AnaPhy 1_Axial Skeleton.pdf

LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario SKELETAL SYSTEM Contributes to homeostasis by...

LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario SKELETAL SYSTEM Contributes to homeostasis by protecting many of body’s organs such as, brain, spinal cord, heart, and lungs Important in support and calcium storage & release Forms the framework of the body Orthopedics → studies the prevention or correction of disorders of the musculoskeletal system DIVISIONS OF THE SKELETAL SYSTEM Human bones consists 206 bones Two principal divisions: ○ Axial skeleton - 80 bones; lie around the longitudinal axis of the body ○ Appendicular skeleton - 126 bones TYPES OF BONES 1. Long Bone Greater length than width Shaft and numerous extremities (ends) Slightly curved for strength Diaphysis → compact bone Epiphysis → spongy bone Examples: i. Femur (thigh) ii. Tibia & Fibula (leg) iii. Humerus (arm) iv. Ulna & Radius (forearm) v. Phalanges (fingers & toes) 2. Short Bone Cube-shaped Nearly equal in length and width Examples: i. Carpal (wrist) - except pisiform (sesamoid) ii. Tarsal (ankle) - except calcaneus (irregular) 3. Flat Bone Thin and composed of two parallel plates of compact bone Serves as protection and provide extensive area for muscle attachment Examples: i. Cranial ii. Sternum iii. Ribs Alexandria Mignonet M. Uson, RMT, MD LESSON 3 1  LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario iv. Scapulae 1. Functions Form large cranial cavity → protects brain 4. Irregular Smaller cavities → open to the exterior (e.g. eye Complex shapes sockets) Vary in amount of spongy and compact bone i. Paranasal sinuses → lined with mucous Examples: membranes and nasal cavity i. Vertebrae ii. Hearing and equilibrium cavities ii. Hip bone Mandible → Only movable bone in the skull iii. Calcaneus Sutures fuse most of the skull bones Cranial bones’ functions: 5. Sesamoid Bone i. Stabilize position of the brain, blood Sesame seed-shaped like bones and lymphatic cells, and nerves Develop in tendons where there is friction ii. Provide attachments for muscles Example: patellae (kneecaps) → located in Facial bones’ functions: quadriceps femoris tendon i. Form framework of the face Protect tendons from wear and tear and improve ii. Provide support for entrances to mechanical advantage at a joint digestive and respiratory systems iii. Support special sense organs 6. Sutural Bone Small bones located in sutures (immovable 2. Features joints in adults) between cranial bones Frontal Bone i. Forms the forehead, roofs of orbits BONE SURFACE MARKINGS Parietal Bones i. Form the sides and roof of cranial 1. Depressions and Openings cavity a. Allow passage of soft tissue or form joints Temporal Bones i. Blood vessels & nerves i. Form the inferior lateral parts of the cranium 2. Processes ii. Temporal Squama → forms anterior a. projections /outgrowths that help form joints or and superior part of the temple serve as attachment points for connective tissue iii. Zygomatic Process → articulates with i. Ligaments & tendons cheek bone iv. Mandibular Fossa → socket v. External Auditory Meatus SKULL (passageway) ○ Contains mastoid air cells 22 bones ○ Mastoiditis → inflammation Rests on the superior end of the vertebral column of ear Two categories vi. Internal Auditory Meatus → opening 1. Cranial Bones where facial nerve and ○ Form cranial cavity → protects brain vestibulocochlear nerve pass ○ 8 bones vii. Styloid Process → point of attachment Frontal bone of tongue and neck 2 parietal bones viii. Stylomastoid Foramen → facial and 2 temporal bones stylomastoid artery pass occipital bone ix. Petrous Portion → base of the skull, Sphenoid bone houses internal & middle ear Ethmoid bone x. Carotid Foramen → carotid artery 2. Facial Bones passes ○ 14 bones xi. Jugular Foramen → jugular vein passes 2 nasal bones 2 maxillae 2 zygomatic bones; mandible 2 lacrimal bones 2 palatine bones 2 inferior nasal conchae Vomer Occipital bone CRANIAL BONES i. Forms the posterior part and base of the cranium Alexandria Mignonet M. Uson, RMT, MD LESSON 3 2  LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario ii. Foramen Magnum → large hole where vi. Ethmoidal cells form ethmoidal sinuses medulla oblongata and spinal cord vii. Superior Nasal Concha & Middle Nasal connect Concha → warms and moistens inhaled iii. Occipital Condyles → articulate air before it passes into the lungs depressions on the neck to form the yes joint FACIAL BONES iv. External Occipital Protuberance → bump on the back of the head just Face shape changes during first two years after birth above the neck Brain and cranial bones expand, first teeth form and v. Ligamentum Cuchae → external paranasal sinuses increase in size occipital protuberance → 7th cervical Growth of face ceases about 16 years of age vertebra Features: Sphenoid bone Nasal bones → forms bridge of nose i. Middle part of the base of the skull Maxillae → form upper jawbone; articulate every bone of ii. Keystone of the cranial floor because it face except mandible articulates with all the other cranial i. Hard palate → bony roof of the mouth; separates bones, holding them together nasal and oral cavity iii. Resembles a butterfly with Palatine process → horizontal outstretched wings projection of maxilla iv. Contains sphenoidal sinus which drains Fusion of maxillary bones is completed into the nasal cavity before birth v. Sella Turcica → superior surface of the Fusion fails = cleft palate body of the sphenoid Infraorbital foramen → allows passage vi. Hypophyseal Fossa → contains pituitary of infraorbital nerve and blood vessels gland Incisor foramen → posterior to the vii. Greater Wings of Sphenoid → forms the incisor teeth anterolateral floor of the cranium Transmit branches of the greater viii. Lesser wings → forms floor of the palatine blood vessels and cranium and posterior part of eye orbit nasopalatine nerve ix. Optic Foramen or Canal → optic nerve Zygomatic Bones → cheekbones and ophthalmic artery passes Lacrimal Bones → smallest bone of the face; contains x. Superior Orbital Fissure → blood vessel lacrimal fossa where it houses the lacrimal sac that is and cranial nerves pass through responsible for gathering tears and passing them into the xi. Foramen Lacerum → transmits a nasal cavity branch of the ascending pharyngeal Palatine Bones → form the posterior portion of the hard artery palate , part of the floor and lateral wall of the nasal xii. Foramen Rotundum → maxillary cavity branch of the trigeminal nerve passes Inferior Nasal Conchae → increase surface area of the through nasal cavity; filter air before it passes the lungs Vomer → triangular bone on the floor of the nasal cavity; Ethmoid bone form interior portion of the nasal septum i. Support the structure of nasal cavity Mandible → largest and strongest facial bone; lower ii. Forms: jawbone; contains condylar process that forms ○ Anterior portion of the temporomandibular joint cranial floor i. Alveolar Process → contain alveoli for the ○ Medial wall of orbits mandibular teeth ○ Superior portion of the nasal ii. Mental Foramen → mental nerve when injecting septum anesthetics ○ Superior sidewalls of the iii. Mandibular Foramen → beginning of mandibular nasal cavity canal; where inferior alveolar nerves and blood iii. Cribriform plate → roof of the nasal vessels pass and are distributed to the cavity; contains olfactory foramina mandibular teeth where olfactory nerves pass iv. Temporomandibular Joint Syndrome → caused iv. Crista Galli → point of attachment for by improperly aligned teeth membranes that separate two sides of Nasal Septum → separates right and left side of nasal the brain cavity v. Contains 3-18 air spaces - ethmoidal Orbits → contains eyeball cells Alexandria Mignonet M. Uson, RMT, MD LESSON 3 3  LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario Foramina → openings for blood vessels, nerves and HYOID BONE ligaments of the skull Suture → immovable joint that holds skull bones together U-shaped i. Coronal Suture → unites frontal and parietal Does not articulate with any other bone bones Often fractured when strangled → often examined at ii. Sagittal Suture → unite parietal bones on the autopsy when strangulation is suspected cause of death midline of the skull; resemble an arrow Functions: iii. Lambdoid Suture → unites parietal and occipital i. Supports the tongue, providing attachment sites bone for some tongue muscles and for muscles of the iv. Squamous Suture → unite parietal and temporal neck and pharynx bones ii. Help the larynx (voice box) open at all times Paranasal Sinuses → cavities within cranial and facial bones near nasal cavity; secretions produced by the mucous membranes of the paranasal sinuses drain into the nasal cavity; affects the voice; lightens the mass of skull i. Sinusitis → inflammation of the mucous membrane of paranasal sinuses Fontanels (soft spots) → between cranial bones VERTEBRAL COLUMN i. Unpaired Anterior Fontanel → largest fontanel; closes 18-24 months after birth Spine, backbone, or spinal column ii. Unpaired Posterior Fontanel → midline between Composed of vertebrae parietal bones and occipital bone Forms the skeleton of the trunk of the body – along with iii. Paired Anterolateral Fontanel → located the sternum and ribs laterally between the frontal, parietal, temporal, 28 in. - male; 24 in. - female and sphenoid bones; are small and irregular in Early development - 33 vertebrae; adult - 26 vertebrae shape; close about 3 months after birth Functions: iv. Paired Posterolateral Fontanel → located i. strong , flexible rod with elements that can move laterally between the parietal, occipital, and forward, backward, sideways and rotate temporal bones; are irregularly shaped; close ii. Enclose and protect the spinal cord about 1-12 months after birth iii. Support the head iv. Point attachment of ribs, pelvic girdle, and muscles of the back and upper limbs 7 cervical vertebrae 12 thoracic vertebrae 5 lumbar vertebrae 1 sacrum – 5 sacral vertebrae 1 coccyx – 4 coccygeal vertebrae Alexandria Mignonet M. Uson, RMT, MD LESSON 3 4  LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario PARTS OF A VERTEBRA Vary in size, shape and detail Consists of: ○ Body ○ Vertebral arch ○ Processes NORMAL CURVES OF THE VERTEBRAL COLUMN A normal adult vertebral column appears straight When viewed from the side, it shows four slight bends called normal curves The curves of the vertebral column increase its strength to: ○ Maintain balance 1. Body ○ Absorb shocks during walking Weight bearing part of the vertebra ○ Protect the vertebrae from fracture Contains nutrient foramina → openings through The fetus has a single anteriorly concave curve which blood vessels deliver nutrients & oxygen 3rd month after birth → cervical curve develops from bone tissue When child sits up, stands, and walks → lumbar curve develops 2. Vertebral Arch 2 pedicles and flat laminae unite to form the All curves are developed by age 10 vertebral arch Primary curve → thoracic and sacral curves Vertebral Foramen Secondary curve → cervical and lumbar curves i. Permits the passage of a single spinal ○ May be progressively lost in old age nerve that passes to a specific region Abnormal curve → exaggerated normal curves or may ii. Contains spinal cord, adipose tissue, acquire lateral bend areolar connective tissue and blood 3 abnormal curves: kyphosis, lordosis, scoliosis cells INTERVERTEBRAL DISCS 3. Processes Transverse process extends laterally on each 25% of the height of the vertebral column side Located between the bodies of adjacent vertebrae from Single spinous process (spine) projects the second cervical vertebra of the sacrum posteriorly from the junction of the laminae Has outer fibrous ring consisting of fibrocartilage → 3 processes serve as points of attachment for annulus fibrosus muscles Under compression = flatten/broaden Articulating surfaces of the articular process, Functions: facets, are covered with hyaline cartilage ○ Form strong joints ○ Permit various movements of the vertebral column ○ Absorb vertical shock Alexandria Mignonet M. Uson, RMT, MD LESSON 3 5  LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario REGIONS OF THE VERTEBRAL COLUMN Cervical Region Bodies of cervical vertebrae (C1-C7) are smaller than other vertebra except the coccyx The vertebral arches are larger All cervical vertebrae have two foramina: ○ Vertebral Foramina Largest spinal column House the cervical enlargement of the spinal cord ○ Transverse Foramina Every transverse process contains this which the vertebral artery and its vein and nerves pass through 1. C1 (ATLAS) First vertebra inferior to the skull Ring of bone with anterior and posterior arches and large lateral masses Lacks a body and a spinous process Articulate with occipital condyles to form atlanto-occipital joints → permits to move your head to signify “yes” 2. C2 Axis Peglike process – dens (tooth) or odontoid process → makes the head rotate/side-to-side movement to signify “no” 3. C1-C2 Joint Atlanto-axial joint Some instances of trauma - the dens of axis may be driven into the medulla oblongata of the brain = death 4. C7 Vertebra prominens Large spinous process may be seen and felt at the base of neck Thoracic Region Thoracic Vertebrae → largest and stronger than cervical vertebrae T1 & T2 → long, laterally flattened, and directed inferiorly Articulation between thoracic vertebrae and ribs → vertebrocostal joints Movement of the thoracic region are limited by the attachment of the ribs to the sternum Alexandria Mignonet M. Uson, RMT, MD LESSON 3 6  LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario Triangular bone Formed by the union of five sacral vertebrae Sacral vertebrae: starts to fuse between 16-18 years old; completed by age 30 Posterior to the pelvic cavity; medial to the 2 hip bones Serves as the strong foundation for the pelvic girdle Female sacrum - shorter, wider, more curved than male sacrum Posterior sacral foramina and anterior sacral foramina are connected to allow the passage of nerves and blood vessels Base of sacrum connects with the 5th lumbar vertebra to form lumbosacral joint Lumbar Region Largest and strongest of the unfused bones Amount of body weight supported by the vertebrae increase toward the inferior end of the backbone Spinous processes → quadrilateral shape, thick and broad ○ Well adapted for the attachment of the large back muscles Coccyx Triangular shape Fusion of 4 coccygeal vertebrae (Co1-Co4) Coccygeal vertebrae fuse later than sacral vertebrae between 20-30 years old Female - coccyx pointed inferiorly; male - coccyx points anteriorly Caudal Anesthesia/Epidural Block → relieve pain during labor Thorax Sacrum Entire chest Alexandria Mignonet M. Uson, RMT, MD LESSON 3 7  LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario Thoracic Cage → bony enclosure formed by the sternum, VERTEBRAL COLUMN ribs, and costal cartilage and bodies of thoracic vertebrae Costal cartilage attaches ribs to the sternum Rib Fractures Function: ○ Common chest injury ○ Encloses and protects the organs in the thoracic ○ Ribs tend to break at the point where the and superior abdominal cavities greatest force is applied ○ Provides support for the bones of the upper Dislocated Ribs limbs ○ Common in body contact sports ○ Plays a role in breathing ○ Displacement of a costal cartilage from sternum Separated Ribs Sternum ○ Displacement of rib and its costal cartilage Breastbone Herniated/Slipped Disc Center of the anterior thoracic wall ○ Lumbar region bears much of the weight of the 15 cm/6 in. in length body Consists of three parts: Abnormal Curves of the Vertebral Column ○ Manubrium ○ Lateral bend ○ Body – middle and largest part ○ Scoliosis → lateral bending of the vertebral ○ Xiphoid process – inferior, smallest part column usually in thoracic region Incorrect position of hands during CPR = fracture the ○ Kyphosis → increase in the thoracic curve of the xiphoid process vertebral column ○ Lordosis → increase lumbar curvature Ribs 12 pairs Give structural support to the sides of thoracic cavity Increase - 1st to 7th rib; decrease - 12th rib 1st seven pairs of ribs have an attachment to the sternum by the costal cartilage Ribs that have costal cartilage attached to the sternum → true (vertebrosternal) ribs Remaining 5 pairs → false ribs/vertebrochondral (do not attach to the sternum) 8th, 9th and 10th pairs are attached to one another Spina bifida 11th and 12th pairs → floating ribs/vertebral ○ Congenital defect of the vertebral column Costochondritis → inflammation of costal cartilages Fractures Chiropractic Angina Pectoris → chest pain associated with heart attack ○ Health care professional who is concerned with the diagnoses, treatment, and prevention of mechanical disorders of the muskuloskeletal Craniostenosis ○ Premature closure of cranial sutures during first 18-20 months of life ○ Distorted skull Craniotomy ○ Surgical procedure where cranium is removed Laminectomy ○ Surgical procedure to remove a vertebral lamina Lumbar ○ Narrowing of the spinal canal in the lumbar Spinal Fusion ○ Surgical procedure which two or more vertebrae are stabilized with a bone graft Whiplash injury ○ Injury to the neck region due to severe hyperextension or hyperflexion Alexandria Mignonet M. Uson, RMT, MD LESSON 3 8  LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario Alexandria Mignonet M. Uson, RMT, MD LESSON 3 9  LESSON 3: SKELETAL SYSTEM SCI002 PRELIMS 1ST SEMESTER | AY 2024-2025 | Mr. Roel Del Rosario Alexandria Mignonet M. Uson, RMT, MD LESSON 3 10