2 Support and Movement Fundamentals of Anatomy & Physiology Unit Frederic H. Martini PowerPoint® Lecture Slides prepared by Professor Albia Dugger, Miami–Dade College, Miami, FL Professor Robert R. Speed, Ph.D., Wallace Community College, Dothan, AL Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Chapter 7: The Axial Skeleton

What are the bones of the axial skeleton, their structures, and functions?

Structures of Bones Articulations: Marks: Foraminae: contacts with other bones Marks: areas of muscle and ligament attachment Foraminae: openings for nerves and blood vessels

The Axial Skeleton 3D Peel-Away of Whole Axial Skeleton PLAY Figure 7–1a

The Axial Skeleton * Figure 7–1b

The Axial Skeleton The axial skeleton: forms the longitudinal axis of the body has 80 bones

Bones of the Axial Skeleton The skull: 8 cranial bones 14 facial bones

Bones of the Axial Skeleton Bones associated with the skull: 6 auditory ossicles the hyoid bone

Bones of the Axial Skeleton The vertebral column: 24 vertebrae the sacrum the coccyx

Bones of the Axial Skeleton The thoracic cage: 24 ribs the sternum

Functions of the Axial Skeleton Supports and protects organs in body cavities Attaches to muscles of: head, neck, and trunk respiration appendicular skeleton

The Skull The skull protects: the brain entrances to respiratory system entrance to digestive system

The Skull PLAY The Adult Skull Figure 7–2

The Skull Has 22 bones: 8 cranial bones: 14 facial bones: form the braincase or cranium 14 facial bones: protect and support entrances to digestive and respiratory tracts

Cranial Bones Enclose the cranial cavity Which contains the brain: and its fluids, blood vessels, nerves, and membranes

The Facial Bones Superficial facial bones: Deep facial bones: for muscle attachment Deep facial bones: separate the oral and nasal cavities form the nasal septum

Sinuses Cavities which decrease the weight of the skull: lined with mucus membranes protect the entrances of the respiratory system

Sutures The immovable joints of the skull Figure 7–3a, b

Sutures Figure 7–3c

Sutures Figure 7–3d, e

The 4 Major Sutures Lambdoid suture Coronal suture Sagittal suture Squamous suture

Lambdoid Suture Separates occipital from parietal bones May contain sutural bones

Coronal Suture Attaches frontal bone to parietal bones The calvaria: consists of occipital, parietal, and frontal bones

Sagittal Suture Between the parietal bones From lambdoid suture to coronal suture

Squamous Sutures Form boundaries between temporal bones and parietal bones

What are the bones of the cranium, and the significance of their markings?

Cranial Bones The 8 cranial bones Figure 7–4a, b

The Cranial Bones Occipital bone Frontal bone Sphenoid Ethmoid Parietal bones Temporal bones

The Occipital Bone Figure 7–5a

The Parietal Bones Figure 7–5b

The Frontal Bone Figure 7–6

The Temporal Bones Figure 7–7

The Sphenoid Figure 7–8

The Ethmoid Figure 7–9

What are the bones of the face, and the significance of their markings?

The Maxillary Bones The largest facial bones Figure 7–10a

The Palatine Bones Figure 7–10b,c

What are the structures and functions of the nasal complex?

The Small Bones of the Face Figure 7–11

Functions of the Inferior Nasal Conchae To create air turbulence in the nasal cavity To increase the epithelial surface area To warm and humidify inhaled air

Functions of the Lacrimal Bones The smallest facial bones Form part of the medial wall of the orbit

The Mandible Figure 7–12a,b

The Hyoid Bone Figure 7–12c

Functions of the Hyoid Bone Supports the larynx Attaches muscles of the larynx, pharynx, and tongue

The Orbital Complex Portions of 7 cranial and facial bones Figure 7–13

The Orbital Complex Forms the eye sockets (orbits): frontal bone (roof) maxillary bone (floor) maxillary, lacrimal and ethmoid bones (orbital rim and medial wall) sphenoid and palatine bones

The Nasal Complex Bones of the nasal cavities and paranasal sinuses Figure 7–14

What are the functions of paranasal sinuses?

Paranasal Sinuses Air-filled chambers connected to the nasal cavities: lighten skull bones provide mucous epithelium (flushes nasal cavities)

What are the differences between the skulls of infants, children, and adults?

The Infant Skull Figure 7–15

The Infant Skull Grows rapidly Is large compared to the body Has many ossification centers

The Infant Skull Fusion is not complete at birth: 2 frontal bones 4 occipital bones several sphenoid and temporal elements

Fontanels Are areas of fibrous connective tissue (soft spots) Cover unfused sutures in the infant skull Allow the skull to flex during birth

The 4 Fontanels Anterior fontanel: Occipital fontanel: frontal, sagittal, and coronal sutures Occipital fontanel: lambdoid and sagittal sutures

The 4 Fontanels Sphenoidal fontanels: Mastoid fontanel: squamous and coronal sutures Mastoid fontanel: squamous and lambdoid sutures

What are the vertebral regions, the curvatures of the vertebral column, and their functions?

The Vertebral Column The spine or vertebral column: protects the spinal cord supports the head and body

Regions and Curves of the Vertebral Column 26 bones: 24 vertebrae, the sacrum, and coccyx PLAY The Vertebral Column Figure 7–16

Regions of the Vertebral Column Cervical (C) Thoracic (T) Lumbar (L) Sacral (S) Coccygeal (Co)

Vertebrae of the Vertebral Column The neck: 7 cervical vertebrae The upper back: 12 thoracic vertebrae each articulate with one or more pairs of ribs The lower back: 5 lumbar vertebrae

The Sacrum and Coccyx The 5th lumbar vertebra articulates with the sacrum The sacrum articulates with the coccyx

4 Curvatures of the Vertebral Column Cervical curve Thoracic curve Lumbar curve Sacral curve

Primary Curves Thoracic and sacral curves: are called primary curves (present during fetal development) or accommodation curves (accommodate internal organs)

Secondary Curves Lumbar and cervical curves: are called secondary curves (appear after birth) or compensation curves (shift body weight for upright posture)

What are the structures and functions of each vertebral group?

Structure of a Vertebra Figure 7–17a,b

The Vertebral Arch Figure 7–17c

Vertebral Foraminae Intervertebral foraminae: Vertebral canal: gaps between pedicles of adjacent vertebrae for nerve connections to spinal cord Vertebral canal: formed by vertebral foraminae encloses the spinal cord

The Vertebral Canal Figure 7–17d,e

Intervertebral Discs Are pads of fibrocartilage Separate the vertebral bodies Absorb shocks

Vertebral Regions Figure 7–16

Vertebral Regions Vertebrae are numbered: Vertebrae of each region: by region, from top to bottom C1 articulates with skull, L5 with sacrum Vertebrae of each region: have characteristics determined by functions

The Cervical Vertebrae PLAY 3D Rotation of Cervical Vertebrae Figure7–18a, b

The Cervical Vertebrae Figure7–18c, d

Characteristics of Cervical Vertebrae (4 of 6) Atlas (C1): articulates with occiptal condyles of skull has no body or spinous process has a large, round foramen within anterior and posterior arches

Characteristics of Cervical Vertebrae (5 of 6) Axis (C2): supports the atlas has heavy spinous process to attach muscles of head and neck Axis and atlas bodies fuse during development to form the dens

Whiplash Whiplash: a traumatic dislocation of cervical vertebrae

The Thoracic Vertebrae PLAY 3D Rotation of Thoracic Vertebrae Figure 7–19a

The Thoracic Vertebrae Figure 7–19b, c

The Lumbar Vertebrae PLAY 3D Rotation of Lumbar Vertebrae Figure 7–20a

The Lumbar Vertebrae Figure 7–20b, c

Characteristics of Lumbar Vertebrae (1 of 3) Lumbar vertebrae (L1–L5): largest vertebrae oval-shaped bodies thicker bodies than T1–T12 no costal or transverse costal facets triangular vertebral foramen

Comparing Vertebrae Table 7–2

The Sacrum and Coccyx 3D Rotation of Sacrum and Coccyx PLAY Figure 7–21

Characteristics of the Sacrum (1 of 3) is curved, more in males than in females protects reproductive, urinary, and digestive organs

Characteristics of the Sacrum (2 of 3) Attaches: the axial skeleton to pelvic girdle of appendicular skeleton broad muscles that move the thigh

Characteristics of the Sacrum (3 of 3) The adult sacrum: consists of 5 fused sacral vertebrae fuses between puberty and ages 25–30 leaving transverse lines

Characteristics of the Coccyx attaches ligaments and a constricting muscle of the anus Mature coccyx: consists of 3 to 5 fused coccygeal vertebrae

What is the significance of articulations between ribs, thoracic vertebrae, and sternum?

The Thoracic Cage The skeleton of the chest: Consists of: supports the thoracic cavity Consists of: thoracic vertebrae ribs sternum (breastbone)

The Rib Cage Formed of ribs and sternum Figure 7–22a

Articulations of Ribs and Vertebrae Figure 7–22b

Functions of the Thoracic Cage Protects organs of the thoracic cavity: heart, lungs, and thymus

The Ribs Figure 7–23

Functions of Ribs Ribs: are flexible are mobile can absorb shock

Functions of Ribs Rib movements (breathing): affect width and depth of thoracic cage changing its volume

Ribs Ribs (costae): Ribs are divided into 2 types: are 12 pairs of long, curved, flat bones extending from the thoracic vertebrae Ribs are divided into 2 types: true ribs false ribs

True Ribs Ribs 1–7 (true ribs) vertebrosternal ribs connected to the sternum by costal cartilages

False Ribs Ribs 8–12 (false ribs): do not attach directly to the sternum

Types of False Ribs Vertebrochondral ribs (ribs 8–10): fuse together merge with cartilage before reaching the sternum Floating or vertebral ribs (ribs 11–12): connect only to the vertebrae have no connection with the sternum

The Sternum The sternum: a flat bone in the midline of the thoracic wall

3 Parts of the Sternum The manubrium The sternal body The xiphoid process

The Manubrium The manubrium: the superior portion of sternum broad, triangular shape articulates with collarbones (clavicles) articulates with cartilages of 1st rib pair has a jugular notch between clavicular articulations

The Sternal Body The sternal body: is tongue-shaped attaches to the manubrium attaches to costal cartilages of ribs 2–7

The Xiphoid Process The xiphoid process: is the smallest part of the sternum attaches to the sternal body attaches to diaphragm and rectus abdominis muscles

Development of the Xiphoid The xiphoid process: is the last part of sternum to fuse can easily be broken away

KEY CONCEPT The axial skeleton: Vertebrae: protects the brain, spinal cord, and visceral organs of the chest Vertebrae: conduct body weight to the lower limbs Lower vertebrae are larger and stronger: because they bear more weight