Fort Atkinson 901 Janesville Avenue, P.O. Box 901 Fort Atkinson, Wisconsin (920)

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1 Other Available Simulators LF00698U Adult Injectable Arm (White) LF03610U Child Airway Management LF00856U Female Catheterization Trainer Head Only LF00901U Prostate Examination LF03611U Child Defibrillation Chest LF00906U Ostomy Care Skin LF00929U Surgical Bandaging LF03612U Child IV Arm LF00957U Enema Administration LF03613U Child Blood Pressure Arm LF00958U Pediatric Injectable Arm LF03614U Child Intraosseous Infusion/ LF00961U Intramuscular Injection Femoral Access Leg Only LF00984U Breast Examination LF03615U Complete Child CRiSis LF00995U Arterial Puncture Arm Update Kit LF00997U Adult Injectable Arm (Black) LF03616U Child CRiSis Manikin LF00999U Pediatric Injectable Head LF03617U Deluxe Child CRiSis LF01008U Intradermal Injection Arm Manikin with Arrhythmia Tutor LF01012U Heart Catheterization (TPN) LF03620U PALS Update Kit LF01019U Ear Examination LF03621U Infant Airway Management LF01020U Supplementary Ear Set Trainer Head Only LF01025U Male Cath-Ed I LF03622U Intraosseous Infusion Right LF01026U Female Cath-Ed II Leg LF01027U Peritoneal Dialysis LF03623U Infant Airway Management LF01028U Suture Practice Arm Trainer LF01036U Spinal Injection LF03626U Child Femoral Access LF01053U Cross-Sectional Anatomy, Injection Pad Replacement Torso, Head LF03627U Child CRiSis Replacement LF01054U Cross-Sectional Anatomy, Lung Set Head LF03628U Child CRiSis Replacement LF01062U Pelvic, Normal & Abnormal Stomach LF01063U Stump Bandaging, Upper LF03629U Child IV Arm Replacement LF01064U Stump Bandaging, Lower Skin and Veins LF01068U Brachial Plexus LF03630U Child Arrhythmia Tutor LF01069U Cervical Effacement LF03631U Child Airway Management LF01070U Birthing Station Trainer Replacement LF01082U Cricothyrotomy Headskin LF01083U Tracheostomy Care LF03632U Child Intraosseous Infusion/ LF01084U Sigmoidoscopic Femoral Access Leg on a Examination Stand LF01087U Central Venous Cannulation LF03633U Child Airway Management LF01094U Cross Sectional Trainer with Torso Anatomy Laminated LF03650U CRiSis Manikin LF01095U Blood Pressure Arm LF03651U ALS Update Kit LF01108U Intraosseous Infusion LF03675U BLS Manikin 10 Pack Simulator LF03676U BLS Manikin 5 Pack LF03000U CPARLENE Series LF03677U BLS Manikin Single LF03601U Adult Airway Management LF04001U GERi Nursing Manikin Trainer LF04020U KERi Nursing Manikin LF03602U Adult Airway Management LF04021U KERi Basic Manikin on Manikin LF04022U KERi Advanced Manikin LF03603U Adult Airway Management LF04030U GERi Advanced Manikin Head Only LF04040U GERi Basic Manikin LF03609U Child Airway Management Trainer Fort Atkinson 901 Janesville Avenue, P.O. Box 901 Fort Atkinson, Wisconsin (920) lifeform@nascofa.com COPYRIGHT NASCO 1999 PRINTED IN U.S.A. NP

2 The user should not be diverted unnecessarily by details. The description provided is undoubtedly difficult to follow for a beginner. The real value in an aid such as this is the overview it can provide. Users are encouraged to spend time simply handling it on a flat surface so that spatial familiarity can be acquired. About the Simulator This specimen was dissected to portray the musculature of the lower extremity. Some of the major vessels and nerves were retained to show their relationships to the muscles. The pelvis was bisected to show the roots of the sacral plexus, the levator ani muscle from above, the anus, the urinary bladder, and seminal vesicle. The muscles of the hip and thigh are all displayed with the exception of the gluteus minimus and the lateral rotators (obturator internus and gemelli, obturator externus, and quadratus femoris). It is realized that the replica is rather bulky and somewhat awkward to manipulate. An actual cadaver specimen of this size would also be difficult to study without benefit of a flat surface. It is recommended that the replica be fully supported by such a surface so that the parts will not tear during use. If tears occur, they can be repaired with a hot spatula and the fused surfaces can be retextured with a hot needle. Ordinary care should obviate against the necessity to do this. NASCO also realizes that its replicas lose some of the texture of actual cadaver material. However, in most cases the detail is extremely close to the real thing. In order to gain maximum use from a single specimen, some compromises must be made to show underlying structures. To that end, some muscles have been molded as separate units to be replaced in their original positions after casting. This allows the user some latitude in manipulation. The following description prepared by Dr. James Pettersen, Professor of Anatomy at the University of Wisconsin, is offered to aid the user in identifying all of the structures. Additional comments are included to assist the beginner in his consideration of muscle function, but it is intended that the replica be used primarily to gain a three-dimensional concept of the anatomy and that the bulk of the detailed information be gleaned from an anatomy text while studying the replica. I. Bisected Pelvis VERTEBRAL COLUMN. The bodies and discs of the lower four lumbar vertebrae can be seen on longitudinal section. Only a portion of the body of the second lumbar vertebra is included. The second lumbar INTERVERTEBRAL DISC is immediately below it. Directly below the fifth lumbar intervertebral disc is the sacrum which is directed dorsocaudally. The angle it makes with the last lumbar vertebra is the SACROVERTE- BRAL ANGLE. The upper anterior portion of the sacrum is the SACRAL PROMONTORY. Behind the bodies of the lumbar vertebrae is the vertebral canal which houses the spinal cord. This level consists of the CAUDA EQUINA (removed from preparation). The mass dorsal to the vertebral canal consists of muscles and ligaments which lie between the vertebral arches. Dorsal to this are the intrinsic muscles of the back which are not displayed in recognizable detail. 12 1

3 Note that the belly of the ADDUC- TOR MAGNUS has been cut away from its attachment to the lower part of the LINEA ASPERA of the femur so that it can be manipulated. With this attachment intact, the HIATUS TENDINEUS (adductor hiatus) would be apparent. The femoral artery passes through this gap between the adductor magnus tendon and the femur to gain the POPLITEAL FOSSA. At this level it becomes the popliteal artery. III. Musculature of the Hip ANTERIOR GROUP. This includes the PSOAS MAJOR, PSOAS MINOR, and ILIACUS MUSCLES. The origins and the common insertion of the psoas major and iliacus are clearly portrayed on the replica. The psoas minor is absent on the specimen. It was reported absent bilaterally in 92 of 182 subjects in a journal article. The ILIOPSOAS (combined psoas major and iliacus) is the most powerful flexor of the thigh. Conversely, it flexes the pelvis on the thigh as in sit-ups. The psoas portion also flexes and abducts the spinal column when acting unilaterally. The direction of rotation of the thigh through action of these muscles is disputed. It is probably medial, but in either case it is a weak, insignificant action. POSTERIOR GROUP. This includes the TENSOR FASCIAE LATAE, GLUTEUS MAXIMUS, GLUTEUS MEDIUS, GLU- TEUS MINIMUS, and the PIRI- FORMIS MUSCLES. The gluteus minimus lies deep to the gluteus medius and is not exposed on the replica. The GLUTEUS MAXIMUS is the huge muscle which forms the contour of the buttock. Note the large fiber bundles. The unusual texture (wavy fibers) resulted from the position 4 established during embalming. In the living they are essentially parallel from origin to insertion. The lateral edge of the muscle is somewhat free because the ILIOTIBIAL TRACT, which provides its major site of insertion, has been removed. The lower most fibers insert into the gluteal tuberosity of the femur and the adjacent vastus lateralis muscle. The gluteus maximus extends the thigh vigorously, as in climbing stairs two at a time, but is relatively inactive during ordinary walking. It also abducts and rotates the thigh laterally at the hip joint. The TENSOR FASCIAE LATAE arises from the ANTERIOR SUPERIOR SPINE of the ilium and inserts into the ILIOTIBIAL TRACT. The iliotibial tract is an aponeurotic band which extends downward to attach to the lateral surface of the tibia. The lower edge of the muscle is free because the iliotibial tract has been removed. Since the tensor f. l. fibers pass anterior to a transverse axis through the hip joint, this muscle is a thigh flexor. It abducts the thigh on an anteroposterior axis and rotates the thigh medially on a vertical axis. At the knee joint, it maintains the extended knee and assists in locking the knee joint by laterally rotating the tibia into a position congruent with the condyles of the femur. It further flexes an already flexed knee. The PERONEUS TERTIUS is essentially a fasciculus of the extensor digitorum longus. It inserts into the base of the fifth metatarsal. It dorsiflexes the ankle and everts the foot (plantar surface faces laterally in eversion) at the intertarsal joints. LATERAL GROUP. Included are the PERONEUS LONGUS and the PER- ONEUS BREVIS. These two muscles are separated from the anterior group by the LATERAL INTERMUS- CULAR SEPTUM. A distinct groove on the replica demarcates them from the extensor digitorum longus. The PERONEUS BREVIS arises from the lateral surface of the fibula. Its tendon passes behind the LATERAL MALLEOLUS and deep into the SUPERIOR PERONEAL RETINACU- LUM. Then it passes deep to the INFERIOR PERONEAL RETINACU- LUM to insert into the tuberosity of the fifth metatarsal. Due to the pulley-like action of the lateral malleolus, the direction of force is changed so that the muscle acts as a plantiflexor of the ankle joint. It everts the foot at the intertarsal joints. The PERONEUS LONGUS tendon takes a similar course behind the lateral malleolus, but then passes across the lateral surface of the calcaneus to enter the peroneal groove of the cuboid bone. It inserts rather broadly on the first cuneiform and first metatarsal on the medial plantar surface of the foot. It everts and plantiflexes the foot. 9 POSTERIOR GROUP. The musculature at the back of the leg is subdivided into superficial and deep groups. The superficial group includes the GASTROCNEMIUS, SOLEUS, and PLANTARIS. The deep group includes the POPLITEUS, FLEXOR DIGITORUM LONGUS, FLEXOR HALLUCIS LONGUS, and the TIBIALIS POSTERIOR. The GASTROCNEMIUS arises from two heads. The medial head attaches to the back of the medial condyle of the femur and the lateral head to the posterolateral surface of the lateral condyle of the femur. The two heads unite and insert into the TENDO CALCANEUS (Achilles tendon). The SOLEUS can be seen by elevating the upper portion of the gastrocnemius. It arises from the back of the fibula and tibia and inserts into the tendo calcaneus with the gastrocnemius. The PLANTARIS can be seen by moving the lateral head of the gastrocnemius laterally. It arises in close association with the muscle belly. It is small with a very delicate tendon which joins the tendo calcaneus. The three muscles together are called the TRICEPS SURAE (calf). They plantiflex the foot with accompanying inversion. The soleus is the most powerful, but its fibers are short (multipennate), limiting its range. The gastrocnemius acts through the full range of ankle flexion and also flexes at the knee. The movement provided by the plantaris is considered insignificant.

4 The adductor magnus is the strongest of the adductors. The upper two fasciculi also flex the thigh and rotate it laterally. The inferior fasciculus assists in medial rotation and extension of the thigh. POSTERIOR (HAMSTRING) GROUP. Included in this group are the two heads of the BICEPS FEMORIS: the SEMITENDINOSUS and the SEMI- MEMBRANOSUS MUSCLES. These muscles flex the leg and extend and adduct the thigh. The semitendinosus, semimembranosus, and long head of the biceps arise from the ischial tuberosity. The short head of the biceps arises from the linea aspera in the lower part of the thigh, and inserts via a tendon which is in common with the long head and into the head of the FIBULA. On the replica, the semitendinosus and semimembranosus are fused throughout their upper extent. They are distinctly separable in cadaver preparation. Near the insertion, the long tendon of the semitendinosus is apparent. It attaches into the medial surface of the tibia and close to the insertions of the gracilis and sartorius (see above). The insertion of the semimembranosus is into the back of the medial condyle of the tibia. From there, aponeurotic expansions obliquely reflect back to blend with the back of the knee joint capsule with specific contributions to the OBLIQUE POPLITEAL LIGAMENT. This reflection is not readily apparent on the replica. 8 V. Musculature of the Leg ANTERIOR GROUP. Included are the TIBIALIS ANTERIOR, EXTENSOR DIGITORUM LONGUS, PERONEUS TERTIUS, and EXTENSOR HALLUCIS LONGUS. The TIBIALIS ANTERIOR is the muscle immediately lateral to the anterior border of the tibia. Its tendon can be followed deep into the SUPERIOR and INFERIOR EXTENSOR RETINAC- ULA at the ankle, but its insertion into the medial surface of the first cuneiform and first metatarsal is not shown. It dorsiflexes the ankle (uniaxial joint) and inverts the foot on an oblique axis through the intertarsal joints. The EXTENSOR HALLUCIS LONGUS can be seen just lateral to the tapering lower portion of the tibialis anterior muscle belly. It appears to be between the tibialis anterior medially and extensor digitorum longus laterally. Its tendon of insertion passes deep to the extensor retinacula and proceeds along the dorsum of the foot to the distal phalanx of the big toe. The muscle dorsiflexes the ankle joint and extends the big toe. The EXTENSOR DIGITORUM LONGUS lies just lateral to the tibialis anterior at its origin, but is separated from this muscle near the ankle joint by the ext. hallucis longus. Its tendon passes deep to the retinacula and quickly divides into four tendons which pass to the distal phalanges of the four respective lateral digits. The muscle dorsiflexes the ankle and extends the four lateral digits. The GLUTEUS MEDIUS arises threefourths of the dorsal surface from the anterior of the iliac blade and inserts into the GREATER TROCHANTER of the femur. The greater bulk of the muscle is exposed on the replica between the superior border of the gluteus maximus and the posterior border of the tensor fasciae latae. Its major function is abduction of the thigh. It is used to stabilize the pelvis in walking while the opposite limb is swinging forward. A peculiar gait occurs when this muscle is paralyzed; the individual compensates for its lack by throwing his weight to one side in order to enable the opposite limb to swing forward. The anterior fibers of the medius flex and medially rotate the thigh; the posterior fibers extend and laterally rotate the thigh. It is similar in function to the deltoid muscle of the upper extremity. The GLUTEUS MINIMUS is not exposed. It arises from the dorsal surface of the iliac blade under the cover of the gluteus medius and inserts into the greater trochanter of the femur. Its functions are similar to those of the gluteus medius, except that its most posterior fibers are too far forward to contribute to lateral rotation. The muscle has roughly half of the power of the gluteus medius. The origin of the PIRIFORMIS MUS- CLE from the anterior surface of the sacrum can be seen within the pelvis. Its fibers pass through the greater sciatic foramen to insert into the greater trochanter. It is an abductor, lateral rotator, and a weak extensor of the thigh. 5 ISCHIOPUBOFEMORAL MUSCULA- TURE. This group includes the OBTURATOR INTERNUS, SUPERIOR and INFERIOR GEMELLI, the QUAD- RATUS FEMORIS, and the OBTURA- TOR EXTERNUS MUSCLES. None of these small muscles are displayed on the replica, save for the internal surface of the obturator internus. They are located anterior to the lower portion of the gluteus maximus muscle where all but the obturator externus could be seen following removal of the g. maximus. They function mainly as lateral rotators of the thigh. The quadratus femoris is also an adductor because its fibers pass below the anteroposterior axis through the hip joint. IV. Musculature of the Thigh ANTERIOR GROUP. Included are the SARTORIUS and the QUADRICEPS FEMORIS. The major function of these muscles is to extend the leg at the knee. The sartorius and rectus femoris portion of the quadriceps span the hip joint. Their functions also involve movements at both hip and knee joints. The SARTORIUS MUSCLE is one of the most interesting muscles in the body to analyze. It assists in a variety of movements at the hip and knee joints. Its attachments, proximally to the anterior superior iliac spine, and distally to the medial surface of the tibia, are well shown on the replica. Its fiber bundles are parallel and represent the longest muscle fibers in the body. Such analysis can only predict what a muscle could do, not necessarily what it does do in the living. Other techniques, such as electromyography and electrical stimulation, are more suitable for providing clues to muscle function in the living.

5 MUSCLE ANALYSIS (sartorius). Note that the sartorius fibers cross anterior to the hip joint. On a transverse axis through this joint, this muscle would flex the thigh. Think of the axis when considering abduction and adduction; passing roughly though the substance of the iliacus portion of the iliopsoas muscle just medial to the upper portion of the sartorius belly. Because the sartorius fibers pass on the lateral side of this vertical axis (a vertical line roughly through the point where the psoas major forms the apex of a V with the iliacus muscle), the sartorius would contribute to lateral rotation of the thigh. Its fibers pass from lateral to medial anterior on this axis. The spoke in this instance is the radius of the shaft of the femur. The above three axes are traditionally used to analyze universal joints, such as the hip and shoulder, even though all possible axes passing through such joints could define movements. All movements for these joints not defined by the terms flexion-extension, abduction-adduction, and medial and lateral rotation must be combinations of these by definition. The knee joint is a biaxial joint because it permits movement about two axes. It is often considered to be a uniaxial (hinge) joint because the movements of flexion-extension about a transverse axis define the major plane of movement permitted. However, there is a slight degree of rotation permitted on a vertical axis. Note that the lower end of the sartorius curves posterior to the transverse axis of the knee joint to gain its insertion into the tibia. Therefore, it assists in flexion of the leg. It also assists in slight medial rotation of the tibia (leg) as in unlocking the knee. 6 The QUADRICEPS FEMORIS consists of four muscles which join into a common tendon (quadriceps tendon) just above the knee joint. The tendon contains a sesamoid bone, the PATELLA, beyond which it continues as the patellar tendon which inserts into the TIBIAL TUBEROSITY. The RECTUS FEMORIS arises from the anterior inferior iliac spine, and also has a reflected tendon (not shown) which arises from the posterior portion of the rim of the acetabulum. The rectus femoris is the only belly of the quadriceps to span both the hip and knee joints. Note that its fiber bundles are bipenniform. This type of fiber arrangement favors strength but sacrifices speed and range of movement. The muscle flexes the thigh and extends the leg. The VASTUS LATERALIS covers most of the lateral aspect of the thigh and almost completely covers the vastus intermedius muscle. It arises from the greater trochanter and from the LAT- ERAL INTERMUSCULAR SEPTUM, which separates it from the biceps femoris posteriorly. It inserts into the quadriceps tendon from the lateral side. The VASTUS MEDIALIS arises from the medial lip of the LINEA ASPERA of the femur and inserts into the medial side of the quadriceps tendon. The VASTUS INTERMEDIUS is not displayed on the replica. It lies deep to the rectus femoris between the vastus medialis and vastus lateralis. It arises from the lateral lip of the linea aspera and from the anterolateral surface of the shaft of the femur and inserts into the quadriceps tendon. It has some deeper fibers (articularis genu) which insert into the capsule of the knee joint and serve to elevate the capsule during extension of the leg. All four of the quadriceps muscles are powerful extensors of the leg. Their combined force is about three times as great as that of their antagonists, the hamstrings. MEDIAL (ADDUCTOR) GROUP. Included in this group are the PECTINEUS, ADDUCTOR LONGUS, GRACILIS, ADDUCTOR BREVIS, and ADDUCTOR MAGNUS MUSCLES. The obturator externus is sometimes included with this group. All of these muscles adduct the thigh. The PECTINEUS is just medial to the upper portion of the femoral artery on the replica. It forms a portion of the floor of the femoral triangle. It adducts and flexes the thigh and may contribute to medial rotation. The GRACILIS arises from the medial margin of the inferior ramus of the pubis. Like the sartorius, its fibers are essentially parallel. Its tendon of insertion curves anteriorly to attach into the medial surface of the tibia. Here it relates to the insertion of the sartorius superolaterally and the semitendinosus inferomedially to form a triad commonly called the goose foot (pes anserina). The gracilis adducts and flexes the thigh and flexes the leg. With the knee flexed, it acts as a medial rotator of the leg. 7 The ADDUCTOR LONGUS arises from the front of the pubis. Its belly lies just medial to the pectineus muscle and inserts into the middle third of the linea aspera. It adducts and flexes the thigh and is a weak medial rotator. The ADDUCTOR BREVIS lies beneath the adductor longus. It can be delineated on the replica by identifying a groove separating it from the adductor magnus. The adductor brevis arises from the medial portion of the inferior ramus of the pubis and inserts into the upper third of the linea aspera. It is an adductor and a weak flexor of the thigh. It is also considered to be a weak lateral rotator, but this is questionable. The ADDUCTOR MAGNUS arises from the inferior ramus of the pubis posterior to the origins of the gracilis and adductor brevis muscles. The muscle can be divided into three fasciculi. The superior fasciculus (adductor minimus) is distinct and inserts into the upper portion of the linea aspera. On the replica it is delineated from the adductor brevis by a groove of somewhat irregular depth and contour. The middle fasciculus is fused with the inferior fasciculus on the specimen, although they are sometimes distinctly separate. The middle fasciculus inserts by way of a tendon into the distal threefourths of the linea aspera. This insertion was cut free on the specimen to allow the muscle to be manipulated. The inferior fasciculus arises dorsal to and in common with the middle fasciculus. The common tendinous insertion of the lower two fasciculi is into the ADDUCTOR TUBERCLE of the femur.

6 The POPLITEUS can be located by separating the two heads of the gastrocnemius. It arises from the lateral condyle of the femur and inserts into the popliteal line of the tibia just above the origin of the soleus. It acts as a flexor and medial rotator at the knee joint. The FLEXOR HALLUCIS LONGUS muscle lies on the posterolateral surface of the leg just behind the peroneus longus. It arises from the fibula and adjacent fibrous septa. Its tendon can be followed posterior to the medial malleolus. Behind this, it gains the plantar surface by passing deep to the abductor hallucis. It inserts into the distal phalanx of the big toe (hallux). It flexes the big toe and plantiflexes the foot. It is an extremely important muscle in walking. It steadies the first metatarsophalangeal joint when the heel is off the ground, i.e. it resists the tendency to fall forward. The FLEXOR DIGITORUM LONGUS is just medial to the flexor hallucis longus. The posterior tibial artery and tibial nerve can be seen between them. Its tendon passes deep to the FLEXOR RETINACULUM behind the medial malleolus and divides into four parts which pass to their respective four lateral digits (distal phalanges). The muscle that inverts the foot is a weak plantiflexor and flexes the four lateral toes. 10 The TIBIALIS POSTERIOR is the deepest muscle on the back of the leg. It arises rather broadly from the tibia, interosseous membrane, and the fibula. Its tendon can be seen just anterior to the flexor digitorium longus tendon near the ankle joint. It enters the plantar surface of the foot to attach rather broadly. The main tendon of insertion is to the navicular and first cuneiform bones. It plantiflexes and inverts the foot. VI. The Foot On the dorsum of the foot, the EXTENSOR DIGITORUM BREVIS can be identified arising from the lateral dorsum of the calcaneus under the cover of the inferior extensor retinaculum. Some of its tendons can be followed to the dorsal surfaces of the toes deep into the long extensor tendons. The plantar surface of the foot illustrates the PLANTAR APONEUROSIS centrally, the ABDUCTOR HALLUCIS MUSCLE medially, and the ABDUC- TOR DIGITI MINIMI laterally. The tendon of the flexor hallucis longus is exposed at the level of the first metatarsal near the medial edge of the plantar aponeurosis. VII. Vessels and Nerves of the Lower Limb In general, it is difficult to duplicate the finer branches of the arteries and nerves by the NASCO molding process. The removal of the adjacent fat and connective tissue necessitates laying them out in a somewhat artificial way to avoid undercutting. For this and other technical reasons, the arteries and nerves are not suited for detailed study on the replica. The veins in all cases have been removed. The ANUS has been retained in the specimen beginning at the site where it makes a right-angled turn posteriorly from the rectum. This angle occurs because of the anterior and superior direction of support provided by the puborectalis muscle. During defecation, this muscle must relax to allow the contents to be evacuated. Just behind the cut edge of the PUBIC SYMPHYSIS is the URINARY BLADDER. The walls of this bladder are thick because it was relatively empty at the time of death. The ductus deferens and the SEMINAL VESI- CLE lie against its posterior surface. A stub of the ureter was also retained. The sagittal section was slightly lateral to the midline, therefore the prostatic urethra is only partially shown. The thickened mass just below the bladder is the substance of the PROSTATE GLAND. The penis and other external genitalia have been removed. MAJOR PELVIS. The small mass on the posterosuperior surface of the crest of the ilium is the origin of the QUADRATUS LUMBORUM MUSCLE and the underlying ILIOLUMBAR LIGAMENT. The ILIACUS MUSCLE arises from the surface of the ILIAC FOSSA. The long, thick, fusiform muscle medial to the iliacus is the PSOAS MAJOR. The PSOAS MINOR was absent on this specimen. Just medial to the belly of the psoas major muscle, the right common iliac artery bifurcates into the EXTERNAL and INTERNAL ILIAC branches. The internal iliac supplies the contents of the pelvic cavity and the external iliac continues into the thigh as the FEMORAL ARTERY. 3 II. Femoral Triangle and Adductor Canal FEMORAL TRIANGLE. This is defined by the inguinal ligament above (not included in the replica), the medial border of the SARTORIUS MUSCLE (laterally), and the medial border of the ADDUCTOR LONGUS MUSCLE (medially). The sartorius should be moved somewhat medially in its midportion to simulate its exact position. The apex of the triangle is the point where the sartorius crosses the adductor longus. This point represents the beginning of the adductor canal. The floor of the femoral triangle, above and laterally, is formed by the iliopsoas muscle, and medially by the pectineus and adductor longus muscles. The FEMORAL NERVE lies in the groove between the iliacus and psoas portions of the iliopsoas muscle. Medial to the psoas is the femoral artery. The femoral nerve, artery, and vein with their branches are the contents of the triangle. The vein and its branches have been removed. The large branch of the femoral artery is the DEEP FEMORAL. Its largest branch, the LATERAL FEMORAL CIRCUMFLEX ARTERY, is seen passing laterally beneath the substance of the REC- TUS FEMORIS MUSCLE. The path of the femoral artery and the saphenous branch (sensory) of the femoral nerve can be followed toward the knee by moving the belly of the sartorius muscle laterally to expose the adductor canal.

7 The ABDOMINAL AORTA lies anterior to the vertebral bodies. It is slightly displaced to the right in this preparation. It bifurcates into the right and left COMMON ILIAC ARTERIES at the body s fourth lumbar vertebra level. Only a stub of the left common iliac has been retained. The INFERIOR VENA CAVA, which lies to the right of the aorta, was not retained. CONTENTS OF THE MINOR PELVIS. The major roots of the SACRAL PLEXUS are shown. The first small root (yellow) is the contribution from L4, which joins L5 to form the LUMBOSACRAL TRUNK. The next two are S1 and S2. These two sacral roots plus the lumbosacral trunk join to form the major portion of the sacral plexus which can be seen passing through the GREATER SCI- ATIC FORAMEN below the PIRI- FORMIS MUSCLE. Note that the superior gluteal artery passes between the lumbosacral trunk and S1 to leave via the greater sciatic foramen above the piriformis muscle. The INFERIOR GLUTEAL and PUDENDAL ARTERIES leave below the piriformis muscle. The lateral sacral and obturator arteries are the only other branches of the internal iliac which were retained. PELVIC DIAPHRAGM. This forms the muscular floor of the pelvic outlet. It consists of two muscles. The upper muscle, the COCCYGEUS, is seen just below the inferior gluteal and internal pudendal arteries. The root of S4 lies parallel to and just above it. It is quite well developed in this specimen but occasionally is rudimentary. It lies just anterior to the SACROSPINOUS LIGAMENT and serves no useful function in the 2 human. It wags the tail in dogs and is well developed in this species. The remaining portion of the pelvic diaphragm consists of the LEVATOR ANI MUSCLE. This muscle provides the major support for the pelvic contents. It is subdivided for descriptive purposes, and a textbook should be consulted for details. Rather schematically, that portion between the lower edge of the internal pudendal artery and a line extending along the ARCUS TENDINEUS to the obturator canal (identifiable by the yellow stub of the OBTURATOR NERVE) is the ILIOCOCCYGEUS. This portion of the muscle is thin and often poorly developed. It is not the crucial weight-bearing part of the diaphragm. The muscle above the arcus tendineus is the obturator internus. Just anterior to the obturator canal is the PUBOCOCCYGEUS. Below this is the PUBORECTALIS. The PUBO- COCCYGEUS is not clearly separate from the ILIOCOCCYGEUS. The pubococcygeus is the most important part of the pelvic diaphragm. It arises anteriorly from the inner surface of the body of the pubis and inserts posteriorly into ANOCOCCYGEAL LIGAMENT. Some of its fibers decussate with those from the opposite side behind the prostrate gland (vagina in the female) as well as the rectum. Contraction of these fibers pulls the respective viscera anteriorly and superiorly while providing support for the pelvic contents. A thorough knowledge of the musculature, however, provides a framework which facilitates a conceptual understanding of the vessels and nerves. The FEMORAL NERVE is seen leaving laterally from the substance of the psoas major muscle. This nerve supplies the anterior surface of the thigh with cutaneous branches. It supplies motor and sensory fibers to the anterior group of thigh muscles as well as the iliopsoas are usually to the pectineus. The saphenous nerve seen with the femoral artery is the longest sensory branch of the femoral nerve and extends down the medial side of the tibia to the instep of the foot. It has been retained only as far as the mid-thigh region. The FEMORAL ARTERY has been discussed. Its only major branch in the thigh is the DEEP FEMORAL. Its continuation, the POPLITEAL ARTERY, divides to send branches to the leg and foot. The deep femoral artery supplies the structures in the thigh. A stub of the OBTURATOR NERVE is seen entering the obturator canal. This nerve is formed from contributions from L2-4 of the lumbar plexus and leaves the substance of the psoas major from the medial side. Because it hangs somewhat loose on a dissection, only the stub was retained. The obturator nerve supplies motor branches to the adductor muscles, the obturator externus, and occasionally the pectineus. The gluteal nerves from the sacral plexus are not seen without reflecting the gluteus maximus muscle. They arise (superior and inferior gluteal nerves) from the back of the large 11 trunk of the sacral plexus and leave via the greater sciatic foramen to enter their respective muscles (gluteus maximus, medius, minimus, and tensor fasciae latae). The sciatic nerve is seen descending down the back of the thigh between the biceps femoris and the other two hamstring muscles. Its bifurcation into COMMON PERONEAL and TIB- IAL divisions is just above the knee. The tibial division supplies the long heads of the hamstrings and all the muscles of the posterior compartment of the leg as well as the plantar surface of the foot. The peroneal division supplies the short head of the biceps in the thigh and divides into the SUPERFICIAL and DEEP PER- ONEAL NERVES below the knee. The superficial peroneal supplies branches to the lateral leg muscles (p. longus and brevis); the deep peroneal supplies branches to the anterior leg muscles and the extensor digitorum brevis. The popliteal artery gives off an ANTERIOR TIBIAL branch just below the knee. The anterior tibial passes above the interosseous membrane into the anterior leg compartment. The continuation of the popliteal divides into a lateral PERONEAL ARTERY and a medial POSTERIOR TIBIAL artery. The posterior tibial artery can be seen accompanying the tibial nerve in the lower part of the leg. These two structures with their accompanying veins enter the sole of the foot by passing the long flexor tendons deep to the flexor retinaculum and deep to the abductor hallucis muscle.