A 43-year-old man comes to the office due to difficulty walking. The patient was seen at an outpatient clinic 2 days ago and received a right-sided deep intramuscular injection. He had no trouble walking at the time of the appointment but started having problems later that day. The patient has no history of trauma or pain at the injection site. Physical examination is negative for local erythema and swelling, and the patient has full strength against resistance on knee flexion and ankle plantar flexion bilaterally. When the patient is asked to walk across the room, his left hip drops every time he raises his left foot. Which of the following locations is the most likely site of this patient's intramuscular injection?

Question

A 43-year-old man comes to the office due to difficulty walking.  The patient was seen at an outpatient clinic 2 days ago and received a right-sided deep intramuscular injection.  He had no trouble walking at the time of the appointment but started having problems later that day.  The patient has no history of trauma or pain at the injection site.  Physical examination is negative for local erythema and swelling, and the patient has full strength against resistance on knee flexion and ankle plantar flexion bilaterally.  When the patient is asked to walk across the room, his left hip drops every time he raises his left foot.  Which of the following locations is the most likely site of this patient's intramuscular injection?

Quizplus · Accepted Answer

11ec160b_35eb_a6f2_9249_632dd563b8e3_MD0001_00 This patient is exhibiting classic Trendelenburg gait (ie, gluteus medius gait), which is characterized by hip drop on the contralateral, unaffected side when that foot is raised. This gait is observed when there is injury to the superior gluteal nerve or to the gluteus medius muscle. The superior gluteal nerve is derived from the L4-S1 ventral rami and leaves the pelvis through the greater sciatic foramen above the level of the piriformis. Injections into the superomedial quadrant of the buttock have a high probability of injuring the superior gluteal nerve. (Choices A, B, and C) Due to its large size, the sciatic nerve is at risk of injury following an injection in any quadrant of the buttock or the superior portion of the posterior thigh. However, the sciatic nerve innervates the knee flexors (eg, hamstrings) and leg/foot muscles, and injury to the nerve would cause weakness in knee flexion and ankle plantarflexion (eg, foot drop) rather than Trendelenburg gait. (Choice D) The superolateral quadrant of the buttocks is considered the safest place for dorsogluteal injections. However, damage to the gluteal and sciatic nerves can still result from injections into this region. Most intragluteal injections should target the anterolateral gluteal area (ie, von Hochstetter triangle) to minimize the possibility of nerve damage. Educational objective: Injections given in the superomedial quadrant of the buttock have a high risk of injuring the superior gluteal nerve, resulting in gluteus medius weakness and Trendelenburg gait. The superolateral quadrant of the buttock is a relatively safe site for intragluteal injections, although the anterolateral gluteal region is preferred. __________ References: Injection nerve palsy. (http://www.ncbi.nlm.nih.gov/pubmed/23546341) Sciatic nerve injury from intramuscular injection: a persistent and global problem. (http://www.ncbi.nlm.nih.gov/pubmed/20670272)

A 43-Year-Old Man Comes to the Office Due to Difficulty