Spinal plexuses
- 2. SPINAL PLEXUSES • Plexus -A plexus (from the Latin for "braid") is a network of nerves • Spinal plexuses is the network of spinal nerves SPINAL PLEXUSES • Cervical plexus - serves the head, neck and shoulders • Brachial plexus - serves the chest, shoulders, arms and hands • Lumbar plexus - serves the back, abdomen, groin, thighs, knees, and calves • Sacral plexus - serves the pelvis, buttocks, genitals, thighs, calves, and feet • Coccygeal plexus - serves a small region over the coccyx
- 3. The spinal cord is the long cylindrical lowest part of central nervous system. It gives rise to 31 pairs of spinal nerves. Length : 18 inch or 45cm in adult male Extent : atlas vertebra to L1 Vertebra Medulla oblongata to conus medullaris Cervical enlargement (C4-T2) for brachial plexus Lumbar enlargement( L2-S3) for lumbosacral plexus
- 4. There are 31 pairs of spinal nerves Cervical – 8 Thoracic -12 Lumbar – 5 Sacral- 5 Coccygeal - 1
- 5. TYPES OF NEURONS NEURONS are the functional unit of nervous system The transmission of impulse through neuron is salutatory conduction.
- 6. DORSAL ROOT GANGLION consists of PSEUDOBIPOLAR NEURON
- 7. ROOT VALUE: Ventral rami of C1,C2,C3,C4 form cervical plexus CERVICAL PLEXUS
- 8. C1 Hypoglossal Geniohyoid Thyrohyoid Superior limb of ANSA CERVICALIS Superior belly of omohyoid Runs along C2, C3 Inferior limb of ANSA CERVICALIS Inferior belly of omohyoid Sternothyroid Sternohyoid
- 9. 4 CUTANEOUS BRANCHES OF CERVICAL PLEXUS • Lesser occipital (C2) • Great auricular (C2,C3) • Supraclavicular ( C3, C4) • Transverse or Anterior nerve of neck (C2,C3)
- 10. APPLIED ANATOMY : • FREY’S SYNDROME: The sign of frey’s syndrome is the appearance of perspiration of the face while the patient eats food. In certain wounds, the aurioculotemporal nerve and great auricular nerves may join with each other, when the person eats food, instead of saliva sweat appears on the face.
- 11. BRACHIAL PLEXUSES • It is a network of nerves which supplies upper limb • ROOT VALUE: Anterior primary rami of C5,C6,C7,C8 and T1 spinal nerves (rami – branch of nerve fibres) • STAGES OF BRACHIAL PLEXUS: It consists of 5 subdivisions 1. Root stage 2. Trunk stage 3. Division stage 4. Cord stage 5. Branches
- 12. ROOT STAGE • It is formed by the anterior primary rami(APR) of C5 to T1 spinal nerves prefixed plexus – In this condition C4 joins to form the plexus and T1 is absent postfixed plexus – In this condition C5 is absent and T2 takes part in forming the plexus . TRUNK STAGE • C5 and C6 joins to form UPPER TRUNK. • C7 continues as MIDDLE TRUNK • C8 and T1 joins to form LOWER TRUNK.
- 13. DIVISION STAGE • Each Trunk divides into anterior and posterior division CORD STAGE • The anterior division of upper and middle trunk joins to form LATERAL CORD. • The anterior division of lower trunk continuous as MEDIAL CORD. • The posterior division of upper, middle and lower trunk joins to form the POSTERIOR CORD. BRANCHES • Branches from Root stage Dorsal scapular nerve(C5) Branch to phrenic nerve Nerve to serratus anterior (C5,C6,C7)
- 14. • Branches from Trunk stage UPPER TRUNK Nerve to subclavius (C5,C6) suprascapular nerve (C5,C6) • Branches form cord stage LATERAL CORD Lateral pectoral nerve Lateral root of median nerve Musculo-cutaneous nerve MEDIAL CORD medial pectoral nerve medial cutaneous nerve of arm medial cutaneous nerve of forearm medial root of median nerve ulnar nerve
- 15. • POSTERIOR CORD Thoraco dorsal nerve (C6,C7,C8) Upper subscapular nerve Lower subscapular nerve Axillary nerve Radial nerve APPLIED ANATOMY: • Erb’s paralysis • Klumpke’s paralysis • Crutch paralysis
- 16. ERB’S PARALYSIS • The point where the 6 nerves meet is called Erb’s point. SITE OF INJURY: The region of the upper trunk of the Brachial plexus. CAUSES OF INJURY: Birth injury sudden fall on the shoulder During anaesthesia NERVE ROOTS INVOLVED: C5 & C6 spinal nerves DEFORMITY: policeman tip hand or porter’s tip hand ARM: adducted and medially rotated FOREARM: Extended and pronated
- 17. KLUMPKE’S PARALYSIS • SITE OF INJURY: Lower trunk of the Brachial plexus. • CAUSES OF INJURY: Undue abduction of arm After a fall from the height Sometimes in birth injury • NERVE ROOTS INVOLVED: C8 & T1 spinal nerves • MUSCLES PARALYSED: Intrinsic muscles of the hand(T1) Ulnar flexors of wrist & fingers (C8) • DEFORMITY: complete claw hand – Extension at the metacarpophalangeal joint Flexion at the interphalangeal joint
- 18. • HORNER’S SYNDROME: If T1 is injured proximal to white ramus communicans to first thoracic sympathetic ganglion results in partial ptosis or drooping of eyelids miosis or narrow pupil Enopththalmos or eye pushed inside the bony orbit & Anhidrosis or absence of sweating on the side of lesion Cutaneous anaesthesia & analgesia in the ulnar border of forearm
- 20. LUMBAR PLEXUS • ROOT VALUE: ventral rami of L1,L2,L3 and L4 spinal nerves ventral rami Ventral division Dorsal division
- 21. • NERVES FROM VENTRAL DIVISIONS Ilioinguinal (L1) Genitofemoral(L1,L2) Obturator nerve (L2,L3,L4) Accessory obturator (L3,L4) • NERVES FROM DORSAL DIVISIONS Lateral cutaneous nerve of thigh (L2,L3) Femoral nerve (L2,L3,L4) • NERVE FROM BOTH VENTRAL AND DORSAL DIVISIONS Iliohypogastric (L1)
- 23. phrase ' Interested In Getting Laid On Friday?‘ • Iliohygastric nerve. (L1) • Ilioinguinal nerve. (L1) • Genitofemoral nerve. (L1, L2) • Lateral cutaneous nerve of thigh (L2, L3) • Obturator nerve (L2, L3, L4) • Femoral nerve. (L2, L3, L4) • 2 nerves arise from one root: iliohypogastric and ilioinguinal from (L1) • 2 nerves arise from 2 roots: genitofemoral from L1 & L2, and lateral femoral cutaneous from (L2 & L3) • 2 nerves arise from 3 roots: femoral and obturator from( L2, L3 & L4)
- 24. SACRAL PLEXUS • ROOT VALUE: Ventral rami of L4,L5,S1,S2,S3 spinal nerves • BRANCHES ARISING FROM VENTRAL DIVISIONS Nerve to quadratus femoris (L4,L5,S1) Nerve to obturator internus (L5,S1,S2) Pudental nerve (S2,S3,S4) Perforating cutaneous nerve (S3,S4) Tibial part of sciatic nerve (L4,L5,S1,S2,S3) Posterior cutaneous nerve of thigh (S1,S2)
- 25. • BRANCHES FROM DORSAL DIVISIONS : Superior gluteal nerve(L4,L5,S1) Inferior gluteal nerve(L5,S1,S2) Common peroneal part of Sciatic nerve (L4,L5,S1,S2)
- 26. BRANCHES OF NERVES MUSCLES SUPPLIED Nerve to Quadratus femoris (L4,L5,S1) Quadratus femoris Inferior gemellus and Hip joint Nerve to obturator Internus(L5,S1,S2) Obturator internus Superior gemellus Pudental nerve(S2,S3,S4) External genital organs Muscles of perineum Perforating cutaneous nerve(S3,S4) Supplies small area of skin of gluteal region Tibial part of Sciatic nerve (L4,L5,S1,S2,S3) All muscles of calf and sole Posterior cutaneous nerve of thigh (S1,S2) Supplies skin of back of thigh Superior gluteal nerve(L4,L5,S1) Gluteus medius Gluteus minimus Gluteus tensor fascia latae Inferior gluteal nerve (L5,S1,S2) Gluteal maximus Common peroneal part of sciatic nerve(L4,L5,S1,S2) Evertors Foot and dorsiflexors Extensor digitorum brevis
- 27. SCIATIC NERVE TIBIAL NERVE (Medial popliteal nerve) COMMON PERONEAL NERVE (Lateral popliteal nerve) Continues as posterior tibial nerve SUPERFICIAL PERONEAL NERVE DEEP PERONEAL NERVE MEDIAL PLANTAR NERVE LATERAL PLANTAR NERVE
- 29. APPLIED ANATOMY • MERALGIA PARAESTHETICA: If the lateral cutaneous nerve of thigh gets compressed as it pierces the inguinal ligament there is pain tingling, numbness and anaesthesia over the anterolateral aspect of thigh. This is called “MERALGIA PARAESTHETICA”. • FOOT DROP: weakness of dorsiflexion of ankle and eversion of the foot. Inversion and plantarflexion are normal and ankle jerk is intact.
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