The document discusses the anatomy, causes of injury, symptoms, treatment, and prognosis of sciatic nerve injury. It also discusses common peroneal nerve injury, including causes, symptoms, and nerve entrapment syndromes that can occur when peripheral nerves pass through fibro-osseous tunnels. Sites of potential nerve entrapment include the carpal tunnel, cubital tunnel, and tarsal tunnel. Treatment involves avoiding compromising postures, splinting, steroid injections, and potential surgical decompression if other treatments fail.

1. Sciatic nerve

2. Anatomy Supplies: Hamstrings (posterior of thigh) Above knee divided into : (1)Common peroneal: Superficial peroneal : The two peronei Skin of lateral of leg and dorsum of foot except 1st cleft Deep peroneal: Muscles of anterior compartment of the leg Skin of 1st cleft (2)Tibial nerve : muscles of the calf Skin of the sole

3. Causes of injury of the main trunk Gunshot Operative accidents Trauma following hip dislocation or fractures of the acetabulum

4. Symptoms and signs Paralysis of (1) Hamstrings (2) All muscles below the knee Foot drop Absent sensation in most of the leg Trophic ulcers ±

5. Treatment Urgent reduction of hip dislocation Proper treatment of fractures Open wounds: Repair While recovery is awaited a drop-foot splint is fitted

7. Common peroneal nerve injury

8. Causes Varus force in the knee Pressure from a splint or plaster cast Lying with the leg externally rotated Anterior compartment syndrome (pressure on deep peroneal nerve)

9. Symptoms and signs Wasting of dorsiflexor and peronei muscles Drop foot Loss of sensation of dorsum of foot

10. Nerve entrapment syndromes Whenever peripheral nerves traverse fibro-osseous tunnels , they are at risk of entrapment or compression

11. Causes ↑ in soft tissue bulk( pregnancy, myxoedema, RA) Local obstruction (ganglion, osteophyte,old #) Idiopathic

12. Sites Carpal tunnel at the wrist (Median nerve)

13. Cubital tunnel at the elbow( ulnar nerve)

14. Tarsal tunnel below the ankle( Posterior tibial nerve)

15. Lateral part of inguinal ligament (lateral cutaneous of the thigh )

16. Thoracic outlet( C8+ T1)

17. Clinical features Intermittent tingling OR pain OR numbness These symptoms are related to specific postures which compromise the nerve. e.g. CTS : flexion or hyperextension of the wrist Ulnar neuropathy : flexion of the elbow for a long time(driving, using telephone) Areas of altered sensation Motor weakness Muscle wasting

18. Treatment Avoiding compromising postures Light splints Local steroid injection If all above failed : Surgical decompression