Note. The following is a guide to answering the questions and is not the "answer."

1. Describe the lymphatic drainage of the breast (6 pts)

   • Laterally, lymph drainage from the breast is into groups of axillary nodes.  Most of this drainage is into the pectoral nodes located along pectoral branches of the thoracoacromial vessels. Pectoral nodes drain into the apical nodes located near the apex of the axilla.  On the left, the axillary nodes give rise to the subclavian lymphatic trunk. This vessel commonly drains into the thoracic duct and then the angle of internal jugular.  The right subclavian duct often drains directly into the venous system.  Apical nodes also have drainages into cervical and supraclavicular nodes.  Metastatic disease in these nodes is especially difficult to remove.
   • The medial aspect of the breast is drained by intercostal vessels into parasternal nodes.  Parasternal and paratracheal drainages combine to form the bronchomediastinal lymph trunks.  Drainage continues into the right lymphatic duct on the right and the thoracic duct on the left.
   • The breast is also drained by subcutaneous vessels.  These vessels have a wide distribution ranging from the cervical region to the inguinal region and crossing the midline.  If the deeper lymph channels are blocked, as may be the case with cancer, subcutaneous drainage may greatly increase and widely disperse cancerous cells.
   • axillary notes receive 75% of lymphatic drainage
   • pectoral nodes - lateral border of pectoralis major
   • apical nodes - beneath the clavicle
   • supraclavicular nodes
   • cervical nodes
   • parasternal nodes
   • along the internal thoracic artery
   • subcutaneous lymphatics
   • distribute to wide area if deep lymphatics are blocked (e.g. cancer)
   • left/right differences
   • right side into right (subclavian) lymph duct
   • left side into thoracic duct and left subclavian v.
   • Summary - Laterally, lymph drainage from the breast is into groups of axillary nodes.  Most of this drainage is into the pectoral nodes located along pectoral branches of the thoracoacromial vessels. Pectoral nodes drain into the apical nodes located near the apex of the axilla.  On the left, the axillary nodes give rise to the subclavian lymphatic trunk. This vessel commonly drains into the thoracic duct and then the angle of internal jugular.  The right subclavian duct often drains directly into the venous system.  Apical nodes also have drainages into cervical and supraclavicular nodes.  Metastatic disease in these nodes is especially difficult to remove.
     The medial aspect of the breast is drained by intercostal vessels into parasternal nodes.  Parasternal and paratracheal drainages combine to form the bronchomediastinal lymph trunks.  Drainage continues into the right lymphatic duct on the right and the thoracic duct on the left.
     The breast is also drained by subcutaneous vessels.  These vessels have a wide distribution ranging from the cervical region to the inguinal region and crossing the midline.  If the deeper lymph channels are blocked, as may be the case with cancer, subcutaneous drainage may greatly increase and widely disperse cancerous cells.

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2. Discuss the anatomy of the popliteal fossa and include an account of the boundaries, vascular supply, innervation, ligaments, bones, contents, muscles, and relationships. (12 pts)

   • General comments
   • posterior to knee, diamond shaped, fat filled, passage of key structures to the lower limb
   • Superior boundary - apex of diamond formed by semimembranosus and semitendinosus diverging from biceps femoris
   • sciatic n. - enters from posterior thigh deep to hamstrings, divides into tibial (medial) and common peroneal (lateral) nn.
   • Superior lateral boundary -  biceps femoris
   • superior lateral genicular a.v. - leaves popliteal fossa femur at lateral femoral epicondyle superior to origin of gastrocnemius
   • Superior medial boundary - semitendinosus and semimembranosus
   • superior medial genicular a.v. - leaves popliteal fossa at medial femoral epicondyle superior to adductor tubercle
   • Inferior lateral boundary - lateral head of gastrocnemius
   • inferior lateral genicular a.v. - leaves popliteal fossa crossing posterior surface of popliteus fascia and arcuate ligament, deep to head of gastrocnemius
   • common peroneal n. - leaves popliteal posterior to lateral head gastrocnemius
   • Inferior medial boundary - medial head of gastrocnemius
   • inferior medial genicular a.v. - leaves popliteal fossa posterior surface of tibia near the plateau, deep to head of gastrocnemius
   • Inferior boundary - apex of diamond formed by convergence of the two heads of gastrocnemius
   • posterior tibial a.v. - leaves popliteal fossa deep to the heads of origin of soleus
   • sural aa. - leaves popliteal fossa by entering the bellies of gastrocnemius
   • branches of tibial n. to the gastrocnemius
   • Posterior boundary - popliteal fascia (deep fascia), tranisition from fascia lata to crural fascia
   • medial and lateral sural nn. - branches for tibial and common peroneal nn.
   • short saphenous v. - pierces popliteal fascia to enter the popliteal v.
   • Anterior boundary - femur, tibial plateau, joint capsule, oblique popliteal lig., arcuate lig., popliteus m.
   • popliteal a.v. - enter through adductor hiatus (superior medial anterior in the fossa) as continuation of the femoral vessels.
   • middle genicular a. leaves popliteal fossa through the posterior aspect of the joint capsule
   • Relations within the fossa - superficial to deep: sciatic n and branches, femoral v., femoral a.
   • Lymphatic drainage - popliteal lymph nodes
   • superficial drainage of leg along channels enter popliteal fossa along with the lesser saphenous v.
   • deep drainage of leg enters popliteal fossa along with posterior tibial vessels
   • lymph from popliteal fossa ascend along femoral vessels to deep inquinal nodes

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3. Discuss the anatomy of the hip joint. Include an account of the innervation, vascular supply, ligaments, bones and articulations, movements and limitations of movements, and stability. (12 pts)

   • General comments
   • This hip joint is a synovial "ball and socket" joint
   • Bones and articulations
   • head of femur (ball fits into the acetabulum (socket)
   • depth of acetabulum is increased by labrum, labrum overlies the transverse acetabulum ligament at the acetabular notch
   • acetabular notch bridged by the transverse acetabular lig
   • articular cartilage on head of femur and on lunate surface of acetabular fossa
   • ligamentum teres attaches to acetabular fossa near transverse acetabular ligament
   • Ligaments - capsular thickenings
   • pubofemoral - from pectin line to intertrochanteric line, resists abduction
   • iliofemoral - from anterior inferior iliac spine (deep to rectus femoris straight head) to intertrochanteric line and lessor trochanter (Y-ligament)
   • fibers spiral from superior anterior medial to inferior posterior lateral - resist extension and shorten on extension to stabilize joint
   • ischiofemoral - from ischium to greater trochanter and intertrochanteric line, resists hyperextension and flexion
   • Movements, limitation of movement, innervations, and muscle stabilization
   • flexion
   • psoas major - lumbar plexus
   • anterior compartment of thigh - femoral nerve
   • rectus femoris - long head
   • sartorius (lateral rotation)
   • tensor fascia lata
   • limited by trunk and hamstrings
   • extension
   • posterior compartment of thigh (hamstrings and posterior adductor magnus) - tibial portion of sciatic
   • gluteus maximus - inferior gluteal nerve
   • limited by ligaments of joint capsule (see above)
   • adduction
   • medial compartment of thigh and obturator externus - obturator nerve
   • limited by opposite thigh and ligament to the head of the femur
   • abduction
   • gluteus minimus and medius and tensor facia lata - superior gluteal nerve
   • limited by pubofemoral ligament and adductors
   • lateral rotation
   • short rotators of gluteal region - lumbosacral plexus
   • long head of the biceps - tibial portion of sciatic
   • sartorius - femoral nerve
   • relatively free - limited by neck of femur and pubofemoral ligament
   • medial rotation
   • anterior part of gluteus minimus (medius) - superior gluteal nerve
   • gracilis - obturator
   • semitendonosus and semimembranosus - tibial portion sciatic
   • limited by joint capsule
   • Muscles - all muscles that cross the joint contribute to stabilization
   • anterior group - flexors: iliopsoas adds major support, rectus femoris, sartorius
   • medial group - all of the adductors
   • posterior group - extensors: the hamstrings
   • gluteal region - rotators and abductors:  the five short lateral rotators, gluteus maximus, medius, and minimus, tensor fascia lata
   • fascial specialization - iliotibial tract
   • The hip joint is maximally stable during extension as is the case during quiet standing.  The line of gravity falls behind the axis causing to hip to extend.  Capsular thickenings (aforementioned ligaments) spiral from posterior to anterior and from medial on the pelvic girdle to lateral on the femur.  As the ligaments tighten the capsule shortens similar to twisting a wet towel.  This forces the head of the femur deep securely into the acetabular fossa.
   • Vascularization
     • Cruciate anastomosis
   • Innervation of hip joint
     • Hilton's law - all nerves that cross the joint provide innervation to the joint tissues

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4. Discuss the collateral circulation of the arterial supply and venous drainage of the thoracic wall, and relate this to the structure (muscles, bones, fascia) comprising the thoracic cage. (10 pts)

   • General Comments. The vasculature supply to the thoracic wall travels within the neurovascular plane defined superficially by the internal intercostal muscles and membrane (posterior) and deeply by the subcostal (posterior), innermost intercostal (intermediate), and transversus thoracis (anterior) muscles. The intercostal veins, arteries, and nerves are located inferior to the costal groove of the superior rib defining an intercostal space. From superior to inferior is vein, artery, nerve. Posterior, lateral, and anterior branches of the intercostal vessels leave the neurovascular plane to supply superficial regions of the thoracic wall. The lateral branches further divide into posterior and anterior branches whereas the anterior branches further divide into medial and lateral branches.
     
     The bulk of the anterior vasculature has the subclavian arteries and brachiocephalic veins as the parent vessels whereas the bulk of the posterior vasculature has the descending aorta (first two intercostal spaces qualified) and azygous system as the parent vessels. The anterior and posterior vasculatures anastomose within the thoracic wall. Thus, the aortic arch can deliver blood directly to the descending aorta or indirectly to the descending aorta by way of the anterior vasculature (subclavian to internal thoracic to anterior intercostals to posterior intercostals to descending). See below for refining considerations.
   • Arteries
     • Posterior intercostal spaces
       • 1-2 Supereme (highest) thoracic artery from costocervical trunk of subclavian artery
       • 3-11 Posterior intercostal arteries from the descending aorta
     • Anterior intercostal spaces
       • 1-6 - Internal thoracic artery from subclavian artery
       • 7-9 - Musculophrenic artery from internal thoracic artery
       • 10-11 - Superior epigastric from internal thoracic artery
   • Veins
     • Right posterior intercostal spaces
       • 1 - Supreme (highest) intercostal vein from brachiocephalic vein
       • 2-4 - superior intercostal vein from azygous vein
       • 5-11 - Posterior intercostal veins from azygous vein
     • Left posterior intercostal spaces
       • 1 - Supreme (highest) intercostal vein from brachiocephalic vein
       • 2-4 - superior intercostal vein from accessory hemiazygous vein, or brachiocephalic vein, or coronary sinus
       • 5-11 - Posterior intercostal veins from hemiazygous vein
     • Anterior intercostal spaces
       • 1-6 - Internal thoracic vein
       • 7-9 - Musculophrenic vein
       • 10-11 - Superior epigastric vein

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5. Discuss the mechanics of breathing, focusing on explaining the basic movements of the thoracic cage and expansion of the lung in respiration. (9 pts)

   • Anterior posterior - pump handle and costotransverse joint
   • cupped tubercle of transverse process results in pump handle of upper ribs
   • costochondral and sternochondral joints involved
   • The pump-handle movement of respiration refers to the movements of the upper 6 ribs during breathing. During inspiration there is an increase in the anterior-posterior diameter of the thorax. The sternum moves superiorly and anteriorly in accord with rib movements occurring at the costovertebral, costotransverse, costochondral, and sternochondral joints. Relative to the lower ribs, the costotransverse joint articulation at the transverse process is cupped and accommodates the tubercle of the rib. This articulation permits the rib to rotate on a transverse axis. A slight downward movement at the head of the rib is amplified distally at the sternum. This movement is transferred to the sternum by the costochondral and sternochondral joints. The result is that the sternum raises on inspiration much like the raising of a pump-handle when drawing water from the depths of a well
   • transverse - bucket handle and costotransverse joint
   • planar tubercle of transverse process permits an outward sliding of the rib and results in bucket handle of lower ribs
   • costochondral and sternochondral joints involved
   • vertical - diaphragmatic
   • phrenic n., pericardiacophrenic vessels, ant. post. intercostal vessels
   • Upon diaphragmatic contraction the height of the diaphragmatic dome drops to increase the vertical extent of the thoracic cavity.
   • capillary effect, negative pressure, etc.
   • pneumothorax - air enters and breaks capillary effect, loss of negative pressure, the lung collapses