Topic 2 The Back PDF

Topic 1: The Back Presented by: Winston Lee, PTRP The Vertebral Column Functions: SIRENA Supports the head Important attachment for muscles Rib attachment Encloses and protects the spinal cord Nagprovide ng flexibility and mobility of the trunk Ability to transmit weight of head and b...

Topic 1: The Back Presented by: Winston Lee, PTRP The Vertebral Column Functions: SIRENA Supports the head Important attachment for muscles Rib attachment Encloses and protects the spinal cord Nagprovide ng flexibility and mobility of the trunk Ability to transmit weight of head and body to the LE The Vertebral Column Composition: Cervical: 7 Thoracic: 12 Lumbar: 5 Sacrum: 5 → 1 (fused in adulthood) Coccyx: 4 → 1 (fused in adulthood) Total: 33 (pediatric), 26 (adult) Typical Vertebra Typical Vertebra (Let’s Get Physical ♪) C3-C6 T5-T8 L1-L4  Characteristics of a Typical Vertebra Parts Cervical Thoracic Lumbar Largest; Vertebral Body Small Medium; Heart-shaped Bean/Kidney- shaped Long and inclined Short, flat and Spinous Process Short and bifid downwards quadrilateral Transverse foramen (passes the vertebral artery, Transverse Process (+) costal pits/facets Conical vertebral vein and sympathetic nerves) Vertebral Foramen Largest and triangular Smallest and circular Triangular Superior: Posterior and Superior: Superior and Facet Joints lateral Superior: Medial posterior Orientation Inferior: Anterior and Inferior: Lateral Inferior: Inferior and anterior lateral Facet Joints 45° 60° 90° Inclination  Characteristics of the Atypical Vertebra Cervical Thoracic Lumbar C1 (Atlas): T1: L5: stout o no body, no spinous process o Spinous process is horizontal transverse o Costal facets located on the superior edge of vertebral body process C2 (Axis/Epistropheus): o (+) odontoid process/dens, T2-T4: creates a pivot joint o spinous process is almost horizontal o large bifid spinous process o Short transverse process T9: o (+) tubercles on transverse process C7: o vertebral prominence T10: o long non-bifid spinous o (+) tubercles process o costal facets are located on the lateral aspect of the vertebral o small or no transverse body foramen T11-T12: o (+) tubercles o costal facets are located on the outer aspect of the pedicle Characteristics of the Atypical Vertebra  Sacrum consists of five rudimentary vertebrae fused together to form a wedge-shaped bone The anterior and upper margin of the first sacral vertebra bulges forward as the posterior margin of the pelvic inlet and is known as the sacral promontory  Coccyx consists of four vertebrae fused together to form a single, small triangular bone that articulates at its base with the lower end of the sacrum  Joints Atlanto-Occipital Joint also known as YES joint Type: condyloid joint 50% flexion-extension Atlanto-Axial joint also known as NO joint Type: Pivot/trochoid joint 50% rotation Joints Intervertebral Discs “shock absorbers” of the spine Capable of withstanding compressive torsional and bending loads Role is to bread and distribute loads in vertebral column and restrain excessive motion in vertebral segment Intervertebral Discs Two regions of Vertebral Disc: Nucleus Pulposus: Gel-like mass in center of disc under pressure such that it preloads disc 80-90% water, 15-20% collagen, 25% of vertebral column height (+) abundant in proteoglycans: imbibes water, absorbs pressure Annulus Fibrosus: 50-60% collagen Lamellae: protein that crisscross by 30° Sharpey’s fibers (results to herniated disc if damaged) Ligaments Intersegmental Ligaments: Global Stability Anterior Longitudinal Ligament: attached anterior of vertebral body; prevents hyperextension Posterior Longitudinal Ligament: attached posterior of vertebral body inside spinal canal, prevents flexion; inferior continuation of tectorial membrane Tapers in the lumbar region, incomplete below L2: common site for disc herniation Supraspinous Ligament: connects the tips of spinous process from C7-sacrum; inferior continuation of ligamentum nuchae Ligaments Intrasegmental Ligaments: Segmental Stability Ligamentum Flavum (yellow ligament): connects adjacent lamina (flavor = lami na) Ligamentum Nuchae: connects the tip of spinous process from C7-occiput; superior continuation of supraspinous ligament in cervical region Interspinous Ligament: connects adjacent spinous process Intertransverse Ligament: connect adjacent transverse process  Ligaments Other Ligaments (Cervical): Alar Ligaments: attaches from the lateral lip of the foramen magnum to the transverse area of the atlas, limits skull and atlas rotation on axis Anterior Axial Accessory (AAA) Ligament: from transverse process of atlas to the axis; assists the alar ligament Transverse Ligament: holds the dens in place Apical Ligament: from anterior surface of foramen magnum to apex of dens Vertical Ligament: from anterior of foramen magnum to the body and/or base of the dens Cruciform Ligament: cross-shaped; transverse + vertical ligament Ligaments  Nerve Supply of Vertebral Joints Innervated by the small meningeal branches of each spinal nerve Joints between the articular processes are innervated by branches from the posterior rami of the spinal nerves Curves of the Vertebral Column Movements of the Vertebral Column  Muscles of the Back (Superficial Layer) Trapezius: upward rotation of scapula; shawl muscle (upper, middle, lower) Levator Scapulae: elevates the scapula; downward rotation of scapula Latissimus Dorsi: broadest/widest muscle; also known as crutch- walking muscle Rhomboids major/minor: retract shoulder, downward rotator  Muscles of the Back (Intermediate Layer) Serratus Posterior Superior: inspiration Inferior: expiration  Muscles of the Back (Deep Layer) Splenius: bandage muscle Capitis Cervicis Superficial Vertically Running Muscles: Erector Spinae: longitudinal muscle, chief erector of spine Iliocostalis Longissimus Spinalis  Muscles of the Back (Deep Layer) Intermediate Oblique Running Muscles: Transversospinalis/Oblique Muscles (SaMuRai) Semispinalis Multifidus (strongest from forward flexion to neutral) Rotatores = Obliques  Muscles of the Back (Deep Layer) Deepest Muscles: Interspinalis: connects the spinous process Intertransversarii: connects the transverse process  Blood Supply of the Back Arteries: Cervical: branches arise from the occipital artery, a branch of the external carotid; from the vertebral artery, a branch of the subclavian; and from the deep cervical artery, a branch of the costocervical trunk Thoracic: branches arise from the posterior intercostal arteries Lumbar: branches arise from the subcostal and lumbar arteries Sacral: branches arise from the iliolumbar and lateral sacral arteries, branches of the internal iliac artery  Blood Supply of the Back Veins: The external vertebral venous plexus lies external and surrounds the vertebral column. The internal vertebral venous plexus lies within the vertebral canal but outside the dura mater of the spinal cord Receives tributaries from the vertebrae by way of the basivertebral veins and from the meninges and spinal cord. Is drained by the intervertebral veins  Lymph Drainage of the Back The deep lymph vessels follow the veins and drain into the deep cervical, posterior mediastinal, lateral aortic, and sacral nodes. The lymph vessels from the skin of the neck drain into the cervical nodes Those from the trunk above the iliac crests drain into the axillary nodes Those from below the level of the iliac crests drain into the superficial inguinal nodes  Nerve Supply of the Back The skin and muscles of the back are supplied in a segmental manner by the posterior rami of the 31 pairs of spinal nerves. The posterior rami of the first, sixth, seventh, and eighth cervical nerves and the fourth and fifth lumbar nerves (C1, C6, C7, C8, L4, L5) supply the deep muscles of the back and do not supply the skin. The posterior ramus of the second cervical nerve (the greater occipital nerve or C2) ascends over the back of the head and supplies the skin of the scalp.  Spinal Cord Cylindrical mass of neural tissue, occupying the upper 2/3 of Vertebral Canal Starts: Foramen magnum Ends L1-L2 vertebrae External Structures: Conus Medullaris: Conical inferior end Filum Terminale: Filament extending from the conus and attaches to 1st segment of the coccyx Cauda Equina: Horsetail composed of rootlets of lumbosacral plexus Spinal Cord  Roots of the Spinal Nerves Along the whole length of the spinal cord are attached 31 pairs of spinal nerves by the anterior or motor roots and the posterior or sensory roots. They unite to form a spinal nerve. Spinal Nerves Roots of the Spinal Nerves  Blood Supply of the Spinal Cord Branches from vertebral artery (1) Anterior Spinal Artery: anterior upper 2/3 of SC (2) Posterior Spinal Artery: posterior upper 1/3 of SC Radicular Artery: reinforcement of the anterior and posterior spinal arteries Artery of Adamkiewicz: largest radicular artery (T8-L4) Watershed Area: poorest blood flow (T4-T6 upper thoracic, midthoracic)  Meninges of the Spinal Cord Dura Mater The outermost layer, thick and durable. Composed of dense connective tissue. Extends from the foramen magnum to the level of the second sacral vertebra. Provides a tough protective covering for the spinal cord. Forms the dural sac, which surrounds the spinal cord and extends into the vertebral canal.  Meninges of the Spinal Cord Arachnoid Mater The middle layer, web-like structure. Lies deep to the dura mater and extends to the level of the second sacral vertebra. Encloses the subarachnoid space, which contains cerebrospinal fluid (CSF). Acts as a barrier to protect the spinal cord.  Meninges of the Spinal Cord Pia Mater The innermost layer, thin and delicate. Directly adheres to the surface of the spinal cord and brain. Follows the contours of the spinal cord, including the anterior median fissure and posterior median sulcus. Contains blood vessels that supply the spinal cord. Forms the filum terminale, a fibrous extension that anchors the spinal cord to the coccyx.  Spaces Associated with Meninges Epidural Space: Located between the dura mater and the vertebral wall. Contains fat and small blood vessels. Subdural Space: A potential space between the dura mater and the arachnoid mater. Normally not visible, but can become a real space if blood or fluid accumulates. Subarachnoid Space: Located between the arachnoid mater and the pia mater. Filled with cerebrospinal fluid (CSF). Site of lumbar puncture for CSF sampling.  Cerebrospinal Fluid is a clear, colorless body fluid found in the brain and spinal cord. produced primarily in the choroid plexus of the brain's ventricles.  Cerebrospinal Fluid Function: Protection: Acts as a cushion, protecting the brain and spinal cord from trauma. Buoyancy: Reduces the effective weight of the brain, preventing it from compressing against the skull base. Chemical Stability: Maintains a stable chemical environment by removing waste products and providing nutrients. Intracranial Pressure Regulation: Helps maintain a stable pressure within the cranium.