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- transverse (axial) plane
- used for CAT Scans/MRIs (radiological imaging)
- rule is you're standing at a person's feet & looking up toward their head
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Afferent
conducting a nerve impulse FROM the periphery TOWARD the CNS (periphery → CNS)
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Efferent
conducting a nerve impulse away from the CNS toward a target muscle (CNS → periphery)
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Flexion
bending or making a decreasing angle between bones or body parts such that 2 ventral surfaces are brought closer together
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Extension
- bending or making an INCREASING angle between 2 ventral surfaces
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Abduction
- movement away from the median plane
- (when a child is ABDUCTED he/she is taken AWAY)
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Adduction
- movement toward the median plane
- (when you ADD something you are putting it TOGETHER)
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Ankle/Foot Movement
- Inversion ~ "sickling"
- Eversion ~ "winging"
- Dorsiflexion (extension): "when you flex your foot"
- Plantarflexion: "when you point your foot"
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During a movement, which part of the muscle moves least & which part moves most?
- muscle origin: moves least
- muscle insertion: moves most (where muscle progresses into tendon & connects to a bone) & causes most of the action during contraction
- movement = muscle contraction
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What are the 2 major functions of the lower limb?
- 1. weight bearing (& balance)
- 2. locomotion
- must be mobile around 3 joints & achieve stability as a bipedal organism
- lower limb is divided into 4 regions separated by joints: 1. hip, 2. thigh, 3. leg (tibia/fibula/calf/shin region), & 4. foot
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Locomotion: The Gait Cycle
- consists of alternating cycles of stance (foot is completely or partially on the ground) & swing (foot is off the ground) phases
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Bony Pelvis
consists of 2 paired (L & R) hip bones + the sacrum
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Hip Bones
- comprised of the Ilium, Pubis, & Ischium (among others)
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Ilium
- contains iliac crest [what you can feel as "hip bones"]
- + the ASIS & AIIS (anterior superior/inferior iliac spine)
- + the PSIS & PIIS (posterior superior/inferior iliac spine)
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Anterior Inferior Iliac Spine (AIIS)
- on the ilium anterior but inferior to the ASIS
- where the rectus femoris muscle attaches (one of the quadriceps muscles)
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Pubis
- consists of superior ramus & inferior ramus (ramus means branch)
- + the pubic tubercle
- both pubis' are fused by the pubic symphysis, a bar of cartilage that units the 2 pubic bones in midline
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- Inguinal Ligament
- runs from the Anterior Superior Iliac Spine (ASIS) on the ilium to the pubic tubercle on the pubis
- serves as a passageway for soft tissues as they course anteriorly from the lower abdomen (trunk) to the thigh region (lower extremity)
- it demarcates the superior border of the femoral triangle
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Ligament
structure that connects 2 or more bones
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Aponeurosis of the External Oblique
- flat tendanous sheet over the abdominal muscles
- its lower edge forms the inguinal ligament (folds underneath itself - forms a kind of trough)
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Ischium
- posterior part of the pelvis
- rounded protuberance = ischial tuberosity ["sits bones" - what you feel when sitting]
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Acetabulum
- a depression where the 3 hip bones (ilium, pubis, ischium) merge to form the socket of hip joint where the head of the femur (ball) sits
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Obturator Foramen
- cavity formed by the fusion of the inferior ramus of the pubis & the ramus of the ischium
- opening is for the obturator nerve to pass through (supplies muscles in the medial part of the thigh)
- is covered over by a layer of fascia
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Condyles
- knuckle-like processes on the distal end of the femur
- medial & lateral
- articulate w/ the upper surface of the tibia (plateaus) to form part of the knee joint
- patella fits between the medial & lateral condyles
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Epicondyles
- ridges on the top of the knuckle-like process on the distal end of the femur ABOVE the condyles
- epi means above
- medial & lateral
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Linea Aspera
- ridge that runs length-wise along the posterior portion of the shaft of the femur
- where medial adductor muscles in the medial part of the thigh that originate on the pelvis INSERT (when they contract they can pull the femur toward the midline)
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Greater & Lesser Trochanter
- lesser: where the psoas major muscle attaches
greater: lots of muscle tendons attach (gluteus medius, gluteus maximus, bursas, obturator externus/internus, & superior/inferior gemellus muscles)
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Intertrochanteric Line (spiral line of the femur)
- a line located on the anterior side of the proximal end of the femur that stretches between the lesser trochanter & the greater trochanter forming the base of the neck of the femur
- iliofemoral ligament attaches above the line
- the lower half gives origin to the upper part of the Vastus medialis
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Intertrochanteric Crest & Line
posteriorly marks the transition between the femoral neck & shaft
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Tibia & Fibula
- the tibia is more medial & bears weight, while the fibula ("pin-like") is lateral & doesn't bear any weight
- both bones flare out near the ankle joint into a malleolus (lateral on the fibula, medial on the tibia)
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arrow on the right points to the Tibial Tuberosity, a bony prominence where the patellar ligament attaches (a continuation of the quadriceps muscle in the thigh)
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Fascia Lata
the deep fascia of the thigh - forms a "stocking" around all the muscles in the thigh
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Great Saphenous Vein
- a long, slender vein that exists superficial to fascia lata
- & runs from dorsal surface of foot up the medial side of leg, behind knee, & up medial inner thigh
- is a superficial vein that drains blood from the skin/other superficial tissues in the lower limb
- has tributaries that extend over much of the thigh
- will pierce through the fascia lata & join a deeper vein, the femoral vein (through a perforating vein), which returns to the inferior vena cava
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Saphenous Opening
- an oval opening in the superomedial part of the fascia lata of the thigh that transmits the great saphenous vein & other smaller vessels (eg. superficial epigastric artery, superficial external pudendal artery) + the femoral branch of the genitofemoral nerve
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Small Saphenous Vein
starts on the lateral side of the foot, runs up the back of the leg, then pierces the fascia lata behind the knee
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Saphenous Cutdown
- can locate the vein anterior to medial malleolus & insert into it a catheter to inject possibly large amounts of drug or fluid into the venous system
- great saphenous vein is also used during the repair of coronary arteries
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Varicose Veins
- enlarged tributaries of the great & small saphenous veins that arise when valves in the perforating veins become incompetent
- this leads to retrograde venous blood flow into the superficial veins
- may be associated w/ venous stasis ulcers, fungal & bacterial infections, phlebitis (inflammation of the veins), or deep venous thrombosis
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Inguinal Region (Groin Region)
region below the inguinal ligament in the upper part of the thigh
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Superficial Inguinal Lymph Nodes
- consist of the superolateral, superomedial, & vertical lymph nodes that lie in the inguinal region
- drain lymph from the superficial skin & subcutaneous tissues BELOW the umbilicus (belly button)
- can be visualized using a lymphangiogram (dye is injected & picked up by lymphatic channels)
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Deep (Investing) Fascia
a fascia (layer of fibrous connective tissue) which can surround individual muscles & also divide groups of muscles into compartments
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Concept of Compartments
- muscles in the extremities (upper & lower limbs) are packaged into compartments
- within a compartment there is 1 major artery & 1 major nerve
- the contents of 1 compartment are contained in a tough connective tissue called the deep fascia
- muscles in a compartment all perform a similar function
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Posterior Compartment
- contain the hamstring muscles - can extend (straighten) the thigh at the hip & flex the leg at the knee
- muscles cross both the hip joint & the knee joint posteriorly
- muscles here are supplied by the tibial division of the sciatic nerve
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Muscles that will Flex the Thigh at the Hip
- need to look inside the abdomen at those muscles
- psoas, iliacus, & iliopsoas muscle
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- Psoas Major Muscle
- originates off lumbar vertebrae, merges with the iliacus muscle, & ends in a tendinous attachment to the lesser trochanter (femur)
- contributes to flexion & external rotation in the hip joint
- forms part of a group of muscles called the hip flexors, whose action is primarily to lift the upper leg towards the body when the body is fixed or to pull the body towards the leg when the leg is fixed
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- Iliacus Muscle
- fills the iliac fossa
- merges with the psoas muscle & ends in the iliopsoas tendon which inserts at the lesser trochanter
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- Iliopsoas Muscle
- contraction pulls on the femur & elevates it into a flexor position
- the main flexor muscle of thigh at the hip
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- Pectineus Muscle
- more medial muscle that helps the iliopsoas to flex & adduct the thigh (muscle fibers are oriented medial → lateral)
- originates at the pubis & inserts below the lesser trochanter
- one of the adductor muscles
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Anterior Compartment
- mainly flexors of the thigh at the hip or muscles (like our quadriceps) that extend the muscle at the knee joint
- all supplied by the femoral nerve or its branches
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Quadriceps Muscle
- has 4 portions that combine to form a common quadriceps tendon: Rectus Femoris, Vastus Intermedius, Vastus Lateralis, & Vastus Medialis
- the vasti originate off the femur - they DON'T cross the hip joint itself
- the rectus femoris originates on the AIIS → anteriorly cross the hip joint → joins the other 3 parts of the quadriceps to form the common quadriceps tendon
- when they contract they pull on the leg & bring it into an extention (main extenders of the leg at the knee joint*)
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Femoral Nerve
supplies the 4 muscles of the quadriceps
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Quadriceps Tendon
attaches to the patella → is extended across the knee joint space → inserts on the tibial tuberosity
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- Sartorius Muscle ("like a tailor")
- starts on anterior superior iliac spine (ASIS) → runs medially & inferior → goes behind the knee a little → inserts on the upper part of the tibia (crosses both the hip & knee joint)
- can help 1) flex the thigh at the hip joint (b/c it crosses the joint anteriorly) 2) abduct the thigh 3) flex the leg at the knee joint (b/c it crosses behind the knee joint)
- supplied by a branch of the femoral nerve
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What can weakness in one part of the quadriceps muscle lead?
quadriceps imbalance, when the patella is pulled in abnormal directions due to one muscle being weak & its opposite being normal → patella can rub against condyle of the femur → knee pain
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Iliotibial Tract
- a thickened layer of fascia lata that surrounds the thigh & has contributions from the tensor fascia lata (originates at the iliac crest) & the gluteus maximus
- it crosses at the knee joint laterally & inserts at the upper tibia
- braces the knee when standing straight so we don't have to use a lot of muscle to keep upright
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Femoral Triangle
- passing through the triangle is the femoral Nerve, femoral Artery, & femoral Vein
- (in that order, lateral → medial, can use mnemonic NAVeL)
- boundaries are formed by the sartorius, adductor longus, & inguinal ligament
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Femoral Sheath
- a layer of fascia that encloses the femoral artery, vein, & the inguinal lymphatics as they pass from the lower part of the abdomen into the upper part of the thigh through the femoral triangle
- fascia is derived from that covering the abdomen & the sheath passes over the iliopsoas muscle
- it's at the femoral triangle where the great saphenous vein penetrates through the femoral sheath & joins the femoral vein
- the femoral nerve is NOT contained by femoral sheath - has its own fascia
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