Lower Limb Anatomy PDF

 Are extensions from the trunk specialized to support body weight, for locomotion and to maintain balance. Have six major regions. Introduction Lower Limb  lower limbs have six major regions – Gluteal region Buttocks Hip region – Femoral region (thigh)...

 Are extensions from the trunk specialized to support body weight, for locomotion and to maintain balance. Have six major regions. Introduction Lower Limb  lower limbs have six major regions – Gluteal region Buttocks Hip region – Femoral region (thigh) – Knee region – Leg region – Ankle region – Foot region Bones of Lower Limb Two functional components: 1. Pelvic girdle (bony pelvis) – Include; Sacrum and right & left hip bones – Attaches the free lower limb to the axial skeleton – Also makes up the skeleton of the lower part of the trunk – Protective and supportive functions serve the abdomen, pelvis, and perineum as well as the lower limbs 2. Bones of the free lower limb  Sacrum & Coccyx Auricular facet for hip bone The lower limb is directly anchored to the axial skeleton by a sacroiliac joint & - strong ligaments, which link the pelvis to the sacrum  Hip Bone Large, irrigular bone (flat) Formed by the fusion of three primary bones; – Ilium – Ischium – Pubis Acetabulum Acetabulum ; cupshaped cavity or socket that articulates with the head of the femur to form the hip joint Lateral view The hip bones meet anteriorly at the pubic symphysis and articulate with the sacrum posteriorly (Sacroiliac joint) ILIUM Hip Bone The largest part of the hip bone – Alae (L. wings), provide broad surfaces for attachment of muscles – Body-joins the pubis and ischium Anteriorly – Anterior superior iliac spine(ASIS) – Anterior inferior iliac spine (AIIS) Both provide attachment for ligaments and tendons Anterior view ILIUM Hip Bone Iliac crest – Long curved and thickened superior border of the ala – Extend Form ASIS to posterior superior iliac spine Tubercle of the iliac crest (iliac tubercle) – Prominence on the external lip of the iliac crest Posterior inferior iliac spine (PIIS) – marks the superior end of the greater sciatic notch Anterior view  Hip Bone ILIUM Lateral surface Gluteal lines Posterior-from the iliac crest to PIIS Anterior- from the iliac crest to the upper margin of the greater sciatic foramen Inferior- From ASIS to posterior margin Lateral view of the acetabulum. ILIUM Hip Bone Medial surface Is primarily concerned with pelvic and perineal structures. Iliac fossa – Origen for the iliacus muscle Posterior surface Iliac tuberosity Auricular surface Articulate with sacrum at sacroiliac joint Medial view Hip Bone ISCHIUM Forms the posteroinferior part of the hip bone Form the posteroinferior aspect of the acetabulum Ischial spine – Separates the greater sciatic notch from lesser sciatic notch Ischial tuberosity – Provides origin of posterior thigh muscles. – The body's weight rests on this tuberosity when sitting Ramus of ischium Greater & lesser sciatic notch converted to foramen by sacrospinous and sacrotuberous ligaments Hip Bone PUBIS Anteromedial part of the hip bone Provides origin for muscles of the medial thigh It has Body and superior and inferior rami Pubic crest – Provides attachment for abdominal muscles – projections at the lateral ends are Pubic tubercles  Hip Bone Obturator Foramen Large oval opening in the hip bone Bounded by the pubis and ischium and their rami Closed by the thin, strong obturator membrane – Has a canal, obturator canal Through which; obturator nerve and vessels pass – Provide muscle attachmet  The margin of Acetabulum the acetabulum is incomplete inferiorly at the acetabular notch Acetabular fossa lunate surface of the acetabulum, – Articular surface receiving the head of the femur  Femur Longest and heaviest bone in the body Transmits body weight from the hip bone to the tibia Consists of – A head, neck & shaft (body) and – Two ends, proximal and distal Proximal end (L-shaped) Femur Head, covered with articular cartilage – Except fovea for the ligament of the head Neck, – Supporting the head – Common fracture site Two trochanters Greater- attachment site for gluteal muscles Lesser- Attachment site of iliopsoas tendon  Femur Angle of inclination Is the angle formed when, long axis of the head and neck projects superomedially at an angle to the shaft Angle of inclination – Less in females – Allows greater mobility of the femur at the hip joint – Decreases with age  Coxa Vara and Coxa Valga The angle of inclination varies with age, sex, and development of the femur (e.g., a congenital defect in the ossification of the femoral neck). When the angle of inclination is decreased, the condition is coxa vara when it is increased, it is coxa valga Femur Proximal end (L-shaped) Intertrochanteric crest – Posteriorly – Quadrate tubercle Rounded elevation on the crest) Intertrochanteric line – Anteriorly – spiral line (less distinct ridge on the line) Trochanteric fossa – deep depression medially Femur Shaft of the femur (posterior aspect) linea aspera – On the posterior middle 1/3 of femoral shaft, Broad & rough line – Provides attachment for adductors muscles of the thigh  Superiorly it forms: – Glutael tuberosity (lateral lip ) – Pectineal line (medial lip)  Inferiorly it forms Lines, supracondylar lines (medial and lateral) Distal Femur Femur Medial and lateral condyles – Make up nearly entire distal femur – Articulate with tibial condyles – Separated posteriorly & inferiorly by an intercondylar fossa Lateral epicondyle Medial epicondyle – Adductor tubercle Patellar surface- to petella, anteriorly.  Patella Triangular, and the largest sesamoid bone Proximal part called the base, distal part the pole or apex  Posterior surface covered with articular cartilage Facets –medial facet &lateral Separated by vertical ridge – Can divide med. and lat. facets to Patellar ligament superior and inferior Distally, the patella is anchored by the patellar ligament Tibia and Fibula (leg bones) Are the bones of the leg Connected by a dense interosseous membrane Tibia (medial) transmits body weight Fibula (lateral) mainly functions as an attachment for muscles – Also important for the stability of the ankle joint Tibia Second largest bone in the body Proximal end Medial and lateral condyles, consists;  Superior articular surface, (tibial plateau) – Separated by intercondylar eminence Proximal Tibia and Fibula  Tibia Tibial tuberosity – Provides distal attachment for the patellar ligament Distal end smaller than the proximal end medial expansion, medial malleolus Posterior surface Soleal line Formed in relationship to the aponeurotic origin of the soleus muscle Leads to a large nutrient foramen Distal end of tibia and fibula  Tibia Shaft Triangular in cross- section, having three surfaces and borders: – Medial surface – Lateral/interosseous, and Posterior surface Anterior border is the most prominent border Medial surface, subcutaneous throughout the length Shaft of tibia and fibula  Fibula No function in weight- bearing Mainly for muscle attachment – Insertion for 1 muscle – Origin for 8 muscles Proximal end Head – has a pointed apex Neck – Articulates with the fibular facet on the posterolateral of lateral tibial condyle  Fibula shaft – Twisted – Triangular in cross-section – Having three borders and three surfaces Distal end – prolonged laterally and inferiorly as, lateral malleolus Provide attachment for the ligaments that stabilize the ankle joint Fibula is a common source of bone grafting – After a segment of the shaft has been removed, walking, running, and jumping can be normal.  Bones of Foot Include: Tarsus (7) – Form proximal foot or hindfoot metatarsus (5) Phalanges (14) – Both metatarsus & pahalanges form distal or forefoot Tarsus Posterior or proximal foot or hindfoot; Talus – articulates with the leg bones Calcaneus, Cuboid, Navicular, and 3 cuneiforms – Medial (M),the largest – Intermediate (I), smallest – Lateral (L) Tarsus Talus – Articulates with the leg bones Has no muscular or tendinous attachments Keystone of a longitudinal arch of foot – Distributes the weight evenly between the heel and the forefoot Tarsus Calcaneus (L., heel bone) largest and strongest lateral surface – fibular trochlea (anchors a tendon pulley for the evertors of the foot ) Posterior part – Calcaneal tuberosity – has medial, lateral, and anterior tubercles Only medial tubericle contacts the ground during standing. METATARSUS Anterior or distal foot, forefoot Tarsometatarsal joints – allow only limited sliding movements – form an oblique tarsometatarsal line – Dividing forefoot and hinffoot 1st metatarsal short & stouter – Medial and lateral sesamoid bones 2nd metatarsal is the longest Tuberosity of the 5th metatarsal – projects laterally over the cuboid Metatarsophalangeal joints- allow flexion, extension, abduction, and adduction of the digits Independent movements of the metatarsals are restricted by deep transverse metatarsal ligaments Interphalangeal joints-are hinge joints and allow flexion and extension ARCHES OF FOOT The metatarsals and tarsals form longitudinal arches (medial and lateral) Are flexible in nature and supported by muscles and ligaments. They absorb and transmit forces during walking and standing. Transverse arch Formed By – Cuniform bones and cuboid bones Bones forming the medial longitudinal, lateral longitudinal, and transverse arches of the right foot. Dynamic and passive supports of foot arch by ligaments and muscles Relationship to other Regions  Relationship to other Regions Unlike in the upper limb where most structures pass between the neck and limb through a single axillary inlet, in the lower limb, there are four major entry and exit points between the lower limb and the abdomen, pelvis, and perineum  Relationship to other Regions 1. The gap between the inguinal ligament and pelvic bone; 2. The greater sciatic foramen 3. The obturator canal (at the top of the obturator foramen); and 4. The lesser sciatic foramen.  Relationship to Abdomen Through a gap between the pelvic bone and the inguinal ligament Structures passing though this gap include: Muscles-psoas major, iliacus, and pectineus; Nerves-femoral and femoral branch of the genitofemoral nerves, and the lateral cutaneous nerve of thigh; Vessels-femoral artery and vein; lymphatics  Relationship to pelvis Posteriorly, structures communicate with the gluteal region through the greater sciatic foramen and include: Muscle-piriformis; Nerves- sciatic, superior and inferior gluteal, and pudendal nerves…. Vessels- superior and inferior gluteal arteries and veins, and the internal pudendal artery. Anteriorly, through obturator canal Structures include; The obturator nerve and vessels,  Relationship to Perineum Structures pass between the perineum and gluteal region through the lesser sciatic foramen The most important with respect to the lower limb is the tendon of the obturator internus muscle. The nerve and artery of the perineum (the internal pudendal artery and pudendal nerve) – Pass out of the pelvis through the greater sciatic foramen into the gluteal region and then immediately pass around the ischial spine and sacrospinous ligament and through the lesser sciatic foramen to enter the perineum. Relationship of lower limb to other Regions Superficial Veins Of Lower Limb Two major superficial veins Great & small saphenous veins Great saphenous vein formed by the union of the Dorsal vein of the great toe & Dorsal venous arch of the foot  Ascends anterior to the medial malleolus  Empties into the femoral vein Has valves  More numerous in the leg than in the thigh  Saphenous Vein Grafts (clinical Anatomy) Great saphenous vein is sometimes used for coronary arterial bypasses because; 1. it is readily accessible 2. Long vein (sufficient distance occurs between the tributaries and the perforating veins ) 3. its wall contains a higher percentage of muscular and elastic fibers than do other superficial veins  Vein is inverted so that the valves do not obstruct blood flow in the venous graft Superficial Veins Of Lower Limb Two major superficial veins Great & small saphenous veins Small saphenous vein arises on the lateral of the foot Formed by union of the Dorsal vein of the little toe & Dorsal venous arch  Ascends posterior to the lateral malleolus  penetrates the deep fascia  Empties into the popliteal vein – in the popliteal fossa Perforating veins Originate from the superficial veins Penetrate the deep fascia Contain valves that allow blood to flow only from the superficial veins to the deep veins Perforating veins are compressed when muscles contract  Musculovenous pump Varicose Veins (clinical anatomy) When either the deep fascia or the valves of the perforating veins are incompetent. This allows blood to flow from the deep to the superfi cial veins. Consequently, superficial veins become enlarged and tortuous. – Frequently, the great saphenous vein and its tributaries Fascia of Lower Limbs Subcutaneous Tissue and Fascia Superficial fascia Consists – variable amount of fat, – Cutaneous nerves, – Superficial veins, lymphatic vessels, and lymph nodes Fascia Lata deep fascia of the thigh encloses the large thigh muscles Laterally it is thickened and strengthened by additional longitudinal fibers to form the iliotibial tract (IT) – Which inserted in tibial tubercle  Fascia Lata Thigh muscles are separated into three compartments Their wall is formed by fascia lata Between compartments is intermuscular septa – attach to the linea aspera  Fascia Lata A gap or hiatus in the fascia lata, saphenous opening – Covered by cribriform fascia – Is passage of Great saphenous vein + lymphatic vessels Saphenous opening Deep fascia of the leg (crural fascia) Attaches to the anterior & medial borders of the tibia Thick in the proximal part & thinner distally Forms thickened bands both superior and anterior to the ankle joint, the extensor retinacula Intermuscular septa and muscle compartments of Leg