Anatomy of the Lower Extremity in Computed Tomography Michael C. Ficorelli, RT

Lesson Description To explain the various exams pertaining to the lower extremity using computed tomography, incorporating cross sectional anatomy from images

Lesson Description To be able to identify anatomy of the lower extremity. Understand the clinical indications for exams of the abdomen. To understand the methods of patient scanning, positioning, and protocols. To understand indications for contrast.

CT of the Lower Extremity (Hip, Knee, Ankle, Foot)

Ankle and Foot Bony Anatomy 7 Tarsal Bones – Talus – responsible with the calcaneus for bearing weight; wedge shaped body with upper surface (trochlea) which articulates with Tibia and Fibula – Calcaneus – Largest tarsal, prominence of the heel, tuberosity which is insertion for ligaments and tendons (Achilles) Sustentaculum Tali – medial surface which supports the talus Sinus Tarsi – canal from articulation between talus and calcaneous – Navicular, Cuboid, Lateral Cuneiform, Intermediate Cuneiform, Medial Cuneiform 5 Metatarsals 14 phalanges – 3 for each toe except hallux (2) Distal Tibia – Medial malleoli Distal Fibula – Lateral malleoli

Ankle and Foot Anatomy Arches: – Longitudinal arch: Two parts – lateral and medial – Provides firm base for support – Transverse arch: Distal row of tarsals (Cuboid, 3 cuneiforms) and bases of metatarsals creating dome – major weight bearing arch Important: – Retinacula – sheaths of tendons around the ankle – Fascia – thickened area on plantar surface

Foot Anatomy

Ankle Joint

Knee Bony Anatomy Made up of: – Distal Femur – lateral and medial condyle and epicondyle Smooth anterior surface for articulation with the patella Posterior - intercondylar fossa Adductor tubercle – above medial epicondyle attachment for adductor magnus – Tibia – widened proximal end with medial and lateral condyles Tibial Plateau – widened medial and lateral surfaces for articulation with femur Intercondylar eminence (Tibial Spine) – between the plateaus with two peaks (tubercles) Tibial Tuberosity – site of attachment of patellar ligament anteriorly – Fibula – long thin bone Head – apex, sharp and superior with surface that articulates with the lateral condyle of the tibia

Knee Anatomy Patella – Largest sesamoid in the body – Flat triangular bone with base proximal and apex distal Joint – 2 separate articulations – Femorotibia and Patellofemoral – Capsule – strong, fibrous membrane reinforced by extracapsular ligaments Anteriorly blends with quadriceps tendon – Synovial membrane is largest synovial cavity of the body – Menisci – (2) found between femoral condyles, connective tissue Medial – attached to MCL, less mobile Lateral – closed ring – Ligaments – External and Internal External – MCL, Lateral Collateral, Patellar Internal – ACL, PCL

GROSS KNEE ANATOMY

KNEE ANATOMY

Ankle / Foot Protocol Lung nodules Cancer Vascular disease Effusion and infiltration Trauma Pulmonary Parenchymal diseases Hilar Masses ParametersSingle Slice4 SLICE16 SLICE PATIENT FEET FIRST. SUPINESAME SCANNING AREA DEPENDS ON WHAT PART SAME CONTRAST 100ML AT 1-2ML/SECSAME DETECTOR COLLI NA0.5MM16X0.75 DFOV 14-18SAME SLICE THICKNESS MMSAME ANGLE NONESAME TABLE FEED/ROT 3MMVARIES PITCH 1VARIES ROT TIME 1 -2 SEC0.75 SEC1.5SEC RECON STANDARD/BONESAME WINDOW 450W/30L— 2000W/200L SAME

Coronal Foot 1 – Calcanous 2 – Talus 3 – Navicular 4 – Medial Cuneiform 5 – Base of 1 st MT 6 – 2 nd MT 7 – 2 nd Prox Phalanx 8 – 2 nd Middle Phalanx 9 – 2 nd Distal Phalanx 10 – 5 th MTP Joint 11- Navicular

Coronal Foot 1 – Base of 5 th MT 2 – Cuboid 3 – Calcaneus 4 – Navicular 5 – Medial Cuneiform 6 – 1 st MT 7 – 1 st Prox Phalanyx 8 – 1 st Distal Phalanyx 9 – 2 nd Middle Phalanyx 10 – 4 th MT Head

AXIAL ANKLE Fibula 2- Tibia

AXIAL Lateral malleolus 2- Tallus 3- Medical malleolus

AXIAL Talus 2- CALCANUS 3- NAVICULAR

AXIAL CUNEIFORM BONES 2- CUBOID BONE

SAGITAL MPR TALUS 2- SINUS TARUS 3- CALCANEUS 4- CUBOID 5- CUNEIFORM 6- NAVICULAR

CORONAL MPR LATERAL MALLEOLUS 2- TALAR JOINT 3- MEDICAL MALLEOLUS 4- TALLUS 5- CALCANEOUS

CORONAL MPR 1 1- Calcaneous

BONE VS SOFT TISSUE BONESOFT TISSUE

KNEE 1 1- FEMUR

KNEE Medial condyle 2- Patella 3- Lateral condyle 4- intercondylar fossa

KNEE 1 1- Tibial Plataeu

KNEE Tibia 2- Head of fibula

CORONAL KNEE Intercondylar fossa 2- Tibial plateau 3- Condyle of femur

PROTOCOL FOR HIP AND BONY PELVIS Lung nodules Cancer Vascular disease Effusion and infiltration Trauma Pulmonary Parenchymal diseases Hilar Masses ParametersSingle Slice4 SLICE16 SLICE PATIENT FEET FIRST. SUPINESAME SCANNING AREA CREST TO PUBIS ABOVE JOINT TO BELOW LESSER TUBEROSITY SAME CONTRAST 100ML AT 30 SECOND DELAY SAME DETECTOR COLLI NA4 X 1MM16 X 0.75 DFOV DEPENDS ON PATIENT FOR PELVIS/ 20 CM FOR HIP SAME SLICE THICKNESS 5 MMSAME ANGLE NONESAME TABLE FEED/ROT 3-5 MMVARIES PITCH 1 OR 1.6VARIES ROT TIME 1- 2SEC0.75 SEC1 SEC RECON STANDARD/BONESAME WINDOW 450W/30L—1600W/600LSAME

HIPS Head of Femur 2- Acetabulum 3- Fovea Capitis 4- Pubic Bone 5- Ischium 1- Head of Femur 2- Acetabulum 3- Fovea Capitis 4- Pubic Bone 5- Ischium

HIPS 1- Pubic Ramus 2- Femoral Neck 3- Ischial Tuberosity 4- Greater Trochanter 1- Pubic Ramus 2- Femoral Neck 3- Ischial Tuberosity 4- Greater Trochanter

HIPS Symphysis Pubis 2- Lesser Trochanter 1- Symphysis Pubis 2- Lesser Trochanter

HIPS 1 1- Pubic Bone

HIP CORONAL MPR SYMPHYSIS PUBIS 2- PUBIC BONE 1- SYMPHYSIS PUBIS 2- PUBIC BONE

HIP CORONAL MPR Greater Trochanter 2- Acetabulum 3- Femoral Neck 4- Lesser Trochanter 1- Greater Trochanter 2- Acetabulum 3- Femoral Neck 4- Lesser Trochanter

BONY PELVIS 1- Sacrum 2- Ilium 3- S.I. Joint 1- Sacrum 2- Ilium 3- S.I. Joint 1 2 3