Download Anterior and Medial Regions of Thigh

ANTERIOR AND MEDIAL COMPARTMENTS OF THIGH Dr. Milton M. Sholley SELF­STUDY RESOURCES Essential Clinical Anatomy 3 rd ed. (ECA): pp. 313­340 Grant's Atlas (11 th Edition): Figs. 5.12A, 5.12B, 5.11A, 5.13F, 5.13A, 5.13G, 5.14A, 5.14B, 5.15A, 5.17, 5.20B, 5.20D, 5.18, Table 5.3 (p. 360), 5.21, 5.19A, 5.29A, 5.29C, 5.30A, and 5.32A&B OR Grant's Atlas (12 th Edition): Figs. 5.13A, 5.13B, 5.15A, 5.16C, 5.16A, 5.18B, 5.17A, 5.18C, 5.18A, 5.20A, 5.22B, 5.22D, 5.20B, Table 5.3 (p. 378), 5.23, 5.21A, 5.29A, 5.29C, 5.30A, and 5.32A&B Head to Toe Questions in Gross Anatomy: Start questions #254­289 LECTURE OBJECTIVES 1. 2. 3. 4. 5. To introduce the anatomy of the lower extremity. To explain the important features of the osteology of the pelvis and femur. To explain the compartmentalization of the thigh. To explain the anatomy of the anterior compartment of the thigh. To explain the anatomy of the medial compartment of the thigh. LECTURE OUTLINE I. General comments A. Parts and regions of the lower extremity (lower limb) 1. 2. Gluteal region (also named buttock, natis, or clunis) a. Surrounds the external aspect of the coxal bone b. Includes the hip joint Thigh ­ contains three compartments for muscles (see Fig. 1) a. Anterior compartment b. Medial compartment c. Posterior compartment
Compartmentalization of the Thigh Fig. 1 3. 4. Knee (genu) ­ has two regions a. Anterior or patellar region b. Posterior or popliteal region Leg (crus) ­ contains three compartments for muscles a. Anterior compartment b. Lateral compartment c. Posterior compartment 5. Ankle (talus) 6. Foot (pes) ­ has two surfaces a. Dorsal surface b. Plantar surface (1) The plantar surface has four layers of muscles.
B. C. Specializations that accomodate for weight­bearing and locomotion 1. The pelvic girdle is firmly attached to the axial skeleton via bony articulations, in contrast to the shoulder girdle, which is less firmly attached to the axial skeleton, primarily via muscles. 2. The hip joint is intrinsically more stable than the shoulder joint. 3. Both of these features yield increased strength and stability with sacrifice of some range of motion. Limb rotation during development 1. The parts of the lower limb are comparable to those of the upper limb (e.g., the knee and the elbow). 2. However, the adult orientation of these parts is different, because during development the lower and upper limbs rotate in opposite directions about their longitudinal axes. 3. II. a. The lower limb rotates almost 90 o medially. b. The upper limb rotates 90 o laterally. Because of the opposite rotations, there is a disparity of almost 180 o between the surfaces of the upper and lower limbs (especially in the more distal parts). a. Thus, in the anatomical position the knee points anteriorly, while the elbow points posteriorly. b. Similarly, the dorsal surface of the foot is on the anterior aspect, while the dorsal surface of the hand is on the posterior aspect. Osteology A. Coxal (hip) bone (see Grant’s Atlas, 12 th Ed., Figs. 4.23A, page 312 and 5.31A, page 397) 1. The two coxal bones articulate with one another anteriorly and with the sacrum posteriorly, to form the pelvis (see Grant’s Atlas, 12 th Ed., Fig. 4.22, page 311). 2. In youth each coxal bone consists of three separate parts, which later become fused; these are the (see Grant’s Atlas, 12 th Ed., Fig. 5.31B, page 397): a. Ilium b. Ischium
c. B. Pubis Femur – the thigh bone (see Grant’s Atlas, 12 th Ed., Figs. 5.22A­D, pages 380­381) III. Hip joint A. Type of joint ­ ball and socket B. Movements at the hip joint ­ flexion, extension, abduction, adduction, medial rotation, lateral rotation, circumduction C. Weight transfer across the hip joint ­ During standing the body weight is transmitted from the upper sacrum across the sacroiliac joint, then forward and downward along the arcuate line of the coxal bone to the top of the acetabulum, then across the hip joint to the femoral head. The femoral head is deeply held within the acetabulum, which with its fibrocartilaginous labrum forms over half a sphere. This deep and tightly fitting socket is an important factor in providing stability for weight­bearing in various positions of the joint. D. Capsule of the hip joint ­ attaches at the distal end of the femoral neck anteriorly and 2/3 of the way down the neck posteriorly E. Blood supply (see Fig. 2) ­ The main blood supply to the head of the femur is derived from the ascending branches of the medial femoral circumflex artery. A secondary supply is derived from the ascending branches of the lateral femoral circumflex artery and a tertiary suppy is derived from the small artery of the ligament of the head of the femur. The ascending branches run up the femoral neck under the reflected synovium of the capsule, Blood Supply to Neck and Head of Femur 3 1 2 2 Fig. 2
1 Grant’s Atlas, 12 th ed. Fig. 5.34 A, p. 400 Ascending branches 1. Medial femoral circumflex artery 2. Lateral femoral circumflex artery 3. Artery of the ligament of the head of the femur Adapted from: Hollinshead’s Text, 5 th ed. Fig.17­17, p. 328 especially posteriorly. Hence, except for the small artery of the ligament of the head, the vessels are tighly bound to the neck of the femur and are often torn by intracapsular fractures of the femoral neck. Such fractures may result in avascular necrosis of the femoral head. F. G. IV. Major ligaments of the hip joint (see Grant’s Atlas, 12 th Ed., Fig. 5.29, pages 394­395) 1. Iliofemoral ligament ­ It runs from the anterior inferior iliac spine to both ends of the intertrochanteric line (also called the Y­ligament of Bigelow). This ligament is tensed by full extension of the hip and provides the major static support of the hip joint during quiet standing, since it prevents the hip from going into hyperextension. 2. Ischiofemoral ligament ­ It arises behind the acetabulum and spirals laterally and upward around the femoral neck to blend with the upper fibers of the iliofemoral ligament. This ligament also tightens during hip extension and because of its spiral course pulls the femoral head deeply into the acetabulum, thereby increasing hip stability. 3. Pubofemoral ligament ­ It arises from the pubis in front of the acetabulum and blends with the lower limb of the iliofemoral ligament as it attaches to the femur. It limits hip abduction. Innervation of the hip joint ­ mostly from branches of the femoral, obturator, and quadratus femoris nerves Anterior compartment of the thigh (contains muscles innervated by the femoral nerve ­­ see Figs. 3 and 4, the muscle chart for the anterior compartment, and Grant’s Atlas, 12 th Ed., pages 374­ 377) A. Iliopsoas muscle complex (Iliacus and psoas major muscles) 1. Innervation ­ branches from the femoral nerve or directly from L2 and L3 ventral rami 2. Major origins ­ from the iliac fossa (iliacus muscle) and lumbar vertebrae (psoas major muscle) 3. Insertion ­ The muscles enter the thigh deep to the lateral part of the inguinal ligament and then insert on the lesser trochanter of the femur. 4. Action ­ This muscle complex is a flexor of the hip, operating when great strength is needed. 5. B. Bursa ­ A large iliopectineal bursa lies deep to this muscle complex inferior to the inguinal ligament. This bursa separates the iliopsoas muscle from the hip joint and provides lubrication between the muscle and the joint capsule. Quadriceps femoris muscle (a muscle with four heads)
C. D. 1. Innervation ­ femoral nerve 2. Major origins ­ The rectus femoris portion arises mainly from the anterior inferior iliac spine. The vastus lateralis, vastus medialis, and vastus intermedius all arise from various parts of the femur (they do not cross the hip joint). 3. Insertion ­ All four heads of the quadriceps femoris join the quadriceps tendon, which inserts into the patella, and then continues as the patellar ligament to insert into the tibial tuberosity. 4. Actions ­ The rectus femoris portion is a flexor of the hip as well as an extensor of the knee. The three vasti are extensors of the knee. The quadriceps femoris muscle complex produces the well­known knee jerk reflex when the patellar tendon is tapped during a neurological examination. Sartorius muscle (the "tailor's muscle") 1. Innervation ­ femoral nerve 2. Origin ­ anterior superior iliac spine 3. Insertion ­ into the upper anteromedial tibia posterior to the flexion­extension axis of the knee (this insertion is a component of the pes anserinus tendon) 4. Actions ­ It flexes, laterally rotates and abducts at the hip and flexes and medially rotates at the knee (when the knee is flexed) Pectineus muscle 1. Innervation ­ usually the femoral nerve, but occasionally the obturator nerve 2. Origins ­ pectineal line of pubis and the pubis anterior to the pectineal line 3. Insertion ­ the pectineal line on the posterior aspect of the femur 4. Actions ­ It is a weak hip flexor and adductor.
IV. A
Anterior compartment of the thigh D (Contains muscles innervated by the femoral nerve­­see the muscle chart) C A. Iliopsoas muscle complex B B. Quadriceps femoris muscle B C. Sartorius muscle B D. Pectineus muscle Fig. 3 Adapted from: Grant’s Atlas, 12 th ed. Fig. 5.20A, p. 375 Compartmental Innervations and Actions of Contained Muscles Fig. 4
E. The Femoral Triangle (Fig. 5) and related Neurovascular Relationships (see Grant’s Atlas, 12 th Ed., Figs. 5.17A­C, page 372 and Figs. 5.18A­C, page 373) Borders of the Femoral Triangle Inguinal ligament Sartorius m. Adductor longus m. Fig. 5
1. The femoral artery enters the thigh posterior to the inguinal ligament, midway between the pubic tubercle and the anterior superior iliac spine. At this point, the femoral nerve lies just lateral to the femoral artery and the femoral vein just medial to it. Medial to the femoral vein is the femoral canal, which is the route by which a femoral hernia may enter the thigh. Remember the mnemonic NAVEL (Fig. 6), which stands for Nerve, Artery, Vein, and Empty space with Lymphatics, going from lateral to medial. The empty space is the femoral canal and the lymphatics are the deep inguinal nodes and lymph vessels. The greater saphenous vein joins the femoral vein below the inguinal ligament at the saphenous hiatus in the fascia lata. Anterior L M Femoral N A V Lateral Fig. 6 EL Medial Head of femur Adapted from: Grant’s Atlas, 10 th ed. Fig. 5.12B, p. 314 2. In the femoral triangle, the femoral artery and vein always give off deep femoral (or profunda femoris) branches, and sometimes give off medial femoral circumflex, and/or lateral femoral circumflex branches. (However, the medial femoral circumflex and lateral femoral circumflex vessels most frequently arise from the deep femoral vessels.) Then, accompanied by the saphenous nerve branch of the femoral nerve, the femoral artery and vein enter a subsartorial (or adductor) canal in the middle of the thigh (see Grant’s Atlas, 12 th Ed., Figs. 5.18A­C, page 373). The vessels then pass through an opening (named the adductor hiatus) in the adductor magnus muscle to enter the popliteal fossa in the inferoposterior part of the thigh 3. The superficial inguinal lymph nodes are divided into two main groups: a vertical group along the proximal end of the greater saphenous vein and a horizontal group just inferior to the inguinal ligament and more lateral than the vertical group (see Grant’s Atlas, 12 th Ed., Fig. 5.13A&B, page 367). 4. V. a. These superficial nodes drain the superficial parts of the lower limb, except for those superficial areas associated with the lesser saphenous vein. b. In addition, the superficial inguinal lymph nodes drain the buttocks, external genitalia (but not the testes), lower vagina and vulva, the anal canal, and the lower abdominal wall. c. It is important to realize, then, that swelling of a superficial inguinal lymph node may be a sign of inflammation or neoplasia located in any of these diverse anatomical areas. The deep inguinal lymph nodes consist of three or four nodes located at the superior end of the femoral vein, in the space medial to the vein (the site of the femoral canal). a. The deep nodes receive drainage from the superficial nodes. b. In addition, the deep nodes directly receive the drainage from the deeper structures of the lower extremity and those superficial areas associated with the lesser saphenous vein. Medial compartment of the thigh (contains muscles mainly innervated by the obturator nerve ­­ see the muscle chart and Grant’s Atlas, 12 th Ed., pages 378­379) A. Adductor longus, brevis and magnus muscles 1. Innervation ­ obturator nerve, except for the posterior (hamstring) part of the adductor magnus, which is innervated by the tibial portion of the sciatic nerve 2. Origins ­ respectively, for the longus, brevis, and magnus: body of the pubis; body and inferior ramus of the pubis; inferior pubic ramus, ischial ramus and tuberosity
B. C. VI. 3. Insertions ­ various levels of the linea aspera of the femur and, in the case of the adductor magnus, also the adductor tubercle 4. Actions ­ While parts of these muscles may contribute to flexion, extension and rotation, their major function is adduction of the hip. Gracilis muscle 1. Innervation ­ obturator nerve 2. Origins ­ body and inferior ramus of pubis 3. Insertion ­ upper end of the tibia below the medial condyle, between the insertions of the sartorius and semitendinosus muscles (the insertions of sartorius, gracilis, and semitendinosus comprise the pes anserinus tendon) 4. Actions ­ weak flexion, adduction and lateral rotation at the hip; flexion and internal rotation at the knee Obturator externus muscle 1. Innervation ­ obturator nerve 2. Origin ­ external surface of obturator foramen area 3. Insertion ­ runs inferior and posterior to the neck of the femur to insert into the trochanteric fossa on the medial side of the greater trochanter 4. Action ­ laterally rotates the thigh The Femoral and Obturator nerves are major branches of the Lumbar Plexus (Figs. 7 & 8). A. Femoral nerve The femoral nerve is formed by the posterior divisions of the ventral rami of spinal nerves L2, L3, and L4. In addition to supplying motor branches to the muscles of the anterior compartment of the thigh, the femoral nerve supplies several cutaneous branches to the skin of the anterior thigh as well as the saphenous nerve, which is a cutaneous nerve that supplies skin of the medial leg and the dorsomedial foot. B. Obturator nerve The obturator nerve is formed by the anterior divisions of the ventral rami of spinal nerves L2, L3, and L4. In addition to supplying motor branches to the muscles of the medial compartment of the thigh, the obturator nerve supplies a cutaneous branch to skin on the lower medial thigh. After the obturator nerve passes through the obturator canal and innervates the obturator externus muscle and hip joint, it splits into anterior and posterior branches, which lie
on either side of the adductor brevis muscle. The anterior branch gives off the cutaneous branch to the medial thigh, while the posterior branch gives off an articular branch to the knee joint. Lumbar Plexus Ventral rami T12 Subcostal nerve Iliohypogastric nerve (T12, L1) L1 Ilioinguinal nerve (L1) Genitofemoral nerve (L1, 2) L2 L3 Lateral femoral cutaneous nerve (L2, 3) L4 Anterior divisions Posterior divisions Obturator nerve (L2­4) Fig. 7 Femoral nerve (L2­4) Lumbar plexus in situ Femoral nerve
Lateral femoral cutaneous nerve Obturator nerve Fig. 8