Notes #1, Lab Exam #2 2022 Update (1) PDF

**[Overview of the Skeleton: Classification and structure of Bones and Cartilage ]** **[\ ]**The **Skeleton** is made up of two tissues, the **Bone** and **Cartilage**.\ The embryo consists of mostly hyaline cartilage and the adult of\ mostly bone.  Cartilage is found only in the bridge of the nose...

**[Overview of the Skeleton: Classification and structure of Bones and Cartilage ]** **[\ ]**The **Skeleton** is made up of two tissues, the **Bone** and **Cartilage**.\ The embryo consists of mostly hyaline cartilage and the adult of\ mostly bone.  Cartilage is found only in the bridge of the nose,\ larynx, the trachea, the joints and some in the ribcage and the ear.\ \ [The functions of the skeleton include:\ ]1. Support.\ 2. Protection.\ 3. Lever system for movement.\ 4. Storage.\ 5. Production of blood cells.\ \ [Subdivisions of the skeleton]\ The **Axial Skeleton** is found at the center of gravity, the torso.\ It consists of the **Skull**, the **Sternum**, and the **Vertebral** **Column**.\ The **Appendicular Skeleton** consists of the limbs and the **Pelvic** and\ **Pectoral** girdles.\ \ [Bone Markings] **Bone Markings** are areas on the surfaces of the bones were\ ligaments...etc. attach, where joints are formed, and where nerves and\ blood vessels pass.\ There are two types of bone markings, projections, and depressions or cavities. [Bone Markings list] (know table 9.1) A **Tuberosity** is a large rounded projection. A **Crest** is narrow ridge of bone: usually prominent. A **Trochanter** is a very large, blunt, irregularly shaped process (only seen in the femur). A **Line** is a narrow ridge of bone: less prominent than a crest. A **Tubercle** is a small rounded projection or process. An **Epicondyle** is a raised area on or above a condyle. A **Spine** is a sharp, slender, often pointed projection. A **Process** is any bony prominence. A **Head** is a bony expansion carried on a narrow neck. A **Facet** smooth nearly flat articular surface. A **Condyle** is a rounded articular projection. A **Ramus** is an arm-like bar of bone. A **Groove** is a furrow. A **Fissure** is a narrow slit-like opening. A **Foramen** is a round or oval opening through a bone. A **Notch** is an indentation at the edge of a structure. A **Meatus** is a canal-like passageway. A **Sinus** is a bone cavity, filled with air and lined with mucous membrane. A **Fossa** is shallow basin-like depression in a bone, often serving as an articular surface. [Classification of bones]\ There are **206 bones** in the human body.\ There are two types of bones.\ 1. **Compact bone**, which is smooth looking and homogenous.\ 2**. Spongy bones**, which consists of small trabeculae, bars of bones, and space. [There are four subtypes of bone:]\ 1. **Long bones**, such as the femur, which are longer than wide, have a shaft and heads\ at the end. These bones are mostly compact bone.\ 2. **Short bones**, such as the tarsals, which are cube shaped, contain more spongy bone\ than compact bone.\ 3. **Flat bones**, such as the bones of the skull, consist of two layers of\ thin compact bone with spongy bone in between. Many of these bones are\ curved.\ 4. **Irregular bones**, such as the vertebrae, which are unusually shaped.\ [There are two other subtypes]:\ 1. **Sesamoid bones** which are found inside of tendons, ex. the patella.\ 2. **Wormian/ Sutural bones** which are small bones found between the\ cranial bones.\ \ \ \ [Anatomy of a long bone] The **Shaft** or **Diaphysis** is found on the long axis, consisting mostly of\ compact bone.\ \ The **Periosteum** is a fibrous membrane covering that surrounds the outside\ of the bone. **Sharpey\'s fibers** from the periosteum plunge into the bone allowing\ blood vessels and nerves to enter the bone.\ \ **Osteoblasts** are bone forming cells and are found in the periosteum.\ \ **Osteoclasts** are bone destroying cells and are found in the endosteum,\ the inner surface lining of the shaft.\ \ The **Epiphysis** is found at the end of long bones, and consists of\ mostly spongy bone and a thin layer of compact bone.\ \ The **Articular cartilage** is made of hyaline cartilage and covers the\ epiphyseal surface of the long bone instead of periosteum. It is a smooth surface that\ prevents friction at the joints.\ \ The **Epiphyseal plate** is an area of hyaline cartilage that allows for\ growth in growing animals. The **Epiphyseal line** is a remnant of plate of bone growth.\ \ The **Central Cavity** of the shaft is also called the **Medullary cavity** and\ stores fat. In infants the cavity stores red marrow, in adults the red\ marrow is only found in the epiphyses spaces in the spongy bone.\ \ [Microscopic Structure of the bone]\ \ A central **Haversian** canal runs parallel to the long axis of the bone.\ It carries blood vessels nerves, and lymph vessels.\ \ **Osteocytes** (mature bone cells) are found in the lacunae, chambers\ arranged in concentric circles (**Lamallae**) around the central canal.\ \ The central canal and all the concentric lamallae are called an **Osteon**\ or a **Haversian** system.\ \ **Canaliculi** are tiny canals radiating from the central canal and are a\ communication and transport network for nutrients.\ \ **Volksmann\'s canals** are perpendicular to the shaft, come from the\ periosteum, and extend to the bone marrow cavity and connect the central cavities to\ each other. [Ossification of Bone] **Endochondral ossification** uses hyaline bones as patterns for bone formation. From the **primary ossification center** the steps to bone formation are: 1. Periosteum replaces perichondrium. 2. Osteoblasts secrete bone around hyaline bone model. 3. Cartilage in shaft center calcifies and hollows forming a cavity. A **periosteal bud** (osteoblasts, osteoclasts, blood vessels, red marrow, and nerves) invades cavity forming a **medullary cavity** on either side of the primary ossification center. During bone growth the medullary cavity grows longer and larger. After adolescence the **epiphyseal plate** of ossifying cartilage is replaced by a calcified bony **epiphyseal line**. **[Cartilage\ ]**\ Cartilage is mostly water with differing amounts of elastic, reticular\ or collagen fibers. Cartilage has an outer covering of perichondrium, which\ plays a role in growth and repair. Cartilage also has no nervous enervation and is relatively avascular. There are three types of cartilage: **Elastic**, **Hyaline** and **Fibrocartilage**.\ \ [Cartilages of the skeleton ] [\ ]1. **Articular cartilage**, which is hyaline, is found at the epiphysis of long bones.\ 2. **Costal cartilage**, which is hyaline, connects the ribs to the sternum (breastbone).\ 3. **Laryngael** cartilage, which is hyaline, constructs the voice box in the larynx.\ 4. **Tracheal and Bronchial cartilages**, which are hyaline, reinforce passageways of\ the respiratory system.\ 5. **Nasal cartilage**, which is hyaline, supports the external nose.\ 6. **Intervertebral discs cartilage**, which are fibrocartilage, separate and cushion the bones.\ of the spine.\ 7. The Ear cartilage, which is elastic, supports the external ear.\ \ **Osteoporosis** is the gradual loss of bone mass, which results in the\ weakening of bones, bone breaks and fractures more easily. Causes are\ hormone deficiency, calcium and vitamin deficiency, physical\ inactivity, vices. **[The Axial Skeleton\ ]**\ The Axial Skeleton consists of the Skull, the Vertebral Column, and the\ Bony Thorax. Consists of 80 bones.\ \ [The skull consists of two sets of bones]:\ 1. The **Cranium** which encloses the brain.\ 2. The **Facial bones** which present the eyes, and have structures for the\ facial muscles.\ \ Bones of the skull are connected by non-moving sutures, except for the\ mandible, which is attached at a freely moving joint. **[Cranium/ Cranial Bones]** The cranium is divided into the superior **Cranial Vault** or **Calvaria** and the Inferior **Cranial Floor** or **Base**. The cranial floor has three concavities that hold the brain: the **Anterior, Middle and Posterior fossa**.\ The cranium consists of four bones; the **Frontal**, the paired **Parietals**, the paired **Temporals**, and the **Occipital**. [**The Frontal bone**\ ]The Frontal bone is the anterior portion of the cranium and contains the\ forehead, superior orbit and the floor of the **Anterior Fossa**. The **Supraorbital foramens (notch)** are openings above each orbit which allow blood vessels and nerves to pass. **[The Parietal bones]** The Parietal bones make up the superior sides of the cranium. The **Saggital Suture** is the midline articulation point of the parietal bones. **[The Temporal bones]** The Temporal bones make up the inferior sides of the cranium. The **Squamous Suture** is the point of articulation of the temporal and parietal bones. The bridge-like **Zygomatic process** forms the cheekbone. The **Mandibular fossa** is a rounded depression that is the site of articulation with the mandible. The **External Acoustic Meatus** is a canal leading to the eardrum and middle ear. The **Styloid process** is an attachment site for muscles and ligaments of the neck. The **Mastoid process** is an attachment site for muscles.\ **Mastoidistis** is an infection of the mastoid process of the temporal bone. Infection in this site can spread to the meninges of the brain, the brain coverings, this is called **Meningitis**. The **Stylomastoid foramen** is an opening for Cranial Nerve \# VII. The **Jugular foramen** is an opening for the internal jugular vein and cranial nerves IX, X, and XI. **The Carotid canal** is an opening for the internal carotid artery. The **Internal acoustic meatus** is a passageway for cranial nerves VII, and VIII. The **Foramen Lacerum** is an opening for the internal carotid artery and small nerves. **[The Occipital bone]** The Occipital bone makes up the posterior portion of the cranium. The occipital bone joins the Sphenoid bone anteriorly. The **Lamboid Suture** is point of articulation between the occipital and parietal bones. The **Foramen Magnum** is the large opening for the spinal cord. The **Hypoglossal Canal** is a passageway for the hypoglossal nerve (cranial nerve \#XII). **Occipital Condyles** articulate with **C1** the **Atlas**. [The **Sphenoid bone**] The **Sphenoid bone** is a bat-shaped bone forming the anterior plateau of the\ middle cranial fossa, runs along the width of the skull. The **Greater wings** form part of the orbital socket. The **Superior Orbital Fissures** are jagged openings that allow passage of cranial nerves III, IV, V and VI into orbit to serve eye. The Inferior Orbital Fissures allow passage of the infraorbital vessels and cranial nerve \#V. The **Sella Turcica** (Turk's Saddle) lies in the central portion of the bone. The seat of the saddle, the **Hypophyseal fossa** holds the pituitary gland. The **Optic canals** are openings for the optic nerves.\ The **Foramen Rotundum** and **Ovale** are openings for branches of the fifth cranial nerve. The **Foramen Spinosum** is an opening for the **Middle Meningeal Artery**. [The **Ethmoid bone**] The **Ethmoid bone** is anterior to the sphenoid and forms the roof of the nasal\ cavity, upper nasal septum and part of the medial orbital wall. The **Crista Galli** is a vertical projection and attachment point for the dura mater of the brain, helping to secure it to the skull. The **Cribiform plates** are bony plates lateral to the crista galli, which hold the **Olfactory foramina,** which allow for passage of the olfactory fibers. The crista galli and the cribiform plates form the **horizontal plate**. **The Perpendicular plate** forms the superior nasal septum. The **Lateral masses** form part of the medial orbital walls. The **Superior and Middle Nasal Conchae** are turbinates which help the mucosa in the nasal cavity warm and humidify incoming air. [**Facial bones** ] The Facial bones are made up of seven paired bones (14) and two single\ bones, the Vomer and the Mandible. [The **Mandible**\ \ ] The **Mandible** is the lower jawbone and articulates with the temporal bone via the only freely moving joint in the skull. The **Mandibular Body** forms the chin. **The Mandibular condyles** are articulation points with the temporal bone. The **Conoid process** is an attachment point for muscles. The **Mental Foramen** is an opening for mental blood vessels and nerves of lower jaw. The **Alveolar margin** contains the superior sockets for teeth. The **Mandibular symphysis** denotes point of mandibular fusion. The **Mandibular Foramen** is an opening for cranial nerve \#V. [The **Maxillae**]\ \ The **Maxillae** is two bones fused together to form the upper jawbone, all\ facial bones, but the mandible are joined at the maxillae. The **Alveolar margin** contains the inferior sockets for teeth. **Palatine processes** form the anterior hard palate. The **Infraorbital foramen** is an opening for infraorbital nerves and blood vessels of the nasal region. The **Incisive fossa** transmits the nasopalatine arteries and blood vessels. The **Lacrimal bones** form part of the medial lateral wall of the eye socket and are between\ the maxillae and the ethmoid. These bones are pierced **by lacrimal\ fossa**, which are the passageways for tears. The **Palatine bones** form the posterior hard palate and part of the\ orbit.\ \ The **Zygomatic bones** are lateral to the maxillae. They are part of the\ cheekbones and are part of the lateral orbit.\ \ \ The **Nasal bones** are small rectangular bones that form the bridge of the nose.\ \ The single **Vomer** is a blade-shaped bone in the medial plane which forms\ the posterior and inferior nasal septum.\ \ The **Hyoid bone** is located in the throat above the larynx, and is a\ point of attachment for neck and tongue muscles. Not articulated to any\ other bone.\ \ **[Paranasal sinuses]**\ The maxillary, sphenoid, ethmoid, and frontal bones contain sinuses.\ The maxillary is the largest. These sinuses may be used for resonance\ chambers and also lighten the facial bones.\ \ **Sinusitis** is the inflammation of the sinuses, resulting fom an allergy\ or a bacterial infection. This causes a blockage of passageways with\ mucus. Symptoms are a sinus headache.\ \ [The Vertebral Column\ \ ]The Vertebal column runs from the skull to the pelvis, and forms the major\ axial support. It protects the spinal cord and allows nerves to issue from\ the cord via openings between the vertebras.\ The Vertebral Column consists of 24 bones, the vertebrae, and the Sacrum and the Coccyx.\ The 7 bones of the neck are called the **Cervical vertebrae**.\ The 12 bones of the upper back are called the **Thoracic vertebrae**.\ The 5 bones of the lower back are called the **Lumbar vetebrae**.\ Each verteba is separated from another by fibrocartilage; these\ **Intervertebral discs** cushion and absorb shock.\ There are two parts to each, an inner **nucleus pulposus**, which is a\ central gelatinous mass, surrounded by an outer ring of collagen\ fibers, the **annulus fibrosus**.\ \ **Ruptured discs** occur when the nucleus pulposus herniates through the\ annulus fibrosus compressing spinal nerves.\ \ The s-shape of the spine, vertebral column, prevents shock and allows\ for flexibilty. The **Primary Curvature** (**Thoracic and Sacral**) of the spine is present at birth,\ later the **Secondary Curvature** (**Cervical and Lumbar**) is seen. [Abnormalities of spinal curvature:]\ 1. **Scoliosis** is an abnormal/ excessive lateral curvature of the spine.\ 2. **Kyphosis** is an abnormal/ excessive dorsal curvature of the spine.\ 3. **Lordosis** is an abnormal/ excessive anterior curvature of the spine.\ \ [Structure of the Vertebrae]\ \ The **Body** or **Centrum** is the rounded central portion that faces anteriorly.\ \ The **Vertebral arch** consists of the **Pedicles** (connects the body to the laminae), **Laminae** (connects the spinous and transverse processes) and a **Spinous process**.\ \ The **Vertebral foramen** is an opening between the arch and the body, the\ space that allows the spinal cord to pass.\ \ The **Transverse process** is the lateral projection of the arch.\ \ The **Spinous process** is the medial/ posterior projection of the arch.\ \ The **Superior and Inferior articular processes** are paired projections\ lateral to the vertebral foramen, that articulates between vertebrae.\ The superior process faces towards the spinous process and the inferior away.\ \ The **Intervetebral Foramina** are spaces in the pedicels that allow for spinal\ nerves to leave between the vertebra.\ \ **[Cervical Vertebae\ ]**\ C1 and C2 have special functions and names. The **Atlas, C1**, has no body,\ and the lateral processes have large depressions that receive the\ occipital condyles of the skull. **The Axis, C2**, acts as a pivot for\ rotation of the atlas. The **odontoid process/ dens** forms the pivot.\ \ The **Vertebral prominence** is C7 which is visible through the skin.\ \ **Costal demifacets** are found in the body of thoracic vertebrae and\ articulate with the ribs.\ \ Positioning of the superior and inferior articulating processes reduces\ mobility.\ \ The spinal cord ends at L2, but the outer coverings (meninges) continue and are\ filled with spinal fluid. **Lumbar puncture/ spinal tap** is done between\ L3-L4 and L4-L5, as well as **Saddle Block** (anesthesia for child birth) to avoid damaging the spinal cord.\ \ **[Sacrum\ ]**The sacrum is five fused vertebrae, it articulates with L5. Inferior to\ the sacrum is the coccyx.\ The **Medial Sacral crest** is made up of fused spinous processes.\ The **Alae** (wings) are fused transverse processes which articulate with the pelvic\ girdle.\ The **Sacral foramina** allow blood vessels and nerves to pass at ridges\ of fusion.\ The **sacral canal** holds the rest of the spinal coverings which enter the\ coccyx at the Sacral Hiatus.\ The **sacral promontory**, the anti-border of S1, is a landmark for obstetricians.\ \ **[The Coccyx]** is the fusion of 3 to 5 small vertebrae, vestige of a tail.\ \ **[The Bony Thorax]**\ the bony thorax consists of the Ribs, the Sternum, and the thoracic Vertebrae. It is\ also known as the thoracic cage.\ \ **Sternum** or breastbone is a flatbone, which is a fusion of three bones;\ 1.The **Manubrium** which is a triangular bone that articulates with the\ clavicles.\ 2. The **Body** which is the bulk of the sternum.\ 3. The **Xiphoid process** the most inferior bone, which if projected\ dorsally when struck can cause trama to the heart or liver.\ \ [Four landmarks that can be seen are;\ ]1. The **Jugular notch** (the concave upper border of the manubrium).\ 2. The **Sternal angle** where the manubrium and the body meet.\ 3. **Xiphisternal joint** where the body and the xiphoid process meet. 4\. **Clavicular Notches** which are sites of articulation with Clavicles.\ \ **[Ribs\ ]**\ There are twelve pair of ribs that form the walls of the thoracic cage.\ The first seven pairs (1-7) are attached directly to the sternum and the\ vertebral column and are called **Vertebrosternal.** Pairs 8-10 are called\ **Vertebrochondral** or **False ribs** and are attached indirectly to the\ sternum by hyaline cartilage. Pairs 11 and 12 are not attached to the\ sternum and are called **Floating** or **Vertebral ribs**.\ \ **[The Fetal Skeleton]** Indentations between bones of the fetal skull are called **fontanels**,\ which are fibrous membranes. These ossify by the 20-22 months after\ birth. They allow for compression during birth, and allow for growth of the brain. There are four\ fontanels; the **Anterior, the Posterior, the Sphenoid, and the Mastoid**. **[Skull depressions and projections summary]** **[Frontal Bone]** **Supraorbital foramens (notch)** are openings above each orbit which allow blood vessels and nerves to pass**[.]** **Coronal Suture** is the point of articulation of the Frontal and Parietal Bones. **[Parietal Bones]** **Sagittal Suture** point of articulation of Parietal bones **[Temporal Bone]** **Squamous Suture** is the point of articulation of the temporal and parietal bones. **Zygomatic process** forms the cheekbone **Stylomastoid Foramen** passage of CN VII (7) **Jugular Foramen** passage of Internal Jugular Vein and CN IX, X, XI (9, 10, 11) **Carotid Canal** passage of internal carotid Artery **Mandibular fossa** is a rounded depression that is the site of articulation with the mandible The **Styloid process** is an attachment site for muscles and ligaments of the neck. The **Mastoid process** is an attachment site for muscles.\ **External Acoustic Canal** passage for sounds to middle ear **Internal Acoustic Canal** passage of CN VII and VIII (7, 8) **Formen Lacerum** passage of Internal Carotid Artery **[Occipital Bone]** **Lambdoid Suture** point of articulation of Occipital and Parietal Bones **Foramen Magnum** passage of Spinal Cord **Hypoglossal Canal** passage of CN XII (12) **Occipital Condyles** point of articulation of Occipital bone and C1, the Atlas **[Sphenoid (Cranial Keystone)]** **Greater Wings** part of eye orbit/ socket **Superior Orbital Fissure passage** of CN III, IV, V, VI (3, 4, 5, 6) **Inferior Orbital Fissure** passage of Infraorbital blood vessels and CNV (5) **Hypophyseal Fossa** holds Pituitary Gland **Optic Canal** passage of CN II (2), Optic Nerve **Foramen Rotundum** and **Ovale** passage of CN V (5) **Foramen Spinosum** passage of Middle Meningeal Artery Ethmoid **Lateral Masses** of part of eye orbit/ socket **Crista Gali** attachment of Dura mater to Skull **Cribriform Plates** hold Olfactory Foramina which are passage for CN I (1), Olfactory Nerve **Horizontal plate** the Crista Gali and the two Cribriform plates **Perpendicular Plate** forms the superior nasal septum **Superior and Inferior Nasal Conchae** are turbinates **[Mandible]** **Mandibular Body** forms the chin **Mandibular Condyle** articulates with the mandibular fossa **Conoid Process** site of muscle attachment **Mental Foramen** passage of Mental blood vessels **Alveolar Margin** site of inferior teeth sockets **Mandibular Symphysis** site of mandibular fusion **Mandibular Foramen** passage of CN V (5) **[Maxillae (Facial keystone)]** **Alveolar Margin** site of superior teeth sockets **Palatine Processes** anterior portion of hard palate **Infraorbital Foramen** passage of Infraorbital blood vessels **Incisive Fossa** passage of Nasopalatine Artery and blood vessel **[Lacrimal Bone]** **Lacrimal Fossa** passage for tears, also part of eye orbit/ socket **[Palatine Bone]** Forms posterior portion of hard palate **[Zygomatic Bone]** Forms cheeks and part of eye orbit/ socket **[Nasal Bone]** Forms bridge of nose and part of eye orbit/ socket **[Hyoid]** Attachment site of neck and tongue muscles