22 Cervical Spine Osteology PDF

Cervical spine, cord and nerves and skull osteology Class Year 2, Semester 1 Lecturer DR. VIJAYALAKSHMI S B Department of Anatomy Email id: [email protected] Date 11-11-2024 LEARNING OUTCOMES Describe the structure of cervical vertebrae, esp...

Cervical spine, cord and nerves and skull osteology Class Year 2, Semester 1 Lecturer DR. VIJAYALAKSHMI S B Department of Anatomy Email id: [email protected] Date 11-11-2024 LEARNING OUTCOMES Describe the structure of cervical vertebrae, especially atlas and axis Describe the joints between the vertebrae Describe the vertebral arteries and their course Discuss the cervical spinal nerves Describe the spinal meninges and associate the anatomy with the procedure of a lumbar puncture Describe the osteology of the skull in frontal, posterior, superior and inferior views Describe the cranial fossae VERTEBRAL COLUMN  REGIONAL VERTEBRAE  Functions of the Vertebral Column Protection Spinal Cord and Nerve Roots Many internal organs Base for Attachment Ligaments Tendons Muscles Structural Support for the Head, Shoulders and Thorax Connects upper and lower body Balance and weight distribution Flexibility and Mobility Flexion (forward bending) Extension (backward bending) Lateral flexion (bending to the left and right sides) Rotation (to the left and right) Any combination of the above movements  Curvatures of the Vertebral Column The primary or first-formed curve in the vertebral column is called the KYPHOSIS. Later, secondary curves appear, curved in the opposite direction. Secondary curves develop in the lumbar region as the child begins to sit upright (LUMBAR LORDOSIS), and in the cervical region when it Model begins to hold its head erect MO3 (CERVICAL LORDOSIS). Vertebral column lordosis kyphosis lordosis kyphosis Abnormal curvature of the spine Vertebral canal General structure of vertebrae The VERTEBRAL COLUMN has three Vertebral essential components: arch 1. The VERTEBRAL BODIES and the Vertebral intervertebral discs between them have an body important weight-bearing function: consequently, they increase in size from above down, i.e., from cervical to lumbar. Vertebral 2. The VERTEBRAL ARCHES protect the body contents of the vertebral canal. 3. The VERTEBRAL CANAL contains the spinal cord, its meningeal coverings and blood vessels, and the roots, dorsal root ganglia and most proximal parts of the Vertebral spinal nerves. arch  Spinous process Lamina The Vertebral Arch is composed on each side of a PEDICLE (Latin, pes, a foot) and a LAMINA (Latin, lamina, anything thin Transverse Pedicle or flat; the word ‘laminated’ comes from process the same root) has a SPINOUS PROCESS, which projects posteriorly in the midline has a TRANSVERSE PROCESS on Transverse Superior each side process articular process has SUPERIOR and INFERIOR ARTICULAR PROCESSES, which articulate with those of adjacent vertebrae. Inferior Spinous articular process process  JOINTS IN THE VERTEBRAL COLUMN Or Facet joints Secondary A type of Plane joints: cartilaginous between articular processes joints/symphyses  Intervertebral disc Cartilaginuos Endplate Fibrocartilaginous joints of the vertebral bodies connection of vertebral bodies Vertebral Annular Epiphysis stability and flexibility Body pressure regulation Spinous „water cushion“ function process Intervertebral Disc Vertebral Spinous process Body Annulus fibrosus: Outer zone→ high tensile strength. Fibrous sheath. It connects adjacent annular epiphyses of vertebral bodies Inner zone → fibrocartilage attached to vertebral body cartilaginous endplate Nucleus pulposus: high resilience Gelatinous structure, 80-85% water Ligaments of the vertebral column The easiest approach is to remember that every part of a vertebra is connected to the same parts of the adjacent vertebra by ligaments.  Ligaments of the vertebral column Post longitudinal lig. nuchal Ant longitudinal lig. interspinous Ant longitudinal lig. Ligamenta flava Ligaments of the vertebral column  Ligaments of the vertebral column Longitudinal ligaments Anterior – along anterior vertebral bodies Posterior – along posterior vertebral bodies Ligamentum flavum – between laminae Yellow due to elastin Interspinous ligament Supraspinous ligament Ligamentum nuchae in the neck JC Holland Intervertebral foramina –spinal nerves and blood vessels Emerge or come through here  CERVICAL VERTEBRAE Typical cervical vertebra CERVICAL VERTEBRAE TYPICAL CERVICAL VERTEBRAE ATYPICAL VERTEBRAE – ATLAS (C1) ATYPICAL VERTEBRAE – AXIS (C2) ATYPICAL VERTEBRAE – C7  Atlanto-occipital joint Articular surfaces on the atlas Occipital Atlas Articular surfaces on the occipital bone Atlanto-occipital joint: Pair of synovial condyloid joints  A lateral view of the cervical spine C1 to T1 Movements Atlanto-occipital joint ‘Nodding’ Flexion/Extention Atlantoaxial joint Rotation Open mouth Odontoid radiograph www.ebmconsult.com  VERTEBRAL ARTERY Two Vertebral arteries (L+R) From the subclavian artery Ascend in transverse foramina Enter foramen magnum Release postero-inferior cerebellar artery (PICA) Release posterior and anterior spinal arteries The two vertebral arteries merge into one Basilar artery  CLINICAL CORRELATE Cervical Spine injury In trauma patients, to clear the airway, avoid extending the cervical spine https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3982371/  SPINAL CORD Continuation of the brain stem into the spinal canal Spinal cord extends from the foramen magnum of the base of the skull to lower border of the first lumbar vertebra  Cervical enlargement 3 Meninges Cover the brain and spinal cord Pia Mater Arachnoid Dura Mater Spinal cord ends at L1/L2 vertebral level– Lumbar adult enlargement L3/L4 vertebral level child Subarachnoid space ends at S2 Lumbar puncture - CSF sampling Filum terminale – extension of pia mater to coccyx PROTECTIVE LAYERS OF THE SPINAL CORD Layers: Dura Arachnoid Pia Spaces: Epidural/Extradural Subdural Subarachnoid  CLINICAL CORRELATE Contraindicated ( Don’t do it !!) with raised intracranial pressure (ICP) Lumbar tap (Puncture) – What is it? – Indications? – How it is done – Expected result SPINAL CORD SEGMENTS AND SPINAL NERVES Cervical (8) Thoracic (12) Lumbar (5) Sacral (5) Coccygeal (1) Vertebral level/spinal cord segments Spinal cord segments do not match with the corresponding vertebra Vertebrae Spinal segment Cervical +1 Thoracic 1-6 +2 Thoracic 7-9 +3 Thoracic 10 L1 & 2 Thoracic 11 L3 & 4 Thoracic 12 L5 Lumbar 1 Sacral/coccygeal  Spinal Nerves There are 7 cervical vertebrae, but there are 8 cervical spinal nerves. The 1st emerges between C1 and the base of the skull. The 8 th emerges between C7 and T1. There are 12 thoracic, 5 lumbar and 5 sacral spinal nerves, all emerging below the corresponding vertebrae. There are usually 4 coccygeal vertebrae but only one coccygeal spinal nerve. In the adult, the spinal cord typically ends between L1 and L2. In a very young child, it may extend as far as L4. Below the end of the spinal cord, the lowermost spinal nerves run steeply downwards as the CAUDA EQUINA (Latin, “The Horse’s Tail”), to emerge from their appropriate foramina.  CERVICAL SPINAL NERVES C1 – C7 emerge above their vertebrae There are 8 cervical spinal nerves. C8 emerges below the C7 vertebra All spinal nerves from T1 down come out below their vertebrae. Spinal nerves emerge out of the intervertebral foramina CERVICAL SYMPATHETIC TRUNK Continuous with thoracic trunk Crosses the neck of the first rib Posterior to carotid sheath On prevertebral fascia Three Cervical ganglia: Superior – located at C1 & C2 vertebral level; branches pass to C1 to C4 spinal nerves Middle – located at the level of C6 vertebra; branches pass to C5 and C6 spinal nerves Inferior - named as Stellate ganglion, if merged with T1 ganglion; branches pass to C7 to T1 spinal nerves  Cervical spinal nerves - plexi Cervical plexus (anterior rami C1-C4) Brachial plexus (anterior rami C5-T1) Nerves of the Cervical Plexus Brachial Plexus  Posterior rami of cervical nerves C1- posterior ramus larger than anterior: Suboccipital nerve C2- posterior ramus larger than the anterior: its medial branch is the Great occipital nerve C3- gives off the Third occipital nerve https://www.sciencedirect.com/topics/veterinary- science-and-veterinary-medicine/suboccipital-nerve  ARTERIAL SUPPLY Longitudinally vessels Anterior spinal artery – from vertebral 2 Posterior spinal arteries - from PICA Segmental spinal arteries Anterior and posterior Radicular arteries enter through intervertebral foramina Artery of Adamkiewicz (Eponym) – arises in the lower thoracic or upper lumbar region  VENOUS DRAINAGE Posterior spinal vein Anterior spinal vein Internal vertebral plexus Veins that drain the spinal cord form longitudinal channels Two pairs of veins on each side One midline channel parallels the anterior median fissure – Anterior spinal vein One midline channel passes along the posterior median sulcus – Posterior spinal vein These longitudinal veins drain into the internal vertebral plexus in the extradural space of the vertebral canal.  PRACTICAL REFERENCES QUESTIONS