HUMAN ANATOMYFifth Edition

Chapter 1 Lecture

Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings

Frederic MartiniMichael Timmons

Robert Tallitsch

Chapter 6The Skeletal System: Axial Division

Chapter 6 Lecture

Introduction• The axial skeleton:

– skull– Vertebral column– Rib cage

• Sternum• ribs

Figure 6.1a The Axial Skeleton

Introduction

Figure 6.2 Cranial and Facial Subdivisions of the Skull

The Skull and Associated Bone

Figure 6.3a The Adult Skull

Sutures

Figure 6.3b The Adult Skull

Sutures

Figure 6.3c The Adult Skull

Sutures

Figure 6.18 The Skulls of Infants

The Skulls of Infants - Fontanels

The Cranium• The cranial cavity is a chamber that

supports and protects the brain.• Bones of the cranium are the:

– Occipital– Parietal (2)– Frontal– Temporal (2)– Sphenoid– Ethmoid

Figure 6.6a,b The Occipital Bone

Occipital Bone

Figure 6.3e Inferior View of Skull

Occipital Bone

Figure 6.7 The Frontal Bone

Frontal Bone

Figure 6.6c The Parietal Bone

Parietal Bone

Figure 6.8 The Temporal Bone

Temporal Bone

Figure 6.3e Inferior View of the Skull

Temporal Bone

Figure 6.9 The Sphenoid Bone

Sphenoid Bone

Sphenoid

Figure 6.10 The Ethmoid

Ethmoid Bone

Ethmoid

Ethmoid in Skull

Figure 6.11a The Cranial Fossae

The Cranial Fossae

Figure 6.11b The Cranial Fossae

The Cranial Fossae

The Facial Bones• The skull contains 14 total facial bones:

– Paired bones:• Maxillae• Palatine• Nasal• Zygomatic• Lacrimal• Inferior nasal conchae

– Single bones:• Vomer• Mandible

Figure 6.12a,b The Maxillae

Maxillary Bones

Figure 6.13 The Palatine Bones

The Palatine Bones

Figure 6.15 The Orbital Complex

The orbital complex

Figure 6.15 The Orbital Complex

The Orbital and Nasal Complexes

FZLEMPS

Figure 6.16a,b The Nasal Complex

The Inferior Nasal Conchae

Figure 6.16c,d The Nasal Complex

The Inferior Nasal Conchae

Figure 6.5 Sectional View of the Skull

The Vomer

Figure 6.14 The Mandible

The Mandible

Figure 6.16a The Nasal Complex

The Orbital and Nasal Complexes

Paranasal Sinuses • Are the interconnected hollow spaces

inside the frontal, ethmoid, sphenoid, and maxillary bones.

• These spaces reduce the weight of the skull, produce mucus, and allow air to resonate for voice production.

• Frontal sinus, maxillary sinus, sphenoidal sinus, and the ethmoidal air cells

Paranasal Sinues

Figure 6.17 The Hyoid Bone

The Hyoid Bone

PLAY The Skull

• 22 Bones of the Skull:– 8 form the

cranium:• Occipital• Parietal (2)• Frontal• Temporal (2)• Sphenoid• Ethmoid

Review of the Skull

– 14 total facial bones:• Paired bones:

– Maxillae– Palatine– Nasal– Zygomatic– Lacrimal– Inferior nasal

conchae • Single bones:

– Vomer– Mandible

The Vertebral Column • The adult vertebral column has ~33 bones:

– Vertebra (24), sacrum ( 5 fused into 1), and coccyx (3 – 5 fused into1)

• Performs several functions:– Encloses and protects the spinal cord– Supports the skull– Supports the weight of the head, neck, and

trunk– Transfers weight to the lower limbs– Helps maintain the upright position of the body

The Vertebral Column • Divided into regions from superior to

inferior:– Cervical (7)– Thoracic (12)– Lumbar (5) – Sacral (1); 5 fused vertebrae– Coccygeal (1); 3–5 fused vertebrae

PLAY Vertebral Column

Spinal Curves• Spinal curves are weight transferring

anterior and posterior curves. – The spinal curves are named for the region of

the vertebral column they occur in:• Cervical curve• Thoracic curve• Lumbar curve• Sacral curve

Figure 6.20a,b,c Vertebral Anatomy

Vertebral Anatomy

Figure 6.20d,e Vertebral Anatomy

Vertebral Anatomy

Intervertebral disk

Cervical Vertebrae • There are seven total; they are the smallest, most superior vertebrae.• The spinous processes: relatively stumpy; may be split, resulting in a bifid

process.• Have Transverse foramina• Superior articular facet faces up• Inferior articular facet faces down• No rib facets• C1 and C2 special – Atlas and Axis

The Atlas (C1) • The atlas has no body and articulates

cranially with the occipital condyles.– The articulations with the occipital condyles

allow one to shake their head “yes”. • The atlas has two arches, the anterior and

posterior vertebral arches.• Superior and inferior articular facets do not

extend beyond the arches.

Figure 6.22a,b The Atlas and Axis

The Atlas (C1)

The Axis (C2)• The body of the atlas fuses with the body

of the axis during development to form the dens (odontoid process).– There is no intervertebral disc because of the

dens.• The articulation between the atlas and axis

allow one to shake their head “no”.

Figure 6.22c–f The Atlas and Axis

The Axis (C2)

Cervical Vertebrae • Bifid spinous• Transverse foramen• Superior articular

facet faces superiorly

Typical Thoracic Vertebrae

Thoracic Vertebrae • There are 12 total; make up the posterior

of the rib cage.• The bodies of the thoracic vertebrae have

a heart shape.• The spinous process is long and slender

and points on a posterocaudal angle.• The transverse processes point

dorsolateral.• Articulates with ribs and therefore contain

extra facets.PLAY

Thoracic Vertebrae• Facets for ribs

Lumbar Vertebrae• There are 5 total; the largest vertebrae,

and make up the lower back region.• The body of lumbar vertebrae is very thick

and oval shaped.• The relatively small vertebral foramen is

triangular.

PLAY Typical Lumbar Vertebrae

Lumbar Vertebrae• The transverse processes point more

laterally than the thoracic vertebrae.• The spinous process resembles a tail fin of

a fish; stumpy and flattened.

Figure 6.25 The Sacrum and Coccyx

Sacrum and Coccyx

Sacrum and coccyx

PLAY Axial Skeleton

The Thoracic Cage • Has two functions:

– Protects the heart, lungs, thymus, and other structures within the cavity.

– Serves as the attachment site for muscles involved in:• Respiration• Positioning the vertebral column• Movements of the pectoral girdle and upper limb