Chapter 6 Front of the thigh I Fascia and Muscles.pptx

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1. Chapter 6 Front of the thigh I Fascia and Muscles Textbook of Human Anatomy Volume 3: Lower Limb Author: Dr Yogesh Sontakke, JIPMER, Pondicherry ©CBS Publishers & Distributors Pvt Ltd, New Delhi

2. As per: Competency based Undergraduate curriculum 1 AN15.1: Describe and demonstrate origin, course, relations, branches (or tributaries), termination of important nerves and vessels of anterior thigh. AN15.2: Describe and demonstrate major muscles with their attachment, nerve supply and actions. AN15.4: Explain anatomical basis of psoas abscess and femoral hernia. Medical Council of India, Competency based Undergraduate curriculum for the Indian Medical Graduate, 2018. Vol. 1; pg 1-80. Human Anatomy/Yogesh Sontakke 2

3. SURFACE LANDMARKS Anterior superior iliac spine (ASIS): It is a bony prominence of anterior end of iliac crest (Fig. 6.1). Tubercle of iliac crest : It is a bony prominence on the outer lip of iliac crest at about 5 cm behind the anterior superior iliac spine. Fold of groin It is a shallow curved groove that separates the anterior abdominal wall and the front of the thigh. It extends from anterior superior iliac spine to the pubic tubercle. It overlies the inguinal ligament. It is convex downward due to the pull of the deep fascia of the thigh. Pubic tubercle: It is a small bony projection that can be felt at the medial end of the fold of groin. Pubic crest: It is a short bony ridge between the pubic tubercle and pubic symphysis. Greater trochanter: It lies a hand’s breadth below the tubercle of iliac crest.

4. SURFACE LANDMARKS Midpoint of inguinal ligament: It is the midpoint of inguinal ligament that lies midway between ASIS and pubic tubercle (Fig. 6.2). Midinguinal point : It lies midway between ASIS and pubic symphysis. Midinguinal point is the most commonly used reference point in clinical examination (Fig. 6.2). Patella: It is a knee-cap. It can be felt and seen in front of the knee joint. It is the largest sesamoid bone that develops in the tendon of quadriceps femoris. Tibial tuberosity: It is a bony projection that lies below the patella. It continues downward as shin of tibia. Condyles of femur and tibia : These are large bony projections on medial and lateral sides of the knee joint. The most prominent points of femoral condyles are called medial and lateral epicondyles. Adductor tubercle: It is a bony projection that is located just above the medial condyle of femur.

5. SUPERFICIAL FASCIA The superficial fascia in the thigh has two layers only in the upper part: Superficial thick fatty layer Deep thin membranous layer . These layers are continued with the two layers of superficial fascia of the anterior abdominal wall. Holden’s line Along the Holden’s line, the membranous layer of superficial fascia is attached firmly with the deep fascia [ Luther Holden, British anatomist, 1815–1905 ]. Extent: Holden’s line extends horizontally from little lateral to the pubic tubercle for about 8 cm (Fig. 6.3). Some interesting facts Fascial fusion along the Holden’s line prevents the urine from descending downward into the thigh in case of injury to ureter in the perineum.

6. Contents of superficial fascia The superficial fascia of the front of the thigh contains the following: Cutaneous nerves Cutaneous arteries Superficial veins: Termination of great saphenous vein and its tributaries Superficial inguinal lymph nodes.

7. CUTANEOUS INNERVATIONS OF FRONT OF THIGH The skin of the front of the thigh is supplied by the following nerves (Fig. 6.4): 1. Ilioinguinal nerve 2. Femoral branch of genitofemoral nerve 3. Lateral cutaneous nerve of thigh 4. Intermediate cutaneous nerve of thigh 5. Medial cutaneous nerve of thigh 6. Saphenous nerve 7. Cutaneous branch of obturator nerve.

8. Some interesting facts Ilioinguinal nerve (L1) It is a branch of the first lumbar nerve (L1). It accompanies spermatic cord in males and round ligament of uterus in females in the inguinal canal. It emerges through superficial inguinal ring that is located just medial to pubic tubercle. Distribution It supplies adjacent skin including upper part of medial aspect of thigh. It gives Anterior scrotal nerve in males for scrotum Anterior labial nerve in females for labium majus Femoral branch of genitofemoral nerve (L1, L2) Genitofemoral nerve arises in abdomen from lumbar plexus. It gives genital and femoral branches. Femoral branch pierces femoral sheath and deep fascia at about 2 cm below the midiguinal point. Distribution It supplies the skin over the femoral triangle.

9. Lateral (femoral) cutaneous nerve of thigh (L2, L3) It arises from lumbar plexus in the abdomen. It enters the thigh by passing deep to the inguinal ligament just medial to the anterior superior iliac spine. Distribution It divides into anterior and posterior branches. It supplies the skin on anterolateral side of thigh and on the anterior part of gluteal region. Intermediate cutaneous nerve thigh (L2, L3) It is the branch of anterior division of femoral nerve. It pierces deep fascia at the junction of upper and middle third. Distribution It divides into two or more branches and supplies the skin of the front of the thigh. Medial cutaneous nerve of thigh (L2,3) It is a branch of anterior division of femoral nerve. It divides into anterior and posterior branches. Anterior branch pierces deep fascia in the lower third of thigh and supplies the skin on the lower part of medial of thigh. Posterior branch pierces deep fascia along the medial border of sartorius and supplies the skin on the medial side of thigh.

10. Saphenous nerve (L3,4) It is the largest cutaneous branch of posterior division of femoral nerve. It pierces the deep fascia on the medial side of knee and runs downward in front of the great saphenous vein in the leg. It gives infrapatellar branch that supplies skin over the ligamentum patellae. Cutaneous branch of obturator nerve (L2, L3) It is a small branch that arises from the anterior division of the obturator nerve. Distribution : It supplies the lower one-third of medial aspect of the thigh. Patellar plexus Patellar plexus is plexus of the fine nerves situated in front of the patella and supplies the overlying skin. Components of patellar plexus Patellar plexus is formed by the branches of the following nerves: Anterior division of lateral cutaneous nerve of the thigh Intermediate cutaneous nerve of the thigh Anterior division of medial cutaneous nerve of the thigh Infrapatellar branch of the saphenous nerve.

11. Clinical integration Meralgia paresthetica (meaning thigh pain in Greek) It is a compression of lateral cutaneous nerve behind the inguinal ligament (Fig. 6.5). It results in numbness, pain, or burning sensation in the outer part of the thigh. It is also termed as skinny pants syndrome (as it occurs in teenagers wearing skin-tight trousers) or Bernhardt-Ruth syndrome [ Martin Bernhardt, German neuropathologist, 1844–1915, Vladimir Roth, Russia neuropathologist, 1848–1916 ].

12. CUTANEOUS VESSELS Three small branches of the femoral artery are present in the superficial fascia covering the femoral triangle. These are (Fig. 6.6): Superficial external pudendal artery Superficial epigastric artery Superficial circumflex iliac artery Some interesting facts Superficial external pudendal artery It is a branch of femoral artery ( pudenda  = external genitalia in Latin). It pierces cribriform fascia and runs medially across the spermatic cord. It supplies external genitalia. Superficial epigastric artery It is a branch of femoral artery that pierces cribriform fascia and runs toward umbilicus. It supplies lower part of anterior abdominal wall. Superficial circumflex iliac artery It is the smallest cutaneous branch of femoral artery. It pierces cribriform fascia and runs laterally parallel to the inguinal ligament.

13. Footnote : Internal pudendal artery is a branch of anterior division of internal iliac of artery. Superior epigastric artery is one of the terminal branches of internal thoracic artery. Inferior artery epigastric artery is a branch of external iliac artery. Deep circumflex iliac artery is a branch of external iliac artery.

14. Great Saphenous Vein It is also called long saphenous vein ( Saphaina  = to be easily seen in Greek) (Fig. 6.6). It is the longest vein of the body. Beginning : It begins on the dorsum of the foot from medial end of the dorsal venous arch. Course : It passes obliquely upward on the medial side of the leg to reach back of the knee. Then it ascends upward and forward in the thigh toward the femoral triangle. It pierces cribriform fascia to enter into the femoral vein.

15. Termination : Great saphenous vein opens into the femoral vein. Tributaries : Tributaries in the thigh Anterolateral vein of thigh Posteromedial vein of thigh Tributaries just before piercing cribriform fascia Superficial epigastric vein Superficial circumflex iliac vein Superficial external pudendal vein Just before opening into femoral vein Deep external pudendal vein Details about the great saphenous vein are described in Chapter 18.

16. INGUINAL LYMPH NODES The inguinal region has two groups of lymph nodes: superficial and deep. Superficial inguinal lymph nodes These are present in the superficial fascia covering the femoral triangle (Fig. 6.7). They are arranged in three groups forming letter ‘T’ as follows: Lower vertical group It is placed along both sides of terminal part of the great saphenous vein. It consists of 4–5 nodes. Drainage : They drain the skin and fascia of lower limb except buttock and the territory of short saphenous vein. Upper lateral group It is placed below the lateral part of inguinal ligament. It consists of 2–3 nodes. Drainage : They drain skin and fasciae of the lateral part of infraumbilical area of anterior abdominal wall, buttock, and flank and back below the umbilical plane.

17. Upper medial group It is placed below the medial end of inguinal ligament. It consists of 2–3 nodes. Drainage : They drain medial part of infraumbilical area of anterior abdominal wall, perineum and external genitalia except glans penis/clitoris, anal canal below the pectinate line, penile part of male urethra, vagina below the hymen, and superolateral angle of uterus via round ligament

18. Deep inguinal nodes These lie medial to the upper part of femoral vein in the femoral triangle. These are 4–5 nodes. Gland of Cloquet or Rosenmüller These are nodes that lie in the femoral canal. They drain superficial inguinal nodes, popliteal nodes, glans penis and clitoris, and deep lymphatics of lower limb accompanying the femoral vessels. Efferent vessels from the deep inguinal nodes go to the external iliac nodes. Clinical integration Elephantiasis It is a hypertrophy of skin and a subcutaneous tissue with massive edema of lower limb. It occurs due to the obstruction of the lymphatic vessels of lower limb by the parasite Wuchereria bancrofti . Inguinal lymphadenopathy It is an enlargement of inguinal lymph nodes. It occurs due to infection, carcinoma, boil, and so on in the drainage area.

19. DEEP FASCIA OF THIGH (FASCIA LATA) Deep fascia of the thigh is known as fascia lata ( latus = extensive in Latin). It is a tough fibrous sheath that encloses the thigh like a sleeve. Attachments Superior It is attached to inguinal, iliac crest, gluteal fascia, pubis, pubic arch, and ischial spine. Through the gluteal fascia, the fascia lata is attached to sacrum, coccyx, and sacrotuberous ligament. Inferior It is attached to the front and sides of the knee, subcutaneous bony prominences, and capsule of knee joint.

20. Modifications of fascia lata Iliotibial tract Q. Write a short note on iliotibial tract. Definition : Iliotibial tract is a thickened band of the fascia lata located on the lateral side of the thigh. Also called Maissiat band (Fig. 6.8). Width: 5 cm Attachments Superiorly the tract splits into two layers: superficial and deep lamina. Superficial lamina is attached to the tubercle of iliac crest. Deep lamina is attached to the capsule of hip joint. Inferiorly, it is attached to a smooth area on anterior surface of the lateral condyle of tibia.

21. Muscular attachments Two muscles insert on the upper part of iliotibial tract: Superficial three-fourth of the gluteus maximus Tensor fasciae latae Functional significance Stabilization of knee : The iliotibial tract stabilizes the knee both in extension and in partial flexion that occurs in walking and running. Support knee against gravity: The iliotibial tract supports the knee against gravity when leaning forward with slightly flexed knee and prevents the individual from falling forward.

22. Clinical Integration Iliotibial tract syndrome : It occurs due to nontraumatic overuse injury of iliotibial tract, mostly in runners and cyclists. It results in pain and tenderness on palpation of lateral aspect of knee (Fig. 6.9).

23. Saphenous opening Q. Write a short note on saphenous opening Definition : Saphenous opening is an oval opening in the fascia lata (Fig. 6.10). Location : It is located about 4 cm below and lateral to the pubic tubercle. Size : 2.5 cm long, 2 cm broad, long axis directed downward and laterally. Margins : The opening has a sharp crescent-shaped superficial inferolateral margin, also called falciform margin . an ill-defined deeper medial margin. Closure of opening The saphenous opening is closed by cribriform fascia – formed by modification of superficial fascia of thigh. Structures passing through saphenous opening Great saphenous vein. Superficial epigastric and superficial external pudendal vessels. Lymphatics from superficial to deep inguinal nodes.

24. FASCIAL COMPARTMENTS OF THIGH The deep fascia (fascia lata ) encloses the content of the thigh like a sleeve. Three intermuscular septa extend from deep fascia to the linea aspera as medial, lateral, and posterior septa. These three intermuscular septa divide the thigh into three compartments: anterior, posterior, and medial (Fig. 6.11). Anterior compartment of thigh : It lies between medial and lateral intermuscular septa. It contains extensor muscles. Posterior compartment of thigh : It lies between lateral and posterior intermuscular septa. It contains flexor muscles. Medial compartment of thigh : It lies between medial and posterior intermuscular septa. It contains adductor muscles.

25. ANTERIOR COMPARTMENT OF THIGH The anterior compartment of thigh lies between medial and lateral intermuscular septa. It is also called extensor compartment as it contains extensor muscles of thigh. Contents Anterior compartment of thigh contains: Muscles Rectus femoris 3 vasti (vastus medialis, intemedius , and lateralis) Sartorius Articularis genu Tensor fascia latae Nerve: Femoral nerve Artery: Femoral artery Fascial space: Femoral triangle and adductor canal. In this chapter, the muscles of anterior compartment of thigh are described.

26. MUSCLES OF ANTERIOR COMPARTMENT OF THIGH The muscles of the anterior compartment of thigh include the following muscles (Fig. 6.12, 6.13): The muscles of the anterior compartment of thigh include the following muscles (Fig. 6.12, 6.13): Rectus femoris Vastus lateralis Vastus medialis Vastus intermidius Articularis genu Sartorius Tensor fasciae latae Quadriceps femoris

27. Quadriceps femoris The four muscles of the thigh (rectus femoris and three vasti ) form a group of muscles that act as extensor of knee and inserts on the tibial tuberosity through patellar ligament. This group of muscle is called quadriceps femoris ( four-headed muscle in Latin). Patella is the largest sesamoid bone in the body. It develops in the tendon of quadriceps femoris. Nerve supply All the quadriceps femoris muscles are supplied by femoral nerve. Actions Extension at knee joint. Helps for rising from sitting or squatting position by extending the knee.

28. Clinical testing Ask the person to extend the knee against the resistance and palpate the contracting muscle (Fig. 6.14). Strengthening exercises (physiotherapy) The strengthening exercise of quadriceps femoris are required during recovery phase of fractures and paralysis. These exercises include passive extension of knee, straight leg raise in spine position, squat position, and step-ups.

29. Sartorius Sartorius is the longest muscle in the body. It is called as tailor’s muscle ( sartor  = tailor in Latin) (Fig. 6.13, 6.15, Flowchart 6.1). It is used for palthi position by people for meal or prayer as well as by tailors. This position includes 1. Flexion of hip 2. Flexion of knee 3. Abduction and lateral rotation of thigh Origin Sartorius originates from anterior superior iliac spine and upper half of the notch below the spine. Direction of fibers The fibers of sartorius run obliquely downward medially across the thigh to reach the posterior aspect of the medial condyle of the femur. Here, the tendon turns forward to reach the upper part of medial surface of shaft.

30. Insertion Sartorius inserts on the upper part of medial surface of shaft of the tibia in front of the insertions of gracilis and semitendineous . Innervation (nerve supply) Sartorius is supplied by anterior division of femoral nerve. Actions Being very long, the sartorius is a weak muscle. It performs the following actions: Flexion of hip and knee joint Abduction and lateral rotation of thigh.

31. Rectus Femoris Rectus femoris is straight, fusiform, bipinnate muscle ( rectus  = straight in Latin) (Fig. 6.13, 6.16, Flowchart 6.2). Location : It lies in the middle of the front of the thigh Origin It has two heads: straight and reflected Straight head : It originates from the upper half of the anterior inferior iliac spine . Reflected head : It is thin and flat. It arises from a groove above the margin of the acetabulum and from capsule of hip joint. Direction of fibers Superficial fibers are bipennate and deep fibers are parallel. Both the heads unite at an acute angle to form a fusiform belly. In the lower part of the thigh, it forms a flat tendon (aponeurosis). Insertion Rectus femoris inserts at the base of patella . Innervation It is supplied by the posterior division of femoral nerve. Actions It acts as a kicking muscle as it flexes the hip and extends the knee.

32. Some interesting facts Sartorius is the longest muscle of the body. It is a flat band of muscle fibers that crosses obliquely (downward and medially). All the muscles of anterior compartment of the thigh. The rectus femoris is bipennate muscle that lie in the middle of the thigh. It is overlapped by sartorius, iliacs , and tensor late in its upper part. Rectus femoris is an antagonist of hamstring muscles. Clinical Integration Rectus femoris strain It occurs in football or soccer player due top jumping kicking. It involves partial or complete tear of the rectus femoris because this muscle crosses both the joints.

33. Vastus lateralis Vastus lateralis or vastus externus is the largest vastus muscle (Fig. 6.13, 6.17, Flowchart 6.3). Origin The origin of vastus lateralis is in a linear fashion and forms the following parts of femur: Upper part of intertrochanteric line Anterior and inferior borders greater trochanter Lateral lip of gluteal tuberosity Upper half of lateral lip of linea aspera Direction of fibers The fibers at the origin are aponeurotic (whitish). Further fibers originate from this aponeurosis. The fibers of vastus lateralis form a bulky muscle on the lateral side of middle of the thigh. Fibers run downward and medially to reach the patella. Insertion Vastus lateralis inserts on Lateral part of base and upper one-third of lateral border of patella. Few fibers to the capsule of knee joint tibia and iliotibial tract. Innervation It is supplied of posterior division of femoral nerve. Actions Extension at knee joint.

34. Vastus medialis (vastus medialis obliques) Vastus medialis is also called vastus internus or teardrop muscle (Fig. 6.13, 6.17, Flowchart 6.4) . Location : It is a bulky muscle that covers the medial aspect of the femur. Origin The origin of vastus medialis is in a linear fashion from the following parts of femur: Lower part of intertrochanteric line Spiral line Medial lip of linea aspera Upper two-thirds of supracondylar line Direction of fibers The fibers of the vastus medialis produce bulge on the lower part of the medial side of thigh just above the knee joint. Fibers run obliquely downward and laterally. Insertion Medial part of the base of patella . Upper two-thirds of medial border of patella. Capsule of knee joint.

35. Innervation Vastus medialis is supplied by posterior division of the femoral nerve. Action Extension of knee joint Prevention of lateral displacement of patella. Locking of knee joint by medial rotation of femur during knee extension. Some interesting facts Sartorius is supplied by anterior division of femoral nerve, whereas rectus femoris, vasti , and articularis genus are supplied by posterior division of femoral nerve.

36. Vastus intermedius Vastus intermedius muscle is situated in the thigh under the cover of rectus femoris. Reflect the rectus femoris muscle to visualize the vastus intermediate muscle (Fig. 6.13, 6.17, Flowchart 6.5). Origin Vastus intermediate originates from 3/4th of the anterior and lateral surfaces of the shaft of femur . Direction of fibers The fibers of vastus intermedius run vertically downward to form flat tendon in the lower part of the thigh. Insertion Vastus intermedius inserts on base of the patella . Innervation It is supplied by posterior division of the femoral nerve. Action Extension of knee joint

37. Articularis genu ( subcrureus ) Articularis genu is a small muscle that consists of three–four slips. It lies deep to vastus intermedius and considered as detached part of the vastus intermedius. Origin It originates from the lower part of the anterior surface of the femur . Insertion It inserts on the upper part of synovial membrane of the knee joint. Innervation It is supplied by a small branch of nerve to vastus medialis through posterior division of femoral nerve. Action It prevents the damage to synovial membrane knee joint by pulling the synovial membrane upward during extension of knee.

38. Muscles of iliac region There are three muscles in the iliac region. They are iliacus, psoas major, and psoas minor (Fig. 6.18). These muscles are described here as the part of iliacus and psoas major muscles that form the floor of femoral triangle. Psoas Major Muscle Psoas major is fusiform muscle that extends from lumbar region to femoral triangle (Fig. 6.18). Origin Form lumbar vertebrae as follows: Anterior surfaces of lower borders transverse processes of L1 to L5 vertebrae. By 5 slips, one each from the bodies of two adjacent vertebrae and their inter vertebrae discs of T12 to L5 From tendinous arches extending across the constricted parts of bodies of lumbar vertebrae. Direction of the fibers The fibers descend downward and laterally. The fibers pass deep to the inguinal ligament and in front of hip joint. Fibers coverage to form a tendon in the thigh.

39. Insertion Ilipsoas tendon : Tendon of psoas major muscle receives the fibers of iliacus muscle and forms iliopsoas tendon. This tendon inserts on the tip and medial part of anterior surface of lesser trochanter of femur. Innervation Psoas major is supplied by the branches of roots of spinal nerve L1 to L3 (sometimes L4). Actions The psoas major muscle performs the following actions: Powerful flexion of hip joint. Raising trunk from recumbent to sitting position. Psoas major also flexes the trunk (For details, refer Volume 4).

40. Iliacus Iliacus is a triangular- or fan-shaped muscle (Fig. 6.18). Origin It originates from Upper 2/3rd of iliac fossa Inner lip of iliac crest Upper surface of lateral part of the sacrum Direction of fibers Its fibers converge and cross the inguinal ligament lateral to the psoas major. Insertion It inserts along with psoas major muscle on the tip of lesser trochanter and part of femur below it. Innervation Iliacus is supplied by femoral nerve. Actions Along with psoas major – flexion of hip and raising trunk from recumbent to sitting position.

41. Some interesting facts Iliacus and psoas major are included here as they are forming the floor of the femoral triangle. For details about psoas minor and other muscles of posterior abdominal wall, refer volume 4. For tensor fascia latae muscle refer Chapter 10 . Iliacus and psoas major are located deep to the inguinal ligament. Iliacus is fleshy (brownish), whereas psoas major is tendinous (whitish; shining) in the floor of femoral triangle.

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