THE SKELETAL SYSTEM

Focus on the Skull

Review Anatomical Terms

Anterior/Posterior

Dorsal/Ventral

Medial/Lateral

Superior/Inferior

Bone Markings - Review

Projections for attachment of muscles, ligaments and tendons

(Process, trochanter, tuberosity, tubercle, crest, line, spine)

Processes for articulation with other bones

(Head, neck, condyle, trochlea, facet)

Openings = holes or spaces in bone for nerves and vessels

to pass (Foramen, canal, meatus, fissure, sinus)

Depressions = indentations (Fossa, sulcus)

Axial Skeleton

Includes bones of the skull, vertebral column and

thoracic cage

Creates a framework of support and protection for

internal organs

Provides sites of attachment of muscles

The Skull

Protects the brain and supports delicate sense organs

Bones that form the skull include

8 cranial bones

14 facial bones

6 auditory ossicles (tiny bones in the ears)

Hyoid bone (the only freely moveable bone)

Bones are joined by sutures

Bones of the Cranium

Frontal bone (1)- forms the forehead and roof of the ocular orbits

Parietal Bone (2) – posterior to the frontal bone; forms the sides and roof of skull

Occiptal Bone (1) – most posterior part of the cranium

foramen magnum = large opening for spine

Temporal Bone (2) – form the sides and base of the skull; a number of distinct anatomical landmarks

Sutures of the Cranium

Sagittal Suture – midline suture; between parietal bones

Coronal Suture – between frontal bone and parietal

bones

Lambdoid Suture – between occipital and parietal bones

Squamous Suture– between the temporal bones and the

parietal bones

Bones and Sutures of the Cranium

Lateral View

Parietal Bone

Frontal Bone

Temporal Bone

Occipital Bone

Coronal Suture

Lambdoid Suture

Squamous Suture

Bones and Sutures of the Cranium

Frontal View

Parietal Bone Frontal Bone

Temporal Bone

Coronal Suture

Bones and Sutures of the Cranium

Inferior View

Parietal Bone

Temporal Bone

Occipital Bone

Bones and Sutures of the Cranium

Horizontal View

Parietal Bone

Temporal Bone

Occipital Bone

Frontal Bone

REVIEW

The skull at birth

The skull at birth

Bones of the Cranium continued

Sphenoid Bone– irregular bat-shaped bone forms part of

the cranial floor

Ethmoid Bone –stabilizes the brain; forms the roof and

sides of the nasal cavity

Vomer – nasal septum

Palatine Bone – posterior hard palate (“roof of mouth”)

Bones of the Cranium – Lateral View

Parietal Bone

Frontal Bone

Temporal Bone

Occipital Bone

Lambdoid

Suture

Squamous Suture

Coronal Suture

Sphenoid Bone

Ethmoid Bone

Bones of the Cranium - Frontal

Parietal Bone Frontal Bone

Temporal Bone

Coronal Suture

Ethmoid Bone

Sphenoid Bone

Vomer

Bones of the Cranium – Inferior View

Parietal Bone

Temporal Bone

Occipital Bone

Palatine Bone

Vomer

Sphenoid Bone

Bones of the Cranium–Horizontal View

Parietal Bone

Temporal Bone

Occipital Bone

Sphenoid Bone

Frontal Bone

Ethmoid Bone

Facial Bones

Maxilla (2) – anterior part of hard palate; upper jaw;

articulates with all other facial bones except the mandible

Zygomatic Bones (2) – “cheek bones”

Nasal Bones– bridge of nose

Lacrimal Bones– tiny bones bearing tear ducts

Mandible – lower jaw

Bones of the Face – Lateral View

Parietal Bone

Frontal Bone

Temporal Bone

Occipital Bone

Lambdoid

Suture

Squamous Suture

Coronal Suture

Sphenoid Bone

Ethmoid Bone

Maxilla

Zygomatic Bone

Nasal Bone

Lacrimal Bone

Mandible

Bones of the Face - Frontal

Parietal Bone Frontal Bone

Temporal Bone

Coronal Suture

Ethmoid Bone

Sphenoid Bone

Vomer

Nasal Bone

Lacrimal Bone Zygomatic Bone

Maxilla

Mandible

Bones of the Face – Inferior View

Parietal Bone

Temporal Bone

Occipital Bone

Palatine Bone

Vomer

Sphenoid Bone

Maxilla

Zygomatic Bone

Maxilla

Teeth (32)

Incisors

Canines

Pre-molars

Molars

Pre-molars

Canines

Incisors

Processes

Any elevation or projection

Can be part of a joint or a site of attachment for

muscles, ligaments and tendons

Processes of the cranium

Styloid process (temporal bone)

Mastoid process (temporal bone)

Zygomatic process (temporal bone)

Occipital condyle (occipital bone)

External occipital protuberance (occipital bone)

Coronoid process (mandible)

Condylar process (mandible)

Mandibular process (mandible)

Pterygoid process (sphenoid)

Hamulus of the pterygoid process (sphenoid)

PROCESS

Protrusion for

attachment of

tendons and

ligaments

Styloid Process

Pointed piece of bone that extends down from the

temporal bone just below the ear

Attaches to

ligaments that support the hyoid bone

muscles that control the tongue and pharynx

Mastoid Process

Built up area of the lower temporal bone where important

neck muscles attach

Muscle that rotate and elevate the head and clavicle

attach here

Zygomatic Process of the Temporal Bone

Connects temporal bone to facial bones (zygomatic

bone)

Occipital Condyle

The site on the occipital bone where skull meets vertebrae

Atlas = the first vertebrae in the spinal column

External Occipital Protuberance

Medial protrusion of the occipital bone

Muscles that keep the head upright and allow the head to

tilt backward attach here

Coronoid Process (coronation day)

“like a crown”

Attachment point for muscle that closes the jaw

Condylar Process

Forms a hinge with the temporal bone

Mandibular Process

Smooth surface of the condylar process

The Sphenoid Bone

Pterygoid Process and the hamulus of

the pterygoid process

Process of the Skull – Lateral View

Parietal Bone

Frontal Bone

Temporal Bone

Occipital Bone

Lambdoid Suture

Squamous Suture

Coronal Suture

Sphenoid Bone

Ethmoid Bone

Maxilla

Zygomatic Bone

Nasal Bone

Lacrimal Bone

Mandible

Zygomatic Process

Mastoid Process

Styloid Process

Process of the Skull - Frontal

Parietal Bone Frontal Bone

Temporal Bone

Coronal Suture

Ethmoid Bone

Sphenoid Bone

Vomer

Nasal Bone

Lacrimal Bone Zygomatic Bone

Maxilla

Mandible

Ethmoid Bone

Process of the Skull– Inferior View

Parietal Bone

Temporal Bone

Occipital Bone

Palatine Bone

Vomer

Sphenoid Bone

Maxilla

Zygomatic Bone

Maxilla

Styloid Process

Mastoid Process

Occipital Condyle

Zygomatic Process

Processes of the Skull – Horizontal View

Parietal Bone

Temporal Bone

Occipital Bone

Sphenoid Bone

Frontal Bone

Ethmoid Bone

Name the Process

Name the Process

Foramina and Other Structures

General terms to describe openings include

Foramen, canal, meatus, fissure sinus

Foramina and Other Structures

Supraorbital foramen (frontal)

Infraorbital foramen (maxilla)

Mental foramen (mandible)

Foramen magnum (occipital)

Jugular foramen (temporal)

Carotid canal (temporal)

External acoustic meatus (temporal)

Mandibular foramen (mandible)

Palatine foramen (palatine)

Foramen lacerum (temporal)

Foramen ovale (sphenoid)

Foramen spinosum (sphenoid)

Foramen rotundum (sphenoid)

Stylomastoid foramen (temporal)

FORAMEN,

MEATUS, FISSURE,

CANAL:

Terms to describe

openings for

passage of nerves

and blood vessels

Supraorbital foramen**

“above” the orbit

blood vessels and nerves that innervate the

eyebrows and eyelids

Infraorbital foramen**

“below the orbit”

Facial nerves

Mental foramen**

Distal/lateral opening for the mental nerve and

vessels that innervate the lip

Mandibular foramen

Proximal/medial opening for the mental nerve and

vessels that innervate the lip and teeth

Palatine foramen

Nerves that innervate the palate

External Auditory meatus**

Opening that leads to the eardrum (tympanum)

Foramen magnum**

Spinal cord

Jugular foramen**

Jugular vein

Carotid Canal**

Carotid artery

Foramen ovale**

Trigeminal nerve – mandibular branch

Foramen spinosum

Nerves that innervate the meninges enter the brain

Foramen lacerum

Fills with cartilage after birth

Foramen rotundum

Trigeminal nerve: maxillary branch

Stylomastoid foramen

Facial nerves exit skull

Foramina of the Skull – Lateral View

Parietal Bone

Frontal Bone

Temporal Bone

Occipital Bone

Lambdoid Suture

Squamous Suture

Coronal Suture

Sphenoid Bone

Ethmoid Bone

Maxilla

Zygomatic Bone

Nasal Bone

Lacrimal Bone

Mandible

Zygomatic Process

Mastoid Process

Styloid Process

Mental Foramen

External Auditory Meatus

Mandible

Foramina of the Skull - Frontal

Parietal Bone Frontal Bone

Temporal Bone

Coronal Suture

Ethmoid Bone

Sphenoid Bone

Vomer

Nasal Bone

Lacrimal Bone Zygomatic Bone

Maxilla

Mandible

Ethmoid Bone

Optic Canal

Superior Orbital Fissure

Supraorbital Foramen

Infraaorbital Foramen

Foramina of the Skull– Inferior View

Parietal Bone

Temporal Bone

Occipital Bone

Palatine Bone

Vomer

Sphenoid Bone

Maxilla

Zygomatic Bone

Maxilla

Styloid Process

Mastoid Process

Occipital Condyle

Zygomatic Process

Foramen Ovale

Carotid Canal

Jugular Foramen

Foramen Magnum

Foramina of the Skull – Horizontal View

Parietal Bone

Temporal Bone

Occipital Bone

Sphenoid Bone

Frontal Bone

Ethmoid Bone

Foramen Ovale

Foramen Magnum

Jugular Foramen

Carotid Canal

Optic Canal

Other Features

Superior Nuchal Line

Inferior Nuchal Line

Mandibular foss

THE SKELETAL SYSTEM

Continue with the vertebrae

Vertebral Column

Consists of 26 bones

24 vertebrae

Sacrum

Coccyx

Vertebrae separated by

cartilage (intervertebral

discs)

Subdivided based on

vertebral structure

Vertebrae Anatomy - general

Vertebral body – massive weight bearing portion

Vertebral foramen – the opening through which the

spinal cord passes

Articular processes – extensions of the vertebrae that

articulate with other bones or provide attachment for

muscles

Transverse processes

Superior articular processes

Inferior articular processes

Vertebrae Anatomy - General

Vertebrae Anatomy by region

Cervical Region

Seven cervical vertebrae (C1 to C7)

The first cervical vertebrae (C1; atlas) articulates

with the occipital condyle

Cervical region

Anatomical Features

oval concave body

large vertebral foramen

Stumpy spinous process with a notched tip

Transverse foramina within the transverse processes

Protect blood vessels supplying the brain

Cervical Vertebrae Anatomy

Cervical region

Spinous Process

Lamina

Superior Articular Processes

Superior Articular Facet

Transverse Foramen

Body

Transverse Process

Pedicle

Vertebral Foramen

Vertebral Arch

Cervical region

The first two cervical vertebrae have unique

characteristics

C1 = ATLAS (‘yes)

Articulation of atlas with skull

allows you to nod your head

C2 = AXIS (“no”)

Articulation of atlas and axis allows you to rotate your head

The Atlas and Axis

Dens (odontoid process)

Atlas

(C1)

Axis

(C2)

Ligament

Articulates with

occipital condyles

Articulates with

atlas

Thoracic Region

Twelve cervical vertebrae (T1 to T12)

Each thoracic vertebrae articulates with one

or more pairs of ribs

Thoracic region

Vertebrae Anatomy

Heart shaped body

More massive than cervical vertebrae

Large, slender spinous processes that point inferiorly

Costal facets – for articulating with one or more pairs of

ribs

Vertebral Anatomy – thoracic region

Spinous Process

Transverse Process

Vertebral Foramen

Vertebral Arch

Body

Pedicle

Lamina

Pedicle

Articular facets

Articular facets

Lumbar Region

Five lumbar vertebrae (L1 to L5)

The fifth lumbar vertebrae articulates

with the sacrum

Lumbar region

Vertebrae Anatomy

Vertebral body is thick and more oval than thoracic

Massive, stumpy spinous process that projects posteriorly

Bladelike transverse processes; no articulation for ribs

Most massive, least mobile

Vertebral Anatomy – lumbar region

Transverse Process

Pedicle

Vertebral Foramen

Body

Spinous Process Lamina

Articular facets

Sacrum Region

sacrum

Single bone formed by the fusion of 5 embryonic

vertebrae

Sacrum

Protects reproductive, digestive and excretory organs

Attaches the axial skeleton to the appendicular skeleton

Broad surface – attachment of leg muscles

Bones fuse shortly after puberty

Prominent bulge (sacral promontory) is an important

landmark in females during labor and delivery

Coccyx

Coccyx

Series of small fused vertebrae

Coccyx

Attachment site for muscle that closes that anal opening

Fusion of the bone is not complete until late in adulthood

May eventually fuse with the sacrum

Normal Spinal Curvature

Four spinal curves (seen in lateral view)

Primary curves

Thoracic and sacral curves

Appear late in fetal development

Secondary curves

Cervical curve as baby holds head up

Lumbar curve as baby learns to stand

Normal Spinal Curvature

Spinal curvature development

Cervical curvature develops as a baby learns to

hold its head

Spinal curvature development

Lumbar curvature develops as a baby learns to

stand

Abnormal spinal curvature

Several abnormal conditions can arise during

childhood and adolescence

Kyphosis – exaggerated thoracic curvature

Lordosis – exaggerated lumbar curvature

Scoliosis – abnormal lateral curvature

Kyphosis

Lordosis

Scoliosis

THE SKELETAL SYSTEM

Continue with the Thoracic Cage

Thoracic Cage

Consists of the thoracic vertebrae, the ribs and the

sternum

Ribs + sternum = rib cage

Provides bony support for the walls of the thoracic cavity

Protects heart and lungs

Serves as base for muscles involved in respiration

Ribs

AKA costal bones

Elongated flattened bones

12 pairs

Ribs 1-7 = true ribs attach to the sternum by separate

cartilage extensions

Ribs 8-10 = false ribs; do not attach directly to the sternum;

cartilages fuse before attachment

Ribs 11-12 = floating ribs; do not connect to sternum at all

Sternum

AKA breastbone

3 parts

1. Manubrium = Broad triangular part

articulates with clavicle

2. Elongated body articulates with ribs

3. Ziphoid process

Damage to this process can puncture the liver

CPR training places special emphasis on location of this part of the

sternum to reduce damage during compressions

Thoracic

vertebrae

Manubrium

Body

Ziphoid

Process

Sternum

Costal Cartilage

Ribs

False Ribs

Floating

Ribs

True Ribs