Case Report

Volume 5, Number 2, February 2014, pages 120-122

Neurogenic Thoracic Outlet Syndrome: Causing by Cervical Rib

Thoracic outlet syndrome is characterized by the presence of compressing to structure at thoracic outlet such as subclavian artery, subclavian vein and brachial plexus. The causes are cervical rib, abnormal posture, trauma, scalene muscle hypertrophy and fibrous band [1]. Cervical rib is a congenital anomaly which is originated from enlargement of the transverse process of C7. This anomaly occurs 1% of the population but induces the symptoms about 5% [2]. The symptoms are depended on compressed structure such as pale, swelling, edema, numbness, weakness and pain [3]. As a result of various symptoms, the diagnosis of this syndrome is very complex [4].

Case twenty one years old female complained a hard palpable mass at left supraclavicular area for 1 year. She underwent tissue biopsy that was diagnosed reactive lymphoid tissue. She felt numbness at left hand and forearm. Sometimes, she felt pain radiating from left shoulder to little finger. She denied other abnormalities. There was no previous history of trauma or systemic disease.

Physical examination revealed a firm mass at left supraclavicular area and no muscle atrophy. There were normal brachial and radial pulsations. Motor power was grade 5 all. Decreased pinprink sensation and temperature sensation at medial side of left hand were noted. Tinel’ sign was positive at left supraclavicular area. Adson’s test at left side was negative. The cervical spine radiograph showed bilateral cervical ribs with the left being more angulation (Fig. 1).

Click for large image

Figure 1. It shows bilateral cervical ribs. The arrow points out left cervical rib.

Nerve conduction studies (NCS) and needle electromyography were conducted. NCS showed prolong latency, normal amplitude and normal nerve conduction velocity at left ulnar motor and sensory nerves while left median motor, lateral antebrachial cutaneous and medial antebrachial cutaneous nerves were within normal range (Table1, 2). In needle electromyography showed normal study at left deltoid, biceps, brachioradialis and dorsal interosseous muscles. This result was summarized to sign of focal demyelin involvement at left ulnar nerve which may caused by neurogenic thoracic outlet syndrome.

Therefore, operation was done under general anesthesia. There was an angulated left cervical rib which was compromised to division of left brachial plexus. Partial left cervical rib resection was undergone by orthopedic surgeon (Fig. 2). There was no operation related complications. Four months after operation, she had no pain and felt better in sensation at left hand and forearm.

Click for large image

Figure 2. It shows partial left cervical rib resection.

The neurogenic thoracic outlet syndrome most commonly involves the lower cervical nerves of the brachial plexus [5]. The symptoms are most frequently impact the ulnar distribution as this case. The Adson’s test is done to mainly assess compression of the subclavian artery which is special test for vasculogenic thoracic outlet syndrome. This report showed neurogenic thoracic outlet syndrome from cervical rib, so the Adson’s test was also negative. Due to the relatively uncommon presentation of cervical rib, patients presenting with a neck mass should be thoroughly assessed to rule out any other pathology such as lymphadenopathy and carcinoma [6]. Cevical rib is usually asymptomatic and may not require any treatment [7]. However, in this case reveals neck mass with persistent pain and numbness. So, it is an indication for surgery.

Diagnosis and treatment of thoracic outlet syndrome is not simple routine. Adequate investigations are required. It is important for physician to be careful to detect cause of thoracic outlet syndrome.

Click to view

Table 1. Motor Nerve Conduction Studies

Click to view

Table 2. Sensory Nerve Conduction Studies

Grant Support

No grant support, No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated.

1. Luoma A, Nelems B. Thoracic outlet syndrome. Thoracic surgery perspective. Neurosurg Clin N Am. 1991;2(1):187-226.
   pubmed
2. Pollack EW. Surgical anatomy of the thoracic outlet syndrome. Surg Gynecol Obstet. 1980;150(1):97-103.
   pubmed
3. Oates SD, Daley RA. Thoracic outlet syndrome. Hand Clin. 1996;12(4):705-718.
   pubmed
4. Wilbourn AJ. Thoracic outlet syndrome is overdiagnosed. Muscle Nerve. 1999;22(1):130-136, discussion 136-137.
   doi
5. Cruz-Martinez A, Arpa J. Electrophysiological assessment in neurogenic thoracic outlet syndrome. Electromyogr Clin Neurophysiol. 2001;41(4):253-256.
   pubmed
6. Leong SC, Karkos PD. A "hard" neck lump. Singapore Med J. 2009;50(4):e141-142.
   pubmed
7. Huang JH, Zager EL. Thoracic outlet syndrome. Neurosurgery. 2004;55(4):897-902, discussion 902-893.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Journal of Medical Cases is published by Elmer Press Inc.