Lower Limb Anatomy Notes PDF

NOTES ON ANATOMY OF LOWER LIMB Contents: 1. An overview on lower limb bones ……………………………………………………… 2 2. Joints of lower limb …………………………………………………………………………….. 8 3. Muscles of lower limb ………………………………………………………………………… 11 4, Nerves of lower limb ………………………………………………………………………….. 22 5. Blood supply ………………...

NOTES ON ANATOMY OF LOWER LIMB Contents: 1. An overview on lower limb bones ……………………………………………………… 2 2. Joints of lower limb …………………………………………………………………………….. 8 3. Muscles of lower limb ………………………………………………………………………… 11 4, Nerves of lower limb ………………………………………………………………………….. 22 5. Blood supply ………………………………………………………………………………………. 28 6. Important anatomical notes ……………………………………………………………….. 33 1  Introduction to Anatomy means cutting –up for studying the normal structure of organs in :Anatomy living. :Types of study  Macroscopic anatomy: Studying normal structure of organs by naked eye.  Microscopic anatomy (Histology): studying of normal structure of cells under microscope.  Developmental anatomy: Studying of intrauterine life.  Applied anatomy: Application of anatomical facts in medicine and surgery.  Surface anatomy: Identification of borders of organs on the skin surface.  Radiographic anatomy: Studying of anatomy by using imaging techniques: CT, MRI, X-ray ….. Anatomical position & anatomical planes Anatomical position: human is standing erect. Face & eyes are looking forward. Arms are hanged beside the trunk. Palms of the hand are facing forward. Anatomical planes:  Sagittal plane: a vertical plane which divides the body into right & left parts. If it is dividing two equal halves, it’s called median plane.  Coronal plane: a vertical plane which divides the body into front & back parts.  Transverse plane: a horizontal plane which divides the body into upper & lower parts. Anatomical terms 2 — Terms of relationship:  Anterior  in front.  Posterior  behind.  Superior  above.  Inferior  below.  Medial  closer to median plane.  Lateral  away from the median plane. — Terms of comparison:  Cranial  nearer to the head  Caudal  nearer to the tail.  Proximal  nearer to the trunk.  Distal  away from the trunk.  Ventral  nearer to the anterior abdominal wall.  Dorsal  nearer to the backbone. — Terms of movements:  Flexion  to bend.  Extension  to straighten.  Abduction  movement away from the median plane.  Adduction movement towards the median plane.  Circumduction  multi-axial movement in a sequence of flexion, abduction, extension & adduction or vice versa.  Protraction (protrusion)  movement forward  Retraction (retrusion) movement backward.  Dorsiflexion of foot  movement to make toes approximate the front of leg.  Planterflexion of foot  the reverse.  Rotation  turning movement around a single axis.  Rotation in hand: supination  palm of the hand is facing forward. 3  Pronation  palm of the hand is facing backward.  Rotation in foot: inversion  sole of the foot is facing inward. Eversion  sole of the foot is facing outward. Body cavities Ventral body cavities —  Thoracic cavity  containing lungs & heart.  Abdominal & pelvic cavities  containing abdominal & pelvic viscera.  These cavities are lined by serous membranes. Dorsal body cavities —  Cranial cavity  containing brain.  Vertebral canal  containing spinal cord.  These cavities are lined by meninges. 4 Superficial fascia: Definition: A layer of loose areolar connective or adipose tissue that connects the skin to the underlying bones or deep fascia. It is known also by Hypodermis. Site & functions:  It is well developed at these sites: trunk wall, abdominal wall, buttocks & face.  It is absent in ear pinna, eye lids, penis & scrotum.  It is condensed in scalp, palm of hand & sole of foot.  Functions: 1. It facilitates skin movement. 2. It forms a soft bed for blood vessels & nerves of skin. 3. It retains body warmth. 4. It gives your body a smooth contour. Deep fascia: Definition: A dense connective tissue that is commonly arranged in sheets that form a stocking around the muscles and tendons beneath the superficial fascia. Site & functions:  Deep fascia is absent in face, scalp & anterior abdominal wall.  Functions: 1. It invests muscles to make a degree of tension to help muscle action. 2. It sends septa between muscles. 3. It invests delicate structures: glands & blood vessels to keep their fixation in place. 4. It is thickened at the palm of hands (Palmar aponeurosis) & sole of feet (Planter aponeurosis) for protection of the underlying soft structures: vessels & nerves. 5  5. It helps venous return from the lower limbs by forming a closed compartments inside which the skeletal muscles contract to squeeze veins (Muscle Pump). Bones Bone tissue & functions — Bone tissue:  Bones are hard forms of connective tissues.  It forms 18% of body weight.  The body is formed of 206 bones.  Cells:  Osteocytes  mature bone cells.  Osteoblasts  young bone cells.  Osteoclasts  phagocytic cells for bone remodeling.  Matrix:  Organic (collagen bundles type-1) 30% of dry bone.  Inorganic salts  calcium carbonate & calcium phosphate, 70%. Bone functions: 1. Gives body shape. 2. Forms joints for locomotion. 3. Protection of vital organs like brain & heart. 4. Containing bone marrow for blood cells formation. 5. Storage for calcium & phosphorus. Types of bones — Histological classification: two types 6   Compact bone  bony matrix contains tiny spaces with no bone marrow. Example: shaft of long bones.  Spongy bone  bony matrix contains large spaces rich in bone marrow. Example: ends of long bones. — Developmental classification: two types  Intra-membranous ossification  young bone cells are arranged in membrane like structure as in flat bones.  Intra-cartilaginous ossification  young bone cells are developed from cartilaginous model as in long bones. Morphological classification: 1. Long bones:  Present in limbs.  They have a shaft & two articular ends.  Growth of long bones:  They are developed by intra-cartilaginous ossification.  Primary centers of ossification appear at the shaft (diaphysis) of bones by 8th : 12th week of intra-uterine life.  Secondary centers of ossification appear at the ends (epiphysis) of bone around time of birth.  Epiphysial cartilage plate persists at junction between epiphysis & diaphysis for bone growth till time of 19th -25th years of age.  Blood supply of long bones: i. Nutrient artery & vein. ii. Peri-osteal twigs of vessels. iii. Articular vessels near the joint ends. 7   Thigh bone (Femur).  Leg bones (tibia & fibula).  Tarsal bones (7 bones).  Metatarsal bones.  Phalanges ( 3 except for big toe, only 2) Joints Types of joints — Joints are junction or articulation between two or more bone. — Types: 1. Fibrous joints: bones are connected by an intervening fibrous tissue. Examples: sutures of skull & syndesmosis between lower ends of tibia & fibula. 2. Cartilaginous joints: bones are connected by cartilaginous tissue. 1. Primary cartilaginous joint  formed of hyaline cartilage as epiphysial cartilage plate. It allows no movement. 2. Secondary cartilaginous joint formed of fibro-cartilage as intervertebral disc. It allows compression & torsion movement (limited). 11 3. Synovial joints: — Joints are connected by a joint with a cavity which contains synovial fluid & enclosed inside a fibrous capsule. — Features: a) Articular cartilage: formed of hyaline cartilage, very smooth surface with no vessels or nerves. b) Fibrous capsule: fibrous sac enclosing the joint. It is perforated by vessels & nerves. c) Synovial membrane: fine delicate membrane secreting synovial fluid. d) Synovial fluid: lubricating egg albumin like fluid to minimize friction between articular surfaces. e) Ligaments: strong fibrous bands connecting bones together. 12 Structures could be found inside the synovial joint:  Articular disc: formed of fibro-cartilage, compressible for shock absorbance & minimize friction. Examples: T/M joint, knee joint & sterno-clavicular joint.  Intra-articular ligaments: ligaments inside the joint cavity. Example: cruciate ligaments inside the knee joint.  Muscle tendons: found in shoulder joint, the tendon of long head of biceps. 13 Classification of synovial joints 1. Plane joints: — Flat articular surfaces allow minimal gliding movement. Example: inter-carpal joint. 2. Uni-axial joints:  Allow two movements around single axis.  Hinge joints: with transverse axis. Example: elbow joint.  Pivot joints: with longitudinal axis. Example: median Atlanto-axial joint. 3. Bi-axial joints:  Allow four movements around two axes.  Ellipsoid joint: an oval convexity is introduced into elliptical concavity. Example: Radio-carpal joint.  Saddle joint: concavo-convex opposing surfaces of saddle shape. Example: carpo-metacarpal joint of thumb. 4. Multi-axial joints:  Allow free movement.  Ball & socket joints. Examples: hip & shoulder joints. 14  OVERVIEW ON LOWER LIMB BONES Pelvic (Hip) bone  Each coxal (hip) bone consists of three bones that fuse together: ilium, pubis and ischium.  Three bones are fused by tri-radiate cartilage by the age of 15 years.  The two hip bones are joined anteriorly by the pubic symphysis and joined posteriorly by the sacrum forming the sacroiliac joints. Acetabulum:  It is a deep socket for articulation with the head of the femur making the hip joint.  Margins of the acetabulum are attached by a rim of fibrocartilage known as (Labrum Acetabulare).  The margin is deficient inferior to form the Acetabular notch, which is closed by (Transverse Acetabular ligament).  The floor of acetabulum has a horse shoe articular surface known as (Lunate surface). Ileum:  It has two surfaces: o Lateral (gluteal) surface: with three gluteal lines: posterior, anterior & 20  inferior gluteal lines. o Medial (pelvic) surface: forms the lateral wall of the greater (false) pelvic cavity.  It has three borders: o Upper border (Iliac crest): it has an outer lip, inner lip & intermediate area. o Anterior border: between anterior superior & anterior inferior iliac spines. o Posterior border: between posterior superior & posterior inferior iliac spines. Pubis: formed of:  Body of the pubis that articulates with the pubis of the opposite side forming symphysis pubis.  Superior pubic ramus: that joins the ileum at Ilio-pubic eminence.  Inferior pubic ramus: that joins the ischial ramus to form the side of the pubic arch. Ischium: formed of:  Body of ischium is the posterior part and formed of: o Ischial tuberosity: the lower supporting part formed of upper quadrangular part & lower triangular part. o Ischial spine: above the ischial tuberosity.  Ischial ramus: that fused with the inferior pubic ramus by the age of 8 years forming the side of the pubic arch. Sciatic notches:  Present on the posterior border of the ischium and ileum.  They are Greater sciatic notch (above) & Lesser sciatic notch (below), separated by ischial spine.  They allow passage of neuro-vascular structures from the pelvic cavity to the gluteal region and perineum. Obturator foramen:  The obturator foramen lies inferior to the acetabulum of the pelvis and is an opening between the ischium and pubic bones.  It is covered almost entirely by the obturator membrane.  A small gap is left between the superior margin of the obturator membrane and the pelvic bone above, known as the obturator canal, which allows a few vessels and nerves to pass out from the pelvic cavity to communicate with the lower limb. Femur It is the longest, the heaviest, and the strongest bone in the body. The upper end:  It is formed of head, neck and two trochanters (Greater & Lesser).  The head; composes two-thirds of a sphere, it articulates with the lunate surface of the acetabulum of the pelvic bone & it has a small groove, or fovea at which the round ligament (ligamentum teres) attach.  The neck of femur that makes about 125 degrees with the line of the shaft. 21   The greater trochanter which is directed laterally.  The lesser trochanter which is directed posterior medially, and is the site of insertion of iliopsoas muscle.  Anterior, the two trochanters are connected by the inter-tochanteric line.  Posterior, the two trochanters are connected by an inter-trochanteric crest with the quadrate tubercle at its middle. The lower end:  It has the medial and lateral condyles and the inter-condylar notch.  Femoral condyles articulate with the condyles of the tibia & back of Patella forming the knee joint. Body (shaft):  It is long, slender and almost cylindrical in form.  The back of the upper 1/3 has a prominent longitudinal lateral rough area known as Gluteal tuberosity & medial S- shaped line which is known as Spiral line.  The back of the middle 1/3 has the linea aspera which is a rough prominent vertical line.  The lower 1/3 has a triangular posterior surface which is known as the popliteal surface of the femur & bounded by medial and lateral supra- condylar lines. 22 Patella - The largest sesamoid bone in the body, roughly triangular in shape, with its apex facing downwards. - Its base is the site of insertion of the quadriceps femoris & its apex is attached by the patellar ligament to the tibial tuberosity. - It articulate with femur to forms the patello-femoral joint (part of knee joint). Tibia It is the larger, medial weight-bearing bone of the leg. The upper end:  It is widened by the medial and lateral tibial condyles. Condyles form a flat surface, known as the tibial plateau.  Between the condyles is the intercondylar eminence for attchement of the cruciate ligament.  Tibial tuberosity is situated at the anterior part of the upper end of the tibia below the tibial condyles. It is the site for insertion of the ligamnetum patellae of quadriceps. The lower end:  Medial malleolus: is a bony prominence located medially.  Fibular notch: is facing laterally, for inferior tibio-fibular joint (Fibrous joint – Syndesmosis). The shaft: is triangular, has 3 borders and 3 surfaces:  Medial surface: is subcutaneous throughout its length. Its upper most part gives insertion for 3 Guy rope muscles: o Sartorius. o Gracilis. o Semi-tendinosus.  Lateral surface: gives of origin of the Tibialis anterior muscle from its upper 2/3.  Posterior surface: it has an oblique Soleal line at its upper 1/2 that extends downward, medially. Fibula  The smaller, non-weight bearing and laterally placed bone of the leg.  The interosseous membrane connecting the fibula to the tibia. 23   The upper end is formed of head & neck of the fibula.  The head is the site for insertion of the Biceps Femoris muscle & makes an articulation with inferior lateral part of the lateral condyle of tibia (Superior tibio-fibular joint; Synovial, plane variety.  The lateral side of the neck of fibula is in a direct contact with lower end of the Common Peroneal nerve. A common site of the nerve injury.  The lower end has a bony prominence called: Lateral malleolus.  The lower end articulates with the fibular notch of the tibia making the inferior tibio-fibular joint: Fibrous joint, syndesmosis. Skeleton of the Foot Tarsal bones: - 7 tarsal bones - talus (articulates with tibia and fibula), calcaneus (heel bone, largest and strongest), navicular, cuboid and 3 cuneiforms Metatarsal bones: 5 long bones (one for each toe). Phalanges: ALL toes have 3 phalanges (proximal, middle, and distal) EXCEPT hallux (has 2 ONLY; proximal and distal). ARCHES OF THE FOOT Function of the arches of the foot: 1. It distributes the body weight. 2. Give foot elasticity during movement. 3. Absorption of shocks falling on the foot. 4. Adaptation to irregular surfaces. 5. Protection of the nerves and vessels of foot. A) Medial longitudinal arch: Bones form it: calcaneus, navicular, the 3 cuneiforms and the medial 3 metatarsals. Factors maintain medial longitudinal arch: 1- Bony factors: the shape of the articulating bones forms an arch. 2- Ligaments:  Spring ligament (Planter calcaneo-navicular), which supports the head of the talus.  Plantar aponeurosis. 3-Muscles: Flexor hallucis longus, Flexor digitorum longus & tibialis posterior. B) Lateral longitudinal arch: Bones form it: calcaneus, cuboid and the 4thand 5thmetatarsals. Factors maintain lateral longitudinal arch: 1- Bony factors: as medial longitudinal arch. 2- Ligaments:  Short plantar ligament (Planter calcaneo-cuboid). 24   Plantar aponeurosis. 3-Muscles: peroneus longus & peroneus brevis. C) Transverse arch: Bones form it: three cuneiforms & cuboid bones. Factors maintain lateral longitudinal arch: 1- Bony factors: due to wedge-shaped of intermediate and lateral cuneiform bones. 2- Ligaments: plantar inter-osseous ligaments. 3-Muscles: peroneus longus, tibialis posterior. JOINTS OF THE LOWER LIMB Hip joint Type: synovial – ball & socket variety. Articular parts: between the head of the femur & lunate surface of acetabulum of the hip bone. The capsule  It is attached to the inter-trochanteric line of femur & reflected on the neck of femur forming retinacula which carry blood supply to femur neck.  It is formed mainly of longitudinal fibers with deep circular fibrous band known as Zona Orbicularis.  The longitudinal fibers are reflected on the neck of the femur making Retincula that carry blood supply to the neck and head of femur. Joint cavity: contains a ring of fibro-cartilage, called labrum acetabualre which is attached to the margins of acetabulum. Ligamnets: 1. Ilio-femoral ligament: (inverted Y- shaped) between anterior inferior iliac spine of hip bone & inter-trochanteric line of femur. It is the strongest ligament in the body. 2. Pubo-femoral ligament: between ilio-pubic eminence of hip bone & inter-trochanteric line of femur. 25  3. Ischio-femoral ligament: ischeum & joint capsule. 4. Round ligament of head of femur: attached to the fovea of head of femur. It carries acetabular branches of obturator & medial circumflex femoral arteries for supplying the head of femur. Stability: is high, due to: – Strong ligaments. – Deep acetabulum. Movement: – Flexion: ilio-psoas, pectineus & rectus femoris muscles. – Extension: Gluteus maximus & Hamstring muscles. – Abduction: Gluteus medius & Gluteus minimus muscles. – Adduction: adductor longus, brevis magnus & gracilis muscles. – Medial rotation: anterior fibers of Gluteus medius, Gluteus minimus & tensor fasciae latae. – Lateral rotation: Piriformis, Obturator internus, Obturator externus, Gemelli & Quadratus femoris muscles. Knee joint Type: synovial – modified hinge variety. Articular parts: between the femoral condyles with patella (plane joint) & femoral condyles with tibial condyles (modified hinge). Joint cavity: containing two lunar fibro-cartilagenous discs; medial meniscus (C-shaped) which is fixed & lateral meniscus (0-shaped). The lateral meniscus is attached to the tendon of popliteus i.e. mobile cartilage. Ligaments: – Ligamentum patellae: support the joint anteriorly. – Tibial collateral ligament: between the medial epicondyle of the femur & medial condyle of tibia. – Fibular collateral ligament: between the lateral epicondyle of the femur & head of fibula. – Cruciate ligament: (intra-articular): Anterior cruciate (ACL): between the anterior part of inter- condylar area of tibia to the lateral femoral condyle. Posterior cruciate (PCL): between the posterior part of inter-condylar area of tibia to the medial femoral condyle. 26  Movements: – Flexion: Hamstring muscles & Popliteus. – Extension: Quadriceps muscle. – Medial rotation of leg: Popliteus, Semitendinosus & Semimembranosus. – Lateral rotation of leg: Biceps femoris. – Knee locking: in full knee extension by lateral rotation of leg (Biceps femoris action). – Knee unlocking: in starting of flexion of fully extended knee by medial rotation of the leg (Popliteus action). Ankle joint Type: synovial –hinge variety. Articular parts: lower end of tibia, inner surface of medial malleolus & inner surface of lateral malleolus of fibula with the trochlear surface of talus. Ligamnets: – Medial ligament of ankle (Deltoid): between the tip of medial malleolus with talus, navicular & calcaneus bones. – Lateral ligament of ankle: between the tip of lateral malleolus with talus & calcaneus bones. Movements: – Dorsiflexion: Tibialis anterior & long extensor of toes. – Planter flexion: Calf muscles, Tibialis posterior & long flexors of toes. Tibiofibular joints: Superior T/F joint: – Type: synovial –plane variety. – Articular parts: side of head of fibula with fibular facet on the back of lateral condyle of tibia. – Ligaments: anterior & posterior tibio-fibular ligaments. Inferior T/F joint: – Type: fibrous (SYNDESMOSIS). 27  – Articular parts: lower end of fibula & fibular notch of tibia. – Ligaments: anterior, inter-osseous & posterior tibio-fibular ligaments. Inerosseous membrane: – Fibrous membrane between tibia & fibula. Its fibers arranged downward laterally. – The membrane is perforated by the anterior tibial artery at its upper border. No Movement is allowed MUSCLES OF LOWER LIMB MUSCLES OF THIGH The muscles of the anterior compartment include: Muscle Origin Insertion Action 1. Sartorius From the Upper part of - Flexion and anterior superior medial side of lateral rotation iliac spine. the shaft of the of the thigh. tibia. - Flexion and medial rotation of leg. 2. Rectus 1. Straight head: Tendons of the Knee Quadricep femoris from the anterior 4 are inserted extension. s Femoris inferior iliac to the base of muscle spine. the patella, the 2. Reflected patellar tendon, head: from a extends from groove above the the patellar acetabulum. apex to the tibial Vastus Intertrochanteric tuberosity. medialis line, spiral line & medial lip of the linea aspera. Vastus Root of the lateralis greater trochanter, lateral lip of gluteal tuberosity & lateral lip of the linea aspera. Vastus Anterior and intermediu lateral surfaces 28 Action of posterior femoral muscles 1- Flexion of the knee joint. 2- They extend the hip joint, pulling the trunk upright from a stooping posture. MUSCLES OF GLUTEAL REGION: Muscle Origin Insertion Action Gluteus Maximus - From back of - Superficial ¾: to - It is the main ilium behind the the ilio-tibial tract. extensor of hip posterior gluteal - Deep ¼: to gluteal joint. line. tuberosity of - Lateral rotation of - Back of the femur. the thigh. sacrum and coccyx. - Back of sacro- tuberous ligament. Gluteus Medius Lateral surface of Lateral surface of - Abduction of ilium between iliac greater trochanter. thigh. crest, anterior and - Medial rotation of posterior gluteal thigh. lines. Gluteus Minimus Lateral surface of Anterior surface of As gluteus medius. the ilium between greater trochanter. the anterior and inferior gluteal lines. Tensor fasciae Arises from the Anterior border of Tension of ilio-tibial latae anterior 5 cm of the ilio-tibial tract. tract. outer lip of the iliac crest. 31 Nerve supply of glutei muscles: - Gluteus maximus is innervated by the Inferior Gluteal Nerve. - Gluteus medius, minimus& tensor fascia lata: by Superior Gluteal Nerve. - Trendlenburg gait is due to weakness or paralysis of Gluteus medius & minimus. The weakness of these muscles causes drooping of the pelvis to the contralateral side while walking. Lateral rotators of the thigh: Muscle Origin Insertion Nerve supply Piriformis Anterior surface Top of the Branches from of middle 3 greater L5, S1 and S2. sacral pieces. trochanter of femur. Obturator Internal surface Medial surface of N. to obturator internus of obturator greater internus. foramen. trochanter. Obturator External surface Trochanteric Obturator nerve externus of obturator fossa of femur. membrane. Gemellus Upper boundary Medial surface of nerve to superior of lesser sciatic greater obturator notch. trochanter internus Gemellus inferior Lower boundary Medial surface of nerve to of lesser sciatic greater quadrates notch. trochanter. femoris Quadratus Upper part of Quadrate Nerve to femoris external aspect tubercle of quadrates of ischial femur. femoris. tuberosity. 32