Deck 17: The Spinal Nerves and Spinal Nerve Blocks

Question 1

A 60-year-old woman fell down the stairs and was admitted to the emergency department with severe right shoulder pain. On examination, the patient was sitting up with her right arm by her side and her right elbow joint supported by her left hand. Inspection of the right shoulder showed loss of the normal rounded curvature and evidence of a slight swelling below the right clavicle. Any attempt at active or passive movement of the shoulder joint was stopped by severe pain in the shoulder. A diagnosis of dislocation of the right shoulder joint was made.

-The following statements concerning this patient are consistent with the diagnosis except which?

A) This patient had a subcoracoid dislocation of the right shoulder joint.
B) The head of the humerus was dislocated downward through the weakest part of the capsule of the joint.
C) The pull of the pectoralis major and subscapularis muscles had displaced the upper end of the humerus medially.
D) The greater tuberosity of the humerus no longer displaced the deltoid muscle laterally, and the curve of the shoulder was lost.
E) The integrity of the axillary nerve should always be tested by touching the skin over the upper half of the deltoid muscle.

Answer 1

The integrity of the axillary nerve should always be tested by touching the skin over the upper half of the deltoid muscle.

Question 2

A young housewife was on a ladder cleaning a window in her home, when she lost her balance and started to fall. To protect herself, she held out her right hand, which smashed through the glass. On admission to the hospital, she was bleeding profusely from a superficial laceration in front of her right wrist. She had sensory loss over the palmar aspect of the medial one and a half fingers but normal sensation of the back of these fingers over the middle and proximal phalanges. She had difficulty in grasping a piece of paper between her right index and middle fingers. All her long flexor tendons were intact.

-The following statements concerning this patient are correct except which?

A) The ulnar artery was cut in front of the flexor retinaculum, and this accounted for the profuse bleeding.
B) The loss of skin sensation on the palmar aspect of the medial one and a half fingers was caused by the severance of the median nerve as it crossed in front of the flexor retinaculum.
C) The normal sensation on the back of the medial one and a half fingers over the proximal phalanges was caused by the fact that the posterior cutaneous branch of the ulnar nerve arises about $2.5 \mathrm{in}$ . $(6.25 \mathrm{~cm})$ proximal to the flexor retinaculum and was spared.
D) The inability to hold the piece of paper was caused by the paralysis of the second palmar interosseous muscle, which is supplied by the deep branch of the ulnar nerve.
E) There was no sensory loss on the palm of the hand because the palmar cutaneous branch of the ulnar nerve was not cut.

Answer 2

The loss of skin sensation on the palmar aspect of the medial one and a half fingers was caused by the severance of the median nerve as it crossed in front of the flexor retinaculum.

Question 3

A 50-year-old woman complaining of severe "pins and needles" in her right hand and lateral fingers visited her physician. She said that she had experienced difficulty in buttoning up her clothes when dressing. On physical examination the patient pointed to her thumb and index, middle, and ring fingers as the areas where she felt discomfort. No objective impairment of sensation was found in these areas. The muscles of the thenar eminence appeared to be functioning normally, although there was some loss of power compared with the activity of the muscles of the left thenar eminence.

-The following statements concerning this patient are correct except which?

A) Altered skin sensation was felt in the skin areas supplied by the digital branches of the median nerve.
B) The muscles of the thenar eminence showed some evidence of wasting as seen by flattening of the thenar eminence.
C) The muscles of the thenar eminence are supplied by the recurrent muscular branch of the median nerve.
D) The median nerve enters the palm through the carpal tunnel.
E) The median nerve occupies a large space between the tendons behind the flexor retinaculum.
F) This patient has carpal tunnel syndrome.

Answer 3

The median nerve occupies a large space between the tendons behind the flexor retinaculum.

Question 4

A 6-year-old boy, running along a concrete path with a glass jam jar in his hand, slipped and fell. The glass from the broken jar pierced the skin on the front of his left wrist. On examination a small wound was present on the front of the left wrist and the palmaris longus tendon had been severed. The thumb was laterally rotated and adducted, and the boy was unable to oppose his thumb to the other fingers. There was loss of skin sensation over the lateral half of the palm and the palmar aspect of the lateral three and a half fingers.

-The following facts concerning this patient are correct except which?

A) Sensory loss of the distal part of the dorsal surfaces of the lateral three and a half fingers was experienced.
B) The median nerve lies superficial to the palmaris longus proximal to the flexor retinaculum and was severed by the piece of glass.
C) The median nerve lies in the interval between the tendons of the flexor digitorum superficialis and the flexor carpi radialis muscles just proximal to the wrist joint.
D) Adduction of the thumb was produced by the contraction of the adductor pollicis muscle, which is supplied by the ulnar nerve.
E) The palmar cutaneous branch of the median nerve had been severed.

Question 5

A 52-year-old woman was admitted to the hospital with a diagnosis of right-sided pleurisy with pneumonia. It was decided to remove a sample of pleural fluid from her pleural cavity. The resident inserted the needle close to the lower border of the eighth rib in the anterior axillary line. The next morning he was surprised to hear that the patient had complained of altered skin sensation extending from the point where the needle was inserted downward and forward to the midline of the abdominal wall above the umbilicus.

-The altered skin sensation in this patient after the needle thoracostomy could be explained by which?

A) The needle was inserted too low down in the intercostal space.
B) The needle was inserted too close to the lower border of the eighth rib and damaged the eighth intercostal nerve.
C) The needle had impaled the eighth rib.
D) The needle had penetrated too deeply and pierced the lung.
E) There is a peritoneal abscess beneath the diaphragm on the left side.

Question 6

A 43-year-old man was involved in a violent quarrel with his wife over another woman. In a fit of rage, the wife picked up a carving knife and lunged forward at her husband, striking his anterior neck over the left clavicle. The husband collapsed on the kitchen floor, bleeding profusely from the wound. The distraught wife called an ambulance.

-On examination in the emergency department of the hospital, the following conditions were found except which?

A) A wound was seen about 1 in. $(2.5 \mathrm{~cm})$ wide over the left clavicle.
B) Auscultation revealed diminished breath sounds over the left hemithorax.
C) The trachea was deflected to the left.
D) The left upper limb was lying stationary on the table, and active movement of the small muscles of the left hand was absent.
E) The patient was insensitive to pin prick along the lateral side of the left arm, forearm, and hand.

Question 7

A 72-year-old man complaining of burning pain on the right side of his chest was seen by his physician. On examination the patient indicated that the pain passed forward over the right sixth intercostal space from the posterior axillary line forward as far as the midline over the sternum. The physician noted that there were several watery blebs on the skin in the painful area.

-The following statements are correct except which?

A) This patient has herpes zoster.
B) A virus descends along the cutaneous nerves, causing dermatomal pain and the eruption of vesicles.
C) The sixth right intercostal nerve was involved.
D) The condition was confined to the anterior cutaneous branch of the sixth intercostal nerve.

Question 8

An obese 40-year-old woman was seen in the emergency department complaining of a severe pain over the right shoulder and in her right side and back below the shoulder blade. She said that she had experienced the pain on several occasions before and that when she ate fatty foods it seemed to make the pain worse. Ultrasound demonstrated the presence of gallstones. Her condition was diagnosed as cholelithiasis, and the pain was attributed to gallstone colic.

-The symptoms and signs displayed by this patient can be explained by the following statement except which?

A)The fundus of the gallbladder lies against the anterior abdominal wall next to the tip of the right ninth costal cartilage.
B) The parietal peritoneum in this area is innervated by the tenth and eleventh intercostal nerves, which give rise to referred pain in the tenth and eleventh dermatomes on the side and back.
C) The parietal peritoneum on the central part of the undersurface of the diaphragm is supplied by the phrenic nerve.
D) The spinal segmental nerves within the phrenic nerve are $\mathrm{C} 3, \mathrm{C} 4$ , and $\mathrm{C} 5$ .
E) The pain was referred to the shoulder along the supraclavicular nerves (C3 and $\mathrm{C} 4)$ .

Question 9

An 8-year-old boy was admitted to the hospital with a temperature of $101^{\circ} \mathrm{F}$ , a furred tongue, and pain in the right lower quadrant. On examination, the skin on the right lower quadrant was tender to the touch, and the abdominal muscles were contracted and rigid. A diagnosis of acute appendicitis was made.

-The symptoms and signs displayed by this patient can be explained by the following statements except which?

A) An acutely inflamed appendix produces an inflammation of the peritoneal coat covering it.
B) Should the inflammatory process spread, for example, if the appendix should rupture, the parietal peritoneum would become involved.
C) The parietal peritoneum, the abdominal muscles, and the overlying skin are supplied by the same segmental spinal nerves.
D) The segmental nerves supplying the right lower quadrant of the abdominal wall are $\mathrm{T} 7, \mathrm{~T} 8$ , and $\mathrm{T} 9$ .
E) The pain in the right lower quadrant and the regional contraction of the abdominal muscles are attempts by the body to keep the inflamed appendix immobile so that the inflammatory process remains localized.

Question 10

A 45-year-old woman was shopping in a liquor store when an armed robbery took place. A shoot-out occurred and a bullet ricocheted off the wall and entered her left side. Fortunately, the bullet did not enter the peritoneal cavity. One year later, in addition to diminished skin sensation over the left lumbar region and umbilicus, she noticed a bulging forward of the left side of her anterior abdominal wall.

-The symptoms and signs displayed by this patient can be explained by the following statements except which?

A) The bullet cut the ninth and tenth intercostal nerves just below the costal margin on the left side.
B) The diminished skin sensation was caused by the loss of the sensory nerve supply to the ninth and tenth thoracic dermatomes.
C) Portions of the oblique, transversus, and rectus abdominis muscles on the left side were paralyzed.
D) Atrophy of the pyramidalis muscle resulted in loss of support to the abdominal viscera, which then sagged forward.

Question 11

After a major abdominal operation, a patient was given a course of antibiotics by intramuscular injection. The nurse was instructed to give the injections into the right buttock. Later, when the patient left the hospital, he developed several symptoms and signs that suggested that the injections into the gluteus maximus muscle had been given over the course of the sciatic nerve and had caused a lesion of the common peroneal nerve.

-The symptoms and signs displayed by this patient included the following except which?

A) He experienced numbness and tingling sensations down the anterior and lateral sides of the right leg and the dorsum of the foot.
B) His right foot tended to catch on steps and on the edges of the carpet.
C) On testing, he had impaired skin sensation on the lateral side of the right thigh.
D) The patient tended to hold the foot plantar flexed and slightly inverted.
E) Dorsiflexion of the right ankle joint was weaker than the same movement of the left ankle.
F) The everter muscles of the right midtarsal joints were weaker than those of the opposite side.

Question 12

A 17-year-old girl was dealing drugs on a street corner when she became involved in a fight. During the brawl she received a deep knife wound to the front of her right thigh. After a thorough examination in the emergency department of the local hospital, it was determined that the knife point had severed the trunk of the right femoral nerve just below the inguinal ligament.

-This patient had the following signs and symptoms except which?

A) The right quadriceps femoris muscle failed to contract when the patient was asked to extend her right knee joint.
B) Skin sensation was lost over the anterior and medial sides of the thigh.
C) Skin sensation was lost along the medial border of the big toe.
D) Skin sensation was lost on the lower part of the leg and the medial border of the foot as far as the ball of the big toe.
E) Weak extension of the knee was possible when walking because of the use of the adductor muscles.

Question 13

A patient was seen in the emergency department with a laceration of the skin over the middle phalanx of the left index finger. What is the sensory nerve supply of that finger? Where is it possible to perform a nerve block so that the wound could be sutured?

Question 14

A 37-year-old woman was involved in an automobile accident and sustained a fracture of her sixth right rib. It was decided to relieve her acute pain caused by the broken rib by performing an intercostal nerve block. Which intercostal nerve innervates the sixth rib? What is the course taken by an intercostal nerve in an intercostal space? From what part of a spinal nerve is an intercostal nerve formed? Name the order of structures forming the neurovascular bundle in an intercostal space from above downward.

Question 15

A 17-year-old boy received a knife wound on the lateral side of his right thigh. What is the sensory nerve supply to this region of the thigh? Which important surface landmarks would you use when blocking the nerves?

Question 16

What is the sensory nerve supply to the skin on the dorsum of the foot? Where would you block these nerves?