Lower Extremity Anatomy PDF

Lower limb (Lower Extremities) Distal Lower Limb FOOT The bones of the foot are fundamentally similar to the bones of the hand and wrist. The 26 bones of one foot are divided into three groups as follows: 1. Phalanges (toes or digits) 14 2. Metatarsals (instep)...

Lower limb (Lower Extremities) Distal Lower Limb FOOT The bones of the foot are fundamentally similar to the bones of the hand and wrist. The 26 bones of one foot are divided into three groups as follows: 1. Phalanges (toes or digits) 14 2. Metatarsals (instep) 5 3. Tarsals 7 Total 26 #RadtechKnows  PHALANGES—TOES (DIGITS) The large toe or first digit : has only two phalanges (similar to the thumb) : the proximal phalanx and the distal phalanx. 2nd, 3rd, 4th,5th middle phalanx, in addition to a proximal phalanx and a distal phalanx  Metatarsal bones. Consist of three parts Head, Body, Base Fifth metatarsal common trauma site for the foot  Joints of Phalanges (Digits) and Metatarsals Joints of digits the first digit has interphalangeal (IP) joint distal interphalangeal (DIP) joint. proximal interphalangeal (PIP) joint.  Joints of metatarsals metatarsophalangeal (MTP) joint and each of the joints at the base of the metatarsal is a tarsometatarsal (TMT) joint.  Sesamoid bones found in the feet and hands extra bones which are embedded in certain tendons. TARSALS The seven large bones of the proximal foot are called tarsal bones. The names of the tarsals can be remembered with the aid of a mnemonic: Come to Colorado (the) next 3 Christmases. (1) Come Calcaneus (os calcis) (2) To Talus (astragalus) (3) Colorado Cuboid (4) Next Navicular (scaphoid) (5, 6, 7) 3 Christmases First, second, and third cuneiforms #RadtechKnows  CALCANEUS. largest and strongest bone of the foot Articulations anteriorly with the cuboid superiorly with the talus The superior articulation with the talus forms the important subtalar (talocalcaneal) joint The larger posterior articular facet Smaller anterior and middle articular facets  THE TALUS The second largest tarsal bone Located between the lower leg and the calcaneus. Function: weight of the body is transmitted by this bone through the important ankle and talocalcaneal joints. ARTICULATIONS The talus articulates with four bones: superiorly with the tibia and fibula, inferiorly with the calcaneus and anteriorly with the navicular.  NAVICULAR Articulations The navicular articulates with four bones: posteriorly with the talus and anteriorly with the three cuneiforms.  CUNEIFORMS three cuneiforms (meaning “wedge-shaped) First cuneiform (medial ) The largest cuneiform articulates with the first metatarsal Second cuneiform ( intermediate ) smallest of the cuneiforms Articulates with the second metatarsal Third cuneiform (lateral ) articulates with the third metatarsal distally and with the cuboid laterally All the three cuneiforms articulate with the navicular proximally  Articulations Medial cuneiform articulates with four bones : navicular proximally the first and second metatarsals distally the intermediate cuneiform laterally Intermediate cuneiform also articulates with four bones navicular proximally the second metatarsal distally medial and lateral cuneiforms on each side Lateral cuneiform articulates with six bones: Navicular proximally the second, third, and fourth metatarsals distally the intermediate cuneiform medially cuboid laterally.  cuboid lateral aspect of the foot, distal to the calcaneus and proximal to the fourth and fifth metatarsals. SUMMARY OF TARSALS AND ARTICULATING BONES 1. Calcaneus (2) 5. Intermediate Cuneiform (4) Cuboid Navicular Talus Second metatarsal 2. Talus (4) Medial and lateral cuneiforms Tibia and fibula 6. Lateral Cuneiform (6) Calcaneus Navicular Navicular Second, third, and fourth 3. Navicular (4) metatarsals Talus Intermediate cuneiform Three cuneiforms Cuboid 4. Medial Cuneiform (4) 7. Cuboid (4) Navicular Calcaneus First and second metatarsals Lateral cuneiform Intermediate cuneiform Fourth and fifth metatarsals #RadtechKnows  Ankle joint Formed by three bones: tibia, fibula, talus A 15° internally rotated AP oblique projection, called the mortise position #RadtechKnows LEG—TIBIA AND FIBULA  TIBIA one of the larger bones of the body the weightbearing bone of the lower leg. can be felt easily through the skin in the anteromedial part of the leg. made up of three parts: the central body (shaft) and two extremities #RadtechKnows  Fibula The smaller fibula is located laterally and posteriorly to the larger tibia. Articulation : tibia proximally and the tibia and talus distally. #RadtechKnows #RadtechKnows #RadtechKnows  MIDFEMUR AND DISTAL FEMUR—ANTERIOR VIEW The patella largest sesamoid bone in the body located anteriorly to the distal femur most distal part of the patella is superior or proximal to the actual knee joint by approximately ½ inch (1.25 cm) in this position with the lower leg fully extended. #RadtechKnows  The patellar surface sometimes is referred to as the intercondylar sulcus. (Sulcus means a groove or depression.) Some literature also refers to this depression as the trochlear groove. shallow, triangular depression at the distal portion of the anterior femur that extends up under the lower part of the patella #RadtechKnows  MIDFEMUR AND DISTAL FEMUR—POSTERIOR VIEW The rounded distal portions of the medial and lateral condyles contain smooth articular surfaces for articulation with the tibia. The medial condyle extends lower or more distally than the lateral condyle when the femoral shaft is vertical, This explains why the CR must be angled 5° to 7° cephalad for a lateral knee to cause the two condyles to be directly superimposed when the femur is parallel to the IR. #RadtechKnows #RadtechKnows Patella Patella (kneecap) flat triangular bone about 2 inches (5 cm) in diameter. its pointed apex is located along the inferior border, and its base is the superior or upper border. patella articulates only with the femur, not with the tibia. The outer or anterior surface is convex and rough, and the inner or posterior surface is smooth and oval-shaped for articulation with the femur. #RadtechKnows #RadtechKnows  SUMMARY OF FOOT, ANKLE, LEG, AND KNEE JOINTS ALL JOINTS OF LOWER LIMB EXCEPT DISTAL TIBIOFIBULAR Classification: Synovial (articular capsule containing synovial fluid) Mobility Type: Diarthrodial (freely movable) Movement Types: #RadtechKnows  DISTAL TIBIOFIBULAR Classification: Fibrous Mobility Type: Amphiarthrodial (slightly movable) of syndesmosis type #RadtechKnows Femur and Pelvic Girdle FEMUR Femur longest and strongest bone in the body. Entire weight of the body is transferred through this bone and the associated joints at each end. frequent source of pathology when trauma occurs #RadtechKnows Proximal Femur The proximal femur consists of four essential parts (1), the head (2) neck (3) and greater (4) and lesser trochanters #RadtechKnows  head of the femur rounded and smooth for articulation with the hip bones. It contains a depression, or pit, near its center called the fovea capitis. #RadtechKnows  neck of the femur trong pyramidal process of bone that connects the head with the body or shaft in the region of the trochanters. greater trochanter large prominence that is located superiorly and laterally to the femoral shaft and is palpable as a bony landmark. The lesser trochanter smaller, blunt, conical eminence that projects medially and posteriorly from the junction of the neck and shaft of the femur The trochanters are joined posteriorly by a thick ridge called the intertrochanteric crest. #RadtechKnows #RadtechKnows PELVIS Pelvis (meaning a basin) serves as the base of the trunk and forms the connection between the vertebral column and lower limbs. The pelvis consists of four bones two hip bones (ossa coxae, also called innominate bones) one sacrum and one coccyx #RadtechKnows  Pelvis versus pelvic girdle Pelvis Aka : pelvic girdle used in reference to the complete pelvis. This term, however, is incorrect in that the pelvic girdle consists only of the two hip (innominate) bones, whereas the term pelvis includes four bones, the right and left hip (innominate) bones, the sacrum, and the coccyx. NOTE: The sacrum and the coccyx also are considered parts of the distal vertebral column along with the lumbar spine. #RadtechKnows #RadtechKnows HIP BONE Each hip bone is composed of three divisions (1) ilium (2) ischium and (3) pubis In a child, these three divisions are separate bones, but they fuse into one bone during the middle teens. The fusion occurs in the area of the acetabulum. The acetabulum is a deep, cupshaped cavity that accepts the head of the femur to form the hip joint. #RadtechKnows Ilium Ilium composed of a body and an ala or wing largest of the three divisions Body of the ilium is the more inferior portion near the acetabulum and includes the superior two-fifths of the acetabulum. #RadtechKnows #RadtechKnows  The crest of the ilium is the superior margin of the ala: it extends from the anterior superior iliac spine (ASIS) to the posterior superior iliac spine (PSIS). In radiographic positioning, the uppermost peak of the crest often is referred to as the iliac crest, but it actually extends between the ASIS and the PSIS. #RadtechKnows  Below the ASIS is a less prominent projection referred to as the anterior inferior iliac spine. Similarly, inferior to the PSIS is the posterior inferior iliac spine. Positioning landmarks The two important positioning landmarks iliac crest and the ASIS. #RadtechKnows #RadtechKnows Ischium ISCHIUM part of the hip bone that lies inferior and posterior to the acetabulum. divided into a body and a ramus. superior portion of the body of the ischium makes up the posteroinferior two-fifths of the acetabulum The lower portion of the body of the ischium (formerly called the superior ramus) projects caudally and medially from the acetabulum ending at the ischial tuberosity #RadtechKnows  Projecting anteriorly from the ischial tuberosity is the ramus of the ischium The rounded roughened area near the junction of the lower body and the inferior rami is a landmark called the tuberosity of the ischium, or the ischial tuberosity. #RadtechKnows  Posterior to the acetabulum is a bony projection termed the ischial spine. Directly superior to the ischial spine is a deep notch termed the greater sciatic notch. Inferior to the ischial spine is a smaller notch termed the lesser sciatic notch. #RadtechKnows #RadtechKnows Pubis PUBIS/ PUBIC BONE last of the three divisions of one hip bone body of the pubis is anterior and inferior to the acetabulum and includes the anteroinferior one-fifth of the acetabulum. superior ramus Extending anteriorly and medially from the body of each pubis symphysis pubis / pubic symphysis two superior rami meet in the midline to form an amphiarthrodial joint #RadtechKnows  Each inferior ramus passes down and posterior from the symphysis pubis to join the ramus of the respective ischium. The obturator foramen large opening formed by the ramus and body of each ischium and by the pubis. largest foramen in the human skeletal system. #RadtechKnows #RadtechKnows SUMMARY OF TOPOGRAPHIC LANDMARKS Important positioning landmarks of the pelvis #RadtechKnows  LANDMARKS iliac crest and the ASIS are easily palpated. ASIS more frequently used positioning landmarks of the pelvis. commonly used to check for rotation of the pelvis and/or lower abdomen by determination of whether the distance between the ASIS and the tabletop is equal on both sides. #RadtechKnows  greater trochanter can be located by firm palpation of the soft tissues of the upper thigh. superior border at the level of symphesis pubis These distances vary between a male and a female pelvis because of general differences in shape #RadtechKnows  Male versus Female Pelvis FEMALE PELVIS MALE PELVIS Wider Narrow with the ilia more flared and more deeper, and less flared shallow from front to back. _____________________________ _________________________________ 1st difference 1st difference overall general shape of the entire overall general shape of the entire pelvis pelvis 2nd difference 2nd difference angle of the pubic arch angle of the pubic arch less than 90° In female, this angle is usually obtuse 3rd difference or greater than 90° shape of the inlet 3rd difference arrower and more oval or shape of the inlet heartshaped. larger and more round #RadtechKnows #RadtechKnows  SUMMARY OF MALE AND FEMALE PELVIC CHARAC TERISTICS Male Female 1. General shape Narrower, deeper, Wider, more shallow, less flared more flared 2. Angle of pubic arch Acute angle (90°) 3. Shape of inlet More oval or Rounder, larger heart-shaped #RadtechKnows Male Versus Female Pelvis Radiographs #RadtechKnows CLASSIFICATION OF JOINTS These joints of the pelvic girdle, as listed below, again are described according to their classification, mobility type, and movement type. Sacroiliac joints joints between the sacrum and each ilium Symphysis pubis structure between the right and left pubic bones Union of acetabulum temporary growth joint of each acetabulum that solidifies in the midteen years Hip joints joints between the head of the femur and the acetabulum of the pelvis #RadtechKnows  CALDWELL-MOLOY Anthropoid PelvisPelvic CLASSIFICATION OF PELVIS Brim is an anteroposterior Gynecoid Pelvis (50%) ellipse Pelvic brim is a transverse ellipse Gynecoid pelvis turned 90 (nearly a circle) Most favorable for delivery degrees Narrow ischial spines Android Pelvis (Male type) Much more common in black Pelvic brim is triangular women Convergent Side Walls (widest posteriorly) Prominent ischial spines Platypelloid Pelvis (3%) Narrow subpubic arch Pelvic brim is transverse More common in white women kidney shape Flattened gynecoid shape