p.6
Brachial Plexus: Anatomy and Function
How are the cords of the brachial plexus named?
In relation to the axillary artery.
p.8
Posterior Thoraco-Appendicular Muscles
Which cranial nerve innervates the trapezius?
Accessory or spinal accessory nerve.
p.1
Anterior Thoraco-Appendicular Muscles
What muscles are part of the anterior thoraco-appendicular group?
Subclavius, Pectoralis Major, Pectoralis Minor, Serratus Anterior.
p.3
Clinical Correlations: Injuries and Conditions
What congenital condition is associated with a shallow socket in the lower extremities?
Congenital hip dysplasia (DDH).
p.14
Anterior Thoraco-Appendicular Muscles
What is the proximal attachment of the Pectoralis major?
Clavicular head: anterior surface of medial half of clavicle; Sternocostal head: anterior surface of sternum, superior six costal cartilages, and aponeurosis of external oblique muscle.
p.5
Axillary Artery and Vein
What is the source of blood supply in the axilla?
Axillary arteries, which are a continuation of the subclavian artery.
p.4
Clinical Correlations: Injuries and Conditions
How can winging of the scapula be tested?
By having the patient push against a wall and observing the scapula.
p.8
Posterior Thoraco-Appendicular Muscles
Where is the levator scapulae located?
Deep to the sternocleidomastoid and trapezius.
p.3
Anterior Thoraco-Appendicular Muscles
What is the function of the subclavius muscle?
It serves as an added cushion for the vascular and neurovascular structures posterior to it.
p.14
Posterior Thoraco-Appendicular Muscles
What is the proximal attachment of the Trapezius?
Medial third of superior nuchal line; external occipital protuberance; nuchal ligament; spinous processes of C7-T12 vertebrae.
p.14
Posterior Thoraco-Appendicular Muscles
What is the main action of the Latissimus dorsi?
Extends, adducts, and medially rotates humerus; raises body toward arms during climbing.
p.13
Clinical Correlations: Injuries and Conditions
What type of fractures are discussed in the case report by Maalouly et al. (2019)?
Bilateral comminuted proximal humerus fractures.
p.10
Scapulohumeral Muscles
What is the role of the rotator cuff in shoulder movement?
Provides a delicate biomechanical balance that allows shoulder movement without instability or pain.
p.2
Scapulohumeral Muscles
What bones are involved in upper limb circumduction?
Humerus, clavicle, and scapula.
p.4
Axilla: Structure and Function
What forms the lateral wall of the axilla?
Intertubercular sulcus (bicipital groove).
p.2
Clinical Correlations: Injuries and Conditions
What conservative treatments are commonly used for a fractured clavicle?
Arm sling and figure 8 splint.
p.5
Brachial Plexus: Anatomy and Function
How can the brachial plexus be visualized?
As a complex train/subway station where roots combine to form trunks.
p.11
Clinical Correlations: Injuries and Conditions
Why is the supraspinatus the most commonly injured rotator cuff muscle?
It is thin and most active in overhead activities.
p.5
Brachial Plexus: Anatomy and Function
Why is the brachial plexus complex?
Due to the complexity of movement of the upper extremities.
p.12
Clinical Correlations: Injuries and Conditions
What injury might Luis have suffered after his pull-up incident?
Luis likely suffered a lower brachial plexus injury, indicated by numbness and loss of hand function.
p.13
Clinical Correlations: Injuries and Conditions
What surgical procedure is highlighted in the 2019 case report?
Simultaneous ORIF (Open Reduction and Internal Fixation).
p.2
Scapulohumeral Muscles
What joint shows palpable movement during upper limb circumduction?
The sternoclavicular joint.
p.10
Scapulohumeral Muscles
How does the supraspinatus contribute to shoulder movement?
It initiates abduction of the shoulder for the first 15 degrees.
p.8
Posterior Thoraco-Appendicular Muscles
What are the two types of rhomboids?
Rhomboid Major and Rhomboid Minor.
p.7
Axillary Artery and Vein
How is the axillary artery divided?
Into three segments by the pectoralis minor muscle.
p.6
Clinical Correlations: Injuries and Conditions
What are the effects of an upper brachial plexus injury?
Inability to raise the arm, weakness of the arm, and inability to flex the elbow.
p.7
Axillary Artery and Vein
What are the branches of the third segment of the axillary artery?
Subscapular, Anterior circumflex humeral, and Posterior circumflex humeral arteries.
What lymph nodes receive drainage from the lateral quadrant of the breast?
Anterior (pectoral) group of axillary lymph nodes.
p.10
Scapulohumeral Muscles
What is the composition of the rotator cuff muscles?
Composed of SITS: Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis.
p.11
Scapulohumeral Muscles
What is the primary function of the subscapularis muscle?
Holds the humeral head against the glenoid fossa of the scapula.
p.3
Clinical Correlations: Injuries and Conditions
What is the treatment for developmental dysplasia of the hip?
It can be treated conservatively if the joint can be mechanically attached during child development; some cases may need corrective bone work.
p.15
Scapulohumeral Muscles
Which nerve innervates the Supraspinatus muscle?
Suprascapular nerve (C4, C5, C6).
p.14
Anterior Thoraco-Appendicular Muscles
What is the innervation of the Pectoralis minor?
Medial pectoral nerve (C8, T1).
p.9
Scapulohumeral Muscles
What is the role of the supraspinatus in shoulder abduction?
It initiates the first 15 degrees of abduction.
p.5
Brachial Plexus: Anatomy and Function
What is the brachial plexus?
A complex network of nerves supplying sensation and motor innervation to the upper extremity and hand.
p.15
Scapulohumeral Muscles
What is the action of the Teres Minor muscle?
Laterally rotates the arm.
p.3
Anterior Thoraco-Appendicular Muscles
What is the appearance of the serratus anterior muscle?
It has serrations, resembling the end of a knife.
p.7
Axillary Artery and Vein
Which two branches arise from the second segment of the axillary artery?
Thoraco-acromial and Lateral thoracic arteries.
p.6
Brachial Plexus: Anatomy and Function
Which nerves arise from the posterior cord of the brachial plexus?
Axillary Nerve and Radial Nerve.
p.4
Axilla: Structure and Function
What is the function of the serratus anterior muscle?
It holds the scapula in place against the thoracic wall.
p.9
Scapulohumeral Muscles
What is the primary function of the scapulohumeral muscles?
To connect the scapula to the proximal humerus.
p.8
Posterior Thoraco-Appendicular Muscles
What is the function of the latissimus dorsi?
Extends, adducts, and medially rotates the upper limb.
p.3
Clinical Correlations: Injuries and Conditions
What type of injury did Doc Jojo's patient sustain?
A midclavicular fracture with superior displacement of the proximal clavicle and inferior displacement of the distal clavicle.
p.8
Posterior Thoraco-Appendicular Muscles
What do the rhomboids do?
Retract and rotate the scapula.
p.15
Scapulohumeral Muscles
What is the action of the Infraspinatus muscle?
Laterally rotates the arm.
p.15
Scapulohumeral Muscles
Which nerve innervates the Infraspinatus muscle?
Suprascapular nerve (C5, C6).
p.9
Clinical Correlations: Injuries and Conditions
What was the cause of the elderly patient's glenohumeral dislocation?
The caregiver pulling the patient back to bed via the shoulder/armpits area.
p.14
Posterior Thoraco-Appendicular Muscles
What is the innervation of the Levator scapulae?
Dorsal scapular (C4, C5) and cervical (C3, C4) nerves.
p.12
Clinical Correlations: Injuries and Conditions
What happens if the long thoracic nerve is injured?
Injury to the long thoracic nerve can result in scapular winging.
p.5
Brachial Plexus: Anatomy and Function
What do the anterior divisions of the trunks form?
Lateral cord, medial cord, and posterior cord.
p.2
Skeletal Components: Clavicle and Scapula
What is the function of the muscles attached to the scapula?
They stabilize the scapula and allow for a wide range of shoulder mobility.
p.9
Scapulohumeral Muscles
What are the components of the rotator cuff muscles?
Supraspinatus, Infraspinatus, Teres minor, Subscapularis (SITS).
p.9
Scapulohumeral Muscles
What is the main action of the deltoid muscle's middle part?
Abduction (strong abductor).
p.5
Axilla: Structure and Function
What are the main contents of the axilla?
Axillary arteries, axillary veins, axillary lymph nodes, brachial plexus, and axillary sheath.
p.9
Clinical Correlations: Injuries and Conditions
What can cause deltoid atrophy?
Injury to the axillary nerve, often from fractures of the surgical neck of the humerus or anterior shoulder dislocation.
p.6
Brachial Plexus: Anatomy and Function
What is the position of the Lateral Cord in relation to the axillary artery?
Lateral to the axillary artery.
p.10
Scapulohumeral Muscles
What is the primary function of the rotator cuff muscles?
To stabilize the humerus and ensure the humeral head is centered in the glenoid cavity during movement.
p.11
Scapulohumeral Muscles
What is the origin and insertion of the subscapularis muscle?
Originates from the subscapular fossa and inserts at the lesser tubercle of the humerus.
p.10
Scapulohumeral Muscles
What is the function of the infraspinatus muscle?
Lateral rotation of the arm and maintaining the humeral head within the glenoid.
p.1
Skeletal Components: Clavicle and Scapula
What structures does the clavicle protect?
Neurovascular structures located posterior to it.
p.11
Clinical Correlations: Injuries and Conditions
What causes pain during shoulder abduction in subacromial bursitis?
Inflammation of the bursae.
p.11
Clinical Correlations: Injuries and Conditions
What is the role of the bursa in the shoulder?
Serves as a cushion to protect tendons from irritation.
p.14
Anterior Thoraco-Appendicular Muscles
What is the main action of the Serratus anterior?
Protracts scapula and holds it against thoracic wall; rotates scapula.
p.1
Surface Anatomy of the Pectoral Region and Axilla
What is the surface anatomy of the pectoral region and axilla associated with?
Muscles like Pectoralis Major, Deltoid, and Trapezius, as well as bones like the Clavicle and Scapula.
p.11
Scapulohumeral Muscles
What are the functions of the teres major muscle?
Medial rotation, arm adduction, and shoulder joint stabilization.
p.3
Clinical Correlations: Injuries and Conditions
What injury can occur to the pectoralis minor?
Injury can occur when it gets overstretched, causing sharp pain around the area when reaching forward.
p.6
Clinical Correlations: Injuries and Conditions
What causes an upper brachial plexus injury?
A sudden forceful movement that widens the angle between the shoulder and neck.
p.14
Scapulohumeral Muscles
What is the main action of the Teres major?
Adducts and medially rotates arm.
p.1
Skeletal Components: Clavicle and Scapula
What is the primary function of the clavicle?
To connect the axial and appendicular skeleton and support the upper extremity.
p.3
Surface Anatomy of the Pectoral Region and Axilla
What is the knobby projection located inferior to the clavicle called?
It is a projection that can be felt when palpated from the clavicle, just before the acromion.
p.1
Skeletal Components: Clavicle and Scapula
How is the shape of the clavicle described when viewed from the top?
It is shaped like an 'S'.
p.14
Anterior Thoraco-Appendicular Muscles
What is the main action of the Pectoralis major?
Adducts and medially rotates humerus; draws scapula anteriorly and inferiorly.
p.3
Anterior Thoraco-Appendicular Muscles
What are the four anterior thoraco-appendicular muscles?
Subclavius, Pectoralis Major, Pectoralis Minor, and Serratus Anterior.
p.1
Axilla: Structure and Function
What is the significance of the axilla in anatomy?
It contains major structures and serves as a passageway for neurovascular bundles.
p.15
Scapulohumeral Muscles
What is the origin of the Teres Minor muscle?
Middle part of the lateral border of the scapula.
p.15
Scapulohumeral Muscles
What is the action of the Subscapularis muscle?
Medially rotates the arm and helps hold the head of the humerus in the glenoid cavity.
p.13
Clinical Correlations: Injuries and Conditions
What is the focus of Byram's 2017 article?
Proximal humerus fractures of the shoulder.
p.1
Skeletal Components: Clavicle and Scapula
What joints are associated with the clavicle?
Acromioclavicular joint (AC Joint) and sternoclavicular joint.
p.4
Axilla: Structure and Function
What structures form the apex of the axilla?
Area between the 1st rib, clavicle, and scapula.
p.7
Axillary Artery and Vein
At what anatomical landmark does the axillary artery begin?
At the lateral border of the 1st rib.
p.12
Skeletal Components: Clavicle and Scapula
What is the shape and function of the clavicle?
The clavicle is an 'S' shaped bone that supports the upper extremity, serves as an attachment point for muscles, and protects neurovascular structures.
p.12
Skeletal Components: Clavicle and Scapula
What is the role of the scapula?
The scapula is a triangular, flat bone that serves as an attachment point for shoulder muscles and contributes to the mobility of the upper extremity.
p.7
Axillary Artery and Vein
What is the mnemonic for the branches of the axillary artery?
Some Times Life Seems A Pain.
p.15
Scapulohumeral Muscles
What is the origin of the Subscapularis muscle?
Subscapular fossa (most of the anterior surface of the scapula).
p.2
Skeletal Components: Clavicle and Scapula
What is the shape and location of the scapula?
Triangular, flat bone lying on the posterior thoracic wall.
p.2
Skeletal Components: Clavicle and Scapula
What is the glenoid fossa?
An oval-shaped depression on the lateral angle of the scapula that connects with the humeral head.
p.15
Scapulohumeral Muscles
What is the origin of the Supraspinatus muscle?
Supraspinous fossa of the scapula.
p.15
Scapulohumeral Muscles
What is the action of the Supraspinatus muscle?
Initiates and assists deltoid in abduction of the arm.
p.15
Scapulohumeral Muscles
What is the origin of the Infraspinatus muscle?
Infraspinous fossa of the scapula.
p.9
Clinical Correlations: Injuries and Conditions
What happens when the axillary nerve is injured?
Deltoid paralysis, weak flexion and extension, loss of shoulder roundedness, and inability to abduct beyond 15 degrees.
p.5
Axilla: Structure and Function
What role do axillary lymph nodes play?
They are important for the immune system and part of the lymphatic system.
p.9
Clinical Correlations: Injuries and Conditions
What incident led to the young adult patient's proximal humerus fracture?
The patient consumed alcohol and then rode a motorcycle home.
p.11
Clinical Correlations: Injuries and Conditions
What are common symptoms of frozen shoulder?
Progressive pain and stiffness without a history of trauma.
p.6
Clinical Correlations: Injuries and Conditions
What are the effects of a lower brachial plexus injury?
Diminished or lost hand function, and the hand may assume a claw position.
p.12
Posterior Thoraco-Appendicular Muscles
What muscles are included in the posterior thoraco-appendicular group?
The trapezius, latissimus dorsi, levator scapulae, and rhomboids.
p.7
Clinical Correlations: Injuries and Conditions
What is the clinical significance of palpating axillary lymph nodes during breast examinations?
To check for possible malignancy or infection in the breast.
p.11
Clinical Correlations: Injuries and Conditions
What happens in a complete supraspinatus tear?
Inability to initiate shoulder abduction.
p.3
Anterior Thoraco-Appendicular Muscles
What is the primary function of the pectoralis major?
It adducts and medially rotates the upper limb.
p.3
Anterior Thoraco-Appendicular Muscles
Where does the pectoralis minor originate and attach?
It originates from the 3rd to 5th rib and attaches to the coracoid process of the scapula.
p.2
Clinical Correlations: Injuries and Conditions
What causes the gross deformity seen in a fractured clavicle?
The displaced broken segment tenting the skin.
p.5
Brachial Plexus: Anatomy and Function
What are the three trunks of the brachial plexus?
Superior trunk (C5, C6), Middle trunk (C7), and Inferior trunk (C8, T1).
p.6
Clinical Correlations: Injuries and Conditions
What causes a lower brachial plexus injury?
A sudden movement of the arm that widens the angle between the arm and chest wall.
p.6
Review Questions and Key Points
What is a useful memory aid for understanding the brachial plexus?
Drawing it in a color-coded format.
p.4
Axilla: Structure and Function
Which muscles form the posterior wall of the axilla?
Subscapularis, Teres Major, Latissimus dorsi.
p.14
Posterior Thoraco-Appendicular Muscles
What is the main action of the Rhomboid major?
Retracts scapula and rotates its glenoid cavity inferiorly; fixes scapula to thoracic wall.
p.12
Axilla: Structure and Function
What is the axilla and its significance?
The axilla, or armpit, is a pyramid-shaped space containing neurovascular structures and serves as a distribution point for blood and nerves.
p.15
Scapulohumeral Muscles
Which nerves innervate the Subscapularis muscle?
Upper and lower subscapular nerves (C5, C6, C7).
p.12
Anterior Thoraco-Appendicular Muscles
What are thoraco-appendicular muscles?
Muscles that attach the thoracic area to the extremities, including the subclavius, pectoralis major, pectoralis minor, and serratus anterior.
p.7
Axillary Artery and Vein
What are the branches of the first segment of the axillary artery?
Superior thoracic artery.
p.12
Axillary Artery and Vein
How is the axillary artery divided?
The axillary artery is divided into three segments by the pectoralis minor muscle.
p.12
Scapulohumeral Muscles
What are scapulohumeral muscles and their function?
Scapulohumeral muscles, including the deltoid and rotator cuff muscles, stabilize the humerus and facilitate shoulder movement.
p.2
Skeletal Components: Clavicle and Scapula
How does the glenohumeral joint differ from the acetabulofemoral joint?
The glenohumeral joint has a shallower depression, specializing it for movement, while the acetabulofemoral joint is deeper, specializing it for stability.
