Examination of External Anatomy and Surface, and Standard Practices

Examination of External Anatomy and Surface, and standard practices.

1. Familiarize yourself with your surgical instruments. Standard surgical scissors, fine scissors, standard forceps, tissue forceps, dull dissection probe, hemostatic forceps, scalpel handle and blades, chisels, hammer, retraction devices. Follow instructor’s instructions for installing scalpel blades and their removal. Note bone shears and autopsy saw locations.

2. Always wear your protective clothing and eye protection while in lab. Extra protective equipment will be necessary for some procedures (bone saw). Know where locations eye wash stations, first aid kit, fire alarm, and exits are.

3. Record all cadaver descriptors into cadaver assessment sheet (COD, age, sex, race, and ID#, and table #).

4. Measure and record height of cadaver, measure the distance between anterior superior iliac crests and record for future estimation of body weight.

5. Remove all cadaver processing catheters. (Small red devices can be unscrewed from skin, may have to use hemostat.)

6. Note and document all skin lesions, marks (scars, tattoos, etc.), surgical devices, etc. Record their locations on assessment sheet and describe location anatomically.

7. Describe cadaver’s state of preservation and appearance, and any other important information on the assessment sheets.

8. Turn cadaver over and repeat above procedure for posterior.

9. When finished, always HYDRATE the dissection thoroughly and tie skin flaps back in place. Close cadaver tanks.

10. Clean work area, clean dissection tools and put in correct containers, Clean any spills on floor and drain and empty tank bucket. Clean off front of apron with damp paper towels and hang up apron.

11. Wash Hands.

NOTE: Steps 9-11 should be performed at end of each lab session.

Lab 1. Back Dissection

Review the following bony structures: (prior to lab)

Temporal bone: Mastoid Process

Occipital bone: External Occipital Protuberance, Occipital condyles, nuchal lines

Scapula: scapular spine, acromion, coracoid, margins, angles, notch, fossae

Ilium: Iliac process and crest

Femur: Greater and lesser trochanter

Cervical Vertebrae: Centrum, spinous process, transverse process, transverse foramen, spinal foramen, lamina, pedicle

Thoracic vertebrae: spinous process, transverse process, spinal foramen, lamina, pedicle, rib facets

Lumbar vertebrae: spinous process, transverse process, spinal foramen, lamina, pedicle

Sacrum: sacral spine, promontory, sacral foramina, sacral hiatus, sacral ridges

1. Place cadaver prone (face down)

2. Locate the following structures through the skin: External occipital protuberance (ECP), spinous processes, acromion, medial margin of scapula, scapular spine, iliac crests, sacrum, mastoid, midaxillary line, greater tochanter, and midline. Note gluteal site of injection.

3. Make the following incisions: (Note: incisions should cut through the skin and superficial fascia only, leaving the deep fascia and muscle untouched)

· Cut from the ECP to the anus along the midline.

· Cut horizontally along occipital to the mastoid

· Cut horizontally between the two acromions

· Cut horizontally along bottom of rib cage near T6, T7, or L1

· Cut along iliac crest from midline

· Cut laterally along top of leg starting from anus.

All incisions should proceed laterally to the midaxillary plane.

DO NOT REMOVE THE SKIN. Leave attached at the midaxillary line.

4. Reflect each skin section back starting at the lower midline corner and reflecting it laterally and superiorly. Use a hemostat to grasp the skin, (later a button hole can be cut to assist in gripping the skin). Look for neurovascular bundles that course between the deep fascia and the superficial fascia. These will need to be cut as you retract the skin. The bundles pass segmentally through fovea close to the midline in the thoracic region and more laterally in the lumbar region.

5. Identify and clean (remove fascia and separate muscles with blunt dissection) the following superficial structures:

-Nuchal ligament
-Thoracolumbar fascia
-Trapezius –orignates on occipital bone, nuchal ligament, and C7-T12 and inserts on lateral clavicle, acromion and scapular spine. It elevates, retracts, depresses and rotates scapula.
-Lattissimus dorsi –originates from T7-sacrum via the thoracolumbar fascia, iliac crest, inferior three ribs and inserts on the intertubercular groove of humerus. Extends, adducts and medially rotates humerus, or raises body toward the arms in climbing.
-Gluteus maximus (starts along iliac crest and inserts to IT band and gluteal tuberosity, extends thigh) and Tensor fasciae latae (Ant. sup. iliac spine (ASIS) to IT band (which attaches to lateral condyle of tibia), abducts thigh) Major site of IM injection safe injections can be made to superior lateral border of this muscle by placing thumb of opposite hand on greater trochanter and fingers along iliac crest to shield roots of nerve passing inferior and medially)
-Triangle of Auscultation –bounded by medial border of scapula, trapezius and lattissimus mm. area where it is easiest to hear breath sounds.
-Lumbar Triangle –bounded by lattissimus, ext. oblique mm. and iliac crest, area where pus may drain from abdominal wall.

6. ON ONE SIDE ONLY. Starting at the inferior site of attachment of the trapezius, detach and reflect the trapezius from its origin. Being careful not to cut the deeper muscles, also free the trapezius from the scapular spine and reflect the muscle laterally. Note: the spinal accessory n. (CN XI) and the transverse cervical a. on the underside of the trapezius m.

7. ON ONE SIDE ONLY. Detach the lattissmus dorsi m. from its origins in an inferior direction. Cut the muscle horizontally parallel to the iliac crest.

8. Identify and clean: Rhomboid major and minor, Splenius capitis, Levator scapulae, and Erector Spinae, Infraspinatus, Teres major and minor, Supraspinatus mm.

9. ON ONE SIDE ONLY. Detach the gluteus maximus from its origin to expose the gluteus medius, piriformis and sciatic n.

10. Put holes in the skin flaps near medial border and thread string through holes to tie skin flaps in place. HYDRATE the dissection thoroughly and tie skin flaps back in place. Close cadaver tanks.

11. Clean work area, clean dissection tools and put in correct containers, Clean any spills on floor and drain and empty tank bucket. Clean of front of apron with damp paper towels and hang up apron.

12. Wash Hands.

Lab 1 List of structures in this lab.

Temporal: Mastoid Process

Occipital bone: External Occipital Protuberance, Sup., Inf., and Medial Nuchal lines, Occipital condyles

Scapula: scapular spine, acromion, coracoid, margins, angles, notch, fossae

Ilium: iliac crests and processes

Cervical Vertebrae (7): Centrum, spinous process, transverse process, transverse foramen, spinal foramen, lamina, pedicle

Thoracic vertebrae (12): spinous process, transverse process, spinal foramen, lamina, pedicle, rib facets

Lumbar vertebrae (5): spinous process, transverse process, spinal foramen, lamina, pedicle

Sacrum (5 fused): sacral spine, promontory, sacral foramina, sacral hiatus, sacral ridges

Coccyx

Muscles:

Trapezius, Lattissimus dorsi, Rhomboid major, Rhomboid minor, Splenius capitis, Levator scapulae, Errector spinae, Supraspinatus, Infraspinatus, Teres major and minor, gluteus maximus, gluteus medius, tensor fasciae latae

Other Structures:

Triangle of Auscultation, Lumbar triangle, Spinal accessory n., transverse cervical a., nuchal ligament, thoracolumbar fascia

Lab 2. Anterior Chest

Review the following structures prior to lab:

Sternum: Jugular notch, manubrium, sternum body, sternal angle, xiphoid process.

Ribs: Head, neck, tubercle, body, costal groove, costal cartilage, angle, demi-facets, number and types

Scapula: acromion, coracoid process, fossae, glenoid cavity

Clavicle: sternal end and acromial end

1. Place cadaver supine (face up).

2. Wipe down skin surface with paper toweling.

3. If you have a female cadaver, make a sagittal incision through the nipple and continue through the entire breast. Identify the nipple, areola, lactiferous ducts, and suspensory ligaments. Note the retro mammary space where you just separated the breast from the body.

4. Make a midline incision from the jugular notch to the xiphoid process.

5. Make a horizontal incision paralleling the clavicle.

6. Make an incision around the base of each arm from the axilla to the distal portion of the deltoid m.

7. Grip the lower section of skin at the midline and retract the skin laterally and superiorly. Look for neurovascular bundles. Complete the skin removal by linking the each skin flap to the back’s flap. This should leave each flap attached to its posterior flap.

8. Measure the depth of the fat pads at the tip of the xiphoid process and the pubic symphysis and record in chart.

9. Clean and identify the following structures separating them from surrounding CT.
-Pectoralis major m. –has clavicular and sternal heads, adducts arm
-Deltoid m.
-Deltopectoral triangle –contains cephalic v.

10. Free Pect. Major from underlying structures with your fingers, detach the muscle from its origins (the sternum and clavicle) and reflect laterally. Watch for the pectoral nerves near the arm.

11. Reflect the Pect. Minor m. laterally by cutting it from its origins.

12. Identify the External and Internal intercostal mm. (best seen in the upper intercostal spaces.

13. Reflect laterally the heads of the Serratus anterior.

14. Identify the origins of the Rectus abdominus m. on the chest. Detach them from their point of origin and reflect to the abdomen.

15. Cut a window through the 1st intercostal space just lateral to the sternum; identify and transect the internal thoracic vessels.

16. Using a marker pencil, mark the following structures: a spot on the manubrium just superior to the sternal angle and at the same level as the internal thoracic vessel transect, the 1st intercostals space inferior to the 1st rib, the midaxillary line until the 8thth intercostal space, along the superior border of the 8th intercostal space, and the sternoxiphoid joint. Using the bone saw or bone forceps, cut the sternum and ribs being sure not to go too deep. (Avoid cutting through the parietal pleura.)

17. Use a scalpel to cut through the intercostal muscles between the bone incisions.

18. Lift the rib cage, using your fingers to separate the endothoracic fascia located between the internal intercostals and the parietal pleura. (note: it may be impossible to lift the rib cage without tearing the parietal pleura, especially if adhesions are present.)

19. Examine the internal surface of the removed anterior chest wall. Identify and isolate the internal thoracic vessels on both sides of the sternum.

20. Identify the transversus thoracis mm.

21. On the cut ends of the rib cage, identify the External, Internal and Innermost intercostal mm. Also identify the Intercostal a. v. and n. running along the costal groove.

22. Put holes in the skin flaps near medial border and thread string through holes to tie skin flaps in place. HYDRATE the dissection thoroughly and tie skin flaps back in place. Close cadaver tanks.

23. Clean work area, clean dissection tools and put in correct containers, Clean any spills on floor and drain and empty tank bucket. Clean of front of apron with damp paper towels and hang up apron.

24. Wash Hands.

Lab 2. List of structures seen in this lab.

Sternum: Jugular notch, manubrium, sternum body, sternal angle, xiphoid process.

Ribs: Head, neck, tubercle, body, costal groove, costal cartilage, angle, demi-facets, number and types

Scapula: acromion, coracoid process, fossae, glenoid cavity

Clavicle: sternal end and acromial end

Muscles: Pectoralis major and minor, Serratus anterior, External intercostals, Internal intercostals, Innermost intercostals, Transversus Thoracis

Pectoral n., Intercostal spaces, a., v, and n., Internal thoracic vessels, nipple, areola, lactiferous ducts, suspensory ligaments, and the retro-mammary space

Lab 3. Pleural Cavity

1. Identify the parietal and visceral pleura, and pleural cavities. Free margins of lungs from wall if adhered. Identify the mediastinum containing the pericardial cavity.

2. Identify the pleura recesses along inferior border of each lung. (costomediastinal and costodiaphragmatic recesses). Cut through the parietal pleura if not already torn to expose each lung.

3. Identify and isolate the right and left phrenic nn. (The left phrenic courses from the left subclavian a. and v., across the aortic arch and over the root of the lung adhered to the pericardium on its way to the diaphragm; the right is located lateral to the IVC proceeding over the root of the lung on to the diaphragm). Do Not Cut either phrenic n.

4. Remove each lung. First, expose the root of each lung by using your hand to pull the each lung laterally. Then use a scalpel to cut the root of the lung being careful not to cut the heart or your hand. (Lung adhesions may have to be cut to free the lung either with your hand or a scissors.)

5. Identify the following structures on each lung:
Hilum, Apex, Pulmonary ligament (a double membrane of the parietal pleura hanging inferiorly from the hilum), Primary Bronchi, Pulmonary a., Pulmonary v., Bronchopulmonary lymph nodes, Cardiac impression, Aortic impression on Left side and Esophageal Impression on right side, Superior and Inferior lobes, horizontal fissure, (Middle lobe on Right lung and Oblique fissure), on left lung the Cardiac notch and Lingula.

6. Mediastinum. The superior mediastinum contains the Thymus gland (which is usually visible only in children) and the Great Vessels of the Heart: Identify SVC, Aorta, and Pulmonary trunk. Identify the Ligamentum arteriosum found at the bifurcation of the Pulmonary trunk into right and left Pulmonary aa. And attached to the underside of the aortic arch. Identify the Left Vagus n. which runs immediately lateral to the Ligamentum arteriosum. The left vagus runs over the aortic arch and continues posteriorly to the root of the lung, find the left recurrent laryngeal n. which branches from the vagus next to the lig. arteriosum, loops around the aortic arch and heads upwards to the larynx. The right vagus running along the right brachiocephalic v.

7. Cut open the pericardial sac by incising it from the superior to the apex and folding it back and cutting horizontally near the great vessels. Identify the visceral pericardium (epicardium) and the fibrous and serous sides of the parietal pericardium (pericardial sac).

8. Identify the Transverse Pericardial Sinus by pushing your right index finger beneath the pulmonary trunk and ascending aorta. Likewise demonstrate the Oblique pericardial sinus, by placing your fingers under the heart and push anteriorly under the aorta into a space between the Pulmonary vv. and the IVC.

Lab 3. List of structures seen.

Pleural cavities with parietal and visceral pleura.

Mediastinum

Pericardial cavity with parietal (pericardial sac, pericardium) and visceral pericardium (epicardium).

Pleural Recesses: costomediastinal and costodiaphragmatic recesses.

Phrenic n., Vagus n., Recurrent Laryngeal n.

Root of the Lung

Lung: Hilum, Apex, Pulmonary ligament (a double membrane of the parietal pleura hanging inferiorly from the hilum), Primary Bronchi, Pulmonary a., Pulmonary v., Bronchopulmonary lymph nodes, Cardiac impression, Aortic impression on Left side and Esophageal Impression on right side, Superior and Inferior lobes, horizontal fissure, (Middle lobe on Right lung and Oblique fissure), on left lung the Cardiac notch and Lingula