END OF SEM ANATOMY MASTER REVISION CONTENTS: 1. KNEE & LEGS 2. ANKLE & FOOT 3. VERTEBRAL COLUMN 4. CERVICAL SPINE 5. THORACOLUMBAR SPINE & PELVIS 6. DIAPHRAGM, PELVIC FLOOR & ABDOMINALS KNEE KNEE JOINT COMPLEX TIBIOFEMORAL Joint (femoral condyles + tibial plateau) ❖ Hinge Joint = Predominantly Uniaxial (limited rotation) ❖ Great Stability in E w/ Screw Home Mechanism ❖ F/E along Sagittal Plane on Coronal Axis ❖ Mobility in F (allow foot clearance & optimal orientation of foot) ❖ Poor degree of interlocking joint surfaces (dependent on active & passive structures such as ligaments, menisci & muscles) ❖ Large Lever Arms (therefore, predisposed to injury due to long bones) ❖ Femoral Articular Surface > Tibial Articular Surface (due to differences in condyle size) *5o of HE is critically important for knee function *Can’t rotate tibia & fibula voluntarily *Recurvatum = hyperextension of kneecap Knee Alignment Q Angle (between axis of tibia & femur): Measured along ASIS Patella (centre)/ Tibial Tuberosity ❖ 14o = Men ❖ 17o = Women 5o Genu Valgus: Tibia is laterally inclined in relation to femur; medial fem condyle extends slightly more distally. Alignment of the femoral condyles on the transverse plane determine the orientation of the F/ E axis of Knee Mechanical Axis of Lower Limb = 2-3o Varus (tibial midline HOF) ❖ Shortens width of Base of Support to for better weight-bearing & gait Knee Tendon Attachment ❖ Semimembranosus Tendon attaches posteriorly to Tibial Medial Condyle, superior to Popliteus ❖ Sartorius, Gracilis & Semitendinosus (Medial Lateral) ❖ Oblique Popliteal Ligament blends in with Posterior Capsule Synovial Membrane ❖ Synovial surfaces surround all articular areas, capsule surrounds the entirety of joint ❖ An intracapsular extrasynovial space exists between menisci 1 ❖ Actively supported by: 1) Quad attachments 2) laterally by ITB 3) medially by Tibial Collateral Ligament 4) posteriorly reinforced by Oblique Popliteal ligament (restricts HE) 5) posterolaterally (pierced by popliteus) Tibial Meniscal Discs ❖ Circular fibrocartilage pieces that ↑ articular contact & congruency, ↓ compression stress & protect articular cartilage ❖ After total meniscectomy, contact areas ↓ ~75% & peak local contact stress ↑ ~235% ❖ Medial Menisci (MM) ↑ AP length w/ thicker posterior horn (as the primary coverage over tibial plateau, it bears a large portion of the articular stress). Thus, the Screw Home Mechanism IR to the MM during Knee E for ↑ weight-bearing ❖ LM are narrower, more mobile compared to MM which is anchored to TCL ‘SCREW HOME’ Mechanism ❖ Tibiofemoral Joint initiates ‘screw home’ mechanism by slightly rotates during a primary action to tighten its ligaments (especially ACL & PCL) for ↑ stability, a ↑ contact area w/ MM ❖ Flexion + LR ❖ Extension + MR ❖ Occurs @ 20oF – 0oE ❖ In terminal extension, this mechanism locks up the knee for greater stability, apart from tightening ligaments, ↑ interlocking between the joints ❖ If tibia is not fixed on the floor, it will LR for the screw home mechanism, if foot is fixed on the ground it will then femur will MR after posteriorly sliding ❖ Popliteus locks TFJ w/ femur IR, to unlock the extended leg it must ER femur during F Femoral/Tibial Gliding ❖ During movement, the kneecap has two directions of movement, sliding (AP) & rolling (of either the tibia or femur), both directions will not happen purely but in conjunction ❖ *ACL/PCL tightens during flexion or gliding, pulling femur back into a slide backwards or forwards ❖ For tibial extension, tibia will slide & roll anteriorly ❖ For femoral extension, it will slide backwards but still roll anteriorly ❖ To prevent excessive knee F, the ACL will tighten, forcing the femur into an anterior slide PATELLOFEMORAL Joint ❖ Patellar glides upon Patella Groove on the Femur ❖ ↑ Leverage of Quads by altering its LOA & ↑ distance from axis (thus moment arm). Net pull towards HOF (in a slightly valgus direction) ❖ Provides protection to the exposed cartilage of femoral condyles in Knee F ❖ Distributes forces & pressure placed on the femur ❖ ↓ Friction of Quads Tendon as it will rub upon the fem condyles w/o Patella ❖ Patella is most inclined to dislocate laterally even w/ the VMO’s medial pull resistance and the greater height of the lateral portion of the Patella Groove ❖ Patellectomy = ↓ Quads Moment Arm, ↓ Knee ROM, Anterior Instability & Loss of Trochlea Protection ❖ Patella glides distally permitted by the unfolding of the Suprapatellar Pouch Translations ❖ Glides distally on femur during Knee F 2 ❖ Glides medially during 0-30oF then lateral during 30-90oF Rotations ❖ Laterally tilts during flexion Contact Area ❖ w/ increasing knee flexion, the patella moves proximally to ↑ contact area Patella Bursae & Spaces Bursae Location Suprapatellar Above patellar, deep to the patellar tendon Subcutaneous Prepatellar Superficial to patellar Subcutaneous Infrapatellar Superficial to patellar tendon, below patellar Deep Infrapatellar Inferior to patellar, deep to patellar tendon Infrapatellar Fat Deep to Infrapatellar bursae Semimembranosus Behind femorotibial joint Subsartorial (pes anserinus) On medial side of the tibia ❖ Fat Pad separates Quads Tendon from Femur (↑ moment arm) ❖ Articular Genus pulls Suprapatellar Bursae back from being pinched during Knee E ❖ Bursae promotes frictionless Knee movement, but pain sensitive and susceptible to inflammation Knee Movement Range ❖ Motion Range o Gait: 60-70o o Stairs: >110o o Sitting: 93o o Shoe Tying: 106o ❖ Loading o Level Ground: 3x BW o Stairs: 4.25x BW Movement Range Flexion 140o Hyperextension 5o Accessory Movements AP Glide Medial/ Lateral Rotation Superior Tibiofibular Joint Medial/ Lateral (Transverse) Glide Arthrodial (Plane) Joint ABD/ADD 3 KNEE MUSCLE COMPLEMENT Action Muscles Extension Quads Flexion Hamstrings (weak contribution from gastro, soleus & sartorius) Internal Rotation Semitendinosus, Semimembranosus, Popliteus, Gracilis & Sartorius External Rotation Biceps Femoris & TFL *popliteus unlocks knee from screw mechanism as well as assisting the PCL w/ resisting anterior gliding Muscle Origin Insertion Innervation Function Anterior Compartment (Knee E) Rectus Femoris (deep Knee E AIIS to satorius) Hip F Medial Lip of Linea Vastus Medialis Aspera & Intertrochanteric Line Patellar via Femoral N (L2-4) Vastus Intermedius Anterior surface of Quadriceps Tendon Knee E (deep to RF) femur Greater Trochanter & Vastus Lateralis Lateral Lip of Linea Aspera Hip F, ADD & LR Sartorius ASIS Pes Anserinus Femoral N (L2-3) Knee MR Medial Compartment (Adduction) Adductor Longus Superior Ramus of (anterior) Pubis Linea Aspera Obturator N (L2-4) Adductor Brevis Pectineal Line & Inferior Hip ADD & F (superior) Pubic Ramus (Hip E only @ Inferior Ramus & 90oF) Adductor Magnus Linea Aspera & Obturator N (L2-4) Ischiopubic Ramus & (posterior, largest) Adductor Tubercle & Tibial N (L4) Ischial Tuberosity Inferior Pubic Ramus & Gracilis Pes Anserinus Obturator N (L2-3) Hip ADD Pubic Symphysis Pecten Pubis (like Femoral N (L2-3) & Pectineus Pectineal Line Hip ADD, F & MR superior pubic ramus) Obturator N (L3-4) Posterior Compartment (Knee Flexion) Long: Ischial Tuberosity Knee F & LR Biceps Femoris Head of Fibula & Hip E (long head *Long Head (left) Lateral Condyle of Short: Lateral Lip of only) *Short Head (right) Tibia Linea Aspera *Tibial ER Semitendinosus Tibial N (L5-S2) (lateral, more posterior Pes Anserinus Knee F & MR to semimembranosus) Ischial Tuberosity Hip E Medial Condyle of *Tibial IR Semimembranosus Tibia *posterior thigh muscles are biarticular (crosses two joints) KNEE LIGAMENT STRUCTURES Ligament Attachments Resists Anterior Tibial Head Posteriorly Posterolateral Band (PLB): largest, tightest in E Anterior Cruciate Ligament (ACL) below Lateral Menisci Anteromedial Band (AMB): tightens in F Posterior Cruciate Ligament Posterior Tibial Head > Anteriorly Anterior Gliding (during Tibial/ Femoral E) (PCL) below Medial Menisci Medial Femoral Condyle Midline of Superficial (longer): Valgus Force (throughout Tibial (medial) Collateral Ligament Medial Tibia F) (TCL) Medial Femoral Condyle Posterior Deep (shorter): Anterior Displacement of Tibia Edge of Medial Tibial Condyle Posterior Edge of Lateral Condyle Anterolateral Ligament (ALL) Tibial IR @ 30oF + Anterolateral Stability Lateral Head of Tibia Fibular (lateral) Collateral Ligament Posterior Edge of Lateral Condyle Varus Force (FCL) Head of Fibula 4 Posterior Tibiofibular Ligament (PTL) Inferior Posterior Tibia Fibula Stability of TFJ Lateral Femoral Epicondyle Medial Oblique Popliteal Ligament (OPL) Knee HE Tibial Condyle Anterior Gliding of Anterior Menisci Horns (as Connects Anterior Lateral & Medial Transverse Ligament they are somewhat mobile & being pinched by Menisci the femur OR tibia) Inferior edges of LM & MM Knee Coronary Ligaments Anchors Menisci @ four points onto the tibia Capsule Posterior Meniscofemoral Posterior Horn of LM Femur ??? *TCL tends to be part of capsule while the FCL is more prominently outside the capsule ANTERIOR CRUCIATE LIGAMENT ❖ Resists anterior translation of tibia on femur ❖ Resists posterior translation of femur on tibia ❖ ↑ rotation stability ❖ Resists valgus forces ❖ Tightens @ terminal E (but not main restraint) ❖ Tightens @ 10oIR & 30oER Injury ❖ Large valgus moment that creates excessive knee ABD & tibial ER ❖ Commonly caused by pivoting sports w/ females being 3-5x more likely to suffer from this injury ACL Deficiency Test: Lachman’s Test (done @ 15o knee F) & Anterior Drawer Test (@