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Questions and Answers
A patient presents with weakness in internal rotation, adduction, and extension of the shoulder. Palpation reveals tenderness just above the latissimus dorsi on the posterior scapula. Which muscle is MOST likely affected?
A patient presents with weakness in internal rotation, adduction, and extension of the shoulder. Palpation reveals tenderness just above the latissimus dorsi on the posterior scapula. Which muscle is MOST likely affected?
- Triceps brachii (long head)
- Teres minor
- Infraspinatus
- Teres major (correct)
During a physical therapy session, a client is asked to perform external rotation and horizontal abduction. Which muscle is NOT a primary mover in these actions?
During a physical therapy session, a client is asked to perform external rotation and horizontal abduction. Which muscle is NOT a primary mover in these actions?
- Teres major (correct)
- Triceps brachii (long head)
- Infraspinatus
- Teres minor
If the lower subscapular nerve is damaged, which action of the shoulder would be MOST affected?
If the lower subscapular nerve is damaged, which action of the shoulder would be MOST affected?
- Horizontal abduction
- External rotation
- Diagonal abduction
- Internal rotation (correct)
A weightlifter is performing a pull-up. Which of the listed muscles is involved in the adduction phase of this exercise?
A weightlifter is performing a pull-up. Which of the listed muscles is involved in the adduction phase of this exercise?
A patient is experiencing difficulty with both external rotation and horizontal abduction of their arm. Which nerve is LEAST likely to be the source of the problem?
A patient is experiencing difficulty with both external rotation and horizontal abduction of their arm. Which nerve is LEAST likely to be the source of the problem?
A patient reports difficulty with internal rotation and adduction of their shoulder. Which muscle is LEAST likely to be involved in these actions?
A patient reports difficulty with internal rotation and adduction of their shoulder. Which muscle is LEAST likely to be involved in these actions?
During a shoulder assessment, you ask the patient to extend their arm from a flexed position. Which portion of the Pectoralis Major is primarily engaged in this movement?
During a shoulder assessment, you ask the patient to extend their arm from a flexed position. Which portion of the Pectoralis Major is primarily engaged in this movement?
A weightlifter is performing a bench press, which involves horizontal adduction of the shoulder. Which muscle would you expect to be MOST active during this exercise?
A weightlifter is performing a bench press, which involves horizontal adduction of the shoulder. Which muscle would you expect to be MOST active during this exercise?
If a patient presents with nerve damage affecting the lateral pectoral nerve, which shoulder action would be MOST affected?
If a patient presents with nerve damage affecting the lateral pectoral nerve, which shoulder action would be MOST affected?
A therapist is palpating a muscle high on the medial arm, posterior to the short head of the biceps brachii. Which muscle are they MOST likely palpating?
A therapist is palpating a muscle high on the medial arm, posterior to the short head of the biceps brachii. Which muscle are they MOST likely palpating?
Which of the following scenarios would MOST effectively allow palpation of the lateral portion of the subscapularis?
Which of the following scenarios would MOST effectively allow palpation of the lateral portion of the subscapularis?
Considering their insertions, which pair of muscles would exert the greatest force promoting internal rotation of the humerus?
Considering their insertions, which pair of muscles would exert the greatest force promoting internal rotation of the humerus?
A patient has weakened adduction of the shoulder. Assuming the issue stems from nerve damage, which nerve would be LEAST likely to be the source of the problem?
A patient has weakened adduction of the shoulder. Assuming the issue stems from nerve damage, which nerve would be LEAST likely to be the source of the problem?
A patient is experiencing difficulty with both flexion and horizontal adduction of their arm. Which part of the deltoid muscle is MOST likely affected?
A patient is experiencing difficulty with both flexion and horizontal adduction of their arm. Which part of the deltoid muscle is MOST likely affected?
During an assessment, you palpate the lateral border of the acromion while the patient resists abduction of the arm. Which muscle are you MOST likely palpating?
During an assessment, you palpate the lateral border of the acromion while the patient resists abduction of the arm. Which muscle are you MOST likely palpating?
Which combination of actions is ONLY performed by the posterior fibers of the deltoid muscle, and not by the anterior or middle fibers?
Which combination of actions is ONLY performed by the posterior fibers of the deltoid muscle, and not by the anterior or middle fibers?
A nerve injury affecting the latissimus dorsi would MOST likely result in weakness in which combination of movements?
A nerve injury affecting the latissimus dorsi would MOST likely result in weakness in which combination of movements?
If a patient has damage to the suprascapular nerve, which muscle function would be MOST affected?
If a patient has damage to the suprascapular nerve, which muscle function would be MOST affected?
A weightlifter is performing a lat pulldown exercise. Which set of actions performed at the shoulder joint are PRIMARILY utilizing the latissimus dorsi?
A weightlifter is performing a lat pulldown exercise. Which set of actions performed at the shoulder joint are PRIMARILY utilizing the latissimus dorsi?
Which of the following actions is shared by ALL portions of the deltoid (anterior, middle, and posterior)?
Which of the following actions is shared by ALL portions of the deltoid (anterior, middle, and posterior)?
A patient presents with weakness in shoulder abduction and is diagnosed with an injury affecting the C5 nerve root. Which two muscles are MOST likely affected by this injury?
A patient presents with weakness in shoulder abduction and is diagnosed with an injury affecting the C5 nerve root. Which two muscles are MOST likely affected by this injury?
Flashcards
Pectoralis Major (Upper Fibers) Actions
Pectoralis Major (Upper Fibers) Actions
Upper fibers: Flexion, abduction, internal rotation, horizontal and diagonal adduction.
Pectoralis Major (Lower Fibers) Actions
Pectoralis Major (Lower Fibers) Actions
Lower fibers: Adduction, internal rotation, horizontal and diagonal adduction, extension from flexed.
Pectoralis Major Insertion
Pectoralis Major Insertion
Lateral lip of intertubercular groove of humerus.
Subscapularis Origin
Subscapularis Origin
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Subscapularis Actions
Subscapularis Actions
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Subscapularis Insertion
Subscapularis Insertion
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Coracobrachialis Origin
Coracobrachialis Origin
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Coracobrachialis Actions
Coracobrachialis Actions
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Anterior Deltoid Actions
Anterior Deltoid Actions
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Middle Deltoid Actions
Middle Deltoid Actions
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Posterior Deltoid Actions
Posterior Deltoid Actions
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Supraspinatus Action
Supraspinatus Action
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Latissimus Dorsi Actions
Latissimus Dorsi Actions
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Deltoid Tuberosity
Deltoid Tuberosity
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Deltoid Innervation
Deltoid Innervation
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Axillary Nerve
Axillary Nerve
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Teres Major
Teres Major
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Infraspinatus
Infraspinatus
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Teres Minor
Teres Minor
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Biceps Brachii (Shoulder)
Biceps Brachii (Shoulder)
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Triceps Brachii (Long Head)
Triceps Brachii (Long Head)
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Study Notes
- OIA refers to origin, insertion, and action of the shoulder joint
Pectoralis Major (Upper Fibers)
- The origin is the medial half of the anterior surface of the clavicle
- The insertion is the lateral lip of the intertubercular groove of the humerus
- Actions include internal rotation (transverse plane), horizontal adduction (transverse plane), diagonal adduction (diagonal plane), flexion (sagittal plane), and abduction (frontal plane)
- Palpation can be performed from the medial clavicle to the intertubercular groove of the humerus during flexion and adduction
- Innervation is via the lateral pectoral nerve (C5, C6, C7)
Pectoralis Major (Lower Fibers)
- The origin is the anterior surface of costal cartilages of the first six ribs, adjoining portion of the sternum
- The insertion is the lateral lip of the intertubercular groove of the humerus
- Actions include internal rotation (transverse plane), horizontal adduction (transverse plane), diagonal adduction (diagonal plane), extension from flexed position (sagittal plane), and adduction (frontal plane)
- Palpation can be performed from the lower ribs and sternum to the intertubercular groove of the humerus during resisted extension
- Innervation is via the medial pectoral nerve (C8, T1)
Subscapularis
- The origin is the entire anterior surface of the subscapular fossa
- The insertion is the lesser tubercle of the humerus
- Actions include internal rotation (transverse plane), adduction (frontal plane), and extension (sagittal plane)
- Palpation is mostly inaccessible; however, the lateral portion may be palpated with active internal rotation
- Innervation is via the upper and lower subscapular nerves (C5, C6)
Coracobrachialis
- The origin is the coracoid process of the scapula
- The insertion is the middle of the medial border of the humeral shaft
- Actions include horizontal adduction (transverse plane) and diagonal adduction (diagonal plane)
- Palpation can be performed high on the medial arm, posterior to the short head of the biceps brachii
- Innervation is via the musculocutaneous nerve (C5, C6, C7)
Deltoid (Anterior Fibers)
- The origin is the anterior lateral third of the clavicle
- The insertion is the deltoid tuberosity on the lateral humerus
- Anterior fiber actions include abduction (frontal plane), flexion (sagittal plane), horizontal adduction (transverse plane), internal rotation (transverse plane), and diagonal adduction (diagonal plane)
- Palpation can be performed from the clavicle to the anterior humerus during resisted flexion
- Innervation is via the axillary nerve (C5, C6)
Deltoid (Middle Fibers)
- The origin is the lateral aspect of the acromion
- The insertion is the deltoid tuberosity on the lateral humerus
- Actions include abduction (frontal plane) and horizontal abduction (transverse plane)
- Palpation can be performed from the lateral border of the acromion to the deltoid tuberosity during resisted abduction
- Innervation is via the axillary nerve (C5, C6)
Deltoid (Posterior Fibers)
- The origin is the inferior edge of the spine of the scapula
- The insertion is the deltoid tuberosity on the lateral humerus
- The actions include abduction (frontal plane), horizontal abduction (transverse plane), external rotation (transverse plane), and diagonal abduction (diagonal plane)
- Palpation can be performed from the lower lip of the scapular spine to the posterior humerus during resisted extension
- Innervation is via the axillary nerve (C5, C6)
Supraspinatus
- The origin is the medial two-thirds of the supraspinous fossa
- The insertion is the greater tubercle of the humerus
- The action is abduction (frontal plane)
- Palpation can be performed above the spine of the scapula in the supraspinous fossa during initial abduction
- Innervation is via the suprascapular nerve (C5)
Latissimus Dorsi
- The origin is the posterior crest of the ilium, sacrum, spinous processes of the lumbar and lower six thoracic vertebrae, and the lower three ribs
- The insertion is the medial side of the intertubercular groove of the humerus
- Actions include extension (sagittal plane), adduction (frontal plane), internal rotation (transverse plane), and horizontal abduction (transverse plane)
- Palpation can be performed in the posterior axillary wall, upper lumbar/lower thoracic area during extension
- Innervation is via the thoracodorsal nerve (C6, C7, C8)
Teres Major
- The origin is posteriorly on the inferior third of the lateral border of the scapula
- The insertion is the medial lip of the intertubercular groove of the humerus
- Actions include extension (sagittal plane), adduction (frontal plane), and internal rotation (transverse plane)
- Palpation can be performed just above the latissimus dorsi on the posterior scapula surface
- Innervation is via the lower subscapular nerve (C5, C6)
Infraspinatus
- The origin is the infraspinous fossa of the scapula
- The insertion is the greater tubercle of the humerus
- Actions include external rotation (transverse plane), horizontal abduction (transverse plane), extension (sagittal plane), and diagonal abduction (diagonal plane)
- Palpation can be performed below the spine of the scapula, lateral to the humerus during external rotation
- Innervation is via the suprascapular nerve (C5, C6)
Teres Minor
- The origin is posteriorly on the upper and middle aspect of the lateral border of the scapula
- The insertion is the greater tubercle of the humerus
- Actions include external rotation (transverse plane), horizontal abduction (transverse plane), extension (sagittal plane), and diagonal abduction (diagonal plane)
- Palpation can be performed above the teres major on the posterior scapula surface
- Innervation is via the axillary nerve (C5, C6)
Additional Muscles Involved
- Biceps Brachii assists in flexion, horizontal adduction, and diagonal adduction
- Triceps Brachii (Long Head) assists in extension, adduction, horizontal abduction, and diagonal abduction
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