Lab 5 Bones and Axial Skeleton

Lab 5: Bones and Axial Skeleton

Learning Objectives

• Identify bones of the axial skeleton and their unique features.
• Identify components of the thoracic cage and their anatomical arrangements.

Overview of the Skeleton

• Axial skeleton: Bones around the body’s center of gravity (indicated in green).
• Appendicular skeleton: Bones of the appendages, shoulder, and pelvis (indicated in tan).

The Skull

• Bones of the Skull: Frontal, Parietal, Temporal, Occipital, Sphenoid, Ethmoid, Lacrimal, Nasal, Zygomatic, Maxilla, Mandible, Vomer, Inferior Nasal Concha.
• Key Features:
  • Sutures: Coronal, Sagittal, Lambdoid, Squamous, Occipitomastoid.
  • Processes: Zygomatic, Mastoid, Styloid, Coronoid, Condylar.
  • Foramen: Mental, Foramen Magnum, Jugular.
  • Fossa: Mandibular, Lacrimal.
  • Other Features: External acoustic meatus, Alveolar margins, Mandibular ramus, Mandibular angle, Mental foramen, Superior and Inferior Nuchal Lines, External occipital protuberance/crest, Nasal concha (superior, middle and inferior).
• Superior View of Skull:
  • Bones: Frontal, Parietal, Occipital, Temporal, Sphenoid, Ethmoid.
  • Features: Cribriform plate, Crista galli, Optic canal, Sella turcica, Foramen ovale, Jugular foramen, Internal acoustic meatus, Foramen magnum.
• Inferior View of Skull:
  • Bones: Maxilla, Palatine, Zygomatic, Temporal, Sphenoid, Occipital, Parietal.
  • Features: Hard palate (palatine process), Mandibular fossa, Styloid process, Mastoid process, Foramen ovale, Carotid canal, Jugular foramen, Occipital condyle, Foramen magnum.

Cranium

• Bones: Frontal, Parietal, Temporal, Occipital, Sphenoid, Ethmoid.
• Frontal Bone: Glabella, Supra-orbital notch (or foramen).
• Parietal Bone: Articulates with Frontal bone via Coronal suture, with Occipital bone via Lambdoid suture, with Temporal bone via Squamous suture, and with the other Parietal bone via Sagittal suture.

Cranium - Temporal Bones

• Parts: Petrous, Squamous, Zygomatic process.
• Features: External acoustic meatus, Mastoid process, Styloid process.

Cranium - Zygomatic Arch

• Formed by the Zygomatic process of the temporal bone and the Temporal process of the zygomatic bone.

Cranium - Temporal Bone Markings

• Mandibular fossa, Styloid process, Stylo-mastoid foramen, Mastoid process.

Cranium - Occipital Bone & Bone Markings

• Occipital condyles, Foramen magnum, Lambdoid suture, Sagittal suture.

Facial Bones

• Zygomatic bones, Lacrimal bones, Inferior nasal conchae, Maxillae, Mandible, Palatine bones, Nasal bones, Vomer

Facial Bones - Maxilla

• Infraorbital foramen, Incisive foramen.

Facial Bones - Mandible

• Body, Ramus, Mandibular notch, Coronoid process, Condylar process, Mental foramen.

Vomer

• Ethmoid-perpendicular plate, vomer.

Ethmoid Bone

• Features: Crista galli, Perpendicular plate, Superior nasal concha, Middle nasal concha, Ethmoid air cells.
• Views: Ventral, Superior, Lateral.
• Cribiform plate with olfactory foramina.

Sphenoid Bone

• Features: Greater wings, Lesser wings, Pterygoid plates (resembling Pterodactyl claws), Sella turcica (with hypophyseal fossa).
• Views: Ventral, Superior.

Foramen

• Cranial Foramina: Optic canal, Foramen rotundum, Superior orbital fissure, Foramen lacerum, Carotid canal, Jugular foramen, Foramen ovale, Internal acoustic meatus, Foramen spinosum, Hypoglossal canal.
• Ventral Foramina: Superior orbital fissure, Optic canal, Inferior orbital fissure, Mental foramen.
• Other Foramina: Stylomastoid foramen.
• Note: Superior orbital notch can sometimes be a foramen.
• Lacrimal fossa: Located on the lacrimal bone and also on the frontal bone (orbital side).

Hyoid Bone

• Parts: Greater cornu, Lesser cornu, Body.

Vertebrae

• Cervical (7), Thoracic (12), Lumbar (5).
• Curvatures: Cervical, Lumbar, Thoracic, Sacral.

Vertebrae - Generic & Stylized

• Features: Arch, Spine, Transverse process, Vertebral foramen, Body, Superior articulating process & facet, Inferior articulating process.

Vertebrae - Generic

• Transverse foramen (specific to cervical vertebrae).

Cervical Vertebrae - Atlas & Axis

• Atlas (C1), Axis (C2), Dens (odontoid process).

Thoracic Vertebrae

• Inferior and superior costal (demi-)facets join to meet the head of ribs.
• Note: Spine points downwards.
• Costal facet (made from 2 demifacets)
• Intervertebral foramen (between 2 vertebrae).

Lumbar Vertebrae

• Superior and Inferior articular processes and facets.

Thoracic & Lumbar Vertebra

• Thoracic vertebrae look like giraffes.
• Lumbar vertebrae look like moose.

Articulated Vertebrae

• Atlas & Axis, Lumbar vertebrae.

Sacrum & Coccyx

• Ala of sacrum, Coccyx, Sacral foramen, Auricular surfaces of sacrum.
• Ventral and Dorsal views.

Thoracic Cage - Sternum

• Jugular notch, Manubrium, Sternal angle, Body of sternum, Xiphoid process.

Thoracic Cage

• Clavicle (usually considered part of pectoral girdle), Costal cartilages.

Thoracic Cage - Ribs

• True ribs (1-7), False ribs (8-12), Floating ribs (11-12).

Ribs

• Features: Head, Neck, Tubercle, Articular facet, Anterior end.

Required Structures

• Skeletal Divisions: Axial, Appendicular.
• Bone Types: Long, Short, Flat, Irregular.
• Bone Markings: Tubercle, Condyle, Epicondyle, Head, Neck, Ramus, Trochanter, Spine, Crest, Meatus, Foramen, Fissure.
• Cranial Bones: Parietal, Ethmoid, Sphenoid, Temporal, Occipital, Frontal.
• Facial Bones: Vomer, Inferior nasal concha, Nasal bone, Maxilla, Mandible, Palatine, Zygomatic bone, Lacrimal bone.
• Skull Features: Foramen magnum, External acoustic meatus, Sella turcica, Crista galli, Cribiform plate, Coronoid suture, Sagittal suture, Lambdoid suture, Squamous suture, Frontal sinus, Ethmoid sinus, Sphenoid sinus, Maxillary sinus.
• Other Bones/Features: Clavicle, Hyoid, Ribs (True, False, Floating), Sternum (Manubrium, Body, Xiphoid process), Transverse process, Spinous process, Transverse foramen, Vertebral foramen, Cervical vertebrae, Axis, Atlas, Thoracic vertebrae, Lumbar vertebrae, Sacrum, Coccyx.