Deck 13: Skeletal Muscles

Question 1

In a 63-year-old man, a magnetic resonance imaging scan of the lower thoracic region of the vertebral column reveals the presence of a tumor pressing on the lumbar segments of the spinal cord. He has a loss of sensation in the skin over the anterior surface of the left thigh and is unable to extend his left knee joint. Examination reveals that the muscles of the front of the left thigh have atrophied and have no tone and that the left knee jerk is absent.

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

A) The tumor is interrupting the normal function of the efferent motor fibers of the spinal cord on the left side.
B) The quadriceps femoris muscles on the front of the left thigh are atrophied.
C) The loss of skin sensation is confined to the dermatomes Ll, 2, 3, and 4.
D) The absence of the left knee jerk is because of involvement of the first lumbar spinal segment.
E) The loss of muscle tone is caused by interruption of a nervous reflex arc.

Answer 1

The absence of the left knee jerk is because of involvement of the first lumbar spinal segment.

Question 2

A woman recently took up employment in a factory. She is a machinist, and for 6 hours a day she has to move a lever repeatedly, which requires that she extend and flex her right wrist joint. At the end of the second week of her employment, she began to experience pain over the posterior surface of her wrist and noticed a swelling in the area.

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

A) Extension of the wrist joint is brought about by several muscles that include the extensor digitorum muscle.
B) The wrist joint is diseased.
C) Repeated unaccustomed movements of tendons through their synovial sheaths can produce traumatic inflammation of the sheaths.
D) The diagnosis is traumatic tenosynovitis of the long tendons of the extensor digitorum muscle.

Answer 2

The wrist joint is diseased.

Question 3

A 43-year-old woman was seen in the emergency department with a large abscess in the middle of the right posterior triangle of the neck. The abscess was red, hot, and fluctuant. The abscess showed evidence that it was pointing and about to rupture. The physician decided to incise the abscess and insert a drain. The patient returned to the department for the dressings to be changed 5 days later. She stated that she felt much better and that her neck was no longer painful. However, there was one thing that she could not understand. She could no longer raise her right hand above her head to brush her hair.

-The following statements explain the signs and symptoms in this case, suggesting that the spinal part of the accessory nerve had been incised, except which?

A) To raise the hand above the head, it is necessary for the trapezius muscle, assisted by the serratus anterior, to contract and rotate the scapula so that the glenoid cavity faces upward.
B) The trapezius muscle is innervated by the spinal part of the accessory nerve.
C) As the spinal part of the accessory nerve crosses the posterior triangle of the neck, it is deeply placed, being covered by the skin, the superficial fascia, the investing layer of deep cervical fascia, and the levator scapulae muscle.
D) The surface marking of the spinal part of the accessory nerve is as follows: Bisect at right angles a line joining the angle of the jaw to the tip of the mastoid process. Continue the second line downward and backward across the posterior triangle.
E) The knife opening the abscess had cut the accessory nerve.

Answer 3

As the spinal part of the accessory nerve crosses the posterior triangle of the neck, it is deeply placed, being covered by the skin, the superficial fascia, the investing layer of deep cervical fascia, and the levator scapulae muscle.

Question 4

A 46-year-old man was seen in the emergency department after being knocked down in a street brawl. He had received a blow on the head with an empty bottle. On examination, the patient was conscious and had a large gaping wound on the top of the head.

-Why did the wound in this patient gape wide open when he was hit with a blunt object and not a knife?

A) The skin on the top of the head was excessively tight.
B) The blow of the bottle had split the epicranial aponeurosis against the underlying skull and the tone of the occipitofrontalis muscle had pulled the skin wound open.
C) The subcutaneous tissue of the scalp contains smooth muscle, which pulled the wound open.
D) A hematoma was formed beneath the scalp and forced the wound open.
E) The underlying parietal bone of the skull was fractured and forced the wound open.

Question 5

A 75-year-old woman was dusting the top of a high closet while balanced on a chair. She lost her balance and fell to the floor, catching her right lumbar region on the edge of the chair.

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

A) A lumbar puncture (spinal tap) should always be performed in back injuries to exclude damage to the spinal cord.
B) Anteroposterior and lateral radiographs exclude the presence of a fracture, especially of a transverse process.
C) A 24-hour specimen of urine should be examined for blood to exclude or confirm injury to the right kidney.
D) Careful examination of the erector spinae muscles or quadratus lumborum muscle may reveal extreme tenderness and therefore injury to these muscles.
E) Examination of the back revealed a large bruised area in the right lumbar region, which was extremely tender to touch.

Question 6

A resident obtained a sample of pleural fluid from a patient's right pleural cavity. He inserted the needle close to the upper border of the sixth rib in the anterior axillary line.

-Name the muscles that the needle pierced in order to enter the pleural cavity.

A) Trapezius and latissimus dorsi
B) Trapezius and serratus anterior
C) Serratus anterior, external intercostal, internal intercostal, and innermost intercostal
D) External intercostal and internal intercostal
E) Latissimus dorsi, serratus anterior, and external intercostal

Question 7

A 75-year-old man with chronic bronchitis noticed that a bulge was developing in his left groin. On examination, an elongated swelling was seen above the medial end of the left inguinal ligament. When the patient coughed, the swelling enlarged but did not descend into the scrotum. The patient had weak abdominal muscles.

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

A)The inguinal swelling was a direct inguinal hernia.
B) The cause of the hernia was weak abdominal muscles.
C) The hernial sac was wide and in direct communication with the peritoneal cavity.
D) A rise in intraabdominal pressure on coughing caused the hernial swelling to expand.
E) The swelling did not involve the conjoint tendon.

Question 8

A 40-year-old woman noticed a painful swelling in her right groin after helping her husband move some heavy furniture. On examination, a small tender swelling was noted in the right groin.

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

A) The neck of a femoral hernial sac is situated below and medial to the pubic tubercle.
B) A hernial sac formed of parietal peritoneum was forced downward.
C) The peritoneum was forced through the right femoral canal.
D) The patient had a right-sided femoral hernia.
E) The excessive exertion caused a rise in intraabdominal pressure.

Question 9

Following a sudden severe blow on the anterior abdominal wall from the hind leg of a horse, a patient complained of pain and swelling below the umbilicus. On examination, extensive bruising of the skin was observed over the lower part of the right rectus muscle. On gentle palpation, a deep swelling confined to the right rectus sheath was felt. Given that the deep swelling was due to a collection of blood (hematoma), which blood vessels were likely to have been ruptured?

Question 10

In a patient with a history of tuberculosis, an angular kyphosis of the lumbar vertebral column suddenly developed. On examination, a swelling was found in the groin, just below the right inguinal ligament. On deep palpation of the anterior abdominal wall above the right inguinal ligament, a further swelling could be felt. Digital pressure on the first swelling caused expansion of the second swelling and vice versa. What is the diagnosis? Explain the swelling in anatomical terms.

Question 11

A multiparous 57-year-old woman visited her gynecologist complaining of a "bearing-down" feeling in the pelvis and of low backache, both of which were worse when she was tired. On vaginal examination, the external os of the cervix was found to be located just within the vaginal orifice. A diagnosis of uterine prolapse was made. What are the main supports of the uterus?

Question 12

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.

Question 13

Following a radical mastectomy operation a woman noticed that her right shoulder blade projected backwards. Can you explain this deformity?

Question 14

A 40-year-old man visited his physician complaining of pain of 3 weeks' duration in his right shoulder. On examination, the patient could actively abduct his right shoulder to $50^{\circ}$ ; thereafter, he experienced severe pain that prevented further movement. If the arm was then passively raised above a right angle, it could be held actively without pain in that position. If the patient attempted to lower the arm, he again experienced severe pain in the middle range of abduction. What is your diagnosis?

Question 15

A 64-year-old man consulted his physician because he had noticed during the past 6 months a thickening of the skin at the base of his left ring finger. As he described it: "There appears to be a band of tissue that is pulling my ring finger into the palm." On examination of the palms of both hands, a localized thickening of subcutaneous tissue could be felt at the base of the left ring and little fingers. The metacarpophalangeal joint of the ring finger could not be fully extended, either actively or passively.

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

A) The deep fascia beneath the skin of the palm is thickened to form the palmar aponeurosis.
B) The distal end of the aponeurosis gives rise to five slips to the five fingers.
C) Each slip is attached to the base of the proximal phalanx and to the fibrous flexor sheath of each finger.
D) Fibrous contraction of the slip to the ring finger resulted in permanent flexion of the metacarpophalangeal joint.
E) The patient had Dupuytren's contracture.

Question 16

A 54-year-old man was told by his physician to reduce his weight. He was prescribed a diet and was advised to exercise more. One morning while jogging, he heard a sharp snap and felt a sudden pain in his right lower calf. On examination in the emergency department, the physician noted that the upper part of the right calf was swollen and a gap was apparent between the swelling and the heel. A diagnosis of rupture of the right Achilles tendon was made.

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

A) With the patient supine, gentle squeezing of the upper part of the right calf did not produce plantar flexion of the ankle joint.
B) The Achilles tendon is the tendon of insertion of the gastrocnemius and soleus muscles.
C) The Achilles tendon is inserted into the posterior surface of the talus.
D) Rupture of the Achilles tendon results in the bellies of the gastrocnemius and soleus muscles retracting upward, leaving a gap between the divided ends of the tendon.
E) Normally, the gastrocnemius and soleus muscles are the main muscles responsible for plantar flexion of the ankle joint.

Question 17

A 25-year-old man was admitted to the emergency department after an automobile accident. Apart from other superficial injuries, he was found to have a fracture of the middle third of the right femur.

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

A) The soleus muscle was responsible for the backward rotation of the distal fragment.
B) A lateral radiograph showed overlap of the fragments, with the distal fragment rotated backward.
C) A large amount of force would be necessary to restore the leg to its original length.
D) The hamstrings and quadriceps femoris muscles were responsible for the leg shortening.
E) The right leg was 2 in. $(5 \mathrm{~cm})$ shorter than the left leg.

Question 18

A 42-year-old woman was seen in the emergency department after slipping on some ice on the way to work. She complained of pain on movement of her right ankle joint. The physician asked the patient to evert her right foot. Which of the following muscles everts the foot?

A) The tibialis anterior muscle
B) The flexor hallucis longus muscle
C) The peroneus longus muscle
D) The tibialis anterior muscle.
E) The flexor digitorum longus muscle.

Question 19

A 61-year-old woman was being examined for osteoarthritis of the left hip joint by an orthopedic surgeon. He flexed the left hip joint with the knee flexed. What structure normally limits the flexion of this joint with the knee flexed?

A) The hamstring muscles
B) The iliofemoral ligament
C) The adductor magnus muscle
D) The anterior abdominal wall
E) The ischiofemoral ligament

Question 20

A physician's assistant asked a patient to walk up and down the examining room so that she might study his gait. Which of the following muscles plays an important role in lifting the left foot off the ground while walking?

A) The left gluteus medius muscle
B) The left gluteus maximus muscle
C) The right adductor longus muscle
D) The right gluteus medius muscle
E) None of the above.