Question

Following a major operation, a patient was placed on a course of antibiotics which were to be delivered via intramuscular injection to the buttocks. After one of these injections, the the patient complained of more pain than usual in the region of the injection. Later, as the patient was taking his afternoon walk in the hall, the nurse noticed that he was walking with a limp that had not been present before-his left hip dropped every time he lifted his left foot off the floor, but on the right side, his pelvis remained level when he lifted up his right foot. The doctor was called, and after a brief examination, she concluded that the injection had damaged a nerve that resulted in muscle weakness, which caused the patient's unusual limp. a. Based on the description above, which muscles are affected? On which side? b. What might other structures in the posterior hip/buttock region be damaged by an inappropriately administered intramuscular injection or other penetrating injury? (You will need to reference an atlas for some nerves and blood vessels in the area.) c. Why might an intramuscular injection be used instead of a subcutaneous or intravenous injection? d. What is the clinical name given to the symptoms the patient displayed following the injury and what other conditions might cause it? (This was briefly discussed in class.)

Answer 1

The patient likely has a damaged gluteus medius muscle on the left side, resulting in a Trendelenburg gait. Damage to the sciatic nerve and major blood vessels could also occur from an improper injection. An intramuscular injection may be preferred for a slower, more sustained release of medication.

Step-by-step explanation:

The patient's symptoms suggest that the gluteus medius muscle on the left side might have been affected by the intramuscular injection, leading to a condition known as Trendelenburg gait or Trendelenburg sign. The gluteus medius is responsible for stabilizing the pelvis during the stance phase of walking. When it is weakened, it cannot prevent the dropping of the contralateral hip, resulting in the pelvis tilting downwards on the opposite side of the weakened muscle when lifting the foot.

Other structures that could be damaged in the posterior hip/buttock region due to an improperly administered injection include the sciatic nerve, which is a major nerve formed from the lower lumbar and sacral spinal nerves. This nerve runs very close to the surface in the buttocks and can be damaged if an injection is given too medially. Damage to the sciatic nerve can cause pain, numbness, or weakness in the lower limb. Also, major blood vessels like the superior and inferior gluteal arteries and veins might be at risk.

An intramuscular injection may be used instead of subcutaneous or intravenous injection when a slower release of medication into the bloodstream is desired, or when a drug might irritate veins or is too viscous for subcutaneous injection.

This patient's limping and inability to maintain pelvis level is known as Trendelenburg gait or Trendelenburg sign. Conditions that might cause similar symptoms include severe hip osteoarthritis, congenital hip dislocation, or muscular dystrophy.

Learn more about Trendelenburg gait