Cranial and Vertebral Osteology PDF

CRANIAL AND VERTEBRAL OSTEOLOGY DR NADINE RAMPF | PHD [email protected] LECTURE OUTLINE Cranial osteology 04 Neuro- and viscerocranium 06 Major landmarks and suture 09 Cranial fossae and foramina 1...

CRANIAL AND VERTEBRAL OSTEOLOGY DR NADINE RAMPF | PHD [email protected] LECTURE OUTLINE Cranial osteology 04 Neuro- and viscerocranium 06 Major landmarks and suture 09 Cranial fossae and foramina 19 Neonatal skull 23 Vertebral osteology 25 General vertebral structures and regional characteristics 27 Joints and ligaments 33 02 OBJECTIVES Identify and name the bones of the skull (neurocranium and viscerocranium) Identify and name structures found on the lateral, inferior, superior, anterior and posterior views of the skull Identify and name the parts, and describe the osteology of the cranial fossae and skull base Identify and name the skull sutures and landmarks Discuss the differences/similarities between skulls of the adult and newborn and identify and name the main fontanelles Identify and name the parts of vertebrae from different regions in the vertebral column, and describe the osteology of the vertebral column, vertebral canal and associated ligaments 03 LECTURE OUTLINE Cranial osteology Neuro- and viscerocranium Major landmarks and suture Cranial fossae and foramina Neonatal skull Vertebral osteology General vertebral structures and regional characteristics Joints and ligaments 04 INTRODUCTION The cranium consists of two parts: Neurocranium The bony case of the brain and cranial meninges containing the proximal parts of cranial nerves and brain vasculature Viscerocrocranium The facial skeleton forming the anterior part of the cranium consisting of the bones surrounding the mouth, nose and most of the orbits 05 LECTURE OUTLINE Cranial osteology Neuro- and viscerocranium Major landmarks and suture Cranial fossae and foramina Neonatal skull Vertebral osteology General vertebral structures and regional characteristics Joints and ligaments 06 NEUROCRANIUM 07 VISCEROCRANIUM Inferior nasal conchae Palatine bone 08 LECTURE OUTLINE Cranial osteology Neuro- and viscerocranium Major landmarks and suture Cranial fossae and foramina Neonatal skull Vertebral osteology General vertebral structures and regional characteristics Joints and ligaments 09 MAJOR LANDMARKS Vertex The midline bony landmark at the most superior part of the calvaria in the standard Lambda anatomical position, near the midpoint of The point where the Bregma the sagittal suture (i.e. between the bregma lambdoid suture and The junction of the coronal and sagittal and lambda). sagittal sutures meet is sutures. This junction indicates the called the lambda.. position of the anterior fontanelle in the foetal skull. Pterion The point of articulation between four bones: Glabella the frontal bone, greater wing of the A smooth raised sphenoid bone, elevation on the external parietal bone, and surface of the frontal squamous part of bone, between the the temporal bone. superciliary arches. Basion Asterion The median (midline) point The mastoid part of the of the anterior margin of temporal bone the foramen magnum. The articulates with the apical ligament attaches parietal and occipital to it. bones at the parietomastoid and Inion Nasion occipitomastoid The inion is the tip of the The point of sutures. The junction external occipital junction between between these sutures protuberance, the the internasal and and the lambdoid midline bony Opisthion the frontonasal suture is termed the asterion. prominence in the occipital bone. The median (midline) sutures. point of the posterior margin of the foramen magnum. 10 MAJOR SUTURES Squamomastoid Suture Located along the superior border of the Coronal Suture squamous part of the temporal bone. It overlaps The suture that forms the junction and joins with the lower border of the parietal between the frontal bone and the bone. It begins anteriorly at the pterion, and two parietal bones, and that terminates posteriorly at the parietal notch, where determines the coronal plane of the it continues as the parietomastoid suture*, body. between the mastoid part of the temporal bone Metopic Suture and the parietal bone. A vertical fibrous joint that divides the two halves of the frontal bone and is present in a newborn. This suture runs through the midline across the frontal bone from the nasion to the bregma, although it may often be incomplete. * Lambdoid Suture Sagittal Suture The lambdoid suture is the joint between the occipital and parietal The sagittal suture is the point in bones. the midline of the cranial roof where the medial borders of the two parietal bones articulate. 11 FACIAL ASPECT Supra-Orbital Formen (Notch) Supraorbital vessels Superior Orbital Fissure Oculomotor nerve Trochlear nerve Abducens nerve Features Ophthalmic nerve Frontal bone Ophthalmic veins Zygomatic bones Orbits Inferior Orbital Fissure Nasal region Infra-orbital vessels Maxillae Zygomatic nerve Mandible Infra-Orbital Formen Zygomaticofacial Formen Infra-orbital nerve and Zygomaticofacial nerve vessels Mental Formen Inferior alveolar vessels 12 PARANASAL SINUSES Frontal Sinuses Paired sinuses that lie within the frontal bone, Ethmoid Sinuses above and behind the superciliary arch. They A series of air cells within the ethmoid bone that communicate with the nasal cavity. communicate with the sphenoidal sinus and the nasal cavity. Sphenoid Sinuses Located in the body of the sphenoid bone, they sometimes communicate with the ethmoidal sinuses. Maxillary Sinuses Located in the cheeks within the maxillae, they communicate with the cavities via variable foramina. 13 LATERAL ASPECT Features Neurocranium Temporal fossa Superior Temporal Line External acoustic meatus Inferior Temporal Line Mastoid process Viscerocranium Infratemporal fossa Zygomatic arch Lateral aspects of the maxilla and mandible Temporal Fossa Boundaries Mastoid Superior: Superior Process temporal line Posterior: Inferior temporal line External Acoustic Meatus Anterior: Frontal and Sound waves zygomatic bones Inferior: Zygomatic arch Infratemporal Fossa Irregular space inferior and deep to zygomatic arch, and mandible and posterior 14 to the maxilla OCCIPITAL ASPECT Features Occiput The convex posterior protuberance of the squamous part of the occipital bone Parietal bones Superior Nuchal Line Mastoid part of temporal bones External Occipital Protuberance Inferior Nuchal Line 15 SUPERIOR ASPECT Frontal Bone Coronal Suture Bregma Parietal Foramen Sagittal Suture Small, inconsistent apertures Paired foramina may be present Highly variable and sometimes absent Transmit parietal emissary veins that Parietal Bone drain into the superior sagittal sinus and occasionally a branch of the occipital artery When both parietal foramina are present, the point along the sagittal suture that is intersected by an Lambdoid Suture imaginary line connecting the two parietal foramina is called the obelion Occipital Bone Lambda 16 EXTERNAL SURFACE OF CRANIAL BASE Features Alveolar arch and palatine processes of the maxillae Palatine bones Sphenoid Vomer Temporal bones Occipital bones 17 INTERNAL SURFACE OF CRANIAL BASE Anterior Anterior Cranial Fossa A depression formed by the frontal, ethmoid, and sphenoid bones. It is occupied mainly by the frontal lobes of the cerebral hemispheres of the brain Middle Cranial Fossa Middle A depression formed by the sphenoid and temporal bones. The central part is occupied mainly by the pituitary gland. The lateral parts contain the temporal lobes of the cerebral hemispheres of the brain Posterior Poterior Cranial Fossa A depression formed by the occipital and temporal bones. It is occupied by the lowest part of the midbrain, pons, cerebellum, and medulla oblongata 18 LECTURE OUTLINE Cranial osteology Neuro- and viscerocranium Major landmarks and suture Cranial fossae and foramina Neonatal skull Vertebral osteology General vertebral structures and regional characteristics Joints and ligaments 19  CRANIAL FOSSAE Borders Features Relations Content Anterior: frontal bone Frontal crest inner surface frontal Inferior: orbit Frontal lobes of Cranial Fossa Lateral: frontal bone bone Inferior to cribriform plate: nasal brain Anterior Floor: orbital plates of the frontal bone, crista Crista galli in midline cavity Olfactory bulbs & galli, cribriform plate of the ethmoid bone, Cribriform plate in midline Posteromedial: optic chiasm, tracts lesser wings of the sphenoid bone Anterior and posterior ethmoidal pituitary gland Posterior: foramina Posterolateral: temporal lobes of Central: chiasmatic groove between optic the brain foramina, anterior clinoid processes Midline: falx cerebri attachment to Lateral: lesser wings of the sphenoid bone crista galli Anterior: lesser wings of the sphenoid, Superior orbital fissure Anterior: posterior aspect of the Temporal lobes Cranial Fossa anterior clinoid processes, chiasmatic groove Foramina rotundum, ovale orbit Trigeminal Posterior: superior borders of the petrous spinosum Posterior: petrous bone with ganglion Middle bone, dorsum sellae Foramen lacerum middle and inner ear cavities Cavernous sinus Trigeminal impression Lateral: squamous part of the temporal bone, Posterior clinoid processes Lateral: grooves for middle greater wings of the sphenoid bone Groove for superior petrosal sinus meningeal artery Floor: body of the sphenoid bone, greater Carotid canal Midline: body of the sphenoid wing of the sphenoid bone Body of sphenoid bone bone with cavernous sinuses and Sella turcica with hypophyseal pituitary gland fossa Anterior: clivus, basilar part of occipital bone Foramen magnum Anterior: petrous bone with middle Brainstem Cranial Fossa Posterior: squamous part of the occipital Internal acoustic meatus, jugular and inner ear cavities Cerebellum bone foramen, hypoglossal canal Lateral: grooves with transverse Posterior Lateral: petrous and mastoid parts of the Basilar part of the occipital bone sinuses, sigmoid sinuses temporal bone, lateral part of the occipital / Clivus Superior: tentorium cerebelli bone Groove for transverse sinuses, Floor: foramen magnum, cerebellar fossa sigmoid sinuses Internal occipital protuberance Cerebellar fossa 20 Source: https://www.netterimages.com/cranial-base-superior-view-labeled-cochard-imaging-1e-61987.html CRANIAL FORAMINA INTERNAL Ethmoid bone Frontal bone Ethmoid bone Lies between the lesser Ethmoid bone and greater wing of the sphenoid bone Lesser wing of sphenoid bone Greater wing of the Greater wing of sphenoid bone sphenoid bone Temporal bone Greater wing of the sphenoid bone Temporal bone Occipital bone Occipital bone Occipital bone 21 Source: https://next.amboss.com/us/article/vK0ARS?q=the+skul&m=IiYYGK#Z42951d3ed62c1b6987f856e87d8e3c56l CRANIAL FORAMINA EXTERNAL 22 Source:https://next.amboss.com/us/article/vK0ARS?q=the+skul&m=qiYCsK#Z42951d3ed62c1b6987f856e87d8e3c56 LECTURE OUTLINE Cranial osteology Neuro- and viscerocranium Major landmarks and suture Cranial fossae and foramina Neonatal skull Vertebral osteology General vertebral structures and regional characteristics Joints and ligaments 23  NEONATAL SKULL An infant's neurocranium consists of five separate bones (two frontal bones, two parietal bones, and one occipital bone) held together by connective tissue sutures This allows for stretching and deformation of the skull to facilitate birth and accommodate the brain's growth at a faster rate than the surrounding bone The larger areas of connective tissue that arise at the gaps between the bone plates are called “fontanelles” Posterior fontanelle Anterior fontanelle Sphenoidal fontanelles Mastoid fontanelles Source: https://www.coursehero.com/sg/anatomy-and-physiology/development-of-the-cranium/ 24 LECTURE OUTLINE Cranial Osteology Neuro- and viscerocranium Major landmarks and suture Cranial fossae and foramina Neonatal skull Vertebral osteology General vertebral structures and regional characteristics Joints and ligaments 25  VERTEBRAL COLUMN Consists of 33 irregular bones connected in such a way that a flexible, curved structure results Five different regions, each characterized by different vertebral structure Cervical (C1 - C7) Thoracic (T1 - T12) Lumbar (L1 - L5) Sacral (S1 - S5) Coccyx Four curvatures when viewed from the side Cervical and lumbar = concave posteriorly Thoracic and sacral = convex posteriorly Gives vertebral column "S" or sigmoid shape Increases resilience and flexibility Functions Protection Support Forms the central axis of the body Movement and postural roles Source:https://quizlet.com/101140747/mcb-245-practical-2-w-pictures-flash-cards/ 26 LECTURE OUTLINE Cranial osteology Neuro- and viscerocranium Major landmarks and suture Cranial fossae and foramina Neonatal skull Vertebral osteology General vertebral structures and regional characteristics Joints and ligaments 27 GENERAL VERTEBRAL STRUCTRE All vertebrae share a basic common structure Forms the anterior part of each vertebra It is the weight-bearing component Superior and inferior aspects of the vertebral body are lined with hyaline Forms the lateral and posterior aspect cartilage of each vertebra Adjacent vertebral bodies are In combination with the vertebral body, separated by a fibrocartilaginous the vertebral arch forms an enclosed intervertebral disc hole – the vertebral foramen The foramina of all the vertebrae line up to form the vertebral canal, which encloses the spinal cord Source:https: https://teachmeanatomy.info/back/bones/vertebral-column/ 28 VERTEBRAL ARCHES The vertebral arches have several bony prominences, which act as attachment sites for muscles and ligaments Spinous Process Each vertebra has a single spinous process, centred posteriorly at the point of the arch Pedicles Lamina Connect the transverse and Connect the vertebral body to spinous processes the transverse processes Articular Process Transverse Process Form joints between one vertebra and its Each vertebra has two transverse processes, which superior and inferior counterparts. The extend laterally and posteriorly from the vertebral body. articular processes are located at the In the thoracic vertebrae, the transverse processes intersection of the laminae and pedicles articulate with the ribs Source:https: https://teachmeanatomy.info/back/bones/vertebral-column/ 29 REGIONAL VERTEBRAL CHARACTERISTICS Cervical (3 - 7) Thoracic Lumbar Small and oval Larger than cervical Massive Body Wide side to side Heart-shaped Kidney-shaped Bears two costal facets Short Long and sharp Short and blunt Spinous process Bifid (except C7) Projects inferiorly Projects directly posteriorly Projects directly posteriorly Large Circular Triangular Vertebral foramen Triangular Contain foramina Bear facets for ribs (except T11 Thin and tapered Transverse processes and T12) Superior facets directed Superior facets directed Superior facets directed Superior and inferior superoposteriorly posteriorly posteromedially (or medially) articular processes Inferior facets directed Inferior facets directed Inferior facets directed inferoanteriorly anteriorly anterolaterally (or laterally) Flexion and extension Rotation Flexion and extension Lateral flexion Lateral flexion is possible but Some lateral flexion Movements allowed Rotation restricted by ribs Rotation prevented Spine region with the greatest Flexion and extension limited range of movement Source:https://www.pinterest.com/pin/464926361534183430/ 30  ATLAS AND AXIS Specialized to support and stabilize the cranium while permitting head movement Atlas (C1) No vertebral body No spinous process Large, round vertebral foramen bounded by anterior and posterior arches Axis (C2) Resembles inferior cervical vertebrae except for the presence of the prominent dens on the superior surface of the body Source:https: https://teachmeanatomy.info/neck/bones/cervical-spine/ 31 POSTERIOR SACRUM AND COCCYX The sacrum is a single bone that consists of the fused components of five sacral vertebrae. These vertebrae begin fusing shortly after puberty and, in general, are completely fused at age 25–30 ANTERIOR The sacrum protects the reproductive, digestive, and urinary organs Through paired joints, the sacrum attaches the axial skeleton to the paired hip bones of the appendicular skeleton The small coccyx begins as three to five separate coccygeal vertebrae. They typically begin fusing into a single bone by age 26 Each coccygeal cornu (plural, cornua) curves to meet the sacral cornu superior to it The coccyx provides an attachment site for ligaments and a muscle that constricts the anal opening Source:https://teachmeanatomy.info/pelvis/bones/sacrum/ and https://teachmeanatomy.info/pelvis/bones/coccyx/ 32 LECTURE OUTLINE Cranial osteology Neuro- and viscerocranium Major landmarks and suture Cranial fossae and foramina Neonatal skull Vertebral osteology General vertebral structures and regional characteristics Joints and ligaments 33 JOINTS AND LIGAMENTS Ligamentum Flavum Extends between lamina of adjacent vertebrae Anterior Intertransverse Ligament Longitudinal Ligament Extends between transverse processes *Not shown on this image Run the full length of the vertebral column Thick and prevents hyperextension of the vertebral column Interspinous Ligament Join the spinous processes of adjacent vertebrae Attaches between processes Posterior Longitudinal Ligament Supraspinous Ligament Run the full length of the vertebral column Join the spinous processes of adjacent vertebrae Weaker than the anterior longitudinal Attaches to the tips ligament and prevents hyperflexion Source: https://teachmeanatomy.info/neck/bones/cervical-spine/ 34  THANK YOU FOR YOUR ATTENTION Content for this lecture: Chapter 4 and 5 | Snell's Clinical Neuroanatomy, 8th Edition