Trapezius Muscle Anatomy and Function

A deep understanding of shoulder musculature is essential for accurately interpreting diagnostic images. If a patient presents with suspected suprascapular nerve entrapment, which muscle would be least helpful to evaluate via imaging?

During a high-speed collision, a driver's shoulder impacts the steering wheel. Later examination reveals difficulty in initiating both abduction and lateral rotation of the arm. Which combination of rotator cuff muscles is most likely affected?

Consider a surgical approach to the axilla. Damage to which nerve would most severely impair the ability to perform scapular protraction against resistance?

A patient presents with limited shoulder mobility following a shoulder dislocation. Imaging reveals damage to the intertubercular sulcus. Which specific action would be most compromised due to the tendon's disruption in this groove?

A genetic mutation results in the absence of the Ligamentum nuchae. Which scapular movement would be most directly affected by this mutation?

Following a wrestling match, a wrestler is unable to elevate, adduct and depress their scapula equally. This is most likely due to damage of which muscle?

A cross-country skier is diagnosed with suprascapular nerve entrapment affecting both the supraspinatus and infraspinatus. What functional adaptation would least compensate for the resulting shoulder weakness?

A patient presents with scapular winging and limited overhead abduction. Upon examination, weakness is noted in depressing and protracting the scapula. Which combination of nerve and muscle is most likely affected?

Damage to the axillary nerve would severely impair the ability to perform which action?

A neurological condition selectively damages the anterior rami of C3-C4 spinal nerves, while sparing the dorsal scapular nerve. Which scapular movement would remain relatively unaffected?

What action do the rhomboid major and minor muscles perform together?

Considering the synergistic action of the rotator cuff muscles, damage to the suprascapular nerve (C5, C6) directly affects the supraspinatus and infraspinatus muscles. Which movement would the Teres Minor be least capable of compensating for?

If a surgeon needs to access the posterior aspect of the subscapularis muscle, which muscle must be surgically transected (cut) to provide the most direct route?

A patient presents with a shoulder injury impacting the triangular space. Considering the anatomical structures passing through this space, which functional deficit would be most likely?

A patient, following a poorly fitted crutch usage, develops weakness in medial rotation and adduction of the arm. Which single muscle injury is the most likely cause?

A baseball pitcher injures his shoulder during a game. The team physician determines there is damage to the musculotendinous collar that surrounds the posterior, superior and anterior aspects of the joint. Which rotator cuff muscle tendons were damaged?

How is the suprascapular notch closed?

Following a nerve-sparing surgical procedure within the quadrangular space, a patient displays weakness in abduction of the arm, but no change in shoulder sensation. Which structure was most likely affected during the procedure?

A deep stab wound to the axilla severs the Cephalic vein as it passes through the Clavipectoral fascia. What other structure is also most directly at risk of concurrent injury?

A patient has difficulty with the motions facilitated by the Pectoralis Major. Which motion would still be possible if the Clavicular head was still functional?

A weightlifter strains the pectoralis major during a bench press where the sternocostal head is injured. Which action would be MOST affected?

Which muscle pulls the tip of the shoulder down and protracts of the scapula?

To best visualize the subclavius in an anatomical dissection, which of the following structures must be carefully reflected (moved aside)?

After a construction accident involving blunt trauma to the anterior chest, a patient exhibits difficulty in depressing the clavicle and stabilizing the sternoclavicular joint. Which muscle is most likely injured?

A surgeon divides the serratus anterior muscle to get better access to a chest wall tumor. What deficit could result from this procedure?

A military recruit, unused to intense physical activity, reports numbness and tingling in the upper limb after a prolonged obstacle course. Examination reveals compression within the axilla. Which structure, if compressed, would least likely cause these symptoms?

A tumor in the axilla is compressing the structures within it. Which nerve could be affected that would result in an inability to evert the arm (turn the palm forward)?

During a surgical procedure, identify the most immediate risk associated with iatrogenic (accidental) damage to the axillary nerve within the quadrangular space?

A patient develops paralysis of muscles originating from the medial cord of the brachial plexus. Identify the resultant deficit of this condition?

If a tumor compresses the axillary artery near its origin, what other blood vessel could potentially provide collateral circulation to the distal part of the arm, bypassing the compression?

Given the anatomical structures that form the boundaries of the axilla, a lesion affecting the medial wall would MOST directly affect which muscle?

Accurate anatomical knowledge is crucial in surgical planning. If a surgeon needs to ligate (tie off) the axillary artery distal to the origin of the thoracoacromial artery, which muscle serves as the most reliable landmark to locate the ligation point safely?

An elite swimmer develops progressively worsening anterior shoulder pain. Examination reveals a significantly reduced subacromial space. Which muscle's hypertrophy (enlargement) would most directly contribute to the narrowing of this space?

A physician is examining a patient with suspected axillary nerve damage. Which approach allows for direct palpation of the axillary artery to assess its pulse in relation to the nerve's course?

A patient's shoulder is being examined. The scapula, acromion, and clavicle can be palpated between the attachments of which two muscles?

A patient presents with difficulty elevating their scapula. Electromyography (EMG) reveals impaired function of both the upper trapezius and levator scapulae muscles. Which of the following nerve lesions would most likely produce this combined deficit?

During a complex shoulder surgery, a surgeon identifies the accessory nerve to ensure its protection. Which anatomical landmark would best guide the surgeon to locate the accessory nerve as it traverses the posterior triangle of the neck?

A patient is diagnosed with isolated paralysis of the middle fibers of the trapezius muscle following a sports injury. Which of the following actions would be most difficult for the patient to perform against resistance?

An individual is performing a lat pulldown exercise at the gym. During the exercise, they concentrate on maximizing the involvement of the lower fibers of the trapezius. What scapular movement should they emphasize to achieve this?

A neurological exam reveals a patient has weakness in shoulder abduction between 15 and 90 degrees, but can initiate the movement. Sensation over the lateral shoulder is also diminished. Which of the following is the most likely site of nerve compression?

A patient reports experiencing muscle fatigue and cramping during overhead activities. Clinical examination reveals slight atrophy of the deltoid muscle and limited shoulder abduction. Selective nerve block of which nerve would most definitively help determine if the deltoid muscle impairment is the primary cause of these symptoms?

During a surgical repair of a fractured scapula, the dorsal scapular nerve is inadvertently damaged. Postoperatively, what specific functional deficit would be most apparent when assessing the patient's active range of motion?

A competitive swimmer presents with chronic shoulder pain. Upon examination, the physician notes point tenderness along the medial border of the scapula and suspects rhomboid muscle strain. Which of the following is the most appropriate strengthening exercise to target these muscles?

During a shoulder operation, the suprascapular nerve is inadvertently ligated (tied off) proximal to the branch innervating the supraspinatus. Which combination of functional deficits would most likely result from this error?

A patient is diagnosed with adhesive capsulitis ("frozen shoulder"). As part of their rehabilitation, the physical therapist aims to improve external rotation of the shoulder. Which of the following exercises would be most effective in targeting the infraspinatus muscle to achieve this goal?

A patient presents with limited shoulder mobility and pain. MRI reveals atrophy of the teres minor muscle and fatty infiltration. Which of the following findings would be least likely to be associated with this condition?

A surgeon is planning a procedure to release the subscapularis tendon to address internal rotation contracture of the shoulder. Which of the following anatomical structures is at greatest risk during this procedure, given its proximity to the subscapularis insertion?

A patient exhibits weakness in internal rotation and adduction of the arm. Clinical examination reveals atrophy of the Subscapularis muscle and a positive lift-off test. Assuming no other muscular or neurological damage, which portion of the Subscapularis is most likely affected?

A patient who recently underwent shoulder surgery is asked to perform a 'belly press' test, where they press their hand against their abdomen while keeping their elbow forward. The patient is unable to maintain this position and their wrist extends to compensate. This finding most strongly suggests weakness in which muscle?

A weightlifter strains their teres major muscle during a powerlifting competition. Which of the following movements would be least affected by isolated injury to the teres major?

An orthopedic surgeon is considering different approaches to access the scapulothoracic joint. Which of the following muscles would provide the most direct access to the anterior surface of the serratus anterior muscle, requiring minimal transection or reflection?

A patient presents with winging of the scapula after radical neck dissection surgery. Electrophysiological testing reveals damage to the nerve responsible. Which of the following compensatory strategies would be least effective in improving scapular stability?

A patient is diagnosed with compression of the clavipectoral fascia. Which of the following structures is least likely to be directly affected by this compression?

An overhead throwing athlete is diagnosed with pectoralis minor tightness and consequent compression of the neurovascular structures underneath. Which of the following clinical findings would be least likely in this patient?

In a cadaver dissection, a medical student is asked to identify the innervation of the subclavius muscle. Which of the following approaches would be most effective in locating the nerve to the subclavius?

A patient presents with anterior shoulder pain that is exacerbated by resisted horizontal adduction. Palpation reveals tenderness over the pectoralis major tendon insertion. To confirm this diagnosis, which of the following clinical tests would be most specific for isolating the pectoralis major's contribution to the patient's pain?

A patient is undergoing treatment for thoracic outlet syndrome involving compression within the costoclavicular space. Strengthening which of the following muscles would least likely alleviate this compression?

A patient is diagnosed with paralysis of serratus anterior due to injury of the long thoracic nerve. In addition to weakness of shoulder abduction, what other observation is MOST likely?

A surgeon is performing a mastectomy with axillary lymph node dissection. To minimize the risk of long thoracic nerve injury, what anatomical landmark should the surgeon primarily use to guide their dissection?

A patient presents with signs of axillary nerve compression within the quadrangular space. Which of the following clinical presentations would least likely be directly attributable to this compression?

During a surgical intervention in the axilla, the thoracodorsal nerve is inadvertently damaged. Which of the following functional deficits would be the MOST likely consequence of this nerve injury?

A patient diagnosed with a tumor affecting the axilla is experiencing upper limb lymphedema. Compression of which structure is the most likely cause for the lymphedema?

During a subclavian vein catheter placement, the needle inadvertently punctures the axillary artery near its origin. What is the potential consequence of this injury?

During an anatomical study of the axilla, a resident is asked to define the boundaries of this region. Which of the following correctly describes the medial border (wall) of the axilla?

During an axillary lymph node dissection, a surgeon ligates the thoracoacromial artery to control bleeding and preserve as many lymphatic vessels as possible. What potential consequence should the surgeon be most aware?

A patient presents with symptoms suggestive of compression within the triangular space. Which of the following clinical findings would be most consistent with this diagnosis?

A patient is diagnosed with a shoulder injury impacting the triangular interval. Injury to what nerve may be expected?

Which of the following muscles is most directly responsible for protraction of the scapula, enabling movements such as pushing or reaching forward?

A patient has limited shoulder mobility following a shoulder dislocation. Imaging reveals damage to the intertubercular sulcus. Disruption of the tendon in this groove would affect what movement?

A patient, following a poorly fitted crutch usage, develops weakness in medial rotation and adduction of the arm. What single muscle injury is likely?

How is the suprascapular notch closed to form the suprascapular foramen?

A weightlifter strains the Pectoralis Major during a bench press exercise such that the Sternocostal head is affected. What action would be MOST affected?

After a construction accident involving blunt trauma to the anterior chest, a patient exhibits difficulty in depressing the clavicle. Which muscle is most likely injured?

A patient exhibits limited range of motion in hyperabduction (arm elevated above 90 degrees). Disruption of coordination in which muscle group would most likely contribute to this specific deficit?

A bodybuilder, while performing a bench press, experiences a forceful eccentric contraction resulting in a complete rupture of the sternocostal head of the pectoralis major. Which of the following scenarios would LEAST likely be observed following this injury?

A surgeon is planning to release the clavipectoral fascia to address thoracic outlet syndrome. What anatomical structure should the surgeon carefully protect to avoid iatrogenic injury during this procedure?

During the approach to the axilla, a surgeon encounters a fibrous band stretching from the coracoid process to the lesser tubercle of the humerus. What action would be most effective in lengthening this band?

A skilled carpenter is performing overhead work for an extended period, and begins to experience fatigue and pain in the neck and shoulder. Electromyography (EMG) reveals increased activity in the upper trapezius and levator scapulae muscles, but decreased activity in the serratus anterior. An imbalance in which movement is most likely the primary cause of the pain?