Rectum: Lower lumbar ganglia by inferior mesenteric and plevic plexuses, through superior and inferior hemorrhoidal plexus to rectum. Adjustment L 4 or 5. Visceral branches from the third and fourth sacral nerves also pass directly to the rectal wall and sacral adjustment may affect rectum or anus.
Bladder: The urinary bladder is innervated by the vesical plexus from the pelvic, and by sacral nerve fibres direct. It is said that the vesical plexus contains many spinal nerve fibres which are derived from the second and fourth lumbar nerves especially. Clinically the second or the fourth lumbar will control the bladder much oftener than the sacrum.
Prostate Gland, Seminal Vesicles, Penis, and Urethra: By the vesical and prostatic plexuses derived from the pelvic plexuses, divisions of the hypogastric plexus, which is formed of the abdominal aortic plexus and filaments from the lumbar ganglia. The latter receive filaments from the second and third lumbar nerves. There is a connection with the sacral nerves also by the pelvic plexus, though the lumbar adjustment appears the more potent.
Testes and Scrotum: Ilioinguinal from second lumbar, genital branch of genito-femoral from second and third lumbar nerves, internal pudic nerve from the pudendal plexus, and spermatic and pelvic plexuses. The most effective adjustment for scrotal or testicular diseases is L 3.
Uterus and Vagina: Uterovaginal plexus from the pelvic and containing spinal nerve fibres from L 4, L 5, and sacrum.
Ovaries and Fallopian Tubes: The ovarian plexus receives fibres from the abdominal aortic and through it from the lumbar ganglia, influenced by second lumbar adjustment.
Brachial Plexus: The brachial plexus of spinal nerves arises from the nerves from the fifth cervical to the first thoracic inclusive and controls the voluntary muscles of the upper extremity, with its integument. Muscle groups, rather than single muscles, are represented for the most part in the spinal segments giving off these nerves, and the ramification of the nerves within the plexus is such that almost any given muscle might be affected by more than one spinal subluxation. Below are given the principal connections:
Pectoralis Major and Minor Muscles: Sixth or seventh cervical through internal anterior thoracic nerve and first dorsal through external anterior thoracic.
Shoulder Joint: The joint, muscles covering the joint, and integument of this region are innervated by the circumflex nerve which traces through the plexus to fifth and sixth cervical nerves. Sixth cervical adjustment usually affects this joint.