, RadiusPage: 233

Forearm (Ulna and Radius) Two parallel long bones, the radius and the

ulna.The ulna is slightly longer than the radius. It

has the main responsibility for forming the elbow joint with the humerus.

The radius (rod) is thin at its proximal end and wide distally- opposite of the ulna. The head of the radius is shaped somewhat like the

head of a nail.

This picture is showing the ulna and the radius.

Leg, Tibia , Fibula

Page: 243

Leg (tibia and Fibula)Two parallel bones, the tiba and fibula, form

the skeleton of the leg, the region of the lower limb between the knee and the ankle.The tibia (shinbone) receives the weight of the

body from the femur and transmits it to the foot.

The fibula (pin) is a sticklike bone with slighty expanded ends.

This picture shows the tibia and the fibula.

Facial BonesBy: Kourtnie Moore

Mandible

The U- shaped or lower jaw bone. It is one of the largest, strongest bone of the face. It has a body, which forms the chin, and two

upright “rami” branches.

Maxillary Bones The Maxillary Bone is also called sometimes Maxillae. They

form the upper jaw and the central portion of the facial skeleton. The Maxillae carry up the upper teeth in the Alveolar Margins. The Maxillae meet medially, forming the pointed Anterior Nasal Spine at their junction. The Palatine Processes of the maxillae

project posterior form the alveolar margins and fuse medially. The Frontal Processes extend superiorly to the frontal bone,

forming part of the lateral aspects of the bridge of the nose. The regions the flank the nasal cavity laterally contain the Maxillary

Sinuses. Laterally, the maxillae articulate with the zygomatic bones via their Zygomatic Processes. The Inferior Orbital

Fissure is located deep within the orbit at the junction of the maxilla.

ZygomaticThe irregularly shaped bones. Are commonly called the “cheek bones”. They join in with the Temporal Posteriorly and with the Zygomatic processes of

maxilla Anteriorly. The Zygomatic Bones form the prominences of the cheeks and part of the inferolateral margins of the orbits.

PG. 220By: Brandon Jenkins

LigamentsIn order for the bone

structures to stand up they have to have a system of cable like supports. The strap like ligaments and

trunk muscles assume that role. There are two major supporting ligaments they

are the anterior and posterior longitudinal ligaments which run a

continuous band down the front and back of the spine

as shown to the right.

Intervertebral DiscsThe intervertebral disc

is a cushion like pad between each disc. It has

two parts the nucleus pulpous which acts like a rubber ball and gives the disc its elasticity and the annulus fibrosus which

limits the expansion of the nucleus pulpous. They act as shock absorbers when your living your everyday lives. These disc are about 25% of your spinal weight.

Homeostatic ImbalanceA homeostatic

imbalance is a sudden physical trauma to the

spine- for example there is a herniated disc also referred to as a slipped disc. The disc can slip

and pinch a nerve causing numbness and severe pain. They can

be treated with medicine but if it fails

they have to do surgery.

StructureAll vertebrae have a common structural pattern.

Each vertebrae consists of a body, or centrum, anteriorly and a vertebral arch posteriorly.

The vertebral arch is a composite structure formed by two pedicles (little foot) and two laminae.

Regional Vertebral Characteristics

&General Structure

1. Flexion and extension (anterior bending and posterior straightening of the spine)

2. Lateral flexion (bending the upper body to the right or left).

3. Rotation (in which vertebrae rotate on one another in the longitudinal axis of the spine).

Vertebral Characteristics

Stevie PeeleAnatomy and Physiology

Sphenoid BoneButterfly-shaped Considered the

keystone of the cranium because it form the central wedge that articulates with all other cranial bones.

Sphenoid Bone Cont. Within the body of the

sphenoid are the paired sphenoid sinuses.

The superior of the body bears a saddle-shaped prominence is the sella turcica meaning “Turk’s saddle”.

The seat of the saddle is called the hypophyseal.

Surfaces The lateral surfaces of the

body are united with the great wings and the medial pterygoid plates. Above the attachment of each great wing is a broad groove, curved something like the italic letter f; it lodges the internal carotid artery and the cavernous sinus, and is named the carotid groove. Along the posterior part of the lateral margin of this groove, in the angle between the body and great wing, is a ridge of bone, called the lingula.

 The posterior surface, quadrilateral in form is joined, during infancy and adolescence, to the basilar part of the occipital bone by a plate of cartilage. Between the eighteenth and twenty-fifth years this becomes ossified, ossification commencing above and extending downward.

Sphenoid Cont.Piercing the lesser wings of

the sphenoid, the optic canals allow passage of the optic nerves from the back of each eye to enter the brain and cross at the optic chiasma above to the pituitary gland. A cleft between the greater and lesser wings of the sphenoid, the superior orbital fissure transmits several critical structures that pass between the orbit and the brain.

EthMoid BoneThe ethmoid bone is

exceedingly light and spongy, and cubical in shape; it is situated at the anterior part of the base of the cranium, between the two orbits, at the roof of the nose, and contributes to each of these cavities. It consists of four parts: a horizontal or cribriform plate, forming part of the base of the cranium; a perpendicular plate, constituting part of the nasal septum; and two lateral masses or labyrinths.

Sutural Bones Also called Wormian

bonesAre tiny irregularly

shaped bones or bone clusters that appear with sutures

Structurally unimportant

Numbers varies, and not all skulls exhibits them

They represent additional ossification centers that appeared when the skull was expanding very rapidly during fetal development.

Stevie Peele

Ischium

Ischium Forms the posterior

inferior part of the hip bone.

Roughly L or arched-shaped

Inferior ramus that joins pubis anteriorally

Its ischial spine projects medially into the pelvic cavity and serves as a point of attachment

Ischium Just inferior to the

ischeial spine is the lesser sciatic notch. A number of nerves and blood vessels pass through this notch to supply the anogenital area. The inferior surface of the ischial body is rough and grossly thickened as the ischial tuberosity.

Thoracic VertebraeStevie Peele

Thoracic vertebrae The 12 thoracic

vertebrae are situated between the cervical (neck) vertebrae and the lumbar vertebrae. The thoracic vertebrae are represented by the symbols T1 through T12.

The thoracic vertebrae provide attachment for the ribs and make up part of the back of the thorax (the chest).

Thoracic vertebrae cont.There are 5 unique

characteristics of the vertebrae.

5 Characteristics of the Vertebrae

1.) The body is roughly heart-shaped and typically bears two facets

2.) The vertebral is foramen is circular

3.) The spinous process is long and points sharply downward

4.) With the exception of T11 and T12, the transverse process have facets that articulate with the tubercles

5.) The superior and inferior particular facets lie mainly in the frontal plane

Homeostatic imbalance, hand, & wrist (pg. 236)

BY Megan Carpenter

Homeostatic ImbalanceColle’s Fracture

A break in the distal end of the radiusCommon fracture when a falling person

attempts to break their fall w/ outstretched hands

HandIncludes the bones of the:

carpus (wrist)metacarpus (palm)phalanges (fingers)

Carpus (Wrist)True wrist

Proximal part of our handConsist of a group of 8 marble size short bones or

carpals, closely united by ligamentsCarpals are arranged in 2 irregular rows of 4 bones

each In proximal row: scaphoid, lunate, triquetral, &

pisiform Only scaphoid & lunate form wrist joint w/ radius

In distal row: trapezium, trapezoid, capitate, & hamateTo help you remember: Sally left the party to take

Cathy home.

Homeostatic imbalance, foot , tarsus, metatarsus, phalanges, &

arches (Pg 243-245)

Homeostatic imbalancePott’s Fracture

Occurs at the distal end of the fibula, the tibia, or both

FootIncludes bones of:

tarsus Metatarsusphalanges

2 important functionsSupports body weightActs as a lever to propel the body forwardwhen

running or walking

TarsusMade from 7 tarsal bones:

Talus & calceneus2 largestAchilles tendon attaches to the posterior surface of

the calceneusCuboid, navicular, & medial, intermediate, &

lateral cuneiform

Metatarsus5 small long bones:

Metatarsal bones # 1-5 beginning on the medial (great toe) side

of the foot1st

Short & thickArranged more parallel than the metacarpals

of the hands

Phalanges (Toes)14 phalanges of the toes are much smaller

than of the hands & are less nimbleStructure & arrangement are much the same

as the hand3 phalanges in each digit except in the great

toe or hallux, which only has 2

Arches3 arches in foot

2 longitudinal & 1 transverse, which account for it’s awesome strength

Are maintained by the interlocking foot bones, strong ligaments & by pull of some tendons during muscle activityProvide springiness