the effectors of the somatic nervous system are

Generally, all sensory information passes into the posterior aspect of the spinal cord, and all motor fibers leave anteriorly. The clusters of sensory nerve cell bodies derived from neural crest cells and located outside the CNS form sensory ganglia. Somatic sensory and somatic motor fibers that are organized segmentally along the neural tube become parts of all spinal nerves and some cranial nerves. Neurons that develop from cells within the spinal cord are motor neurons and those that develop from neural crest cells are sensory neurons. Lateral processes pass into the differentiating regions of the adjacent dermatomyotome. Medial processes pass into the posterior aspect of the neural tube. Simultaneously, derivatives of neural crest cells (cells derived from neural folds during formation of the neural tube) differentiate into neurons on each side of the neural tube and extend processes both medially and laterally ( Fig. If this potential event is not anticipated and accounted for, severe bladder perforation may occur.

Electrocautery employed during a transurethral resection of bladder tumor (TURBT) procedure may result in obturator nerve stimulation with subsequent rapid, forceful hip adduction. The function of the obturator nerve includes hip adduction via motor innervation to the medial thigh compartment, which is of clinical significance during lateral transurethral resection and pelvic lymph node dissection. The obturator nerve originates from the anterior rami of L2-L4 posterior to the psoas muscle and courses inferiorly to the obturator canal. The lateral cutaneous nerve of the thigh (lateral femoral cutaneous nerve) arises from L2 and 元 and provides sensory innervation to the anterior and lateral thigh. The genitofemoral nerve may be injured during a psoas hitch procedure (suture placement) and laparoscopic varicocelectomy (ligation).

In addition to the motor component, the genital branch supplies sensation to the anterior scrotum in males and the mons pubis and labium majus in females. This motor component allows for contraction of the muscle during the cremasteric reflex. The genital branch enters the inguinal canal at the deep internal ring to provide motor innervation to the cremaster muscle. The femoral branch passes under the inguinal ligament and enters the femoral sheath to supply sensation to the upper anterior thigh. The nerve typically divides near the level of the inguinal ligament. The genitofemoral nerve originates from L1 and L2 and courses anterior and parallel to the psoas muscle. They provide innervation to the muscles of the abdominal wall and sensory innervation to the posterolateral gluteal skin, upper medial thigh, and genitalia.

These three nerves run laterally over the anterior aspect of the quadratus lumborum and travel through the transversus abdominis to run deep to the internal oblique muscle. The ilioinguinal and iliohypogastric nerves arise from the anterior ramus of L1. The subcostal nerve is an extension of the 12th thoracic nerve and runs inferior to the 12th rib. Diagrammatic representation of the lumbosacral nervous plexus.

The effectors of the somatic nervous system are