Daily answer
Scott Rand
Your 24-year-old stud baseball pitcher
complains of vague right shoulder pain. It is most noticeable at the late
cocking phase of windup. On physical exam the patient is noted to have weakness
with external rotation. EMG findings are consistent with quadrilateral space
syndrome. Along with the deltoid, what other muscle is affected?
1. Teres major
2. Teres minor
3. Pectoralis major
4. Supraspinatus
5. Subscapularis
The axillary nerve passes through the quadrilateral space on its path to
innervate the teres minor and deltoid and provide sensation to the lateral arm.
This syndrome is caused by compression of the posterior humeral circumflex
artery and axillary nerve or one of its major branches in the quadrilateral
space. Forward flexion and/or abduction and external rotation of the humerus
aggravate the symptoms. In some individuals, especially, throwers, the nerve
can become irritated from the repetitive motion leading to nerve dysfunction.
The condition is usually self-limited.
Scott E Rand, MD FAAFP CAQSM
Director, Primary Care Sports Medicine Fellowship
Co Director of Sports Medicine, Houston Methodist Orthopedics and Sports Medicine Willowbrook
Assistant Professor of Clinical Family Medicine Houston Methodist Academic Institute
Adjunct Assistant Professor of Family and Community Medicine, Texas A&M University
Assistant Professor of Family Medicine in Clinical Medicine Weill Cornell Medical College.
13802 Centerfield Dr Suite 300
Houston, TX 77070