Scapula, Pectoral, and Breast Flashcards
Two vessels embedded in superficial fascia
- Cephalic v.
-Travels laterally
-Pierces part of the clavipectoral fascia - Basilic v.
-Travels medially
-Pierces brachial fascia
Both drain into axillary v.
Deltoid muscle
O: Lateral 1/3 clavicle, acromion, spine of scapula
I: Deltoid tuberosity of humerus
Inn: Axillary n.
Action(s): Clavicular: flex and medially rotate
Acromial: abducts arm (beyond initial 15 degree)
Spinal: extends & laterally rotates arm
Teres Major Muscle
Lats little helper
O: Posterior surface of inferior angle of scapula
I: Medial lip of bicipital groove of humerus
Inn: Lower subscapular n.
Action(s): Adduct, & medially rotates arm
Supraspinatus muscle
O: Supraspinous fossa of scapula
I: Superior facet of greater tubercle of humerus
Inn: Suprascapular n.
Action(s): Assists deltoid with abduction of the arm (initial 15 degrees)
Infraspinatus Muscle
O: Infraspinous fossa of scapula
I: Middle facet of greater tubercle of humerus
Inn: Suprascapular n.
Action(s): Laterally rotates the arm
Teres Minor Muscle
O: Middle part of lateral border of scapula
I: Inferior facet of greater tubercle of humerus
Inn: Axillary n.
Action(s): Laterally rotates the arm
Subscapularis muscle
O: Subscapular fossa of scapula
I: Lesser tubercle of humerus
Inn: Upper & lower subscapular nn.
Action(s): Medially rotates the arm
Bursa
trying to prevent friction with movement
Rotator cuff injuries
-Repeated abduction and flexion (e.g., a throwing motion) causes wear on the tendons as they rub on the acromion and coracoacromial ligament
-The tendon of the supraspinatus is most vulnerable to injury
-Weakest inferiorly
Shoulder dislocation
Anterior humeral dislocation
Pectoralis Major Muscle
O: clavicular attachment and sternocostal head
I: lateral lip of bicipital groove of humerus
Inn: lateral & medial pectoral nn.
Action(s): Adducts and medially rotates humerus, draws scapular anteriorly and inferiorly
Acting alone: clavicular head flexes while sternocostal head extends the humerus from a flexed position
Pectoralis Minor muscle
O: 3rd to 5th ribs never costal cartilages
I: Coracoid process of scapula
Inn: Medial pectoral n.
Action(s): Stabilizes scapula by drawing it inferiorly and anteriorly against the thoracic wall
Subclavius muscle
O: Junction of 1st rib & costal cartilage
I: Inferior surface of clavicle
Inn: N. to subclavius
Action(s): Depresses & anchors clavicle
Serratus Anterior Muscle
O: Lateral part of ribs 1-8
I: Medial border of scapula
Inn: Long thoracic n.
Action(s): Protracts, rotates, & holds scapular against thoracic wall
Quadrangular Space
Boarders:
Sup: teres minor
Inf: teres major
Med: triceps brachii long head
Lat: shart of the humerus
Contents: axillary n. & posterior circumflex humeral artery
Triangular space
Boarders:
Sup: teres minor
Inf: teres major
Lat: triceps brachii long head
Contents: circumflex scapular a.
Breast shape
round and mostly from fat, 2/3 rests on pectoralis major and 1/3 on serratus anterior fascia
oEnlarges during puberty and pregnancy from new glandular tissue
Nipples
don’t have far, hair or sweat glands, tip is fissured with lactiferous ducts opening, composed of circularly arranged smooth muscle fibers
Areola
contains numerous sebaceous glands, secrete protective oily substance
Breast Quadrants
used for anatomical description and location of a hard mass or cyst
Suspensory ligaments
condensations of fibrous connective tissue- support lactiferous ducts and lobules
Lactiferous ducts
give rise to buds that develop into 15-20 lobules
Lobules of mammary gland
are parenchyma (functional substance)- enlargement during lactation
Lactiferous sinus
are dilated portion of each duct located deep to the areola, where milk will accumulate or remain in a nursing mother, causing “let-down reflex”
Neurovascular of the breast
-Inn: anterior and lateral cutaneous branches of the 4th- 6th intercostal nn.
-Lateral thoracic a.
-Medial internal intercostal a. & posterior intercostal aa.
-Axillary v.
Lymphatic drainage of the Breast
-Most of the breast drains via pectoral, central, and apical axillary nodes to subclavian lymph trunk
oMedial breast drains to parasternal nodes
-Subclavian lymph trunk drains into venous system at subclavian and internal jugular junction
-Lymph-> central -> subclavian -> r. lymphatic duct and thoracic duct
Potential breast cancer abnormalities
Skin dimpling, edema of skin, nipple retraction, abnormal contours
