Spinal Cord and Spinal Nerves Chapter 13 Lab

Spinal Cord and Spinal Nerves Chapter 13 Lab Exercises 17 -19

Introduction The purpose of this part of the course is to: 1. Identify & describe anatomical features of spinal cord & spinal nerves 2. Discuss functions of spinal cord & spinal nerves homeostasis 3. Understand spinal reflex arcs Integration of EPSP + IPSP Sensory and motor tracts

Functions of the Spinal Cord 1. Processes reflexes 2. Integrates nerve impulses 3. Conducts sensory impulses to the brain and motor impulses to effectors

Protection of the Spinal Cord The spinal cord is protected by: – Bone – Meninges – CSF

Meninges The meninges are composed of three layers 1. Dura mater 2. Arachnoid mater 3 3. Pia mater § Denticulate ligaments 2 1

Meninges • Epidural space • Subarachnoid space • A spinal tap can be done to withdraw CSF for diagnostics 3 2 1

Anatomy

Fig. 13. 1 Gross Anatomy of Spinal Cord

SUPERIOR Fourth ventricle Cerebellum of brain (cut) Glossopharyngeal (IX) and vagus (X) nerves Occipital bone (cut) Accessory (XI) nerve Posterior median sulcus Gracile fasciculus Vertebral artery Cuneate fasciculus Denticulate ligament Dura mater and arachnoid mater (cut) Posterior (dorsal) rootlets of spinal nerve INFERIOR (b) Posterior view of cervical region of spinal cord

View Transverse plane POSTERIOR Dura mater and arachnoid mater Spinal cord Pia mater Spinous process of vertebra Epidural space Subarachnoid space Posterior (dorsal) root of spinal nerve Denticulate ligament Anterior (ventral) root of spinal nerve Transverse foramen Body of vertebra Superior articular facet of vertebra Posterior (dorsal) ramus of spinal nerve Spinal nerve Anterior (ventral) ramus of spinal nerve Vertebral artery in ANTERIOR transverse foramen Figure 13. 1 (b) Transverse section of the spinal cord within a cervical vertebra

External Anatomy of the Spinal Cord Begins… Ends… Landmarks

Fig. 13. 2 External Anatomy of Spinal Cord Medulla oblongata CERVICAL PLEXUS (C 1–C 5): Lesser occipital nerve Great auricular Ansa cervicalis Transverse cervical nerve Supraclavicular nerve Phrenic nerve BRACHIAL PLEXUS (C 5–T 1): Musculocutaneous nerve Axillary nerve Median nerve Radial nerve Ulnar nerve Intercostal (thoracic) nerves Subcostal nerve (intercostal nerve 12) LUMBAR PLEXUS (L 1–L 4): Iliohypogastric nerve Ilioinguinal nerve Genitofemoral nerve Lateral femoral cutaneous nerve Femoral nerve Obturator nerve SACRAL PLEXUS (L 4–S 4): Superior gluteal nerve Inferior gluteal nerve Sciatic nerve: Common fibular nerve Tibial nerve Posterior cutaneous nerve of thigh Pudendal nerve C 1 C 2 C 3 C 4 C 5 C 6 C 7 C 8 T 1 T 2 T 3 T 4 T 5 T 6 T 7 T 8 T 9 T 10 T 11 Atlas (first cervical vertebra) CERVICAL NERVES (8 pairs) Cervical enlargement First thoracic vertebra THORACIC NERVES (12 pairs) Lumbar enlargement First lumbar vertebra T 12 Conus medullaris L 1 LUMBAR NERVES (5 pairs) L 2 Cauda equina L 3 Ilium of hip bone L 4 L 5 S 1 S 2 S 3 S 4 S 5 Posterior view of entire spinal cord and portions of spinal nerves Sacrum SACRAL NERVES (5 pairs) COCCYGEAL NERVES (1 pair) Filum terminale