The pectoral region is external to the anterior thoracic wall and consists of superficial and deep compartments. What are the components of the superficial and deep compartments?
superficial compartment: skin, fascia, breasts
deep compartment: muscles and associated structures
Lymphatic and venous drainage passes from _____ and ____ parts of the breast into the axilla.
lateral and superior
The branches of what arteries supply blood to the breast?
branches of axillary, internal thoracic, and intercostal arteries
What triangle does the cephalic vein emerge from (has 2 names)?
What are the names of the 2 "heads"/portions of the pectoralis major?
clavicular head (attaches to clavicle)
sternocostal head (attaches to sternum)
What are the names of the muscles in this picture?
What are the names of the fascias surrounding the pectoralis major and minor?
pectoralis major: pectoral fascia
pectoralis minor: clavicpectoral fascia
Identify the nerves and artery in this picture. What do they supply/innervate?
lateral pectoral nerve: innervates sternocostal portion of pectoralis major
medial pectoral nerve: passes through pectoralis minor into pectoralis major
(pectoral nerves are named for their branches in the brachial plexus)
thoracoacromial artery (pectoral, deltoid, acromial, and clavicular branches). can track pectoral arteries back to it
The posterior triangle of the neck lies over the _____ inlet and is associated with nerves and vessels that pass to and from the upper extremities into and from the neck.
What are the boundaries of the posterior triangle?
anterior border: SCM (sternocleidomastoid)
posterior border: trapezius
base: middle 1/3 of the clavicle
apex: occipital bone at point where attachments of SCM and trapezius meet
roof: investing layer of cervical fascia that surrounds the SCM and trapezius
floor: cervical fascia, splenius capitus muscles, levator scapluae muscle, scalene muscles
What are subdivisions of the posterior triangle? What muscle allows for these subdivisions?
The _____ _____ vein crosses the SCM and enters the posterior triangle. It pierces the investing layer of cervical fascia and ends as a tributary to the ____ vein.
1. external jugular vein
2. subclavian vein
Name 3 veins in the posterior triangle that are tributaries to the external jugular vein.
1. transverse cervical vein
2. suprascapular vein
3. anterior jugular vein
What 3 arteries can be found in the posterior triangle? Where do they originate?
transverse cervical artery suprascapular artery originate in the thyrocervical trunk. the third part of the subclavian artery may also be found in this region.
transverse cervical artery: originates from the thyrocervical trunk. This artery runs superficially and laterally across the phrenic nerve and anterior scalene, in a position just superior to the clavicle. It then crosses or passes through the trunks of the brachial plexus and then passes deep to the trapezius. It may divide into superficial and deep branches with the superficial branch running on the deep (anterior) surface of the trapezius with the accessory nerve and the deep branch (a.k.a. dorsal scapular artery) passing deep (anterior) to the rhomboid musculature.
suprascapular artery: is also a branch of the thyrocervical trunk. It initially follows a course parallel but inferior to the transverse cervical artery, but will then pass posterior to the clavicle and enter the posterior scapular region (passes over superior transverse scapular ligament. suprascapular nerve passes under this ligament)
third part of the subclavian artery: begins at the lateral border of the anterior scalene and will give off branches that supply the upper limb. may be difficult to locate in the posterior triangle because it lies posterior and just superior to the subclavian vein
(Dorsal/ventral) rami innervate muscles in the posterior portion of the neck. (Dorsal/ventral) rami innervate muscles in the posterior triangle of the neck.
dorsal rami innervate muscles in the posterior portion of the neck (rectus capitus major and minor, obliquus capitus posterior and superior)
ventral rami innervate muscles in the posterior triangle of the neck (SCM, scalene muscles)
The cervical plexus can be found in the posterior triangle of the neck and includes cutaneous branches as well as a nerve that innervates the trapezius. Discuss what nerves are included in the cutaneous branches and what they innervate as well as what nerve innervates the trapezius that is located in this region.
1. cutaneous branches of the cervical plexus emerge posterior to the sternocleidomastoid (SCM) and supply the skin of the neck, superior-lateral thoracic wall, and scalp. These nerves include the transverse cervical nerve, lesser occipital nerve, greater auricular nerve, and supraclavicular nerves
2. the accessory nerve (CN XI) passes deep to the SCM, innervates that muscle, then enters the posterior triangle of the neck. this nerve disappears deep to the anterior border of the trapezius muscle (innervates the trapezius muscle)
Identify these muscles located in the posterior triangle of the neck. What structures pass through the muscles labeled 1 and 2 and why is this significant?
origins of the brachial plexus and the subclavian artery (innervates upper ext). ppl may have tension in btwn these muscles and may experience neurological sx in the upper ext due to entrapment of the brachial plexus
Identify the structures in the posterior triangle of the neck. What is significant about the order in which the strucutres are arranged (as you go from anterior to posterior)?
the subclavian vein is anterior/superficial to these structures (including subclavian artery). is good bc when getting access to this vein, do not want to pierce other structures
The subclavian artery is called what after is passes the clavicle?
What is the origin, insertion, function, and innervation of the pectoralis minor?
origin: ribs 3-5 near costal cartilages
insertion: coracoid process of the scapula
function: draws scapula anteriorly and inferiorly to allow for movements such as reaching to scratch the center of the back or putting arm in a shirt sleeve
innervation: medial pectoral nerve
What is the origin, insertion, function, and innervation of the pectoralis major?
origin: clavicular head-medial clavicle. sternocostal head-sternum and costal cartilages of the first 6 or 7 ribs
insertion: lateral lip of the intertubercular groove (bicipital groove) of the humerus
function: adducts and medially rotates the arm at the glenohumeral joint, draws shoulder girdle (clavicle and scapula) anteriorly and inferiorly, flexes are at the glenoumeral joint to 90 degrees, extends the arm at the glenohumeral joint from a flexed position
innervation: medial and lateral pectoral nerves
What is the origin, insertion, function, and innervation of the subclavius?
origin: first rib
insertion: inferior surface of the clavicle
function: support the clavicle in the sternoclavicular joint
innervation: subclavian nerve
What are the origins, insertions, functions, and innervation of the anterior, middle, and posterior scalene muscles? (remember these muscles are located in the posterior triangle of the neck)
the anterior, middle, and posterior scalene muscles originate on transverse processes of cervical vertebrae
the anterior and middle scalenes insert on the first rib. the posterior scalene inserts on the second rib
the scalene muscles are innervated by ventral rami of cervical nerves
group function: laterally flex (side-bend) the neck to the same side and elevate the throacic cage during respiration through rib attachment
What are the origins, insertions, functions, and innervations of the serratus anterior muscle?
origin: ribs 1-8/9 on anterolateral thoracic wall
insertion: medial border of the scapula on its anterior surface
fxn: protracts and upwardly rotates the scapula, fixes the scapula to the thoracic wall. is the most powerful protractor of the scapula. protraction and upward rotation are critical for lifing the arm overhead
innervation: long thoracic nerve