WBR0552: Difference between revisions

Jump to navigation Jump to search
VisualWikitext
No edit summary
No edit summary
Line 1: Line 1:
{{WBRQuestion
{{WBRQuestion
|QuestionAuthor=William J Gibson
|QuestionAuthor=William J Gibson (Reviewed by {{YD}})
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Anatomy
|MainCategory=Anatomy
Line 21: Line 21:
|MainCategory=Anatomy
|MainCategory=Anatomy
|SubCategory=Musculoskeletal/Rheumatology, Vascular
|SubCategory=Musculoskeletal/Rheumatology, Vascular
|Prompt=A 22-year-old college baseball pitcher presents to his sports medicine physician for shoulder weakness and pain. The patient reports feeling a sharp pain in his right posterior shoulder after throwing a fastball. The pain was followed by numbness and tingling down his right arm, which persisted for several hours after the injury.   Physical exam reveals pain with passive internal rotation of the arm, and weakness in external rotation of the arm.  Which of the following muscles in most likely injured in this patient?
|Prompt=A 22-year-old college baseball pitcher presents to his sports medicine physician for shoulder weakness and pain. He reports feeling a sharp pain in his right posterior shoulder after throwing a fastball. The pain was followed by numbness and tingling down his right arm, which persisted for several hours. Physical examination reveals pain with passive internal rotation of the arm and weakness during external rotation of the arm.  Which of the following muscles in most likely injured in this patient?
|Explanation=The patient in this vignette has injured his infraspinatus muscle as a result of large rotational forces during pitching. The infraspinatus is a rotator cuff muscle that is responsible for lateral rotation of the arm. It is innervated by the suprascapular nerve, which originates from the superior trunk of the brachial plexus (C5,C6).
|Explanation=The patient in this vignette has injured his infraspinatus muscle as a result of large rotational forces during pitching. The infraspinatus muscle is a rotator cuff muscle that is responsible for lateral rotation of the arm. It is innervated by the suprascapular nerve, which originates from the superior trunk of the brachial plexus (C5-C6). 
|AnswerA=Infraspinatus
|AnswerAExp=The infraspinatus is a muscle of the rotator cuff that is responsible for lateral rotation of the arm. Injuries of the infraspinatus and its tendon are common among baseball pitchers.
|AnswerB=Subscapularis
|AnswerBExp=The subscapularis is a large flat muscle that overlies the anterior surface of the scapula (subscapular fossa). It aids in medial rotation and adduction of the arm.
|AnswerC=Supraspinatus
|AnswerCExp=The supraspinatus is a muscle of the rotator cuff that is responsible for the first 15 degrees of shoulder abduction. Injuries of the supraspinatus are the most common cause of rotator cuff injuries. Typically, patients with supraspinatus injuries cannot initiate arm abduction.
|AnswerD=Teres minor
|AnswerDExp=The teres minor is a rotator cuff muscle that is responsible for adduction and lateral rotation of the arm. It is innervated by the posterior branch of the axillary nerve (C5-C6).
|AnswerE=Teres major
|AnswerEExp=The teres major not a rotator cuff muscle. It is a large, flat muscle that medially rotates and adducts the humerus. It is innervated by the subscapular nerve (C5-C6).
|EducationalObjectives=The infraspinatus is a muscle of the rotator cuff that is responsible for lateral rotation of the arm. Injuries of the infraspiantus muscle and its tendon are common among baseball pitchers.
|References=
First Aid 2014 page 411<br>


'''Mnemonic:''' Rotator cuff muscles = SITS (Subscapularis, Infraspinatus, Teres minor, Suprascapularis).
|AnswerA=Infraspinatus
|AnswerAExp=The infraspinatus is a muscle of the rotator cuff that is responsible for lateral rotation of the arm.  The infraspinatus and its tendon are commonly injured in baseball pitchers.
|AnswerB=Subscapularis
|AnswerBExp=The subscapularis is a large flat muscle that overlies the anterior surface of the scapula (subscapular fossa).  It aids in medial rotation of the arm.
|AnswerC=Supraspinatus
|AnswerCExp=The supraspinatus is a muscle of the rotator cuff that is responsible for the first 15 degrees of shoulder abduction.  Injuries of the infraspinatus are the most common cause of rotator cuff injuries, but would present with inability to initiate abduction of the arm.
|AnswerD=Teres minor
|AnswerDExp=The teres minor is a rotator cuff muscle that is responsible for adduction and lateral rotation of the arm.  It is innervated by the posterior branch of the axillary nerve (C5,C6).
|AnswerE=Teres major
|AnswerEExp=The teres major is large, flat muscle that medially rotates and adducts the humerus.  It is innervated by the subscapular nerve (C5,C6).
|EducationalObjectives=The infraspinatus is a muscle of the rotator cuff that is responsible for lateral rotation of the arm.  The infraspinatus and its tendon are commonly injured in baseball pitchers.
|References=First Aid 2014 page 411<br>
*[http://www.youtube.com/watch?v=6TeMev62NK8 Rotator Cuff Review]
*[http://www.youtube.com/watch?v=vG1XQkj3Yx0 Overview of the shoulder joint]
|RightAnswer=A
|RightAnswer=A
|WBRKeyword=Scapula, Rotator cuff, Shoulder, Upper limb, Arm, Muscle, Tendon
|WBRKeyword=Scapula, Rotator cuff, Upper limb, Arm, Muscle, Tendon, Infraspinatus, Infraspinatus muscle, Rotator cuff injury, Shoulder pain, Shoulder, Shoulder weakness
|Approved=Yes
|Approved=Yes
}}
}}

Revision as of 19:35, 17 October 2014
Author [[PageAuthor::William J Gibson (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Anatomy
Sub Category SubCategory::Musculoskeletal/Rheumatology, SubCategory::Vascular
Prompt [[Prompt::A 22-year-old college baseball pitcher presents to his sports medicine physician for shoulder weakness and pain. He reports feeling a sharp pain in his right posterior shoulder after throwing a fastball. The pain was followed by numbness and tingling down his right arm, which persisted for several hours. Physical examination reveals pain with passive internal rotation of the arm and weakness during external rotation of the arm. Which of the following muscles in most likely injured in this patient?]]
Answer A AnswerA::Infraspinatus
Answer A Explanation AnswerAExp::The infraspinatus is a muscle of the rotator cuff that is responsible for lateral rotation of the arm. Injuries of the infraspinatus and its tendon are common among baseball pitchers.
Answer B AnswerB::Subscapularis
Answer B Explanation AnswerBExp::The subscapularis is a large flat muscle that overlies the anterior surface of the scapula (subscapular fossa). It aids in medial rotation and adduction of the arm.
Answer C AnswerC::Supraspinatus
Answer C Explanation [[AnswerCExp::The supraspinatus is a muscle of the rotator cuff that is responsible for the first 15 degrees of shoulder abduction. Injuries of the supraspinatus are the most common cause of rotator cuff injuries. Typically, patients with supraspinatus injuries cannot initiate arm abduction.]]
Answer D AnswerD::Teres minor
Answer D Explanation AnswerDExp::The teres minor is a rotator cuff muscle that is responsible for adduction and lateral rotation of the arm. It is innervated by the posterior branch of the axillary nerve (C5-C6).
Answer E AnswerE::Teres major
Answer E Explanation AnswerEExp::The teres major not a rotator cuff muscle. It is a large, flat muscle that medially rotates and adducts the humerus. It is innervated by the subscapular nerve (C5-C6).
Right Answer RightAnswer::A
Explanation [[Explanation::The patient in this vignette has injured his infraspinatus muscle as a result of large rotational forces during pitching. The infraspinatus muscle is a rotator cuff muscle that is responsible for lateral rotation of the arm. It is innervated by the suprascapular nerve, which originates from the superior trunk of the brachial plexus (C5-C6).

Educational Objective: The infraspinatus is a muscle of the rotator cuff that is responsible for lateral rotation of the arm. Injuries of the infraspiantus muscle and its tendon are common among baseball pitchers.
References: First Aid 2014 page 411
]]

Approved Approved::Yes
Keyword WBRKeyword::Scapula, WBRKeyword::Rotator cuff, WBRKeyword::Upper limb, WBRKeyword::Arm, WBRKeyword::Muscle, WBRKeyword::Tendon, WBRKeyword::Infraspinatus, WBRKeyword::Infraspinatus muscle, WBRKeyword::Rotator cuff injury, WBRKeyword::Shoulder pain, WBRKeyword::Shoulder, WBRKeyword::Shoulder weakness
Linked Question Linked::
Order in Linked Questions LinkedOrder::
Retrieved from "https://www.wikidoc.org/index.php?title=WBR0552&oldid=1033174"