the Pectoral Girdle and Breast Flashcards
What is another name for the costocoracoid membrane?
clavipectoral fascia
what is the enclosed structures of costocoracoid membrane
subclavius and the pectoralis minor
what are the piercing structures of the costocoracoid membrane
medial and lateral pectoral nerves
pectoral branch of the thoraco acromial artery
cephalic vein
List the rotator cuff muscles
infraspinatus
supraspinatus
teres minor
subscapularis
Describe the arteries that participate in scapular anastomoses
Transverse cervical artery
Dorsal scapular artery (the anastomosing branch of the transverse cervical)
Suprascapular artery
Circumflex scapular artery (from subscapular artery of the third part of axillary)
Thoracodorsal artery (from subscapular artery of the third part of axillary)
Posterior intercostal arteries (from thoracic aorta)
Arterial Supply of the breasts
1.perforating branches of internal thoracic artery at 2nd to 4th interspaces
2.perforating branches of 3rd to 5th intercostal artery
3. pectoral branches of the thoraco-acromial artery (2nd part of axillary artery)
4.branches of the lateral thoracic artery (2nd part of axillary artery)
5. branches of the subscapular (3rd part of the axillary artery)
what part of the body is the pectoral lymph nodes responsible for
Pectoral nodes are found at the inferior border of the pectoralis minor, and it drains central and lateral breast
Describe the nerve supply of the breast
- Anterior and lateral cutaneous branches of 3rd to 6th intercostal nerves
o Convey sympathetic fibers to blood vessels and smooth muscles - Nervous plexus around nipple helps signaling suckling
List the nerves vulnerable during a masectomy
o Intercostal brachial n.
o Medial brachial cutaneous n.
o Long thoracic n.
o Thoracodorsal n.
o Medial pectoral n.
What are the contents of the quadrangular space
axillary nerve
posterior circumflex humeral artery
What are the contents of the triangular space
circumflex scapular artery
What are the contents of the triangular interval
radial nerve and the profunda brachii vessels
what are the superior, inferior, lateral and medial boundaries of the quadrangular space
- Superior: teres minor
- Inferior: teres major
- Lateral: surgical neck of humerus
- Medial: long head of triceps
what are the superior, inferior and lateral boundaries of the triangular space
Boundaries
* Superior: teres minor
* Inferior: teres major
* Lateral: long head of triceps
what are the superior, medial and lateral boundaries of the triangular interval
Boundaries
* Superior: subscapularis (anteriorly) and teres major (posteriorly)
* Medial: long head of triceps
* Lateral: humerus
origin of the supraspinatus muscle
supraspinous fossa of the scapula
origin of the infraspinatus muscle
infraspinous fossa of the scapula
origin of the teres minor
middle part of the lateral border of the scapula
origin of the subscapularis
subscapular fossa of the scapula
insertion of the supraspinatus
superior facet of the greater tubercle of the humerus
insertion of the infraspinatus
middle facet of the greater tubercle of the humerus
insertion of the teres minor
inferior aspect of the greater tubercle of humerus
insertion of subscapularis
lesser tubercle of humerus
innervation of supraspinatus
suprascapular nerve
innervation of the infraspinatus
suprascapular nerve
innervation of the teres minor
axillary nerve
innervation of the subscapularis
upper and lower subscapular nerve
muscle action of supraspinatus
initiates & assists deltoid in abduction of humerus for first 15°
muscle action of the infraspinatus
laterally rotates humerus
muscle action of the teres minor
laterally rotates humerus
muscle action of subscapularis
medially rotates humerus and helps hold head of humerus in glenoid cavity
origin of deltoid muscle
Clavicular part – lat. ⅓ of clavicle
Acromial part – acromion
Spinal part – scapular spine
insertion of deltoid
deltoid tuberosity of humerus
innervation of deltoid
axillary nerve
muscle action of deltoid
Acromial part – abduction of arm (assisted by supraspinatus for 1st 15°)
Clavicular part – flexes & medially rotates arm
Spinal part – extends & laterally rotates arm
Helps stabilize glenohumeral joint
Holds head of humerus in glenoid cavity
blood supply of the glehumral joint
Ant. & post. circumflex humeral aa.
Suprascapular a
innervation of the glenohumral joint
- Nerve:
Suprascapular n.
Axillary n.
Lateral pectoral n
origin of teres major
posterior surface of inferior angle of scapula
insertion of teres major
medial lip of intertubercular sulcus of humerus
innervation of teres major
lower subscapular nerve (C5,C6)
Origin of levator scapulae
Posterior tubercles of
transverse processes of C1-
C4 vertebrae
origin of rhomboid minor and major
Minor:
* Nuchal ligament
* Spinous processes of
C7&T1 vertebrae
Major:
* Spinous processes of
T2-T5 vertebrae
insertion of levator scapula
Medial border of scapular
superior to root of
scapular spine
insertion of rhomboid minor and major
Minor:
* Smooth triangular
area at medial end
of scapular spine
Major:
* Medial border of
scapula from level
of spine to inferior
angle
innervation of levator scapula
- Dorsal
scapular
nerves (C4,C5) - Cervical nerves
(C3,C4)
innervation of rhomboid major and minor
Dorsal scapular
nerve (C4,C5)
muscle action of levator scapula
- Elevates
scapula - Rotates
glenoid cavity
inferiorly
muscle action of rhomboid minor and major
- Retract
scapula and
rotates glenoid
cavity inferiorly - Fix scapula to
thoracic wall
origin of trapezius
Medial third of
superior nuchal line
* External occipital
protuberance
* nuchal ligament
* Spinous processes of
C7-T12 vertebrae
origin of latissimus dorsi
- Spinous processes of
inferior 6 thoracic
vertebrae - Thoracolumbar fascia
- Iliac crest
- Inferior 3/4 ribs
insertion of trapezius
- Lateral third of
clavicle - Acromion and
spine of scapula
insertion of latissimus dorsi
Floor of the
intertubercular sulcus
of the humerus
innervation of trapezius
- Spinal accessory
nerve (CN XI)
(motor fibres) - C3, C4 (pain and
proprioceptive
fibres)
innervation of latissimus dorsi
Thoracodorsal nerve
(C6,C7,C8)
muscle action of trapezius
- Descending part
elevates - Ascending part
depresses - All parts retract
scapula - Ascending and
descending rotate
glenoid cavity
superiorly
muscle action of latissimus dorsi
- Extends, adducts,
medially rotates
humerus - Raises the body
towards arms during
climbing
what factors stabilize the glenohumeral joint
- Factors for stability:
o Glenoid labrum- increases concavity
o Coracoacromial arch- prevents upward dislocation
o Tendon of long head of biceps- superior support
o Long head of triceps- inferior support during abduction
o Ligaments
o Rotator cuff muscles- strong lateral stability, stabilizes head of humerus in glenoid cavity - Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
