The Skeletal System: Axial Division Chapter 6 Lecture Chapter 6 The Skeletal System: Axial Division Frederic Martini Michael Timmons Robert Tallitsch

Introduction The axial skeleton: skull Vertebral column Rib cage Sternum ribs

Introduction Figure 6.1a The Axial Skeleton

The Skull and Associated Bone Figure 6.2 Cranial and Facial Subdivisions of the Skull

Sutures Figure 6.3a The Adult Skull

Sutures Figure 6.3b The Adult Skull

Sutures Figure 6.3c The Adult Skull

The Skulls of Infants - Fontanels Figure 6.18 The Skulls of Infants

The cranial cavity is a chamber that supports and protects the brain. 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

Occipital Bone Figure 6.6a,b The Occipital Bone

Occipital Bone Figure 6.3e Inferior View of Skull

Frontal Bone Figure 6.7 The Frontal Bone

Parietal Bone Figure 6.6c The Parietal Bone

Temporal Bone Figure 6.8 The Temporal Bone

Temporal Bone Figure 6.3e Inferior View of the Skull

Sphenoid Bone Figure 6.9 The Sphenoid Bone

Sphenoid

Ethmoid Bone Figure 6.10 The Ethmoid

Ethmoid

Ethmoid in Skull

The Cranial Fossae Figure 6.11a The Cranial Fossae

The Cranial Fossae Figure 6.11b The Cranial Fossae

The skull contains 14 total facial bones: The Facial Bones The skull contains 14 total facial bones: Paired bones: Maxillae Palatine Nasal Zygomatic Lacrimal Inferior nasal conchae Single bones: Vomer Mandible

Maxillary Bones Figure 6.12a,b The Maxillae

The Palatine Bones Figure 6.13 The Palatine Bones

The orbital complex Figure 6.15 The Orbital Complex

The Orbital and Nasal Complexes FZLEMPS Figure 6.15 The Orbital Complex

The Inferior Nasal Conchae Figure 6.16a,b The Nasal Complex

The Inferior Nasal Conchae Figure 6.16c,d The Nasal Complex

The Vomer Figure 6.5 Sectional View of the Skull

The Mandible Figure 6.14 The Mandible

The Orbital and Nasal Complexes Figure 6.16a The Nasal Complex

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

The Hyoid Bone Figure 6.17 The Hyoid Bone

Review of the Skull 22 Bones of the Skull: 8 form the cranium: Occipital Parietal (2) Frontal Temporal (2) Sphenoid Ethmoid 14 total facial bones: Paired bones: Maxillae Palatine Nasal Zygomatic Lacrimal Inferior nasal conchae Single bones: Vomer Mandible PLAY The Skull

The adult vertebral column has ~33 bones: 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

Divided into regions from superior to inferior: 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

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 PLAY Vertebral Column

Vertebral Anatomy Figure 6.20a,b,c Vertebral Anatomy

Vertebral Anatomy Figure 6.20d,e 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 has two arches, the anterior and posterior vertebral arches. 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.

The Atlas (C1) Figure 6.22a,b The Atlas and Axis

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”.

The Axis (C2) Figure 6.22c–f The Atlas and Axis

Cervical Vertebrae Bifid spinous Transverse foramen Superior articular facet faces superiorly

There are 12 total; make up the posterior of the rib cage. 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 Typical Thoracic Vertebrae

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.

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. PLAY Typical Lumbar Vertebrae

Sacrum and Coccyx Figure 6.25 The Sacrum and Coccyx

Sacrum and coccyx

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 PLAY Axial Skeleton