A 54-year-old woman comes to the office due to right upper limb weakness and fatigue. She has no problem during most activities but develops symptoms when attempting to raise her arm overhead. The patient first noticed the symptoms after a recent hospitalization. On examination, there is no sensory loss in the upper extremities, but she has difficulty abducting her right arm past the horizontal position. The patient is instructed to press her outstretched arms against a wall, and the medial border of the right scapula lifts off the thoracic wall and becomes prominent. This patient was most likely hospitalized for which of the following conditions?

Question

A 54-year-old woman comes to the office due to right upper limb weakness and fatigue.  She has no problem during most activities but develops symptoms when attempting to raise her arm overhead.  The patient first noticed the symptoms after a recent hospitalization.  On examination, there is no sensory loss in the upper extremities, but she has difficulty abducting her right arm past the horizontal position.  The patient is instructed to press her outstretched arms against a wall, and the medial border of the right scapula lifts off the thoracic wall and becomes prominent.  This patient was most likely hospitalized for which of the following conditions?

Quizplus · Accepted Answer

This patient has paralysis of the serratus anterior muscle due to long thoracic nerve injury. The serratus anterior originates on the surface of the first 8 ribs and inserts on the medial border of the scapula. It functions to stabilize and rotate the scapula upward. The deltoid and supraspinatus muscles abduct the arm up to the horizontal position, after which the serratus anterior and trapezius are required to rotate the glenoid cavity superiorly, thereby allowing complete abduction of the arm over the head. Innervation of the serratus anterior is from the long thoracic nerve, which arises from the C5-C7 nerve roots via the brachial plexus and follows a lengthy course along the lateral chest wall. Injury to the nerve can occur during penetrating trauma or iatrogenically during axillary lymph node dissection or chest tube insertion. Paralysis of the serratus anterior causes scapular winging due to inability of the serratus to hold the scapula against the thorax. Patients will also show weakness in abducting the arm above horizontal due to impaired rotation of the scapula. (Choice A) Anterior dislocation of the shoulder or fracture of the neck of the humerus can injure the axillary nerve. This causes paralysis of the deltoid and teres minor muscles and localized sensory loss in the upper arm. (Choice B) Clavicular fracture only occasionally causes neurovascular compromise, usually involving the subclavian vessels and supraclavicular nerve. (Choice D) Thyroidectomy may cause injury to the recurrent laryngeal nerve. Injury causes weakness of the posterior cricoarytenoid muscles, with hoarseness and impaired breathing. (Choice E) Injury to the upper brachial plexus (musculocutaneous and suprascapular nerves) can occur due to traction between the head and shoulder. This can occur in the neonate due to dystocia or in the adult from violent injury. The resulting palsy is characterized by shoulder adduction, elbow extension, and forearm pronation. Educational objective: Dissection of the axillary lymph nodes can injure the long thoracic nerve. This results in weakness of the serratus anterior with winging of the scapula and impaired abduction of the shoulder past the horizontal. __________ References: Long thoracic nerve injury in breast cancer patients treated with axillary lymph node dissection. (http://www.ncbi.nlm.nih.gov/pubmed/25035064)

A 54-Year-Old Woman Comes to the Office Due to Right