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

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

Functions of the Spinal Cord Processes reflexes Integrates nerve impulses 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 Dura mater Arachnoid mater Pia mater Denticulate ligaments 3 2 1

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

Anatomy

Fig. 13.1 Gross Anatomy of Spinal Cord

(b) Posterior view of cervical region 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 Posterior (dorsal) rootlets of spinal nerve Dura mater and arachnoid mater (cut) INFERIOR (b) Posterior view of cervical region of spinal cord

View Transverse plane Dura mater and arachnoid mater POSTERIOR Spinal cord Pia mater Spinous process of vertebra Epidural space Subarachnoid space Superior articular facet of vertebra Posterior (dorsal) root of spinal nerve Posterior (dorsal) ramus of spinal nerve Denticulate ligament Anterior (ventral) root of spinal nerve Spinal nerve Anterior (ventral) ramus of spinal nerve Transverse foramen Body of vertebra Vertebral artery in transverse foramen ANTERIOR 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 Posterior view of entire spinal cord and portions of spinal nerves CERVICAL PLEXUS (C1–C5): Lesser occipital nerve Great auricular Ansa cervicalis Transverse cervical nerve Supraclavicular nerve Phrenic nerve BRACHIAL PLEXUS (C5–T1): Musculocutaneous nerve Axillary nerve Median nerve Radial nerve Ulnar nerve Intercostal (thoracic) nerves Subcostal nerve (intercostal nerve 12) LUMBAR PLEXUS (L1–L4): Iliohypogastric nerve Ilioinguinal nerve Genitofemoral nerve Lateral femoral cutaneous nerve Femoral nerve Obturator nerve SACRAL PLEXUS (L4–S4): Superior gluteal nerve Inferior gluteal nerve Sciatic nerve: Common fibular nerve Tibial nerve Posterior cutaneous nerve of thigh Pudendal nerve Medulla oblongata Atlas (first cervical vertebra) CERVICAL NERVES (8 pairs) Cervical enlargement First thoracic vertebra THORACIC NERVES (12 pairs) Lumbar enlargement First lumbar vertebra Conus medullaris LUMBAR NERVES (5 pairs) Cauda equina Ilium of hip bone Sacrum SACRAL NERVES (5 pairs) COCCYGEAL NERVES (1 pair) Filum terminale C1 C2 C3 C4 C5 C6 C7 C8 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 L1 L2 L3 L4 L5 S1 S2 S3 S4 S5

External Anatomy of the Spinal Cord

Internal Anatomy of the Spinal Cord Gray matter White matter Landmarks

Fig. 13.3 Internal Anatomy of Spinal Cord

Fig. 13.3 Internal Anatomy of Spinal Cord

Internal Anatomy of the Spinal Cord

Sensory and Motor Processing

Spinal Cord Segments Table 13.1 Cervical (Segment C6) Thoracic (Segment T5) Lumbar (Segment L4) Sacral (Segment S3)