Spine Anatomy: Bony and Ligamentous Structures PDF

Spine : bony and ligamentous structures Saïd ZAYANE  Introduction 1 : Spine Composition The vertebral column (spine or backbone) is a curved structure composed of 33 bony vertebrae. Vertebrae are interlaced by strong joints (intervertebral discs) and ligaments the spi...

Spine : bony and ligamentous structures Saïd ZAYANE  Introduction 1 : Spine Composition The vertebral column (spine or backbone) is a curved structure composed of 33 bony vertebrae. Vertebrae are interlaced by strong joints (intervertebral discs) and ligaments the spinal cord is the tubular nervous tissue that travels through the vertebral canal of the spine. Posterior View of the SPINE The Five regions Divided into five regions, the spine is part of Cervical C. C7 the axial skeleton and extends from the base of the skull to the tip of the coccyx. Thoracic C. Cervical column : 7 vertebrae Thoracic column : 12 vertebrae Lumbar column : 5 vertebrae T12 Sacrum : 5 fused vertebrae Lombaire C. Coccyx : 4 fused vertebrae L5 Sacrum Coccyx  Posterior Curvatures of Vertebral Column The adult spine has four curvatures: Cervical lordosis (posterior concavity) Anterior Thoracic kyphosis (anterior concavity) Lumbar lordosis Sacral kyphosis 01/10/2024 Lateral View Spine function The spine allows us to twist, bend and sway our trunk in almost any direction. All of these movements are influenced by the joints and ligaments and by thoracic and back muscles. Movements in the cervical and lumbar regions of the spine are freer than the thoracic and sacral ones. The vertebral column also protects the fragile spine cord and helps support the weight of the upper body. Plan of the course 1. Vertebrae 1.1. Typical vertebrae 1.2. Cervical vertebrae 1.3. Thoracic vertebrae 1.4. Lumbar vertebrae 1.5. Sacrum 1.6. Coccyx 2. Joints and Ligaments of the Spine Plan of the Part 1 1. Vertebrae 1.1. Typical vertebrae 1.2. Cervical vertebrae 1.3. Thoracic vertebrae 1.4. Lumbar vertebrae 1.5. Sacrum 1.6. Coccyx Typical vertebrae No two vertebrae are identical. They vary in size and characteristics, especially from one region to the next. However, they all have the following basic structure: Cervical Vertebra Thoracic Vertebra Lumbar Vertebra  Posterior. Vertebral Body (V.B.) The V.B. is the large cylindrical V.B. part located anteriorly that V.B. gives strength to the spine. Anterior. Their size increases from the cervical column to the lumbar column Adjacent vertebral bodies are Disc separated by intervertebral discs. Vertebral arch Pedicle Located posterior to the body. It consists of two pedicles and two laminae. The pedicles contain vertebral Lamina notches (superior, inferior) which form intervertebral foramina. These facilitate the passage of spinal nerves from the spinal cord. Interverbral Foramina The vertebral Foramen and canal Pedicles+laminae (the vertebral arch) + body of each vertebra form a cavity (vertebral foramen V. F. ). The vertebral canal is formed by the superposition of the vertebral V.F. foramina. This canal allows the passage of the spinal cord which lets out the right and left spinal nerves at each level. Vertebral processes 1 There are seven in total all projecting from the vertebral arch: one spinous process (S.P. S.P. posteroinferior), two transverse processes (T.P. posterolateral), T.P. Vertebral processes 2 A.P. Four articular processes (A.P.) : two superior and Articular Facets two inferior A.P. That contain articular facets. Plan of the Part 1 1. Vertebrae 1.1. Typical vertebrae 1.2. Cervical vertebrae 1.3. Thoracic vertebrae 1.4. Lumbar vertebrae 1.5. Sacrum 1.6. Coccyx 2. Joints and Ligaments of the Spine 3. Neurovasculature of the Spine Cervical vertebrae : Common features 1 They are seven cervical vertebra, that form the column of the neck. Located between the skull and the Posterior Cadaveric View of the cervical column thoracic vertebrae They have the smallest and thinnest intervertebral discs. However, they are the most mobile in the entire vertebral column. Lateral View of the cervical column Common features 2 Transverse F. Anterior T. In addition, cervical vertebrae have distinctive features like transverse foramina (T.F.), two tubercles (anterior T., posterior T.) Posterior T. and split (bifid) spinous processes (S.P.) Bifid S.P Superior View of C3 Special features Among the seven cervical vertebrae, three are atypical. The first one : C1, called ATLAS, The second one : C2, called AXIS, And the seventh cervical vertebrae The Atlas = C1 ATLAS The ATLAS (C1) consists of two arches (anterior, posterior) and contains two lateral masses. The masses articulate with the occipital condyles of the skull, supporting its weight. The Four cardinal views of the ATLAS Anterior view Posterior view Lateral view Superior view Anterior Arch of Atlas Anterior View of C1 The anterior arch is the short, curved, anteromedially located It is shorter than the posterior arch. The anterior arch: Superior View of C1 is continuous posterolaterally with both the right and left lateral masses of atlas; Articular Facet consists of the anterior tubercle of with C2 atlas and the articular facet of dens; Anterior tubercle 01/10/2024  Right Lateral Mass of C1 Lateral Mass of the Atlas 1 The lateral masses are the two expanded, oval, laterally located. They are both continuous: anteromedially, with the anterior arch of atlas; Superior View of C1 posteromedially, with the posterior arch of atlas; Lateral masses laterally, each with a transverse process which contain a foramen transversarium. 01/10/2024  Left Lateral Mass Lateral Mass of the Atlas 2 On its corresponding side, each lateral mass of atlas: consists of superior and inferior articular facets and a transverse ligament tubercle; A articulates superiorly with an occipital condyle, forming an atlantooccipital joint; articulates inferiorly with a superior articular process of the axis, forming a lateral atlantoaxial joint. Articular Facets for occipital condyles B A : Superior view of C1 B : Anterior view of C1 Articular Facets for sup. articular process of C2  posterior tubercle of atlas Posterior Arch of Atlas Groove for left vertebral artery The posterior arch is the curved, posteromedially located part of the atlas. It is the longer than the anterior arch is continuous anterolaterally with both the right and left lateral masses of atlas; consists of the posterior tubercle of atlas and both the right and left grooves for vertebral arteries;  Transverse Process of Atlas The transverse processes are the Superior view of C1 two small, laterally projecting processes of the atlas. Transverse process On its corresponding side, each Foramen transversarium transverse process of atlas: consists of anterior and posterior roots that extend from a lateral mass; consists of a foramen transversarium; Foramen Transversum of Atlas The foramina transversaria of the upper six cervical vertebrae allow for the passage of the vertebral arteries and veins, while the foramina transversaria of the seventh cervical vertebra only allows the passage of the accessory vertebral veins. Left Foramen Transversum 01/10/2024 Vertebral Foramen of Atlas 1 The vertebral foramen (V.F.) is the large, centrally located, narrowed, in its anterior part, by V.F. the lateral masses. Its margins are formed: anteriorly, by the anterior arch; laterally, by both the right and left lateral masses; posteriorly, by the posterior arch. 01/10/2024 Vertebral Foramen of Atlas 2 The V.F. of atlas is divided into two areas by the transverse ligament of atlas. The anterior area holds the dens of the axis. The posterior area contributes to the formation of the vertebral canal, which extends throughout the length of the vertebral column. The vertebral canal allows for the passage of the spinal cord, along with its accompanying meninges and vasculature. 01/10/2024 The Axis = C2  Superior View of C2 AXIS Features The AXIS (C2) contains an upwards tooth-like projection (dens or odontoid process) Superior Articular odontoid Facets of C2 and two superior articular process facets. These facilitate articulation with the atlas and head rotation. Anterior View of C2  Apex Dens of Axis Anterior articular The dens (odontoid process or tooth) Facet extends superiorly from the upper aspect of the vertebral body of the axis. It articulates with the anterior arch of atlas, forming the median atlantoaxial joint. Posterior Its Posterior Articular Facet Articular Facet articulates with the Transvers ligament of C1 to allow rotation of the head. Posterior View of C2 Inferior Articular Process of Axis Right Inferior Articular Process The inferior articular processes extend inferiorly from the junctions between the pedicles and laminae. They articulate with the superior articular processes of the third cervical vertebra, forming Left Inferior Articular Process zygapophyseal joints. 01/10/2024  Right Lamina of Axis Lamina of Axis The laminae form the posterolateral parts of the vertebral arch, the posterolateral walls of the vertebral foramen, and their posterior ends unite at the midline. The spinous process extends from the Left Lamina of Axis junction between the two laminae. The laminae of the axis provide attachment sites for the ligamenta flava. 01/10/2024  Right Pedicle of Axis Pedicle of Axis The pedicles are the two short cylindrical processes that form the anterior parts of the vertebral arch, the lateral walls of the vertebral foramen, and connect the vertebral body to the laminae. The superior articular processes extend from the junctions between the pedicles and Left Pedicle of Axis vertebral body, Each pedicle of the axis consists of an inferior vertebral notch. 01/10/2024 Spinous Process of Axis The spinous process is the single, posteriorly projecting process located at the posterior part of the vertebral arch of the axis. It extends from the junction between the two laminae, which itself is found at the midline. The spinous process of the axis is large, bifid and horizontally oriented.  Right Superior Articular Process The Superior Articular Process The superior articular processes extend superiorly from the junctions between the pedicles and vertebral body. The superior articular processes of the axis consist of superior articular facets that face superolaterally. Left Superior Articular Process They articulate with the inferior articular processes of the atlas, forming the lateral atlantoaxial joints.  Right Transverse Process Transverse Process of Axis The transverse processes (T.P.) are the two laterally projecting processes found along the lateral aspects of the vertebral arch of the axis. Their anterior roots extend from the pedicles, while their posterior roots extend from the junctions between the pedicles and laminae. The T.P. of the axis are small, and each consist of a Left Transverse Process foramen transversarium, which provide passage of vertebral artery. The lateral ends of the T.P. provide attachment sites for muscles of the neck and upper back 01/10/2024  Vertebral Body of the Axis The vertebral body (V.B.) is the small, anteriorly located cylindrical part of the axis. The dens axis arise from the superior surface of the V.B. Adjacent vertebral bodies articulate with each other via intervertebral discs, forming the intervertebral symphysis joints.  Vertebral Foramen of Axis The vertebral foramen (V.F.) is the large, triangular, centrally located opening of the axis. Its margins are formed: anteriorly, by the vertebral body; anterolaterally, by both the right and left pedicles; posterolaterally, by both the right and left laminae; posteriorly, by the spinous process. The V.F. of axis contributes to the formation of the vertebral canal (V.C.), which extends throughout the length of the vertebral column. The V.C. allows for the passage of the spinal cord, along with its accompanying meninges and vasculature. 01/10/2024  C1-C2 joint in Anterior View Conclusion for C1-C2 Atloido-axoidian joint. Huge role in head motion : C1-C2 joint in Oblique Rotation View Laterality motion Where the Dens of C2 has a central role Transverse Ligament of C1 The Standard Cervical vertebrae : C7 compared to C3 Seventh Cervical Vertebra Vertebra prominens (C7) has the C2 longest spinous process. C7 It’s the bony point sticking out the most at the back of the neck. Lateral View of the cervical column Right Inferior Articular Process of C3 and C7 The inferior articular processes (inferior zygapophysesextend inferiorly from the laminae. The inferior articular processes of typical cervical vertebrae (C3), or of C7 generally consist of inferior articular facets that face anteroinferiorly. They articulate with the superior articular processes of the vertebra below (respectively C4 and TH1), forming zygapophyseal joints. Right Inferior Articular Process of C3 above and of C7 below Right Laminae of C3 and C7 The laminae are like a crossroads : C3 The transverse and superior articular processes extend from the junctions between the pedicles and laminae, The spinous process extends from the junction between the two laminae, And the inferior articular processes C7 extend inferiorly from the laminae. Overall, the laminae of the vertebral column provide attachment sites for deep back muscles and the ligamenta flava.  Right Pedicles of C3 and C7 C3 The pedicles form the anterior parts of the vertebral arch, the lateral walls of the vertebral foramen, and connect the vertebral body to the laminae. The transverse and superior articular processes extend from the junctions between the pedicles and laminae. Each pedicle consists of superior and inferior vertebral notches. C7 The pedicles of adjacent vertebrae form spaces known as intervertebral foramina, and it is through these foramina that spinal nerves and vessels exit the vertebral column. 01/10/2024  Comparison of Spinous Processes C3 vs C7 The spinous processes (S.P.) of typical cervical vertebrae (T.C.V. : here C3) are generally short and horizontally oriented. These spinous processes can be bifid or nonbifid, depending on the race and sex of an individual (Duray, Morter and Smith, 1999). The spinous process of the seventh cervical vertebra differs from those of the typical cervical vertebrae by having a long spinous C3 process that is not bifid. The seventh cervical vertebra is also known as the vertebra prominens due to the prominent and palpable nature of its spinous process. Both S.P. of C3 and C7 provide attachment sites for the nuchal ligament. 01/10/2024 C7 Right Superior Articular Process of C3 and C7 C3 The superior articular processes (superior zygapophyses) extend from the junction between the pedicles and laminae. The superior articular processes of typical cervical vertebrae (C3) or of C7 consist of superior articular facets that face posterosuperiorly. C7 They articulate with the inferior articular processes of the vertebra above, forming zygapophyseal joints. 01/10/2024 Right Transverse Processes of C3 and C7 The transverse processes of typical C3 cervical vertebrae (C3) or of C7 are small. They each consist of : a foramen transversarium, a groove for spinal nerve, and anterior and posterior tubercles. They provide attachment sites for muscles of the neck and upper back. C7 Vertebral Bodies of C3 and C7 The anterior aspect of the vertebral body (V.B.) is concave, while its posterior aspect, which forms the anterior wall of the vertebral foramen, is flat. Both its superior and inferior surfaces are saddle-shaped. The V.B. of both C3 and C7 consists of: C3 superior and inferior intervertebral surfaces; superior and inferior annular epiphyses; a pair of uncinate processes; vascular foramina. C7 Anatomical relations of C3 and C7 vertebral bodies The vertebral body of the third cervical vertebra provides an insertion site for the vertical part of longus cervicis muscle, as well as attachment sites for the anterior and posterior longitudinal ligaments. Overall, the sizes of the vertebral bodies gradually increase caudally along the vertebral column. Adjacent vertebral bodies articulate with each other via intervertebral discs, forming the intervertebral symphysis joints. In terms of function, each vertebral body provides structural support to the body weight that lies superior to it.  Boundaries of Vertebral Foramina of C3 and C7 The vertebral foramen is the large, triangular, centrally located Its margins are formed: anteriory, by the vertebral body; anterolaterally, by both the right and left pedicles; posterolaterally, by both the right and left C3 laminae; posteriorly, by the spinous process. We can notice here that the vertebral Foramen of C7 is narrower than this of C3. In this aspect C7 is closer to the thoracic vertebrae C7 Plan of the Part 1 1. Vertebrae 1.1. Typical vertebrae 1.2. Cervical vertebrae 1.3. Thoracic vertebrae 1.4. Lumbar vertebrae 1.5. Sacrum 1.6. Coccyx 2. Joints and Ligaments of the Spine 3. Neurovasculature of the Spine Thoracic vertebrae The twelve thoracic vertebrae form the second region of the vertebral column, the thoracic spine (upper back). They play a role in forming the thoracic cage. Thoracic vertebrae contain several distinctive features:  5 4 Distinctive features of thoracic 3 vertebrae Costal facets that articulate with the ribs (1), 2 1 Heart shaped vertebral bodies (2), smaller vertebral foramina (3), Superior View of Th. V. and long and strong spinous (4) and transverse 1 (5) processes which point inferiorly. 1 4 Costal Facets Lateral View of Th. V. The different segments of the thoracic Spine The first four (TH1-TH4) and last four (TH9-TH12) thoracic vertebrae share some characteristics with the cervical and lumbar spine, respectively. The middle four (TH5-TH8) are typical thoracic vertebrae. The adjacent bodies of thoracic vertebrae are separated (or linked) by thicker discs compared to the cervical spine. Comparison of TH1 with TH12 Right Inferior Articular Processes of TH1 and TH2 Extending inferiorly from the laminae, the inferior articular processes of thoracic vertebrae TH1 generally consist of inferior articular facets that face anteriorly and slightly medially. They articulate with the superior articular processes of the vertebra below, forming zygapophyseal joints. 01/10/2024 TH12 Right Lamina of TH1 and TH12 The laminae form the posterolateral parts of the vertebral arch. The transverse and superior articular processes extend from the junctions TH1 between the pedicles and laminae, The spinous process extends from the junction between the two laminae, And the inferior articular processes extend inferiorly from the laminae. TH12  Right Pedicle of TH1 and TH12 The pedicles are the two short, cylindrical processes that project posteriorly from the upper corners of the posterior aspect of the vertebral body of a thoracic vertebra. They connect the vertebral body to the laminae. TH1 Each pedicle consists of superior and inferior vertebral notches. The pedicles of adjacent vertebrae form spaces known as intervertebral foramina, and it is through these foramina that spinal nerves and vessels exit the vertebral TH12 column. Morphologic Features of the Spinous Processes of Thoracic Vertebrae TH1 The spinous process extends from the junction between the two laminae, which TH1 itself is found at the midline. The spinous processes of thoracic vertebrae are generally long, thin, and tapered. They are obliquely oriented in the posteroinferior direction, resulting in adjacent spinous processes overlapping each other. TH12 01/10/2024 Right Superior Articular Processes of TH1 and TH12 The superior articular processes (superior zygapophyses) extend from the junction between the pedicles and laminae. The superior articular processes of TH1 thoracic vertebrae generally consist of superior articular facets that face posteriorly and slightly laterally. They articulate with the inferior articular processes of the vertebra above, forming zygapophyseal joints. 01/10/2024 TH12 Right Transverse Processes of TH1 and TH12 The transverse processes are the two laterally projecting processes that extend from the junction between the pedicles and laminae. The transverse processes of thoracic TH1 vertebrae are generally long, thick, and have expanded lateral ends. All thoracic transverse processes, except those of the eleventh and twelfth thoracic vertebrae, consist of transverse costal facets. 01/10/2024 TH12  Vertebral Body of Thoracic Vertebra The vertebral body is the anteriorly located cylindrical part of the thoracic vertebra. When viewed from above, it appears heart-shaped. Its anterior aspect is concave, while its posterior aspect, which forms the anterior wall of the vertebral foramen, is flat (or slightly concave). Superior View of Thoracic TH1 Vertebra TH12 Common and distinctive features of of Thoracic Vertebral Bodies It is connected to the vertebral arch via two pedicles. It consists of: superior and inferior intervertebral surfaces; superior and inferior annular epiphyses; vascular foramina; a pair of superior costal facets from TH1 to TH10; a pair of inferior costal facets from TH1 to TH10; Bodies of eleventh and twelfth thoracic vertebra display only one pair of costal facets 01/10/2024 Muscles and ligaments attaches provided by Bodies of Thoracic Vertebrae The vertebral bodies of all thoracic vertebra provide attachment sites for the anterior and posterior longitudinal ligaments, and the radiate ligament of the head of the rib. When the vertebral body of the twelfth thoracic vertebra provides, in addition, an origin site for the psoas major and psoas minor muscles,  Common features of Vertebral Bodies of Thoracic Vertebrae The sizes of the vertebral bodies gradually increase caudally along the vertebral column. Adjacent vertebral bodies articulate with each other via intervertebral discs, forming the intervertebral symphysis joints. In terms of function, each vertebral body provides structural support to the body weight that lies superior to it. 01/10/2024  Vertebral Foramina of TH1 and TH12 The vertebral foramen is the small, circular, centrally located opening of the thoracic vertebra. Its margins are formed: TH1 anteriorly, by the vertebral body; anterolaterally, by both the right and left pedicles; posterolaterally, by both the right and left laminae; posteriorly, by the spinous process. 01/10/2024 TH12 Features of Thoracic vertebral Foramina compared to other regions of the spine The size and shape of the vertebral foramina in the different regions of the vertebral column are as follows: cervical vertebral foramina are the largest and triangular; thoracic vertebral foramina are the smallest and circular; lumbar vertebral foramina are intermediate in size and triangular. Cervical Vertebra Thoracic Vertebra Lumbar Vertebra  Anterior, lateral, superior and posterior views of Thoracic Vertebrae As a Conclusion of this chapter concerning Thoracic vertebrae, here they are different views of these vertebrae to highligh their features that differentiate them from other groups of vertebrae : like STURDY Spinous and transverse processes. The orientation of the spinous processes, the form of the body and narrowness of the vertebral foramen Plan of the part 1 1. Vertebrae 1.1. Typical vertebrae 1.2. Cervical vertebrae 1.3. Thoracic vertebrae 1.4. Lumbar vertebrae 1.5. Sacrum 1.6. Coccyx 2. Joints and Ligaments of the Spine 3. Neurovasculature of the Spine  The First Lumbar Vertebra L1 Compared to the Fifth one L5  The Lumbar Column (or Lower back) It’s made of 5 vertebrae, having their specific form : They don’t have, as cervical vertebrae foramen transversium They differe from thoracic vertebrae principally with the pedicle which is thick and strong, and the orientation of the articular facets They could present transition abnormalities with the thoracic column or with the Sacrum 01/10/2024  Other Features of Lumbar vertebrae They have the largest vertebral bodies in the entire vertebral column, a feature that facilitates weight bearing. L5 is the largest vertebra of the entire human body – it supports and transmits body weight to the base of the sacrum. Laminae, as pedicles, are thick and strong. Their spinous processes are short and sturdy for the attachment of strong lumbar muscles. The lumbar spine also contains accessory and mammillary processes. The spinal cord terminates as the conus medullaris (medullary cone) at the level of the L1/L2 vertebra.  Features and Anatomical Relations of L1 The first lumbar vertebra (vertebra L1) is the smallest of the five lumbar vertebrae of the vertebral column. It is classified as an irregular bone and includes the following bony features: - parts: vertebral body, laminae, pedicles, superior and inferior articular processes, and transverse and spinous processes; Arterial Supply: Lumbar arteries. 01/10/2024 Many features ofSpinous Process of Lumbar Vertebrae The spinous processes of lumbar vertebrae are generally short, thick, and blunt. They are more horizontally oriented than other vertebrae Provide attachment sites for L1 intrinsic back muscles, thoracolumbar fascia, and the supraspinous and interspinous ligaments. L5 01/10/2024  Superior View of Vertebral Body of a Lumbar Vertebra Thoracic Vertebra When viewed from above, the Lumbar Vertebral body appears kidney-shaped. Its anterior aspect is concave, while its posterior aspect, which forms the anterior wall of the vertebral foramen, is flat. The sizes of the vertebral bodies gradually increase caudally along the L1 vertebral column. L5 Constitution of Vertebral Body of a Lumbar Vertebra It is connected to the vertebral arch Annular epiphyse via two pedicles, which extend from the upper corners of its posterior aspect. It consists of: superior and inferior intervertebral surfaces; superior and inferior annular epiphyses; vascular foramina vascular foramina. 01/10/2024  In Conclusion of this Chapter The Lumbar Column is, as well as the Cervical Colomn, the mobile part of the spine, when the thoracic column and the sacrum are fixed. Lateral View of Lumbar Vertebra The Lumbar column allows rotations and Tilt of the trunk This mobility is usefull, but could be source of pain : Back pain is among the firsts reason to consult Doctors in the word. Lumbar Spine pathology is thus frequent : Disc Herniae, Osteoarthritis or Facet syndrom…. Superior View of Lumbar 01/10/2024 Vertebra Plan of the Part 1 1. Vertebrae 1.1. Typical vertebrae 1.2. Cervical vertebrae 1.3. Thoracic vertebrae 1.4. Lumbar vertebrae 1.5. Sacrum 1.6. Coccyx 2. Joints and Ligaments of the Spine Sacrum The sacrum consists of five sacral vertebrae fused together. It is located between the lumbar spine (lumbosacral angle) and the coccyx and forms part of the pelvis. Its main role is to transmit the entire weight of the upper body to the pelvis in order to reach the lower limbs.  Median part Features of the Sacrum Lateral parts The sacrum has a base, an apex, and three 1 surfaces (pelvic, posterior, lateral). Within its center is the sacral canal which is the continuation of the spinal canal. Anterior View The sacral canal contains the cauda equina of the spinal cord. Sacral foramina (anterior (1), posterior (2)) 3 allow for the exit of the spinal nerves. 4 2 The sacral crests (median (3), intermediate 5 (4), lateral (5) )represent the fused processes of the sacral vertebrae. Posterior View  Superior View The Sacral Canal and Sacral Hiatus 1 The sacral canal (1) is the narrow channel found within the sacrum. It is the inferior continuation of the vertebral canal and is collectively formed by the vertebral foramina of the sacral vertebrae. The sacral hiatus (2) is the inverted U-shaped Inferior View gap found between the sacral cornua on the dorsal surface of the sacrum. The sacral hiatus forms the caudal opening of the sacral canal and transmits the fifth sacral and coccygeal nerves. 2 01/10/2024 Plan of the Part 1 1. Vertebrae 1.1. Typical vertebrae 1.2. Cervical vertebrae 1.3. Thoracic vertebrae 1.4. Lumbar vertebrae 1.5. Sacrum 1.6. Coccyx 2. Joints and Ligaments of the Spine Coccyx 1 The tailbone (coccyx) articulates with the sacrum and consists of three to four fused coccygeal vertebrae. It has two surfaces (pelvic, posterior), short transverse processes, and coccygeal cornua. The coccyx is a point of attachment for the gluteus maximus muscle and coccygeal muscles. Coccyx or tail Bone It’s an irregular bone, that continue the sacrum Constituted by the fuse of 4 coccygeal vertebrae. It has : An Apex, A base, Pelvic and dorsal surfaces, coccygeal cornu, and transverse processes. Arterial Supply: Median sacral artery. 01/10/2024 Anterior and Posterior View of the Sacrococcygeal complexe 01/10/2024 Plan of the Part 1 1. Vertebrae 1.1. Typical vertebrae 1.2. Cervical vertebrae 1.3. Thoracic vertebrae 1.4. Lumbar vertebrae 1.5. Sacrum 1.6. Coccyx 2. Joints and Ligaments of the Spine Part 2: Joints and ligaments of the Spine Introduction The joints and ligaments of the spine are the junction elements between the differents vertebral parts. They ensure their cohesion and allow them to move without risk for the spinal cord that the bony and ligamentous column protects Plan of Part 2 : Joints and Ligaments of the Spine 1. Situation : Lumbar Column 5. Supraspinous ligament as example 6. Intertransvers ligaments 2. The Discs 7. Anterior Longitudinal 2.1. Annulus Fibrosis liament 2.2. Intervertebral Symphisis 8. Posterior Longitudinal 3. Ligamenta Flava liament 4. Interspinous ligaments 9. Importance of the middle vertebral segment. Plan of Part 2 : Joints and Ligaments of the Spine 1. Situation : Lumbar Column 5. Supraspinous ligament as example 6. Intertransvers ligaments 2. The Discs 7. Anterior Longitudinal 2.1. Annulus Fibrosis liament 2.2. Intervertebral Symphisis 8. Posterior Longitudinal 3. Ligamenta Flava liament 4. Interspinous ligaments 9. Importance of the middle vertebral segment. Flexibility of the Spine The superior articular processes articulate with the Superior articular inferior articular processes Facet of L2 of the vertebra above, forming zygapophyseal Zygapophyseal joints. joint These joints, enclosed by a capsule, participate, with the spine ligaments, to the flexibility of the column  Spine Stability Anteriorly the discs, and posteriorly interspinous and supraspinous Interspinous Zygapophyseal ligaments ensure the link joint ligament between the stacked vertebrae They provide, associated Intervertebral to ligamenta flava and the disc Supraspinous zygapophyseal joints, the Ligamenta Flava ligament stability of the spine  Anulus Fibrosus and Nucleus Pulposus : Anatomical Relations and Function The anulus fibrosus is the outer component of the intervertebral disc. They insert into the epiphyseal rim on the outer perimeter of the vertebral bodies. Function : The anulus fibrosus aids in the structural integrity of the vertebral column. The intervertebral discs are made up of an inner nucleus pulposus and an outer, narrower lamellated annulus fibrosus, while the vertebral end plates are bi-layered hyaline cartilages. The intervertebral symphyses are thickest in the lumbar region, and thinnest in the upper thoracic region.  Ligamenta Flava Interspinous and supraspinous ligaments The ligamenta flava (L.F.) are paired structures that adjoin the lamellae of adjacent vertebral foramina. I.S.L. Function : The L.F. keep adjacent laminae together and prevent hyperflexion. The interspinous ligaments (I.S.L.) connect adjacent spinal processes. They extend from the ligamenta flava, anteriorly, to the supraspinous ligament S.S.L. (S.S.L.) posteriorly, at the apex of the spinous process. Ligamenta Function : These ligaments aid in the stability of Flava the lumbar vertebrae, limit hyperflexion. Anterior and Posterior Longitudinal Ligament 1 Anterior Longitudinal Ligament (1) descends along the anterior surfaces of the vertebral bodies, joining the anterior part of vertebral bodies and discs Function : The anterior longitudinal ligament prevents hyperextension of the vertebral column The posterior longitudinal ligament (2) descends within the vertebral canal along the posterior aspect of the 2 vertebral bodies and intervertebral discs. Function : This ligament prevents hyperflexion of the vertebral column NB: For both, the fibers have particularly strong attachments to the annulus fibrosus of the intervertebral discs. Plan of Part 2 1. Situation : Lumbar Column 5. Supraspinous ligament as example 6. Intertransvers ligaments 2. The Discs 7. Anterior Longitudinal 2.1. Annulus Fibrosis liament 2.2. Intervertebral Symphysis 8. Posterior Longitudinal 3. Ligamenta Flava liament 4. Interspinous ligaments 9. Importance of the middle vertebral segment Importance of the middle vertebral segment Middle vertebral segment (M.V.S.): Posterior wall of the vertebral bodies, intevertebral disc and the posterior longitudinal ligament Pedicles laminae and ligamenta flava Intertransverse ligaments and the anterior parts of the interspinous ligaments The spinal cord and the area of the nerves’ exit are surronde by the M.V.S. GENERAL CONCLUSION There are Five segments of vertebrae that altern, when seen laterally, Lordosis and kyphosis curvatures. In the cervical, thoracic and Lumbar segments, the vertebrae present commun and special features and structures All the vertebrae present a central vertebral foramen. The superposition of these foramen constitute the vertebral canal that provides passage for the spinal cord til L2, and the lower spinal nerves below this level Laterally, the interevertebral foramen give passage for the spinal nerves, two per level, one right and one left.