Anatomy - Lower limbs Flashcards
What is the pelvis made of?
- two hip bones (innominate)
- sacrum
What bones make up the leg?
- tibia and fibula
What is the ‘top’ of the foot?
the dorsum
Hip joint
- synovial ball and socket joint (between acetabulum and proximal femur)
- allows: flexion and extension, abduction and adduction, medial and lateral rotation of lower limb
- stable and quite mobile
Knee joint
- synovial hinge joint (between distal femur and tibia)
- allows: flexion and extension
Ankle joint
- synovial hinge joint (between distal ends of tibia and fibula with the talus)
- allows: flexion and extension of the foot
Flexion of the ankle joint is also known as…
- plantarflexion
Extension of the ankle joint is also known as…
- dorsiflexion
The pelvis takes the weight of the body and…
transmits it to the lower limbs
What are the three bones that make up each hip bone?
- pubic bone
- ilium
- ischium
Where do the pubic bone, ilium and ischium fuse?
acetabulum (which is the socket of the hip joint)
Where do the hip bones articulate anteriorly with each other?
pubic symphysis
Where do the hip bones articulate posteriorly with the sacrum?
sacroiliac joints
What do the superior and inferior pubic rami surround?
the obturator foramen
Obturator foramen (in life)
- almost completely closed over by the obturator membrane and muscles attached to it
- a small gap in the membrane and the muscles (the obturator canal), allows vessels and nerves to pass between the pelvis and thigh
What is the obturator canal?
- small gap in membrane and the muscles
- allows blood vessels and nerves to pass between the pelvis and the thigh
Iliac crest
- palpable
- uppermost part of the ilium
ASIS
anterior superior iliac spine
AIIS
anterior inferior iliac spine
Examples of important posterior landmarks
- ischial tuberosity
- ischial spine
- greater and lesser sciatic notches
Ischial tuberosity
Ischial spine
Greater and lesser sciatic notches
Describe the femur
- head (articulates with acetabulum of pelvis to form the hip joint)
- neck (extends from the head)
- shaft
- greater and lesser trochanters (lie distal to the neck)
What are greater and lesser trochanters?
they are sites of muscles attachment
Intertrochanteric line
- lie between greater and lesser trochanters
- on anterior surface of the femur
Trochanteric fossa
- small hollow
- on medial aspect of greater trochanter
Linea aspera
- bony vertical ridge on the posterior aspect of the shaft of the femur
- site of muscle attachment
Medial and lateral femoral condyles
- distal end of femur expanded to form these
- articulate with the proximal tibia at the knee joint
Adductor tubercle
- superior to medial femoral condyle
The Patella
- lies anterior to the knee joint
What are the possible movements of the hip joint?
- flexion and extension
- abduction and adduction
- medial (internal) and lateral (external) rotation
- circumduction
What do muscles in the anterior thigh do to the thigh at the hip joint?
flex the thigh
What do muscles in the medial thigh do to the thigh at the hip joint?
adduct the thigh
What do the muscles in the posterior thigh do to the thigh at the hip joint?
extend the thigh
What are the possible movements of the knee joint?
flexion and extension
What do the muscles in the anterior thigh do to the leg at the knee joint?
- extend the leg
What do the muscles in the posterior thigh do to the leg at the knee joint?
- flex the leg
Fascia lata
- deep fascia
- surrounds the thigh like a sleeve
Iliotibial band (tract)
- thickening of the lateral part of the fascia lata
- attaches to lateral aspect of the proximal tibia and is important for stabilising the knee joints
Intermuscular septa
- extend from the fascia from fascia lata to linea aspera
- separate the thigh into anterior, medial and posterior compartments
How many muscles are in the anterior compartment of the thigh?
- 7
(they primarily act as extensors of the knee, some act on the hip joint)
What are the muscles in the anterior compartment of the thigh innervated by?
- femoral nerve (spinal nerves L2-L4)
What are the muscles in the anterior compartment of the thigh?
- quadriceps femoris (x4)
- sartorius
- iliopsoas
- pectineus
Quadriceps femoris
- prime extensor of the knee
- forms the bulk of the anterior thigh
- converge onto the quadriceps tendon which runs over the patella to insert onto the tibial tuberosity via the patellar ligament
Name the Quadriceps femoris
- Rectus femoris
- Vastus lateralis
- Vastus medialis
- Vastus intermedius
Patellar ligament
distal portion of the common tendon of the quadriceps femoris, which is continued from the patella to the tibial tuberosity
Rectus femoris
- lies in midline of anterior thigh of the anterior thigh
- attached to the AIIS proximally
- can contribute to flexion of the hip as it crosses it
Vastus lateralis
- lies lateral to the rectus femoris
- attaches to the linea aspera on the posterior aspect of the femoral shaft
Vastus medialis
- lies medial to rectus femoris
- attaches to the linea aspera
Vastus intermedius
- lies deep to rectus femoris
- attaches to anterior aspect of femoral shaft
Linea aspera
- prominent longitudinal ridge or crest that runs along the axis of the femur
Sartorius
- lies superficially in anterior thigh
- attaches proximally to ASIS
- inserts on the medial aspect of the proximal tibia
- crosses both the hip and knee joints
- flexes and laterally rotates the hip joint and can flex the knee joint
Ilipsoas
- lies proximally in anterior thigh
- psoas major and iliacus converge via a common tendon onto the lesser trochanter of the femur
- prime flexor of the hip joint
Pectineus
- lies in proximal anterior thigh, medial to iliopsoas
- it attaches proximally at the superior pubic ramus and distally on the femur, just inferior to the lesser trochanter
- flexes and adducts the hip joint
How many muscles does the medial compartment of the thigh contain?
- 5 muscles
Describe the muscles of the medial compartment of the thigh
- primarily act as adductors of the hip
- innervated by obturator nerve (spinal nerves L2-L4)
What is the importance of the muscles of the medial compartment being able to adduct?
- adductors play an important role in normal gait as they help to draw the leg back towards the midline as we walk
Name the muscles of the medial thigh
- adductor brevis
- adductor longus
- adductor magnus
- gracilis
- obturator externus
True or false? Adductor brevis and adductor longus have similar points of attachment to the pubic bone
true, adductor brevis just lies deep to the longus
Where does the obturator nerve lie?
in between the adductor brevis and adductor longus
What is adductor Magnus?
- large muscle
- has an adductor part and a hamstring part (function differently and have different nerve supplies)
Adductor part of the adductor Magnus
- attaches to inferior pubic ramus and the linea aspera
- acts as an adductor
- innervated by obturator nerve
Hamstring part of the adductor Magnus
- attaches to the ischial tuberosity and adductor tubercle
What is the adductor hiatus?
- gap formed between the distal attachments of the two parts of adductor magnus
- femoral artery and vein travel through the adductor hiatus to enter the posterior thigh
Gracilis
- most medial muscle
- attaches to the pubic bone and medial aspect of tibia
- it is a weak adductor and flexor of the hip
- a weak flexor of the knee
- not a prime mover
Obturator externus
- attached to the external surface of the obturator membrane
- inserts on the femur near the greater trochanter
- stabilises and laterally rotates the hip joint
The femoral artery is a continuation of…
the external iliac artery
Describe the course of the femoral artery
travels deep to inguinal ligament to enter proximal anterior thigh
Branches of the femoral artery
- large branch called PROFUNDA FEMORIS (deep thigh_
- femoral artery will continue distally and transverses adductor hiatus
- enters distal posterior thigh to become POPLITEAL ARTERY
What is the obturator artery a branch of?
- branch of internal iliac artery
What does the obturator artery travel through?
- obturator canal into medial compartment of thigh
True or false? The obturator artery anastomoses with branches from the femoral artery
true
Femoral vein
- follows course of femoral artery
- lies medial to it in proximal thigh
- travels under inguinal ligament
- is continuous with external iliac vein
Obturator vein
- follows course of obturator artery
- travels through obturator canal
- joins internal iliac vein in pelvis
Femoral nerve
- formed from L2-L4 spinal nerves
- travels deep to inguinal ligament to enter proximal anterior thigh (lateral to femoral artery)
- branches innervate anterior thigh muscles
- saphenous nerve
Saphenous nerve
- sensory branch of femoral nerve
- innervates skin over the leg
Obturator nerve
- L2-L4 spinal nerves
- travels along lateral wall of pelvis and exits through obturator canal
- emerges onto superficial surface of adductor brevis
- gives rise to branches that innervate medial compartment muscles and skin over medial thigh
What is the lateral border of the femoral triangle?
medial border of sartorius
What is the medial border of the femoral triangle?
lateral border of adductor longus
What is the superior border of the femoral triangle?
inguinal ligament
What is the floor of the femoral triangle?
- iliopsoas laterally
- pectineus medially
Contents of the femoral triangle?
- femoral artery
- femoral vein (medial to femoral artery)
- femoral nerve (lateral to femoral vein, deep to inguinal ligament to enter anterior thigh)
Why are the femoral artery and vein vulnerable to penetrating injuries?
- they lie superficially in the femoral triangle
- because of their superficial position, bleeding vessels can be compressed at the mid-inguinal point
What are the three ridges of the ileum of the pelvis?
- anterior, posterior and inferior gluteal lines
Greater and lesser sciatic notches
What ligaments close the greater and lesser sciatic notches?
What do these form?
- sacrotuberous and sacrospinous ligaments
- form the greater and lesser sciatic foramina
Ischial spine
- projects from the posterior ischium
- sacrospinous ligament attaches to it
Ischial tuberosity
- bulky prominence of bone at posterior aspect of ischium
- muscles of posterior thigh and sacrotuberous ligament attach here
What is the intertrochanteric crest?
- ridge of bone between the trochanters on the posterior aspect of femur
Gluteal tuberosity
- inferior to trochanters on posterior aspect of the femur
- site of muscle attachment
Name the 4 muscles of the superficial gluteal muscles group
- gluteus maximus
- gluteus medias
- gluteus minimus
- tensor fascia latae
Gluteus maximus
- most superficial muscle
- has several proximal attachments
- extensor of hip
- important for standing and sitting position
- acts as a lateral rotator of the hip
- it stabilises the knee joint (because it inserts onto the iliotibial tract)
What are the proximal attachments of the gluteus maximus?
- attached to most posterior parts of the posterior surface of the ilium
- sacrotuberous ligament
- sacrum
- distally -> iliotibial tract (smaller proportion attaching onto the gluteal tuberosity)
Gluteus medius
- lies deep to maximus
Gluteus minimus
- lies deep to gluteus medius
True or false? Both the gluteus medius and minimus have similar points of attachment
- true
- attach to anterior parts of the posterior ilium
- insert onto the greater trochanter
Movements allowed by gluteus medius and minimus
- abduct and laterally rotate
- due to their similar bony attachments
What is the importance of gluteal medius and minimus?
- play an important role in gait (walking, running etc.)
Describe how gluteal medius and minimus are used
- standing on one leg: medius and minimus contract to hold the pelvis level so it doesn’t tilt
- if they are weak or paralysed in one limb the pelvis tilts to the contralateral side every time the contralateral leg is off the ground (resulting in a limp)
Tensor fascia latae
- attached to ASIS
- inserts into the iliotibial band (which itself inserts onto lateral part of proximal tibia)
- contraction tenses fascia lata and iliotibial band
- stabilises knee when it is extended and also flexes the hip joint
- NOT A PRIME MOVER THO
Innervation of the superficial gluteal muscles
- gluteal nerves
- these leave the sacral plexus in pelvis via greater sciatic foramen
Innervation of the gluteus maximus
- inferior gluteal nerve
Innervation of gluteus medius and minimus + tensor fascia latae
- superior gluteal nerve
What are the 4 deep gluteal muscles?
- piriformis
- superior and inferior gemelli
- obturator internus
- quadratus femoris
What is the role of the deep gluteal muscles?
- small muscles that primarily stabilise and laterally rotate the hip joint
Insertions of the 4 deep gluteal muscles
- all insert onto or close to the GREATER TROCHANTER
Piriformis
- key landmark
- attaches to anterior surface of the sacrum
- passes through the greater sciatic foramen
- inserts onto the greater trochanter
- nerves of the sacral plexus lie over it in the pelvis
- sciatic nerve
Sciatic nerve
- emerges below inferior border of piriformis in gluteal region
- divides into tibial and common peroneal (common fibular ) nerves in the posterior thigh
Where do the other deep gluteal muscles arise from?
- ischium
- EXCEPT for obturator internus
Obturator internus
- arises from obturator membrane
- its tendon passes through the lesser sciatic foramen
What are the 4 muscles of the posterior thigh?
- semimembranosus
- semitendinosus
- biceps femoris (long and short head)
- hamstring part of adductor magnus
Which muscles are referred to as the ‘hamstrings’ which span both the hip and knee joints?
- semimembranosus
- semitendinosus
- long head of biceps femoris
Where are the ‘hamstrings’ attached to?
- proximally to ischial tuberosity
Movement and innervation of the ‘hamstrings’?
- extend the hip
- flex the knee
- innervated by tibial nerve
Insertions of semimembranosus and semitendinosus
- medial aspect of proximal tibia
Insertions of long and short head of biceps femoris
- they have a common tendon
- inserts onto head of fibula
Where does the short head of biceps of femoris arise from?
- linea aspera
- therefore it flexes the knee but does not move the hip but does not move the hip joint
Innervation of the short head of biceps of femoris
- common peroneal nerve
Where does the hamstring part of the adductor magnus arise from?
- arises from ischial tuberosity and inserts into adductor tubercle of femur
- extends the hip but does not move into the knee joint
Innervation of the hamstring part of the adductor magnus
innervated by tibial nerve
Arterial supply of the hamstring muscles
- supplied by three or four perforating arteries that arise from the profunda femoris
- travel through small apertures in adductor magnus to reach the posterior compartment
Arterial supply of lower thigh
- femoral artery traverses the adductor hiatus to enter the region behind the knee
- region is known as popliteal fossa
- artery called after passing through here: popliteal artery
Superior and inferior gluteal veins
- follow corresponding arteries through the greater sciatic foramen into the pelvis
- drain into the internal iliac vein
Popliteal vein
- in popliteal fossa it enters anterior thigh via adductor hiatus
- now is known as femoral vein
- ascends through anterior thigh
- receives great saphenous vein in femoral triangle before travelling under inguinal ligament to become continuous with external iliac vein
What spinal nerves make up the sciatic nerve?
- L4-S3
What does the tibial nerve innervate?
- muscles of the posterior thigh and posterior leg
What does the common peroneal (fibular) nerve innervate?
- muscles of anterior and lateral leg
(lesion of sciatic nerve can result in severe functional deficits)
True or false? Both the tibial and common peroneal nerve innervate regions of skin of the lower limb
true
What is the popliteal fossa?
- diamond-shaped depression behind knee joint
Borders of the popliteal fossa
- superomedial: semimembranosus and semitendinosus
- superolateral: biceps femoris
- inferomedial and inferolateral: two heads of gastrocnemius
What is the gastrocnemius?
superficial muscle in posterior leg
Contents of the popliteal fossa
- popliteal artery
- popliteal vein
- tibial nerve
- common peroneal (fibular) nerve
Popliteal artery
- continuation of femoral artery
- traverses adductor hiatus to enter popliteal fossa
- flexing patient’s knee gives best chance of palpating it
- Bifurcates into anterior and posterior tibial arteries which supply the leg
Popliteal vein
- formed by deep veins of leg
- traverses adductor hiatus
- continues as femoral vein
Tibial nerve
- descends through midline of fossa
- innervates muscles of posterior leg
Common peroneal (fibular) nerve
- travels along the superolateral border of popliteal fossa alongside biceps of femoris
- wraps around neck of fibula then splits into superficial and deep branch
- superficial: innervates muscles of lateral leg
- deep: innervates muscles of anterior leg