220 likes | 232 Vues
Organization of the Skeleton. The Human Skeleton. 206 bones Divided into two portions. Axial Skeleton - Contains the bones which are in the mid-vertical axis of the body. Appendicular Skeleton- Bones which are outside the mid-vertical axis, associated with the appendages. Axial Skeleton.
E N D
The Human Skeleton • 206 bones • Divided into two portions. • Axial Skeleton- Contains the bones which are in the mid-vertical axis of the body. • Appendicular Skeleton- Bones which are outside the mid-vertical axis, associated with the appendages.
Axial Skeleton • Skull • Contains 22 bones. • Bones of the skull include; (8) cranial, (13) facial and the (1) mandible. • Sutures- Connection between the bones of the skull. • Sinus-Chamber- Located in the skull, are lined with mucous membranes, and filled with air. • Connect with the nasal cavity to drain fluids and reduce the weight of the skull.
Axial Skeleton • Cranium (8) bones • 1.Frontal Bone- Large bone forming the anterior part of the skull (forehead). • Orbits: Eye sockets, partially formed by the frontal bone. • Supraorbital Foramen: Hole above each orbital where blood vessels pass.
Axial Skeleton • Cranium • 2.Parietial Bone(s)-Two bones which form most of the superior/lateral cranium. • Meet at the top of the skull at the sagittal suture. • Meet the frontal bone at the coronal suture.
Axial Skeleton • Cranium • 3.Occipital Bone- Thick bone which forms the posterior wall and floor of the cranium. • Meets the parietal bone at the lambdoid suture. • Foramen Magnum- Opening for the spinal cord. • Occipital Condyles- Processes that articulate with the first vertebrae, to allow head movement.
Axial Skeleton • Cranium • 4.Temporal Bone(s)- Two bones on either side of the cranium, below the parietal bones. • Meet the parietal bones at the squamous suture. • Styloid Process- Serves as an anchor for muscles of the tongue and pharynx.
Axial Skeleton • Cranium • 5. Sphenoid Bone- Butterfly shaped bone that forms the lower lateral walls and floor of the cranium, also the posterior walls of the orbits. • Optic foramen- Location of the optic nerve passage. • 6.Ethmoid Bone- Small bone anterior to the sphenoid bone. • Forms sections of the cranial floor, orbital walls, and nasal cavity.
Axial Skeleton • Facial Bones • Contains 13 immovable bones and a movable mandible. • 1.Maxillary Bone(s)- Two bones on each side of the face that form the upper jaw. • 2.Palatine Bone(s)- Two L-shaped bones that are posterior to the maxillary bones. • Forms posterior roof of mouth and floor of the nasal cavity.
Axial Skeleton • Facial Bones • 3.Zygomatic Bone(s)- Two bones on the side of the face that form the cheeks. • 4.Nasal Bone(s)- Two small rectangular bones that meet to form the bridge of the nose. • 5.Lacrimal Bone(s)- Two fingernail shaped bones, form part of the orbits medial walls.
Axial Skeleton • Facial Bones • 6.Vomer- Single bone along the midline within the nasal cavity. • Meets with the ethmoid bone to form the nasal septum, which divides the nasal cavity in half. • 7.Inferior Nasal Concha- Two thin scroll-like bones attached to the lateral walls of the nasal cavity. • Forms shelves which air is channeled into the nasal cavity.
Axial Skeleton • Facial bones • 8.Mandible-Single lower jaw bone, articulates with the temporal bones. • Only movable bone of the skull. • Forms TMJ (temporal-mandibular joint) • Lock Jaw • Dislocated Jaw
Axial Skeleton • Hyoid Bone • Single bone that doesn’t articulate with any other bones. • Located in the upper neck region. • Horse-shoe shaped • supports the tongue and provides attachments for muscles.
Axial Skeleton • Vertebral Column • Strong flexible rod that supports the trunk, while allowing for movement. • Extends from the base of the skull to the pelvis. • Comprised of a series of irregular bones known as vertebrae. • Between each vertebrae is an intervertebral disc. • The adult vertebral column contains 26 vertebrae (after fusion).
Axial Skeleton • Structure of typical vertebra: • Body: Thick, disc-shaped front portion, designed for supporting weight. • Vertebral Arch: Forms a ring to hold the spinal cord called the Vertebral Foramen. • Seven processes arise from this vertebral arch and serve for either joint formation or muscle attachment.
Axial Skeleton • Types of Vertebrae and their Structures. • Cervical- (7) Vertebrae of the neck region, the support the head. • The lightest of the vertebrae • Transverse foramen- small hole that permits the passage of arteries to the brain.
Axial Skeleton • Types of Vertebrae and their Structures. • Cervical- (7) Vertebrae of the neck region, the support the head. • Atlas- First vertebrae that connects with the occipital condyles of the cranium. • Contains no body • Allows for the up and down movement of the head • Axis- Second vertebrae that contains a tooth like projection called the: • Odontoid process- It projects up through the rings of the atlas and allows for twisting of the head.
Axial Skeleton • Types of Vertebrae and their Structures. • Thoracic- (12) Only vertebrae that articulate with the ribs. (upper and middle of the back) • Lumbar- (5) Vertebrae that are larger and thicker, this is due to the increase in the body weight stress they support. (lower back)
Axial Skeleton • Types of Vertebrae and their Structures. • Sacrum- Large triangular bone that forms the posterior part of the pelvis. • (5) vertebrae fused together. • Sacral Canal: contains the spinal cord. • Coccyx- A series of 3-5 fused bones that is attached to the sacrum by ligaments. (tail bone)
Axial Skeleton • Thoracic Cage • Formed by thoracic vertebrae, sternum, and the ribs. • Conical, basket-shaped structure (cone shaped). • Partially encloses the internal structures of the chest. • Supports the upper limbs.
Axial Skeleton • Thoracic Cage • Sternum- AKA breast bone, It’s a flat, narrow bone at the center of the chest. • Articulates with the clavicles on one end. • Articulates with the ribs via the costal cartilage. • Consists of three (3) parts: • Manubrium- Superior part • Body- Large middle part • Xiphoid Process- Small pointy inferior end.
Axial Skeleton • Thoracic Cage • Ribs • (12) sets in every individual. • Attach to the thoracic vertebrae in the back and the sternum in the front. • True Ribs- First seven (7) pair, connects directly to the sternum via the costal cartilage. • False Ribs- Remaining five (5) pair, have an indirect connection or no connection at all to the sternum. • Floating Ribs- Last two (2) or sometimes three (3) pairs of ribs, have no connection at all to the sternum.