External Spinal Cord (Surface, Segments, Spinal Nerve, Enlargements, Reflex Arch) - Anatomy

Content: 0:00 Introduction 1:07 Topography of Spinal Cord 2:44 External Surface of Spinal Cord 3:41 Spinal Segments 5:15 Spinal Nerve and Vertebral Canal 7:33 Enlargements of the Spinal Cord 8:27 Spinal Nerve Anatomy 14:13 Reflex Arch ------------------------------- 🫀 Join: https://www.youtube.com/channel/UCEr7pkSXVsHcBLLBcJAGV-Q/join 📷 Follow my IG: https://www.instagram.com/taimtalksmed/ 💝 Donation link: https://www.buymeacoffee.com/taimtalksmed ------------------------------- Topography of Spinal Cord (Medulla Spinalis) - Vertebral Canal (Canalis Vertebralis) - Covered by: ○ Pia Mater ○ Arachnoid Mater ○ Dura Mater - Foramen Magnus to L1/L2 - 40-45 cm long - Medullary Cone (Conus Medullaris) - Filum Terminale (Terminal Thread) - Cauda Equina External Surface of Spinal Cord: - Anterior Surface ○ Anterior Median Fissure (Fissura Mediana Anterior) ○ Right Anteriolateral Sulcus (Sulcus Anterolateralis Dexter) ○ Left Anterolateral Sulcus (Sulcus Anterolateralis Sinister) - Posterior Surface ○ Posterior Median Sulcus (Sulcus Medianus Posterior) ○ Right Posterolateral Sulcus (Sulcus Posterolateralis Dexter) ○ Left Posterolateral Sulcus (Sulcus Posterolateralis Sinister) Segments of the Spinal Cord - 8 cervical segments - 12 thoracic segments - 5 lumbar segments - 5 sacral segemnts - 1 coccygeal segments - Spinal nerves going out throguh Intervertebral Openings (Foramina Intervertebralis) Relationship between the spinal cord and the vertebra: - Spinous processes of cranial cervical vertebrae Correspond to same segment - Spinous processes of caudal cervical vertebrae - Segment +1 (e.g. vertebra C7 = spinal segment C8) - Spinous processes of cranial thoracic vertebrae – segment + 2 (e.g. vertebra T3 = spinal segment T5) - Spinous processes of caudal thoracic vertebrae – segment + 3 - Vertebrae T10–T12 – lumbar segments L1–L4 - Vertebrae T12–L1 (epiconus) – lumbar and sacral segments L5–S2 - Vertebrae L1–L2 (conus) – sacral and single coccygeal segments S3–S5 and Co Enlargements of the Spinal Cord - Cervical Enlargement (Intumenencia Cervicalis) ○ Brachial Plexus - Lumbosacral Enlargement (Intumenencia Lumbosacralis) ○ Sacral and Lumbar Plexuses Anatomy of the Spinal Nerve: - Spinal Nerves synapse with nuclei in gray matter of spinal cord - Posterior Root / Sensory Root (Radix Sensoria) ○ Enter through the posterolateral sulci ○ Spinal Ganglion / Dorsal Root Ganglion (Ganglion sensorium nervi spinalis) ○ Pseudounipolar neurons - Anterior Root / Motor Root (Radix Motoria) ○ Enter throguh the anterolateral sulci - Spinal Nerve contain: ○ Sensory Fibers ○ Motor Fibers ○ Sympathetic Fibers (Between C8-L2) ○ Parasympathetic Fibers (Between S2-S4) - Branches of the Spinal Nerve ○ Ventral Branch § Cervical Plexus § Brachial Plexus § Lumbar Plexus § Sacral Plexus ○ Dorsal Branch ○ White Ramus Communicans ○ Meningeal Branch Reflex Arch - Mono-Synaptic Reflex ○ Patellar Tendon Reflex - Multi-Synaptic Reflex ○ Withdrawal Reflex Sources used in this video: - Memorix Anatomy 2nd Edition by Hudák Radovan (Author), Kachlík David (Author), Volný Ondřej (Author) - Biorender - University notes and lectures