Intercostal nerves

Assisting the diaphragm with inspiration are the external intercostal muscles, which connect adjacent ribs. When the external intercostal muscles contract, the ribs are lifted upward and outward (much like a handle on a bucket). Therefore, contraction of these muscles causes an increase in the horizontal dimension of the thoracic cavity and a further increase in thoracic volume. The external intercostal muscles are supplied by the intercostal nerves. 

Concomitant anesthesia - Certain forms of conduction anesthesia, such as spinal anesthesia and some peridural anesthetics, can alter respiration by blocking intercostal nerves. Fentanyl can also alter respiration through other mechanisms. 

The authors of this chapter have studied the effect of C and D toxin serotypes, as well as A, B, and E, on human intercostal muscle (Hihnas, unpublished data). All serotypes showed a similar ability to produce complete muscular paralysis in ex vivo human intercostal muscle. Intercostal muscle was excised from patients receiving a thoracotomy and intercostal muscle flap procedure. The muscle was removed tendon to tendon by surgical excision without electrocautery and dissected into multiple bundles with their associated intercostal nerves. The nerve-muscle units were placed in a vertical twitch bath and stimulated at 0.03 Hz (0.2 ms pulses of supramaximal strength) using a novel nerve clamp electrode to illicit an indirect muscle twitch. Potent toxins (1 nM) from various serotypes were added to the bath after confirming the stability of control muscle responses. In each case, twitch tensions declined to negligible amplitudes by 1 h after direct toxin application to the tissue bath. 

Brachial plexus anesthesia Buccal anesthesia Caudal anesthesia Cervical plexus anesthesia Dental anesthesia Digital anesthesia Epidural anesthesia Intercostal nerve anesthesia Interpleural anesthesia Intra-articular anesthesia Intradermal anesthesia Intrathecal (spinal) anesthesia Intravenous regional anesthesia Laryngeal anesthesia Lumbar plexus anesthesia Nasal anesthesia Neck anesthesia Obstetric anesthesia Ocular anesthesia Oropharyngeal anesthesia Otic anesthesia Paravertebral anesthesia Perianal anesthesia Peritonsillar anesthesia Respiratory anesthesia Sciatic nerve anesthesia Stellate ganglion anesthesia... 

High spinal anesthesia after inadvertent injection is a possible complication of intercostal nerve block (SED-12, 252). Pneumothorax is another reported complication (55). 

Injection of a local anesthetic into or around individual peripheral nerves or nerve plexuses produces even greater areas of anesthesia than do the techniques described above. Blockade of mixed peripheral nerves and nerve plexuses also usually anesthetizes somatic motor nerves, producing skeletal muscle relaxation, which is essential for some surgical procedures. The areas of sensory and motor block usually start several centimeters distal to the site of injection. Brachial plexus blocks are particularly useful for procedures on the upper extremity and shoulder. Intercostal nerve blocks are effective for anesthesia and relaxation of the anterior abdominal wall. Cervical plexus block is appropriate for surgery of the neck. Sciatic and femoral nerve blocks are useful for surgery distal to the knee. Other useful nerve blocks prior to surgical procedures include blocks of individual nerves at the wrist and at the ankle, blocks of individual nerves such as the median or ulnar at the elbow, and blocks of sensory cranial nerves. 

The respiration rate is altered by changes in the chemical composition of the blood, and also as a result of emotional stress or voluntary efforts. Passing from quiet respiration to dyspnea affects different nerves, such as the intercostal nerve. Breathing patterns are controlled by a complex network of neurons connected to efferent fibers chemoreceptors, stretch receptors, pressure receptors. The efferent fibers send impulses to the motor nuclei in the spinal cord, and from there the impulse is transferred to the respiratory muscles. 

In thoracotomy studies, damage to the intercostal nerves sustained from direct pressure, stretching and ischemia may contribute however, some investigators have shown little relationship between nerve injirry and chronic pain after 3 months. 

Surgical acute pain amitriptyline may be beneficial for adjunctive use for pain control as well as nighttime sedation. Patients recovering from amputation, traumatic or surgical nerve injuries (intercostal nerves, branches of the brachial plexus, inguinal and genitofemoral nerve, etc.). Consider starting dose of 12.5-25 mg qhs and increase to 50 mg as tolerated. Monitor for urinary retention/constipation that may coincide with post-operative symptoms. Consider nortriptyline or desipramine to reduce side effects. 

The vertebral region is supplied primarily by dorsal rami, and the ventral rami form the eleven pairs of Intercostal nerves and the pair of subcostal nerves. They begin in the intercostal space and then enter the costal groove of the first through eleventh ribs at the level of the angle. The intercostals connect to the sympathetic chain via the rami communicantes. The sympathetic trunks are located anterior to the heads ol the ribs. 

The electrode is inserted two-fingers breadth lateral to the abdominal midline. The exact point of insertion will depend upon the intercostal nerve to be evaluated. The supraumbilical portion is supplied by T7-8-9 the umbilical portion by TIO and the infraumbili-cal portion by T11-T12. 

By phrenic nerves (C3-4-5) and peripherally by lower intercostal nerves (T6-11). 

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