spinal cord and Spinal nerves indepth ppt
- 2. Spinal Cord • Spinal cord a tubular extension of the brain distal to the medulla oblongata • It occupies the vertebral canal suspended in the CSF and sorrounded by the meninges. www.similima.com 2
- 4. Spinal Cord • Spinal cord extends from the medulla oblongata to the lower border of L1 vertebra in adults. www.similima.com 4
- 5. • Conus medullaris. • Cauda equina. • Filum terminale, www.similima.com 5
- 6. Spinal Cord • Structurally spinal cord can be said to be made up of 31 slices (segments) bound together to make one cylindrical unit. • Each connected to a pair of spinal nerves. • Ventral and Dorsal roots www.similima.com 6
- 7. Cross Sectional Anatomy of the Spinal Cord • Gray matter is in the core of the cord and surrounded by white matter. www.similima.com 7
- 8. • On section the gray matter of the spinal cord resembles a butterfly. • 2 lateral gray masses connected by the gray commissure. • posterior or dorsal horns. • anterior or ventral horns. • lateral horns. www.similima.com 8
- 9. Gray Matter • Posterior horns contain sensory neurons • Anterior horns contains the cell bodies of motor neurons. – These cell bodies project their axons via the ventral roots of the spinal cord to the skeletal muscles. – The amount of ventral gray matter at a given level of the spinal cord is proportional to the amount of skeletal muscle innervated. www.similima.com 9
- 10. Gray Matter • Lateral horn neurons are sympathetic motor neurons serving visceral organs. – Their axons also exit via the ventral root. www.similima.com 10
- 12. White Matter • Myelinated nerve fibers. • White matter on each side of the cord is divided into columns or funiculi. www.similima.com 12
- 13. Sensory and Motor Tracts What is the purpose of knowing the position of the tracts? www.similima.com 13
- 14. Spinal Nerves • 31 nerves connecting the spinal cord and various body regions. • 8 paired cervical nerves • 12 paired thoracic nerves • 5 paired lumbar nerves • 5 paired sacral nerves • 1 pair of coccygeal nerves www.similima.com 14
- 15. Spinal Nerves • Each connects to the spinal cord by 2 roots – dorsal and ventral. • Ventral roots are motor while dorsal roots are sensory. www.similima.com 15
- 16. Spinal Nerves • The 2 roots join to form a spinal nerve prior to exiting the vertebral column. • After emerging from its intervertebral foramen, a spinal nerve will divide into a dorsal ramus, a ventral ramus, and a meningeal branch that reenters and innervates the meninges and associated blood vessels. www.similima.com 16
- 17. • Motor fibres arise from the motor neurons in the anterior gray horn • Sensory fibres arise from the sensory neurons in the dorsal root ganglion www.similima.com 17
- 18. • Each ramus is mixed. • Joined to the base of the ventral rami of spinal nerves in the thoracic region are the rami communicantes. • Dorsal rami supply the posterior body trunk whereas the thicker ventral rami supply the rest of the body trunk and the limbs. www.similima.com 18
- 22. Motor supply of Spinal cord www.similima.com 22
- 23. Nerve Plexuses • Except for T2 to T12, all ventral rami branch extensively and join one another lateral to the vertebral column forming complicated nerve plexuses. • W/i a plexus, fibers from different rami crisscross each other and become redistributed. www.similima.com 23
- 26. Spinal Cord • Spinal cord has two maintains homoeostasis in 2 ways – Through Nerve impulse propagation and integration of information. – By serving as an integrating centre for some reflexes. www.similima.com 26
- 27. Spinal Cord – Homoeostasis 1. Nerve impulse propagation and integration of information. – White matter: highways or electrical wires for Nerve impulse propagation – Gray matter: centre for integration of information. www.similima.com 27
- 28. Spinal Cord – Homoeostasis 2. Centre for integrating reflexes Reflex: A reflex is a fast, automatic, unplanned sequence of actions that occur in response to a stimulus www.similima.com 28
- 29. Types • Spinal reflex – integration takes place in spinal cord • Cranial reflex – integration takes place in brain stem. • Somatic reflex – involves contraction of skeletal muslce • Autonomic reflex – not perceived consciously. Targeted at smooth muscle, cardiac muscle or a gland www.similima.com 29
- 30. Reflex Arc • The pathway followed by nerve impulse to produce a reflex is called a reflex arc • It has 5 functional components – Sensory receptor – Sensory neuron – Integrating centre – Motor neuron – Effector www.similima.com 30
- 31. Somatic reflexes • The stretch reflex • The tendon reflex • The flexor (withdrawal reflex) • The crossed extensor reflex www.similima.com 31
- 35. Reflexes • Reflexes may be inborn or learned. www.similima.com 35
- 36. • Reflexes may be monosynaptic or polysynaptic. www.similima.com 36
- 40. Autonomic Reflexes • May be spinal (e.g., urination and defecation) or cranial. • The thalamus, hypothalamus and brain stem are in charge of multiple reflexes – HR, BP, breathing, eating, osmotic balance, temperature, vomiting, gagging, sneezing. • All are polysynaptic. www.similima.com 40
- 42. • Reflexes provide information about the health of the nervous system and can greatly aid in the diagnosis of disease. • Damage or Disease any where along the reflex arc can cause a reflex to be absent or abnormal www.similima.com 42
- 43. • Patellar reflex (Knee jerk) • Achilles reflex (Ankle jerk) • Babinski’s sign • Abdominal reflex www.similima.com 43
- 44. Trauma to Spinal cord • Causes – Automobile accidents – Falls – Contact sports – Diving – Acts of violence www.similima.com 44
- 45. Common sites of injury • Cervical • Lower thoracic • Upper lumbar www.similima.com 45
- 46. Result of the damage - paralysis • Monoplegia • Diplegia • Paraplegia • Hemiplegia • Quadriplegia www.similima.com 46
- 47. • Paraplegia – Rx. Arg nit, Ars, Nux v. • Hemiplegia – Rx. Alum, Anac, Ars, Caust, Graph, Kali c, Lach, Mur ac, Phos, Rhus t, Stann, Sulph ac. www.similima.com 47
- 48. Complete transection • Loss of all sensations and voluntary movement below the level of the transection • The extent of the paralysis of skeletal muscle depends on the level of the injury www.similima.com 48
- 49. Functions retained • C1 – C3: No function maintained from the neck down; ventilator needed for breathing • C4 – C5: Diaphragm, which allows breathing • C6 – C7: some arm and chest muscles, which allows feeding and propelling wheel chair • T1 – T3: intact arm function www.similima.com 49
- 50. Functions retained • T4– T9: control of trunk above the umbilicus • T10– L1: most thigh muscles, which allows walking with long leg braces • L1– L2: most leg muscles which allows walking with short braces www.similima.com 50
- 51. Hemisection • Brown-Sequard syndrome – Loss of proprioception and touch sensation on the same side as the injury – Ipsilateral paralysis – Loss of pain and temperature sensations www.similima.com 51
- 52. Spinal shock • Areflexia – loss of function • Signs of spinal shock – Slow heart rate – Low blood pressure – Flaccid paralysis of skeletal muscle – Loss of somatic sensations – Urinary bladder dysfunction • Rx www.similima.com 52
- 53. Spinal Cord Compression • Causes of spinal cord compression – Injuries – Extra dural • Herniation of intervertebral disc • Tubercular infection of the vertebrae • Tumors of the vertebrae • Leukemic deposits • Extradural abscess – Intra dural • Primary tumors of the spinal cord such as gliomas www.similima.com 53
- 54. Spinal Cord Compression • Pressure on spinal arteries causes ischemia of the spinal cord with degeneration of nerve cells and their fibres • Pressure on the veins causes edema of the spinal cord with interference in the function of the neurons • Pressure on the white and gray matter of the spinal cord causes interference in the nerve conduction. www.similima.com 54
- 55. Spinal Cord Compression • Clinical signs – Pain. Local pain in the vertebra involved or radiating pain along the distribution of one or more spinal nerve roots. • Pain < by coughing, sneezing. < at night. – Involvement of the anterior gray column motor cells at the level of lesion cause complete or partial paralysis with loss of tone and wasting – Muscular weakness and increased muscle tone, increased tendon reflexes below the lesion and extensor plantar response. www.similima.com 55
- 56. Spinal Cord Compression • Clinical signs – Lesion of the posterior white column causes loss of muscle joint sense, vibration and tactile discrimination below the level of the lesion on the same side. – Involvement of lateral spinothalamic tract causes loss of pain and temperature sense on the opposite side of the lesion. www.similima.com 56
- 57. • Affects the posterior root ganglia • Pain • Discoloration of skin • Characteristic line of blisters Shingles (Herpes zoster) www.similima.com 57
- 58. Shingles (Herpes zoster) Affects the posterior root ganglion. Homoeopathic therapeutics… Erruptions: Herpes zoster – All-s, Ars alb, Lach, Merc, Nat.carb, Sepia, Rhu.tox and Zinc. www.similima.com 58
- 59. Poliomyelitis • Affects the motor neurons in the anterior horn and in the brain stem. • Signs and symptoms – Fever, severe headache, a stiff neck and back – Deep muscle pain and weakness – Loss of somatic reflexes www.similima.com 59
- 61. Poliomyelitis • Poliomyelitis infection – Acon, Calc, Caust, Gels, Latherus, Plb, Rhus tox. – Neuralgic pain after – Rhus tox – Paralysis of diaphragm with – Cupr, Opium and Sil. www.similima.com 61