Sept 16 - Lower Extremity Flashcards
Name the functions of the lower extremity
Responsible for stability (posture) and locomotion
They work concentrically: jumping (hip extension), climbing stairs (hip extension), rising from sitting to standing (hip extension), skating (hip abduction/extension/lateral rotation).
Muscles of the lower limb have an anti-gravity function (they work eccentrically): descending stairs, lowering from a standing to sitting position
Name the 3 regions of the lower extremity and their extremities
Pelvic region (between iliac crest and gluteal fold) Thigh (between hip and knee) Lower leg (region below the knee)
Describe the pelvic girdle
Strong, stable, weight bearing joint
Bones firmly united to form a basin
Structured for bipedal movement (upright walking)
Bone form a complete ring that is virtually immovable
Comprised of three bones that fuse together
Where the upper body meets the lower body
Name the three bones of the pelvic girdle
Ilium
Ischium
Pubis
Describe the ilium
Large fan shaped bone that makes up the proximal portion of the innominate bone (hands on hips)
Protects the lower abdominal contents
Provides a surface area for attachment of large powerful muscles
Absorbs force
Describe the ishium
The bone that makes the posterior and inferior aspect of the innominate bone (what you sit on)
Describe the pubis
Makes up the anterior/inferior aspect of the innominate bone
What is innominate fusion? Why is it important?
The fusion of the three bones of the hips. It is best observed as “Y” shaped markings inside the socket of the hip joint (acetabulum). It’s important because it’s the socket and it’s comprised of sections of all three hip bones
What is the iliac crest?
Where you put your hands on your hips
what is the tuberosity of the ischium?
What you sit on
It’s the most prominent
What is the anterior iliac spine?
It’s where your hands fall off your hips
What is the importance of the obturator foramen?
It allows neurovascular structures to exit into the leg
What is the importance of the acetabulum?
It’s the socket for the ball and socket of the hip joint; it’s designed to move whereas the pelvis is designed to be stable
Name the three hip joints
The right sacroiliac joint
The left sacroiliac joint
The symphisis pubis
Describe the sacroiliac joint
The joint between the auricular surface of the ilium and the auricular surface of the sacrum. It is partly synovial (anterior) and partly fibrous (posterior)
Allows for some flexion/extension
What is the importance of the sacroiliac joint?
Important for walking and in full forward flexion
Name the three ligaments that support the SI joint
Sacroiliac ligaments (anterior/posterior)
Sacrospinous ligaments
Sacrotuberous ligament
What is the importance of the greater sciatic foramen?
The sciatic nerve is the largest nerve in the human body and it comes out the greater sciatic foramen
Describe the symphysis pubis
It is the point where the two pubic bodies joint anteriorly. It is joined by two very strong ligaments superiorly and inferiorly. It has a dense fibrocartilagenous disc in between which allows minimal movement. It softens and loosens in late pregnancy
Describe the hip joint
Best example of a ball and socket joint. Articulation between the head of the femur and the acetabulum of the innominate bone (about two-thirds of the femoral surface interact. It is one of the most secure joints, yet very mobile joints. It is a synovial multi-axial joint
Describe the acetabulum
It has an incomplete ring on the lateral surface of the innominate bone. It is closed in by the transverse acetabular ligament
Describe the acetabular fossa
Deepest part of the acetabulum. Does not articulate with the femur
Describe the lunate surface
Horseshoe shaped articular (hyaline) cartilage. Articulates with the head of the femur
Describe the importance of the acetabular labrum
Helps with shock absorption. Helps reinforce contact. Creates space for circulation of synovial fluid
What is the difference between a synovial joint and a fibro-cartilage joint?
A synovial joint provides movement, has fluid and a bag. A fibro-cartilage joint does not
Describe the hip capsule
Tight, strong and extensive. It extends from just beyond the outer edge of the acetabulum over femur to attach to level area around intertrochanteric line. It’s reinforced by 3 strong thick ligaments which all resist excessive abduction
Name the three ligaments of the hip capsule
Iliofemoral ligament
Ischiofemoral ligament
Pubofemoral ligament
Name the six hip movements
Hip extension/flexion
Hip abduction/adduction
Internal rotation/external rotation
What muscles are involved in hip extension. When do you use hip extension?
Primarily gluteus maximus, but also hamstrings adductor magnus. Hip extension is used for walking, stairs, skating, running
What muscles are involved in hip flexion. When do you use hip flexion?
Primarily ilio psoas and rectus femoris, but also TFL, pectineus and adductor longus & brevis. Hip flexion is used every time kick, climb stairs, run on spot
What muscles are involved in hip abduction?
Primarily gluteus medius and minimus, but also tensor fascia lata (TFL) and ilio tibial band (ITB)
What muscles are involved in hip adduction?
Pectineus, adductor magnus, gracilis and adductor longus & brevis
What muscles are involved in internal rotation of the hips? When do you use internal rotation?
Gluteus medius and minimus. When you bring your knees together and separate your ankles
What muscles are involved in external rotation of the hips? When do you use external rotation
Gluteus maximus and piriformis. When you cross your legs
Name the four muscles of the gluteal region
Gluteus maximus (most superficial) Gluteus medius (deep to gluteus maximus) Gluteus minimus (deep to gluteus medius) Piriformis (most deep)
Name the five “little brother” muscles that make up the piriformis
Obturator internus Obturator externus Superior gemelli Inferior gemelli Quadratus femoris
Describe the gluteus maximus. What are it’s functions?
Largest muscle of the gluteal region. It is a powerful hip extensor. It is also involved in lateral rotation of the extended hip and a composite motion (push-off in skating)
What nerve innervates the gluteus maximus?
The inferior gluteal nerve (L5-S2) (because of how far down the nerve it extends, it is not innervated by the superior gluteal nerve)
What are the function of the gluteus medius and minimus
Critical stabilizer of the pelvis during single leg support such as walking and running. Maintains horizontal pelvic alignment during single leg stance phase. Responsible for internal hip rotation and abduction of hip
What happens if the gluteus medius and minimus are unable to stabilize the pelvis?
It results in “waddling” or Trendenlenburg gait pattern
What nerve innervates the gluteus medius and minimus?
The superior gluteal nerve L4, L5 and S1
Describe the Trendenlenburg test
If someone stands on a single leg, the pelvis should remain parallel to the ground. Injury can cause the hip to fall during this test (indicator of pathologies, osteoarthritis or lack of mobility, as seen in obese people)
Describe the piriformis
Deep to gluteal muscles. It exits the pelvis to gluteal region via the greater sciatic foramen; the sciatic nerve is position just inferior to the piriformis muscle
What is the function of the piriformis?
Lateral hip rotation
What nerve innervates the piriformis?
Nerve to piriformis S1 and S2
Describe the iliopsoas
This muscle is 2 seperate muscles at its proximal end, the psoas major and iliacus, which join distally and have a common attachment on the femor. It attaches to the lesser trochanter.
What are the functions of iliopsoas?
Flexion of the thigh/hip joint. Very involved in cycling
What nerve innervates iliopsoas?
The psoas is innervated by ventral rami L1-L3
The iliacus is innervated by femoral nerve
Describe the sartorius
Superficial, strap like muscle
Runs from lateral hip to medial knee
Longest muscle in the body (longest fibre - 20cm)
Commonly referred to at “Tailor Sit Muscle”
Helps separate the anterior compartment and the medial compartment
What is the function of the sartorius
Knee and hip flexion (N.B. when we need both at the same time
What nerve innervates the sartorius?
The femoral nerve
What does the Tailor Sit FABER stand for?
Flexion, Abduction, External Rotation, flexion of the knee
Can’t do any of these movements without the sartorius
Name the 4 compartments of the thigh muscles, how many muscles are in each compartment, and their function
Medial (5; Hip adduction)
Anterior (4; Knee extension and hip flexion)
Posterior (3; Knee flexion and hip extension)
Lateral (2; Hip abduction)
Describe the muscles of the medial thigh compartment. What nerve innervates them?
There are 5 muscles that all cross the hip joint. Only one crosses the knee joint; the gracilus. They are innervated by the obturator nerve (L2-L4). They power hip adduction
Describe the muscles of the anterior thigh compartment. What innervates them? Where does their circulation comprise of?
Large, powerful, antigravity muscles. Essential for daily living: walking, running, jumping, sitting up or down, climbing or descending stairs, sporting activities. They are innervated by the femoral nerve L2-L4. Circulation is via the femoral artery and vein. They are also known as the quadriceps or “quads” and they all insert into the tibial tuberosity via the quadriceps tendon - patella - patellar tendon/ligament
Name the four muscles of the quadriceps
Rectus femoris
Vastus medialis
Vastus intermedius
Vastus lateralis
Describe the rectus femoris
Straight superficial portion that crosses both hip and knee joints
Powers hip flexion and knee extension
It crosses the knee and the hip
Describe the vasti muscles
They surround the shaft of the femur and wrap around the thigh from the back
They power knee extension
Name the muscles of the medial thigh compartment
Adductor brevis Adductor longus Adductor magnus Gracilis Pectineus
Describe the patellofemoral joint
aka PFJ aka knee cap
Articulation between the trochlea of the femur and the posterior surface of the patella. Considered the centrepiece of the extensor mechanism. Common site of dysfunction. Well defined structure with many variables involved in function
Name the three muscles of the posterior thigh compartment
Biceps femoris
Semi-membranosus
Semi-tendinosus
Describe the muscles of the posterior thigh compartment. What innervates them?
3 muscles, 2 joints. Cross both the hip and the knee. Common origin: ischial tuberosity of the innominate bone. They are involved in rotation of the flexed knee (modified hinge joint). They are all innervated by the sciatic nerve
Name the muscles of the lateral thigh compartment
Tensor fasciae latae
Ilotibial band
What is the role of the patella?
It provides/reinforces the strength of the quads and moves the tendon away from the centre of the knee joint
Describe the knee joint
It’s where the femur meets the tibia. There are 4 ligaments and 2 meniscus (medial and lateral). It’s the largest and most complex joint in the human body. Modified hinge type synovial joint that allows flexion/extension and some rotation. Lacks bony stability; stability is dependant on soft tissue structures (ie. muscles, tendons, ligaments, etc.)
Name the 4 ligaments of the knee joint
The anterior and posterior crucuate ligaments, and the medial and lateral collateral ligaments
Describe the movements of the knee joint
Flexion/extension (approx 135˚)
Medial/lateral rotaion when flexed (approx 45˚ of rotation when knee is flexed 90˚)
Describe the lateral collateral ligament
Cord like (nearer to the back of the joint)
From lateral epicondyle of the femur to fibular head
Easily palpated (can roll with finger)
Resists varus force
aka LCL
Describe the medial collateral ligament
Fan shaped Attaches to the medial femoral epicondyle proximally and medial surface of the tibia distally. Also attaches to the medial meniscus Resists valgus force Stronger than LCL aka MCL
Describe the cruciate ligaments
They are contained in the thin, vascularized envelope formed by synovial lining. They have poor blood supply and an inadequate ability to heal
What is the function of the cruciate ligaments
First degree of restraint - tibial translation (help control it)
Second degree of restraint - internal/external rotation and varus/valgus angulation (help control it)
What does valgus stress cause?
It tears the medial collateral ligament which attaches to the medial meniscus and blows apart the ACL
Describe the anterior cruciate ligament
It attaches to the anterior portion of the intercondylar eminence. It runs in a posterior/superior direction. It runs towards the external aspect of the joint ie. the lateral femoral condyle, but note the medial surface of the lateral femoral condyle
aka ACL
APEX = Anterior, Posterior/superior, EXternal aspect
Describe the posterior cruciate ligament
Attaches to the posterior aspect of the intercondylar eminence. It runs in an anterior direction toward the front of the knee joint. It runs towards the internal aspect of the knee, ie. the medial femoral condyle, but the lateral surface of the medial femoral condyle
aka PCL
PAIN = Posterior, Anterior, INternal aspect
Describe the medial meniscus
C shaped, attached to the joint capsule and medial collateral ligament (MCL)
Describe the lateral meniscus
O shaped, connected to popliteus muscle
Describe the meniscuses
Both are disc-like structures with a high outer edge. They are connected anteriorly by the transverse of the knee.
What is the function of the meniscuses
They deepen the tibial surface to increase stability. They spread out the load bearing force on the joint (shock absorption). They help control of rotational and gliding motion at the tibio-femoral joint. They help circulate the synovial fluid thru the joint
Describe the bones of the foot
They are analogus to the bones of the hand but modified for weight bearing and locomotion. There are 7 tarsal bones, 5 metatarsals and 14 phalanges
Name the two joints of the ankle
Two synovial joints: talocrural ankle joint (permits plantar and dorsi flexion) and subtalar joint (permits inversion and eversion)
Describe the subtalar joint
The joint between the superior aspect of the calcaneus and the inferior aspect of the talus. It is stable in dorsi flexion and unstable in plantar flexion. It has strong ligaments and weak muscles
Describe the talocrural joint
It’s the true ankle joint between the distal end of the leg bones and the talus. It is referred to as a brick and mortar joint because of it’s bony configuration. The tibia and fibula forma mortise in which the dome of the talus fits. It is more stable with eversion than with inversion
Describe the lateral ligaments of the ankle
There are three ligaments on the lateral side of the ankle joint and they are named to describe their location relative to each other as well as the bones to which they attach
Name the lateral ligaments of the ankle
Posterior and anterior talofibular ligaments, and the calcaneofibular ligaments
Describe the medial ligaments of the ankle
The deltoid ligament is very strong medial ligament that extends from the medial malleolus of the tibia and attaches on the talus, calcaneus and navicular bones
Name the three muscular compartments of the lower leg, as well as their respective funtions
Anterior (dorsiflexors/toe extensors)
Lateral (Everters)
Posterior (Plantarflexors/toe flexors)
Name the four muscles of the anterior compartment of the lower leg
Tibialis anterior
Extensor Hallucis longus
Extensor digitorum longus
Peroneus tertius
What innervates the anterior muscle compartment of the lower leg
The deep peroneal nerve (L4-S1)
Name the two muscles of the lateral compartment of the lower leg
Fibularis (peroneus) longus
Fibularis (peroneus) brevis
What innervates the muscles of the lateral compartment of the lower leg?
The superficial peroneal nerve (L5-S2)
Name the three superficial muscles of the posterior compartment of the lower leg
Plantaris
Gastronemius
Soleus
What innervates the superficial muscles of the posterior compartment of the lower leg
The tibial nerve (S1-S2)
Name the three deep muscles of the posterior compartment of the lower leg
Flexor hallicus longus
Flexor digitorum longus
Tibialis posterior muscle
