BIOL 2457 - Anatomy & Physiology I - Module 5 - The Skeleton

By the end of this lesson, students will be able to:

Explain the difference between the axial & appendicular skeletons, their functions, types (shapes), and identify specific examples of bones found in each.
Identify the locations where cartilage is found in & around the skeletal system.
Name the bones of the skull and classify each as either a cranial bone or a facial bone.
List the bones of the thoracic cage.
Explain the difference between true, false, and floating ribs.
Identify the number and location of each kind of vertebrae in the vertebral column and identify their major anatomical features.
Describe the normal curvature of the spine and the appearance of each of the abnormal curvatures.
List the bones of the pectoral girdle and identify their major anatomical features.
List the bones of the pelvic girdle and identify their major anatomical features.
Describe the major anatomical differences between male and female pelvises.
Note: Limb bones will be covered in lab!

Protection: Safeguards internal organs.
Structural Support: Provides a framework for the body.
Muscle Attachment: Serves as points of attachment for muscles, facilitating movement.
Hematopoiesis: Blood cell formation takes place in the red bone marrow.
Triglyceride Storage: Occurs in yellow bone marrow.
Mineral Storage: Stores essential minerals, including calcium and phosphorus.
Osteocalcin Production: A hormone that plays a role in glucose homeostasis.

Cartilage: Found at many locations within and around the skeleton:
- Hyaline Cartilage: Present in joints, as well as attached to ribs and in the respiratory tract (nose & trachea).
- Elastic Cartilage: Located in the external ear and epiglottis.
- Fibrocartilage: Found between the vertebrae (intervertebral discs) and in the pubic symphysis.

Long Bones: Longer than they are wide, primarily made of compact bone.
Short Bones: Cube-shaped, consisting mainly of spongy (trabecular) bone.
Flat Bones: Thin and often curved in appearance.
Cranial Bones: Located in the skull, with spongy bone situated between layers of thin compact bone.
Irregular Bones: Comprise parts of more than one shape, e.g., the vertebrae.
Sesamoid Bones: Found within tendons, such as the patella.

Long Bones (Examples): Humerus, ulna, radius, femur, tibia, fibula, metacarpals, metatarsals, phalanges.
Short Bones (Examples): Carpals, tarsals.
Sesamoid Bones (Examples): Patella.
Flat Bones (Examples): Scapulae, clavicles.

Composition: Made up of cranial and facial bones.
Cranial Bones Function: Protect the brain, attach neck muscles, contain sinuses to reduce weight and for acoustics.
Facial Bones Function: Provide facial structure, serve as attachment points for facial muscles, and include cavities for special senses (vision, smell, taste).

Located in four skull bones: frontal, ethmoid, sphenoid, and maxilla.
Functions: - Warm and moisten the air.
-** Lessen skull weight.
-** Enhance voice resonance.

Cranial Bones:
- Parietal bones (2)
- Temporal bones (2)
- Frontal bone (1)
- Occipital bone (1)
- Sphenoid bone (1)
- Ethmoid bone (1)
Facial Bones:
- Maxilla (2)
- Zygomatic (2)
- Nasal (2)
- Lacrimal (2)
- Palatine (2)
- Nasal conchae (2)
- Mandible (1)
- Vomer (1)

Lateral View: Key suture and bone features identified.
Anterior View: Lists various anatomical features including canals and foramina.
Inferior and Sagittal View: Overview of internal bones and passages.
Superior Transverse View: Shows the layout and articulations of skull bones.

Definition: Located below the mandible, held in place by ligaments (stylohyoid and thyrohyoid).
Functions include providing attachment for neck muscles involved in swallowing and speech.

Total vertebrae: 24 in adults consisting of:
- 7 cervical vertebrae
- 12 thoracic vertebrae
- 5 lumbar vertebrae
The sacrum and coccyx are at the end of the vertebral column, consisting of:
- Sacrum: Comprises 5 fused vertebrae.
- Coccyx: Comprises 4 fused vertebrae.
Function: Supports the head, neck, and body; protects the spinal cord; and serves as an attachment point for ribs and back muscles.

C1 (Atlas): Supports the skull, allowing movement for nodding and rotation.
C2 (Axis): Contains the dens, allowing rotational movement of the skull.
C3 to C7:
- Bifid spinous process (for muscle attachment).
- Transverse foramen (for blood vessels).
T1-T12 (Thoracic Vertebrae):
- Contains costal facets for rib attachment.
- Features a longer spinous process for muscle attachment.
L1-L5 (Lumbar Vertebrae):
- Broadest body to support upper body weight.
- Shorter spinous processes for muscle attachment to the lower back.

Normal Curvature: Includes lordosis, kyphosis, and scoliosis.
Abnormal Curvatures: Exaggerated thoracic and lumbar curvatures observed in certain conditions.

True Ribs: Directly attached to the sternum via costal cartilage.
False Ribs: Indirectly attached (ribs 8-10 connect to cartilage of true ribs).
Floating Ribs: Ribs 11-12, which have no anterior attachment to the sternum.

Composition: Comprises the scapula and clavicle.
Key Characteristics: Highly mobile as only the clavicles anchor to the axial skeleton, resulting in increased mobility but decreased stability.

Composition: Consists of the os coxae (hip bone) and the sacrum/coccyx.
Characteristics: Stable with a larger, strongly reinforced joint structure, but possesses less mobility compared to the pectoral girdle.
Os Coxae Components: Include ilium, ischium, and pubis.

Male:
- Smaller, more obstructed pelvic opening.
- Pubic Arch: V-shaped.
Female:
- Larger, less obstructed pelvic opening.
- Pubic Arch: U-shaped, allowing for childbirth.