Lumbosacral plexus lumbo sacral plexus-1.pptx

Lumbosacral plexus

1. Lumbosacral plexus The lumbosacral plexus results from the anastomosis of ventral branches of last 3 lumbar and first 2 sacral spinal nerves. The root from the 4 th lumbar is small. Usually the 3 rd sacral nerve gives a small bundle of fibers to the plexus. Branches: FOGGST 1. Femoral nerve (F) 2. Obturator nerve (O) 3. Anterior / cranial gluteal nerve (G) 4. Posterior / caudal gluteal nerve (G) 5. Sciatic nerve (it is the largest nerve of the body) (S) 6. Tibial nerve(T)

2. SNo Name of Nerve (Formed by) Innervates 1 Femoral nerve (4, 5 & 6 th lumbar nerve) Thigh muscles 2 Obturator nerve (4, 5 & 6 th lumbar nerve) Obturator externus, pectineus, adductor & graciallis muscles 3 Anterior gluteal nerve (6 th lumbar & 1 st sacral spinal nerve) Middle & deep gluteus muscle and tensor fascia lata 4 Sciatic nerve – has following branches (6 th lumbar and 1 st & 2 nd sacral spinal nerve)   thin muscular Obturator internus (ii) small muscular Gamellus , quadratus femoris (iii) thick muscular Biceps femoris, semitendinosus, semimembranosus (iv) caudal cutaneous (external saphenus ) nerve Gastrocnemius (v)peroneal nerve (external popleteal ) nerve (a) superficial branch (b) deep branch Gastrocnemius, extensors 5 Posterior gluteal nerve (1st & 2nd sacral spinal nerve) ( i ) superficial branch (ii) deep branch Gluteus, biceps femoris, semitendinosus muscle and skin of the area

3. (v)Peroneal nerve (external popleteal ) nerve : At the lateral aspect of gastrocnemius (a) superficial branch: runs bw extensor muscles at metatarsal region and devides in 3 branches, i . lateral- ant. Lateral abaxial digital, ii. Medial- medial abaxial digital, iii. Middle- joins with lateral of deep- ant. Common axial digital (b) deep branch: i . lateral- ant. Common axial digital, ii. Medial- joins with axial branch of edial division of tibial nerve to form posterior common axial digital.

4. Tibial nerve:- It is the continuation of the sciatic nerve. It passes between the two heads of gastrocnemius and descend down behind the superficial digital flexor and gastrocnemius. This nerve becomes superficial near the front of achillis tendon and divides into medial and lateral branches at the hock joint. a. Medial branch goes up to the fetlock joint and divided into i . Axial- joins with axial branch of deep part of peroneal and forms the posterior common axial digital nerve ii. Abaxial branches continues as medial abaxial digital nerve. b. L ateral branch descends down and continues as posterior lateral abaxial digital nerve.

5. Pudendal nerve (2+3+4 sacral spinal nerves) In male: dorsal nerve of penis and superficial perineal nerve (scrotum and prepuce) In female: dorsal nerve of clitoris and nerve of mammary gland A. Pelvic nerve: sphinter ani externus B. prximal cutaneous: skin, semitend . C. distal cut.- medial thigh, perin . Skin D. deep perineal: bulbo cavernosus , sph . Ani, ext. and urethralis musc . Middle haemarrhoidal : (3+4 Sacral): coccy . Levator ani Caudal rectal(4 sacral): rectum and above