1: anatomy of deltoid, pectoral and scapular regions Flashcards
What’s the blood supply to glenohumeral joint?
Anterior and posterior circumflex humeral arteries
Fascia at pectoral region attaches to what bones?
Clavicle & sternum
What ligament is responsible of holding the skin when adducting the arm
Suspensory ligament (which is thickening of pectoral fascia)
The muscle works from insertion to origin. Which is proximal and which is distal?
Origin (proximal)
Insertion (distal)
Pectoralis major (origin, insertion, action, innervation)
• Origin (proximal attachment): clavicle, superior six costal cartilages.
• Insertion (distal attachment): Intertubercular groove of humerus.
• Function : adduct and medially rotates humerus.
• Innervation : lateral & medial pectoral nerves.
Pectoralis minor (origin, insertion, action, innervation)
• Origin : 3rd-5th ribs
• Insertion : coracoid process of scapula
• Function : stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall
• Innervation : medial pectoral nerve
This muscle helps you raise the scapula slightly when trying to reach something upward
Pectoralis minor
Subclavius (origin, insertion, action, innervation)
• Origin : 1st rib
• Insertion : inferior surface of the clavicle
• Action : anchors and depresses clavicle
• Innervation : nerve to subclavius
Serratus anterior (origin, insertion, action, innervation)
• Origin: lateral parts of 1st-8th ribs.
• Insertion: anterior surface of the medial border of scapula.
• Action: protracts scapula and holds it against thoracic wall, rotates scapula.
• Innervation: long thoracic nerve.
Trapezius (origin, insertion, action, innervation)
• Origin: external occipital protuberance, superior nuchal line of occipital bone, ligamentum nuchae, spinous processes C7 & T1-T12.
• Insertion: posterior border of the lateral third of clavicle, acromion and scapular spine.
• Action: rotate the scapula for full abduction, elevate the shoulder, retract the shoulder and draw scapula downward.
• Innervation: accessory nerve.
Lattisimus dorsi (origin, insertion, action, innervation)
• Origin: aponeurosis of thoracolumber fascia, spinous processes of lower 6 thoracic vertebrae, iliac crest
• Insertion: intertubercular groove of humerus
• Action: extend, adduct, and medially rotates the humerus
• Innervation: thoracodorsal nerve
Rhomboids (origin, insertion, action, innervation)
• Origin : spinous processes of C7 –T5
• Insertion : medial border of scapula
• Function : retract scapula and rotate it to depress glenoid cavity, fix scapula to thoracic wall
• Innervation : dorsal scapular nerve
Levator scapulae (origin, insertion, action, innervation)
• Origin : posterior tubercles of transverse processes of C1-C4 vertebrae
• Insertion : medial border of scapula superior to root of spine.
• Action : elevates scapula and tilts its glenoid cavity inferiorly by rotating scapula.
• Innervation : dorsal scapular and cervical nerves.
Deltoid (origin, insertion, action, innervation)
• Origin: lateral third of clavicle, superior surface of the acromion, and spine of the scapula
• Insertion: deltoid tuberosity
• Action: abduct the arm with supraspinatus, medial and lateral rotation + (slight flexion & extension at walking)
• Innervation: axillary nerve
Subscapularis
• Origin: subscapular fossa
• Insertion: lesser tubercle
• Action: medially rotate and adduct arm
• Innervation: upper and lower subscapular
Supraspinatus
• Origin: supraspinatus fossa
• Insertion: greater tubercle
• Action: initiates abduction, lateral rotator of humerus
• Innervation: suprascapular nerve
Infraspinatus & teres minor
• Origin: Infraspinatus fossa (infraspinatus), posterolateral surface of scapula scapula (teres minor)
• Insertion: greater tubercle
• Action: laterally rotate arm
• Innervation: axillary (teres minor), suprascapular (infraspinatus)
Teres Major
• Origin: scapula
• Insertion: intertubercular groove of humerus
• Action: adduct and medially rotates
• Innervation: lower subscapular
What muscle holds scapula in place?
Pectoralis minor
Boxer’s muscle
Serratus anterior
A patient presented with winging of scapula, what’s the problem?
A. Pectoralis major
What’s this muscle?
Subclavius
When you’re hanging, this muscle will bring your body towards your arms so it’s the muscle that pulls the body/
Lattisimus Dorsi
Main medial rotator ?
Subscapularis
Initiates abduction?
Supraspinatus
The triangle of auscultation is a good spot to ascultate the lungs. Where is this triangle located?
Between border of scapula and trapezius
muscle that elevate the medial fragment of fractured clavicle?
SCM (sternocleidomastoid)
Which muscle is attached proximally to the coracoid process?
a. Pectoralis major
b. Pectoralis minor
c. Subclavius
d. Coracobrachialis
D. Coracobrachialis
Which muscle is responsible for shrugging off against resistance?
a. Trapezius
b. Subclavius
c. Biceps
d. Rhomboids
A. Trapezius ( shrugging off against resistance = elevate the shoulder)
Which muscle is used for pushing the trunk up while climbing a tree?
Latissimus Dorsi
(from google , pushing the trunk up = need powerful adductor muscles [ pectorals major + latissimus dosri + teres major )
First 15 degrees of abduction is by this muscle
Answer: Supraspinatus
(Note: Beyond that deltoid abducts)
What muscle swings the arm back and forth while walking?
Deltoid
What is a consequence of rotator cuff muscle injury?
a. Painful arc
b. Bursitis
c. Tendinitis
d. Sprain
A. Painful arc
Which nerve damage causes winging of scapula?
Long thoracic nerve
Which rotator cuff muscle is easily impinged?
Supraspinatus
What action is lost if Subscapular nerve is affected?
Medial shoulder rotation
Injury to spinal accessory nerve lead to paralysis of which muscle?
Trapezius
Which two muscles are the chief lateral rotators?
Infraspinatus + Teres minor
Injury to which nerve results in the inability to initiate abduction?
Suprascapular nerve
Injury to which nerve results in the inability to retract the scapula?
Dorsal scapular nerve
Boxer said: “Ow, I can’t punch!”. Which nerve is injured?
Long thoracic nerve
In fracture of the middle part of the clavicle, the proximal side is elevated while the lateral part is stationary. What keeps the lateral side in such position?
Coracoclavicular ligament
What structure depresses the clavicle and is associated with the subclavian groove of the clavicle?
Subclavius
Scapular winging occurs in:
a. Roots injury
b. Superior trunk injury
c. Inferior trunk injury
d. Divisions injury
e. Medial cord injury
a. Roots injury
(Greys Qs): A
27-year-old man was admitted to the emergency department after an automobile collision in which he suffered a fracture of the lateral border of the scapula. Six weeks after the accident, physical examination reveals weakness in medial rotation and adduction of the humerus. Which nerve was most likely injured?
A. Lower subscapular
B. axillary
C. radial
D. spinal accessory
E.ulnar
A. Lower subscapular
(Teres major affected)
(Greys Qs): A
55-year-old man is examined in a neighborhood clinic after receiving blunt trauma to his right axilla in a fall. He has difficulty elevating the right arm above the level of his shoulder. Physical examination shows that the inferior angle of his right scapula protrudes more than the lower part of the left scapula. The right scapula protrudes far more when the patient pushes against the examiner’s hand with resistance. Which of the following neural structures has most likely been injured?
A. The posterior cord of the brachial plexus
B. The long thoracic nerve
C. The upper trunk of the brachial plexus
D. The site of origin of the middle and lower
subscapular nerves
E. Spinal nerve ventral rami C7, C8, and T1
B. The long thoracic nerve
(Greys Qs): A 19-year-old man is brought to the emergency
department after dislocating his shoulder while playing
soccer. Following reduction of the dislocation, he has pain over the dorsal region of the shoulder and cannot abduct the arm normally. An MRI of the shoulder shows a torn muscle. Which of the following muscles is most likely to have been damaged by this injury?
A. Coracobrachialis
B. Long head of the triceps brachii
C. Pectoralis minor
D. Supraspinatus
E. Teres major
D. Supraspinatus
(Greys Q): A 35-year-old male wrestler is admitted to the
emergency department with excruciating pain in his right shoulder and proximal arm. During physical examination, the patient clutches the arm at the elbow with his contralateral hand and is unable to move the injured limb. Radiographic studies show that the patient has a dislocation of the humerus at the glenohumeral joint. Which of the following conditions is the most likely?
A. Head of humerus is displaced anteriorly
B. Head of humerus is displaced Posteriorly
C. Head of humerus is displaced inferiorly
D. Head of humerus is displaced medially
C. The head of humerus is displaced inferiorly because in that location it is not supported by the rotator cuff muscles tendons or the coracoacromial arch.
(Greys Q): During a fight in a tavern, a 45-year-old male construction worker received a shallow stab wound from a broken beer bottle at a point near the middle of the left posterior triangle of his neck. Upon physical examination, it is observed that the left shoulder is drooping lower than the right shoulder, and the superior angle of the scapula juts out slightly. Strength in turning the head to the right or left appears to be symmetric.
Which of the following nerves is most likely injured?
A. Suprascapular nerve in the supraspinous fossa
B. The terminal segment of the dorsal scapular nerve
C. The upper trunk of the brachial plexus
D. The spinal accessory nerve in the posterior cervical triangle
E. The thoracodorsal nerve in the axilla
D. The spinal accessory nerve in the posterior cervical triangle
(Greys Q): A
45-year-old woman is admitted to the hospital with neck pain. A computed tomography (CT) scan reveals a tumor on the left side of her oral cavity. The tumor and related tissues are removed and a radical neck surgical procedure is performed. Two months
postoperatively the patient’s left shoulder droops quite noticeably. Physical examination reveals distinct weakness in turning her head to the right and impairment of abduction of her left upper limb to the level of the shoulder.
Which of the following structures was most likely injured during the radical neck surgery?
A. Suprascapular nerve
B. Long thoracic nerve
C. Spinal accessory nerve
D. The junction of spinal nerves C5 and C6 of the brachial plexus
E. Radial nerve
C. Spinal accessory nerve
Shoulder droops what nerve and muscle affected?
Spinal accessory nerve
Trapezius muscle
(Greys Q): A 43-year-old man visits the outpatient clinic with a painful shoulder. Physical examination reveals a painful arc syndrome due to supraspinatus tendinopathy. Which of the following conditions are expected to be present during physical examination as the patient abducts his arm?
A. Painful abduction 0 to 15
B. Painful abduction 0 to 140
C. Painful abduction 70 to 140
D. Painful abduction 15 to 140
E. Painful abduction 40 to 140
A. Painful abduction 0 to 15 degrees
(Greys Q): A 36 year old woman is admitted to the emergency department after an athletic injury that has caused weakness in both lateral rotation and the initial 15 to 20° of abduction of the arm which nerve was most probably injured?
Suprascapular nerve
What’s the nerve supply for glenohumeral joint?
Nerve supply by suprascapular, axillary, and lateral pectoral pectoral nerves.
What are axioappendicular muscles (anterior)?
What are axioappendicular muscles (posterior)?
Clinical relevance of fascia (good + bad)?
(Greys Q): After an orthopedic surgeon examined the MRI of the shoulder of a 42-year-old woman he informed her that the supraspinatus tendon was injured and needed to be repaired surgically. Which of the following is true of the supraspinatus muscle?
A. It inserts onto the lesser tubercle of the humerus.
B. It initiates adduction of the shoulder.
C. It is innervated chiefly by the C5 spinal nerve.
D. It is supplied by the upper subscapular nerve.
E. It originates from the lateral border of the scapula.
C. The supraspinatus muscle inserts on the greater tubercle of the humerus and is said to initiate abduction of the arm at the shoulder. It is supplied principally by spinal nerve C5. The subscapularis muscle is the only muscle that inserts on the lesser tubercle. The subscapularis muscle is innervated by the upper and lower subscapular nerves. The teres minor muscle takes origin from the lateral border of the scapula; the teres major muscle takes origin from. the region of the inferior angle and the lateral border of the scapula.
(Greys Q): A 21-year-old woman who is an athlete dislocated her glenohumeral joint while playing soccer and the shoulder was reduced in the emergency department. However, after 1 week the physician noted that the woman had lost strength when she attempted internal rotation of her arm at the shoulder.
This finding was most likely caused by a tear in which of the following muscles?
A. Infraspinatus
B. Pectoralis minor
C. Subscapularis
D. Supraspinatus
E. Teres minor
C. Subscapularis
(Explanation: Anterior dislocation of the humerus may damage the nerves located in the axilla or cause tears in the rotator cuff muscles. Internal rotation is the primary function of subscapularis muscle; with this being the only action impaired it is the most likely damaged muscle, probably as a result of injury to the upper and/or lower subscapular nerves that innervate this muscle.)
Shoulder joint movements
