University:
Kentucky State University
Course:
BIO 301 | Human Anatomy
Academic year:

2019
Views:

301

Pages:

27
Author:

pravitate8aj16

The Axial Skeleton The Skull   The skull (Cranium) Consists of 22 bones Bones of the skull are grouped into two categories: 1. 2. Cranial bones  Eight cranial bones form the cranial cavity  Frontal bone, two parietal bones, two temporal bones, the occipital bone, the sphenoid bone, ethmoid bone Facial bones  Fourteen facial bones form the face  Two nasal bones, two maxillae, two zygomatic bones, the mandible, two lacrimal bones, two palatine bones, two inferior nasal conchae, vomer Features of the Skull  The cranial and facial bones protect and support special sense organs and the brain  Besides forming the large cranial cavity, the skull also forms several smaller cavities  Nasal cavity  Orbits (eye sockets)  Paranasal sinuses  Small cavities which house organs involved in hearing and equilibrium     Immovable joints called sutures fuse most of the skull bones together The skull provides large areas of attachment for muscles that move various parts of the head Skull and facial bones provide attachment for muscles that produce facial expressions The facial bones form the framework of the face and provide support for the entrances to the digestive and respiratory systems Cranial Bones:     Frontal Bone  Forms the forehead Parietal Bones  Form the sides and roof of the cranial cavity Temporal Bones (Zygomatic process and Mandibular fossa of TMJ  Form the lateral aspects and floor of the cranium  Consists of 5 parts: squamous part, petrous part, tympanic part, mastoid part and the styloid process Occipital Bone (foramen magnum?)  Forms the posterior part and most of the base of the cranium  The perceptible protrusion on the back of the head is the external occipital protuberance Temporal & zygomatic bones Greater wing Pterion: middle meningeal artery.  Sphenoid Bone (optic nerve)   1. 2. 3. 4. 5. Lies at the middle part of the base of the skull It’s formed of: Body (Sella turcica): contain the pituitary gland Lesser wings Greater wings Pterygoid processes Sphenoid sinus Ethmoid Bone (olfactory nerve)  Located in the midline in the anterior part of the cranial floor and forms the roof of the nasal cavity  1. 2. 3. 4. 5. 6. Parts: Superior and middle conchae: thin bony projections (nose) Transverse plate Perpendicular plate Crista galli Cribriform plate Ethmoid sinuses   Cribriform plate Crista galli Facial Bones:  Nasal Bones   Form the bridge of the nose Maxillae   1. 2. 3. 4.  Form the upper jawbone Has the following processes: Frontal process superiorly Zygomatic process laterally Palatine process posteriorly Alveolar process inferiorly. This one contains sockets for the teeth. The palatine process form most of the hard palate   Maxillae bone articulates with every bone of the face except the mandible Separates the nasal cavity from the oral cavity Zygomatic Bones   Commonly called cheekbones, form the prominences of the cheeks The temporal process of this bone unite with the zygomatic process of the temporal bone to form the zygomatic arch.  Lacrimal Bones   Palatine Bones   Form a part of the inferior lateral wall of the nasal cavity Vomer   Form the posterior portion of the hard palate Inferior Nasal Conchae   Form a part of the medial wall of each orbit Forms the inferior portion of the nasal septum Mandible    Lower jawbone The largest, strongest facial bone The only movable skull bone Temporomandibular joint (TMJ) Temporal bone and the mandible Parts of the Mandible: TMJ The Nasal Septum: A partition that divides the nasal cavity into right and left halves. It’s formed of 2 bony part and 1 cartilaginous part: 1. The perpendicular plate of the ethmoid bone posterior and superior 2. The vomer bone posterior and inferior. 3. Septal cartilage (hyaline cartilage) anteriorly . The Orbital Cavity: The bones that participate in the formation of the orbital cavity are: 1-Frontal 2-Lacrimal 3-Ethmoid 4-Maxillary 5-Zygomatic 6-Sphenoid  Main Sutures: 1) Coronal Suture: between the frontal and the two parietal bones. 2) Sagittal Suture: between the two parietal bones. 3) Lambdoid Suture: between the two parietal and the occipital bones. 4) Squamous suture: Temporal and parietal Paranasal Sinuses:  Cavities within cranial and facial bones near the nasal cavity  Secretions produced by the mucous membranes which line the sinuses, drain into the nasal cavity  Serve as resonating chambers that intensify and prolong sounds  Found in the following bones 1-Frontal 2-Ethmoid 3-Sphenoid 4-Maxillary : Largest Sinusitis is an inflammation of the mucous membrane. Fontanels:  Areas of unossified tissue that link the cranial bones at birth  Eventually, they are replaced with bone to become sutures  Provide flexibility to the fetal skull, allowing the skull to change shape as it passes through the birth canal Locatio n Anterior Fontanel Between the frontal and parietal bones Posterior Fontanel Between the parietal and occipital bones Shape Size Diamond ♦ Larger than the posterior Triangular ▲ Smaller than the anterior Closes Later than the posterior (1.5 - 2 years) Before the anterior (2 months) Principal Foramina of the Skull Foramen Location Olfactory Optic Carotid Ethmoid Sphenoid Temporal bone Between Temporal and Occipital Jugular Mandibular Mandible Magnum Occipital Structures passing through Cranial nerve I Cranial nerve II Internal carotid artery Internal jugular vein Mandibular branch of cranial nerve V Medulla oblongata and meninges The Hyoid Bone     Located in the upper part of the neck The only bone in the body that does not articulate with any other bone Supports the tongue, providing attachment sites for some tongue muscles and for muscles of the neck and pharynx and some ligaments Formed of body, greater horns and lesser horns The Vertebral Column   Also called the spine, backbone, or spinal column Functions to: Protect the spinal cord  Support the head  Serve as a point of attachment for the ribs, pelvic girdle, and muscles Composed of a series of bones called vertebrae (Adult=26)  7 cervical are in the neck region  12 thoracic are posterior to the thoracic cavity  5 lumbar support the lower back  1 sacrum consists of five fused sacral vertebrae  1 coccyx consists of four fused coccygeal vertebrae  

The Axial Skeleton

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