bones of the lower limb Flashcards
Bones of the Lower Limb
What are the different segments of the lower limb?
What are the bones within each segment?
What increases distally?
How are lower limb bones different from upper limb bones?
Pelvic Girdle
- Hip bone, sacrum, coccyx
Thigh
- Femur
- Patella
Leg
- Tibia (medially)
- Fibula (laterally)
Foot
- Tarsal bones(x7)
Talus, calcaneus, navicular, cuboid, medial, intermediate and lateral cuneiforms
- Metatarsal bones (x5)
- Phalanges (x14)
- the number of bones increases distally
- leg bones are much more robust, thicker and stronger than upper limb bones
Pelvic girdle
What is the pelvic girdle (pelvis) formed by?
what it the pelvic girdle well suited for?
what is its physical anatomical function? (attaches – to —)
what are the 5 functions of the pelvic girdle?
- The pelvic girdle is formed by the hip bones, sacrum and coccyx
- it is well suited for stability during standing, walking and running
- It attaches the lower limb to the axial skeleton
5 functions:
- transfers body weight (upper body weight) to the lower limbs
- provides an almost rigid, complete ring for weight bearing and child birth
- supports the pelvic organs
- provides muscle attachment for limb movement
- provides “gateways” for neurovascular structures to pass to and from the limbs
Hip bone
What 3 bones fuse to form the Hip bone?
What is between the 3 parts of the hip bone?
Where do the hip bones articulate with each other?
- Ilium, Ischium and Pubic bones are fused to form the Hip bone
- Tri-radiate cartilage between the 3 parts of the hip bone. The cartilage is visible radiologically, but ossifies by late teens
- The hip bones articulate with each other at the pubic symphysis
Pelvic Girdle
On a coronal plane, what 3 structures of the pelvic girdle are in line together?
what is the highest point of the iliac crest?
the anterior superior iliac spine is on the same coronal plane as the pubic tubercle and pubic crest
the highest point of the iliac crest is at the level of L4
Pelvic joints
What are the two pelvic joints?
What type of joint are they?
what ligaments are they each supported by?
what is the function of each?
Pubic symphysis
- Is a secondary cartilaginous (or fibrocartilage) joint
- Supported by superior and arcuate ligaments
- Disc between articular surfaces
Sacro-iliac joint
- Synovial anteriorly, fibrous posteriorly
- Supported by the Anterior and Posterior sacro-iliac and Interosseous ligaments
- Extremely limited movement
Pelvic joints
what does body weight want to rotate?
what ligaments prevent the sacrum from tilting forward?
what do these same ligaments also do?
- Body weight wants to rotate S1 downwards and S4 upwards
- The Sacrospinous and Sacrotuberous ligaments prevent the sacrum tilting forwards (support the sacro-iliac joint)
- Sacrospinous and Sacrotuberous ligaments also convert the sciatic notches into Greater and Lesser sciatic foramina for the passage of nerves and vessels
What are the 4 gateways for the Pelvic Girdle?
- Sciatic Nerve and Gluteal Neurovascular Bundle
- Internal Pudendal Neurovascular Bundle
- Obturator Neurovascular Bundle
- Femoral Neurovascular Bundle
Hip Joint
what type of joint is the Hip joint?
what is its characteristic?
Ball and socket type synovial joint
STABLE but LIMITED MOBILITY
Hip Joint
what are the features of the Acetabulum: hip joint at the hip bone?
what are the features of the Head of femur: hip joint at the femur?
- The acetabular rim is raised by the acetabular labrum (a special type of cartilage which is more effective for stability)
- the labrum bridges across the acetabular notch as the Transverse acetabular ligament
- Lunate surface covered with cartilage
- Acetabular fossa (2)
- Acetabular notch (1)
- all of below covered by hyaline cartilage except fovea
- Head of femur (3)
- Fovea of head of femur (1)
- Neck of femur (6)
- Greater trochanter (2)
- Lesser trochanter (5)
- Intertrochanteric crest (Quadrate tubercle) (8)
- Intertrochanteric line (4)
(insert image)
Hip Joint: joint capsule
what 4 structures is the joint capsule attached to?
what does the synovial membrane cover?
what do the synovial layers of the capsule do?
- Attached to the acetabular rim, transverse acetabular ligament, intertrochanteric line and neck of the femur
- Synovial membrane covers everything except the articular cartilage and forms a sleeve around the ligament of the head of femur.
- The synovial layers of the capsule sends retinacular fibres medially along the femoral neck towards the head.
Hip joint: ligaments
what do intrinsic/capsular ligaments do around the joint?
for what 4 reasons does it do this?
what do some deep fibres of the fibrous capsule do and what do they form?
- All (intrinsic) capsular ligaments of the hip joint spiral around the joint and attach to femur
- they are taut in extension.
- Prevent hyper-extension
- Stabilize the joint
- Save energy during standing
- Some deep fibres of the fibrous capsule wind circularly around the neck and form Zona orbicularis
Hip joint: capsular (intrinsic) ligaments
what are the 3 capsular ligaments and what do they prevent?
Iliofemoral - strongest
- Prevents hyper-extension of hip joint during standing
Pubofemoral
- Prevents hyper-abduction of hip joint; tightens during abduction and extension of hip
Ischiofemoral – weakest
Demonstrate the following movements:
- flexion
- extension
- abduction
- adduction
- medial rotation
- lateral rotation
Hip Joint: X-ray
What is the purpose of Shenton’s line on the X-ray of the hip joint
If Shenton’s line is disturbed when there is a fracture of dislocation (not a smooth continuous line)
Knee joint:
How big is the knee joint compared to other joints?
what features allow it to be weight bearing?
what are the 3 common characteristics of all hinge joints that the knee joint shows?
- Knee is largest and one of the most complex joints
- free movement in one plane only+ joint stability = weight-bearing
Shows the common characteristics of all hinge joints.
- The articular surfaces are reciprocally shaped
- They have strong collateral ligaments
- The muscles are grouped at the sides of the joint where they do not interfere with movement
Knee joint: distal femur + patella
what are the key features of the distal femur?
what are the key features of the patella?
Medial condyle (8) and epicondyle (9)
Lateral condyle (5) and epicondyle (6)
Patellar surface (11)
Popliteal surface (12)
Intercondylar fossa (4)
Base of patella
Lateral articular surface (3)
Apex of patella (1)
Knee joint: Proximal tibia and Fibula
what are the key features of proximal tibia?
Lateral condyle (6)
Medial condyle (9)
Intercondylar tubercles (eminence) (13)
Tibial tuberosity (14)
Anterior intercondylar region (2)
Posterior intercondylar region (11)
Medial (9) and lateral (6) tibial plateaus
Intercondylar eminence (14)
(insert image)
Knee joint: cruciate ligaments
how are cruciate ligaments named?
what does the anterior cruciate ligament prevent?
what does the posterior cruciate ligament prevent?
what other action do they also do?
- Named according to their tibial attachment
Anterior cruciate ligament - Prevents anterior movement of tibia and hyperextension
- if unstable, anterior drawer sign
Posterior cruciate ligament - Prevents posterior movement of tibia (as in walking downhill)
- if unstable, posterior drawer sign
- They also act as a pivot for rotatory movements between the bones
ankle joint: distal tibia + fibula
what are the features of the distal tibia?
what are the features of the distal fibula?
Fibular notch (2)
Medial malleolus (6)
Inferior articular facet
Groove for flexor hallucis longus (3)
Groove for tibialis posterior (4)
Lateral malleolus (9)
Malleolar fossa (10)
Articular surface (6)
ankle joint: talus
what is the stability like in the talus bone?
label the diagram
Broad anteriorly: More stable in dorsiflexion
Narrow posteriorly: Less stable in plantar flexion
insert photo
