|
Second Block
|
|
Thorax, Abdomen and Pelvis Medical Students
LABORATORY: #12 TITLE: Begin anterior thoracic wall and lungs (Group C), Begin anterior abdominal wall and inguinal region (Group D). I
Ignore removal of thoracic wall, instructions will be given in prosection.
4. Know the position of the intercostal vein, artery, and nerve.
1. Review landmarks and surface anatomy, Fig. 2.2, p41. In addition, note the position of the pectineal line or pecten pubis (Moore, p335). This landmark is a ridge passing laterally from the pubic tubercle which serves as an attachment for the lacunar and pectineal ligaments and the lateral part of the conjoint tendon. 2. Remove the skin on the abdomen with incisions C-F (Fig.2.5., p43). Circumvent the umbilicus and remain superficial in the region of the inguinal ligament near the base of the trunk.Observe Camper’s and Scarpa’s fascia.
3. Understand the organization of the cutaneous nerves of the anterior abdominal wall (what dermatomes they supply). Distinguish between the lower 6 thoracic nerves, which supply the muscles of the wall including the rectus abdominis, and the iliohypogastic and ilioinguinal nerves which do not supply the rectus abdominis. Identify some cutaneous nerves. 4. Examine the three flat muscles and the contributions of their aponeuroses to the rectus sheath. Fig. 2.15., p50. Follow instructions in the dissector to expose the three muscles but only above the iliac crest first by splitting the external oblique into a superior and an inferior portion (p47). Dissect the muscles but not the inguinal region before you pop the top. 5.In your examination of the internal oblique and transversus abdominis muscles note the direction of the muscle fibers and the course of the nerves and the vessels passing between them.
transversalis, extraperitoneal fat, and peritoneum but only dissect to the fascia transversalis at this time. vessels. Observe the arcuate line. INSTRUCTIONS FOR OPENING ANTERIOR THORACIC AND ABDOMINAL WALLS 1. Reflect laterally the breast, pectoralis major, pectoralis minor and serratus anterior en bloc on undissected side. Protect subclavian vein as it enters the axilla. 2. Detach sternal insertions of sternocleidomastoid muscles on both sides. Make sure that sternal attachments of pectoralis minor have been cut on both sides. 3. Open sternoclavicular joints using scalpel and chisel. Pry joint open with chisel and sever costoclavicular ligament between 1st rib and clavicle. Run scalpel blade laterally from head of clavicle to separate the clavicle from the subclavius muscle. This will allow ligaments to be severed without damage to subclavian vessels. 4. Block body up in posterior midline. This will permit the shoulders and the clavicles to retract. 5. Cut the first rib anterior to the subclavian vein. First, cut intercostal mm. in 1st interspace with a scalpel and then cut 1st rib using bone cutters. A flat saw may also be used. 6. Cut ribs 2-10 in midaxillary line using bone cutters and cut intercostal muscles with a scalpel. Protect pleura by sweeping fingers between ribs and lungs during cutting and elevation of ribs. 7. After rib 10 is cut, extend an incision from the 10th interspace to the anterior superior iliac spine and carefully reflect each layer of abdominal muscles to expose transversalis fascia, extraperitoneal fat and peritoneum. Press the peritoneum onto the viscera as widely as is possible! 8. Return to retrosternal space and cut attachments of infrahyoid muscles and internal thoracic arteries. With hand, press parietal pleura away from chest wall and onto lungs. Try to keep pleura intact! 9. Raise chest wall laterally until attachments of diaphragm to costal margins are observed. Diaphragm should be cut from its attachments in a cranio-caudal direction. Again, protect pleura and peritoneum. 10. Gently fold chest and anterior abdominal wall forward and cut any remaining attachments of the diaphragm. Sweep any remaining pleural or peritoneal attachments as the wall is lifted.
11. Group C dissect lungs, group D dissect the inguinal region.
Group C: Pleural Cavity and Lungs.
It is the responsibility of Group C to see that ALL groups examine the thoracic cavity before the lungs are removed. (1) Examine the two pleural sacs and mediastinum. Define the mediastinum (Dissector p. 11). (2) Identify the visceral and parietal pleura. (3) Identify the pleural recesses. (4) What are the various parts of the parietal pleura? (5) What is the root of the lung? (6) Examine the pericardial cavity with the heart in situ. Once the structures listed above are examined, Group C should remove the lungs and begin their dissection in order to demonstrate the following: (1) Examine the root of the lung and the pulmonary ligament. (2) Be able to demonstrate where a pleural tap is performed. (3) Before removing the mediastinal pleura, what structures can be identified through this membrane? (4) Identify the sympathetic trunk and the two rami communicans. (5) Identify the greater splanchnic nerve. Next examine both lungs and identify the following: (1) Three surfaces of the lungs. (2) The lobes of the lungs. (3) Identify as many impressions on the lungs as possible. (4) Examine the hilus of both lungs.
(5) Dissect the bronchial tree from the main bronchus to the segmental bronchi. It will not be necessary to identify the segments of the lungs although you should know what defines a segment.
Group D: Inguinal region (1) Understand how membraneous layer of superficial fascia (Scarpa's): (a) Fuses to fascia lata of thigh.
(2) Demonstrate the following derivatives of external oblique aponeurosis:
(4) Demonstrate transversalis fascia, which continues out over cords as their innermost coverings, the internal spermatic fascia, at deep inguinal rings.
(6) On females, carry your incision superior to the superficial ring (leave ring intact) when reflecting external oblique. Identify cremaster and falx inguinalis. Split cremaster and find the deep ring lateral to inf. epigastric vessels as in males. Note that:
(7) Know that the inguinal canal contains the ilioinguinal nerve, and the spermatic cord (ductus deferens, vessels, nerves, lymphatics; male) or round ligament of uterus (female), but do not dissect these structures at this time. (8) Identify the conjoint tendon and the muscles that contribute to it.
(10) Examine inguinal region of both sexes (arrange to switch with other tables or use prosections). DISSECTOR MODIFICATIONS:
(3) If possible, trace ilionguinal nerve deep to internal oblique. This will give you the cleavage plane between internal oblique and transversus abdominis. Split cremaster muscle away from the rest of internal oblique to join the vertical incision made by the dissectors of the anterior abdominal wall. Work together with them to reflect internal oblique medially and define the conjoint tendon.
vessel.
(5) On the females (optional on males): clean the exposed portion of sartorius muscle. Define, by blunt dissection, the femoral sheath (the femoral nerve lies just lateral to it, the adductor muscles lie just medial to it). Transect the sheath and its contents about midway between inguinal ligament and sartorius. Note the cut ends of femoral artery and vein. Cut tributaries free proximally so that the sheath can be elevated to expose the pectineal ligament deep to it, on the pectineal line (Dissector 2.1). Palpate the femoral canal (empty space in the sheath between femoral vein and lacunar ligament). The blind pocket of transversalis fascia that occupies this space, and transmits lymphatics, is the femoral canal.
Cross-sectional anatomy: (Group D)
C. Identify the testicle, scrotum, tunica albuginea, and epididymis in transverse section.
TITLE: Introduction to superior mediastinum (Group A); Continue thoracic wall, pleural cavity and lungs (Group C), Continue abdominal wall/inguinal region (Group D). PAGES: Group (A) Dissector: 30-35 Moore: Group (C) 8-18 60-78 Group (D) 32-35 178-209
GENERAL OBJECTIVES: (A) Group A: Receive instructions for dissection of superior mediastinum.
(C) Group D: Continue abdominal wall/inguinal region.
SPECIFIC OBJECTIVES:
Group A: Dissection of the superior mediastinum. (1) What are the boundaries of the superior mediastinum? (2) Identify the thymus gland or its fatty remnant. What is its function? Blood supply? (3) Identify the brachiocephalic, superior vena cava, and azygos veins. (4) Identify the arch of the aorta and its three branches. (5) Identify the phrenic, vagus, and recurrent laryngeal nerves. (6) Note the ligamentum arteriosum. It is derived from what embryological structure? (7) Identify the deep cardiac plexus and tracheobronchial lymph nodes. (8) Identify the bifurcation of the trachea (carina). DISSECTOR MODIFICATIONS: Group C and D should have removed the anterior thoracic wall and the intercostal muscles, vessels Once your table examines the general organization of the pleural and pericardial cavities as described above, begin your dissection according to the directions in the dissector (pp. 17-20).
Group A may reflect the sternocleidomastoid muscle (SCM) superiorly by first making a vertical saw cut through the clavicles lateral to the clavicular attachment of the SCM. Then saw horizontally through the manubrium of the sternum. Now reflect the clavicles and manubrium with the attached SCM superiorly. LABORATORY DEMONSTRATIONS: Examine the thymus gland and ductus arteriosus
LABORATORY DEMONSTRATIONS: In a heart with the atria removed, observe the fibrous skeleton of the heart from above. It consists of interconnecting fibrous rings surrounding the AV and semilunar orifices. It reinforces the valves; the cusps cannot be spread apart around their periphery. They also provide attachment for atrial musculature above the AV valves and ventricular musculature below the AV valves.
TITLE: Introduction to heart (Group B); Continue superior mediastinum (Group A); Complete thoracic wall, pleural cavity, and lungs (Group C); Continue abdominal wall/inguinal region (Group D) PAGES: Group (B) Dissector: 19-27 Moore: Group (A) 30-35 Group (C) 8-18 Group (D) 41-45 175-208 (Case 2.17); 323
GENERAL OBJECTIVES: (A) Group B: Introduction to heart. (B) Group A: Continue dissecting the superior mediastinum.
(D) Group D: Continue abdominal wall and inguinal region. ALL: All groups should examine the peritoneal cavity and viscera before dissection of the abdomen begins. Group C will lead this examination. SPECIFIC OBJECTIVES:
Group B: Heart dissection (1) Examine the pericardium. Identify its two layers. (2) Identify the transverse and oblique pericardial sinuses. (3) Review the projection of the heart and the anterior chest wall (Dissector p 3, Fig. 1.5). (4) After removing the heart, identify the great vessels which enter and exit the heart. (5) Identify the coronary arteries and their major branches.
DISSECTOR MODIFICATIONS: Use the containers provided at your table to soak and wash out the interior of the heart. DO NOT FLUSH THE CLOTTED BLOOD DOWN THE SINKS. You will clog the drains.
TITLE: Present the thoracic wall and lungs. Introduction to posterior mediastinum (Group C); Continue the heart. (Group B); Continue the superior mediastinum(Group A); Complete abdominal wall and inguinal region (Group D). PAGES: Group (C) Dissector: 28-30 Moore:
Group (B) 19-28 Group (A) 30-35
Group (D) 41-54 175-208, Cases 2.17, 2.12, p323-324
GENERAL OBJECTIVES:
(B) Group B: Continue the heart (C) Group A: Continue the superior mediastinum (D) Group D: Complete abdominal wall, inguinal region. SPECIFIC OBJECTIVES:
Group C: Dissection of posterior mediastinum (l) Review the boundaries of the posterior mediastinum. (2) Identify the course of the esophagus. (3) Identify the right and left vagus nerves. (4) Examine the location of the thoracic duct within the posterior mediastinum. (5) Examine the descending aorta. (6) Identify the azygos and hemiazygos veins (Atlas Fig. 1.74). What are their tributaries?
TITLE: Present abdominal wall /inguinal region. Introduction to celiac artery, portal vein, bile passages, and associated organs (Group D); Continue posterior mediastinum (Group C); Complete superior mediastinum (Group A); Continue heart (Group B).
All Groups: Examine and identify abdominal organs and peritoneal subdivisions before Group D begins this dissection. (Dissector 55-60)
Pages: Group (D) Dissector:61-68 Moore: 226-242,263-279 Cases 2.9. and 72-77 2.15., p321
Group (C) 28-30
Group (A) 30-35 Group (B) 19-28
GENERAL OBJECTIVES:
(C) Group A: Complete superior mediastinum (D) Group B: Continue heart SPECIFIC OBJECTIVES:
ALL: All groups should examine the peritoneal cavity and viscera before dissection of the abdomen begins. Group D will lead this examination. Groups not receiving prosections (A and B) will lead ALL groups in examining the abdominal contents before proceeding with further dissections. Using your dissector (pp. 55-60) as a guide: (1) Understand the difference between the abdominal and peritoneal cavities. (2) What are the greater and lesser sacs? (3) Identify the ligaments, mesenteries, and omenta formed by peritoneum as listed in your dissector.
(4) Note the general distribution of the abdominal organs. (5) Identify those organs categorized as associated digestive organs such as the liver, gallbladder, pancreas and spleen. (6) What are peritoneal gutters?
Group D: Dissection of celiac trunk (1) Identify branches of celiac trunk, namely common hepatic, splenic, and left gastric arteries. (2) Follow each artery to its termination. Identify and trace branches as described in the dissector. (3) Identify veins that contribute to the portal system. (4) Trace the course of the common bile duct and understand how the duct is formed. Open the G.I. tract from pylorus of stomach to second (descending) part of duodenum. Note: pyloric sphincter, duodenal bulb and major and minor duodenal papilla . (5) Identify main pancreatic duct, divisions of pancreas and blood supply. (6) Examine spleen and note hilus and borders.
(7) Next, examine gallbladder (dissector p.74). (8) Examine liver (dissector p. 74-76), associated ligaments lobes, and porta hepatis. (9) Cross-sectional anatomy: A. Identify the major and minor branches of the celiac artery on cross sections in the laboratory whenever possible including the A.) short gastric arteries (B.) left gastric arteries ( C.) hepatic artery , and D.) splenic artery. Look for these and other branches of the celiac axis in the cross sectional materials in the laboratory. B. Identify the spleen. Under which ribs does the spleen lie ? What is the position of the spleen relative to the position of the left kidney in transverse section ? C. Identify the portal vein in cross section. D. Identify the liver and its lobes, the pancreas, gallbladder, and common bile duct in cross section .
E. Identify these structures in the cross sections within the laboratory. NOTE: To observe all four lobes as well as diaphragmatic and visceral surfaces, cut coronary and triangular ligaments thus freeing liver from its attachment to diaphragm. Next, cut inferior vena cava as it exits the liver and reflect the liver forward.
TITLE: Present superior mediastinum, Introduction to superior and posterior mesenteric arteries (Group A): Continue posterior mediastinum (Group C); Complete heart (Group B) Continue celiac artery, portal vein, bile passages and associated structures (Group D). Group (D) Dissector: 61-68 Moore: 226- 242,263-279 72-77 Cases 2.9., 2.15., p321
Group (C) 28-30 Group (A) 68-70 243-256 Case: 2.13,p321
Group (B) 19-28
GENERAL OBJECTIVES:
(B) Group C: Continue posterior mediastinum (C) Group B: Complete heart (D) Group D: Continue celiac artery, portal vein, bile passages, and associated structures.
SPECIFIC OBJECTIVES:
Group A: (l) Identify origins of branches and fields of supply of superior and inferior mesenteric arteries. (2) Identify marginal artery. (3) Identify superior and inferior mesenteric veins and note contribution to portal venous system. (4) Examine and compare mucosa of jejunum and ileum. (5) Identify ileocecal valve. (6) Cross-sectional anatomy: A. Identify the superior mesenteric vessels in cross-section. Which region of which organ do these vessels make direct contact with? Hint: What is the uncinate process of the pancreas?
B. Identify the ileocecal junction in transverse section . C. Identify the duodenum, jejunum, ileum, cecum , ascending colon , descending colon and transverse colon in cross section . D. Identify the intestinal branches of the superior mesenteric artery within the mesentery in transverse section. E. Identify the above structures on the transverse sections available in the laboratory. DISSECTOR MODIFICATIONS:
Do Not remove G.I. tract (p. 71-72)
TITLE: Present heart, introduction to posterior body wall (Group B); Complete posterior mediastinum (Group C); Continue superior and inferior mesenteric arteries (Group A); Continue celiac artery, portal vein, bile passages, and associated organs (Group D). PAGES: Group (B) Dissector: 77-85 Moore: 297-302
Group (C) 28-30
Group (D) 61-68 72-77 226-242, 263-279 Cases 2.9, 2.15, p321 GENERAL OBJECTIVES: (A) Group B: Present heart, introduction to posterior body wall. (B) Group C: Complete posterior mediastinum (C) Group A: Continue superior and inferior mesenteric arteries (D) Group D: Continue celiac artery, portal vein, bile passages, and associated organs.
Specific Objectives: Group B: Posterior body wall Identify: (1) kidneys and suprarenal glands. (2) renal vessels and ureters noting their origins and courses. (3) structures composing kidney. (4) blood vessels supplying suprarenal glands. (5) testicular or ovarian vessels noting origin and course. (6) muscles composing posterior abdominal wall. (7) nerves along posterior abdominal wall. (8) parts of diaphragm. (9) structures passing through diaphragm.
Cross-sectional anatomy: A. Identify the kidneys in transverse section. Be aware that the living kidneys have mobility which gives them some variability in position. Viewing cross-sections of the kidney, however, helps you to appreciate that one kidney is slightly higher than the other. Which one is higher and which organ is responsible for this effect? Which vertebral levels do the kidneys span? B. Identify the suprarenal glands, the hilus of the kidney, and the renal vessels in transverse section C. Identify the abdominal aorta and the inferior vena cava in transverse section. D. Identify the psoas major muscle, the iliacus muscle and the qudaratus lumborum muscle in cross-section. Can you identify the diaphragm and the crura of the diaphragm in transverse section.? E. Identify these structures on the transverse sections available within the laboratory.
TITLE: Present posterior mediastinum, Introduction to nerves and vessels of the pelvis (Group C); Complete celiac artery, portal vein, bile passages and associated organs (Group D); Continue posterior body wall (Group B); Continue superior and inferior mesenteric arteries and associated organs (Group A). PAGES: Group (C) Dissector: Moore: Male 106-107 Female 117,123,176 347-357
Group (B) 77-85 297-302
Group (D) 61-68 226-242,263-279, 72-77 Group (A) 68-70 243-256, Case 2.13., p321
GENERAL OBJECTIVES:
(D) Group A :Continue superior and inferior mesenteric arteries and associated organs. SPECIFIC OBJECTIVES
Group C: Dissection of pelvic vessels and nerves: (1) Examine branches of internal iliac vessels. (2) Identify obturator foramen. What passes through this structure? (3) In females, identify uterine and vaginal arteries. What is the relationship of uterine artery to ureter? (4) Examine sacral plexus. Understand its general organization. (5) What are the pelvic splanchnic nerves? What structures do they supply?
(6) Identify the testicular or ovarian vessels.
Cross-sectional anatomy A. Identify the internal iliac vessels and the external iliac vessels in transverse section. Identify the internal pudendal vessels traversing the pudendal canal . B. Identify the position of the ischial tuberosity and the superior ramus of the pubis the pubic symphysis , the inferior ramus of the pubis, the sacrum , and the coccyx . C. Identify the structures listed above in the cross sections within the laboratory.
DISSECTOR MODIFICATIONS: NONE
TITLE: Present celiac artery, portal vein, bile passages and associated structures. Introduction to pelvis and pelvic organs (Group D); Continue vessels and nerves of pelvis (Group C); Continue posterior body wall (Group B); Complete superior and inferior mesenteric vessels and associated organs (Group A). PAGES: Group (D) Dissector: Moore: Male 100-105 356-388 Female 117-125 Group (C) Male: 106-107 347-357 Female: 117,123,126 Group (B)
Group (A) 68-70 243-256, Case 2.13., p321 GENERAL OBJECTIVES:
(B) Group C: Continue vessels and nerves of pelvis (C) Group B: Continue diaphragm and posterior body wall. (D) Group A: Continue superior and inferior mesenteric artery and associated organs.
SPECIFIC OBJECTIVES: You should begin examining bony pelvis and general organization of pelvic viscera. Identify as many organs and peritoneal reflections as possible. You will be able to identify viscera on the r split pelvis. Make arrangements with other tables so that you can view and present both sexes. (1) Examine parts of bony pelvis. (2) Learn differences between a male and female bony pelvis. (3) Learn attachments for sacrotuberous and sacrospinous ligaments. What foramina do they form? (4) Examine the peritoneal relationships of the male and female pelvis. (5) Identify the various pouches in both sexes. (6) Identify the various spaces in both sexes. (7) Re-examine coverings of the spermatic cord. From which abdominal wall muscles are these structures derived? (8) Identify constituents of the cord. (9) Examine structures that compose the testis.
Cross sectional anatomy: A. Male pelvic organs: Identify the urinary bladder, the seminal vesicle, the vas deferens, the prostate gland, the ureter . Identify the sigmoid colon and the rectum. Look for these structures in the laboratory. Observe the anococcygeal ligament (a structure found in both sexes) and attempt to find it in the transverse sections in the laboratory. Can you identify the puborectalis portion of the levator ani muscle in cross section? What is the importance of this muscle? B. Female pelvic organs. Identify the urinary bladder and the rectum in the female. Identify the uterus, fallopian tubes vagina and ovary ( if possible ) on the transverse sections available in the lab. (Grants 3.44 B). Identify structures in the MRI’s of the female pelvis is Grants Atlas (3.51,). C. Identify the structures listed above in the transverse sections in the laboratory.:
DISSECTOR MODIFICATIONS: Group A should not examine nerves or blood vessels as listed in the dissector. This dissection is scheduled for another group. Therefore, Group A should disregard any description in the dissector regarding the location and course of blood vessels and nerves.
TITLE: Present superior and inferior mesenteric vessels and associated organs. Introduction to perineum (Group A); Continue nerves and arteries of pelvis (Group C); Continue pelvis and pelvic organs (Group D); Complete posterior body wall and diaphragm (Group B). PAGES: Group (A) Dissector: 89-95 Moore: Male 95-98 Female 110-114 Group (C) Male: 106-107 347-357 Female 117,123,126 Group (D) Male 100-105 356-388 Female117-125 Group (B) 77-85 297-302, Case 2.16. GENERAL OBJECTIVES: (A) Group A: Present superior and inferior mesenteric arteries, introduction to perineum. (B) Group C: Continue nerves and arteries of pelvis (C) Group D: Continue pelvis and pelvic organs. (D) Group B: Complete posterior body wall and diaphragm. SPECIFIC OBJECTIVES:
DISSECTOR MODIFICATIONS: NONE
TITLE: Present diaphragm and posterior body wall(Group B); Continue perineum (Group A), Complete nerves and arteries of the pelvis (Group C), Continue pelvis and pelvic organs (Group D)
PAGES:
Group (A) Dissector 89-95 Moore: Male 95-98 Female 110-114
Group (C) Male 106-107 Female 117,123,126 347-357 Group (D) Male 100-105 Female 117-125 356-388
GENERAL OBJECTIVES:
SPECIFIC OBJECTIVES: None
DISSECTOR MODIFICATIONS: None.
TITLE: Present nerves and vessels of pelvis (Group C); Complete pelvis and pelvic organs (Group D) ; Continue perineum/genitalia (Group A) PAGES: Group (D) Dissector: Moore: Male 100-105 Female 117-125 356-388
DISSECTOR MODIFICATIONS: None.
Title: Present pelvis and pelvic viscera (Group D); Complete perineum (Group A) Pages: Group (A) Dissector: 89-95 Male: 95-98 Female: 110-114.
|