Lower Limb Anatomy (Bones and Joints)

Question 1

Hip bones articulate with one another at the ____ ____.
Each hip bone is firmly fixed to ____ part of ____ at ____ joint.
Rigid bony pelvis transmits body weight through ____ to the lower limbs.

Answer 1

Hip bones articulate with one another at the PUBIC SYMPHYSIS.
Each hip bone is firmly fixed to LATERAL part of SACRUM at SACROILIAC joint.
Rigid bony pelvis transmits body weight through ACETABULUM to the lower limbs.

Question 2

State the distribution of body weight starting from vertebral column down to the foot.

State the bone that does not bear any body weight.

Answer 2

vertebral column -> sacroiliac joints -> pelvic girdle -> femur -> knee joint -> tibia -> talus

fibula does not bear any weight as it does not articulate with femur

Question 3

Female femurs are more ____ than males –> ____ pelvis

Answer 3

Female femurs are more OBLIQUE than males –> WIDER pelvis

Question 4

Identify structures of hip bone

Answer 4

Question 5

Identify structures of femur (anterior aspect)

Answer 5

Question 6

Identify structures of femur (posterior aspect)

Answer 6

Question 7

Head of femur is covered with ____ cartilage, except for ____ (medially placed depression) which is for ____ of the head of femur ( ____ ____ )

State the arteries located in the ligamentum teres. State its significance.

Answer 7

Head of femur is covered with ARTICULAR cartilage, except for FOVEA (medially placed depression) which is for LIGAMENT of the head of femur (LIGAMENTUM TERES)

Artery located in ligamentum teres = artery to the head of femur (branch of obturator A)
- Neck of femur fracture –> avascular necrosis

Question 8

Which surface of the neck of femur is intracapsular?

Answer 8

anterior surface of neck of femur is completely intracapsular + medial half of posterior surface is intracapsular

Question 9

HIP JOINT
- Function
- Type of Joint
- Articulation
- Capsule
- Ligaments involved

Answer 9

HIP JOINT
- Function = forms connection between LL and pelvic girdle –> stability over a wide range of motion
- Type of Joint = ball and socket synovial joint
- Articulation = hemispheral head of femur + acetabulum of hip bone (deepened by acetabular labrum formed by fibrocartilage)
- Capsule = outer longitudinal, inner circular (encloses joint and is attached to acetabular labrum, intertrochanteric line and neck of femur)
- Ligaments involved = iliofemoral, pubofemoral, ischiofemoral

Question 10

State the functions and location of each ligament involved in stability of hip joint

Answer 10

(1) ILIOFEMORAL LIGAMENT
- strongest ligament
- function = prevents hyperextension of hip joint
- AIIS –> intertrochanteric line

(2) PUBOFEMORAL LIGAMENT
- function = prevents overabduction of hip
- lies inferiorly

(3) ISCHIOFEMORAL LIGAMENT
- function = prevents hyperextension of hip joint and limits medial rotation of hip
- lies posteriorly

Question 11

State the 4 ways that the stability of hip joint is maintained.

Answer 11

1. depth of acetabulum (increased by presence of fibrocartilage labrum)
2. 3 ligaments - iliofemoral, pubofemoral, ischiofemoral
3. strength of surrounding muscles
4. length and obliquity of neck of femur

Question 12

SUMMARISE!
(State muscles and nerve roots)

Hip flexion
Hip extension
Hip abduction
Hip adduction
Hip medial rotation
Hip lateral rotation

Answer 12

Hip flexion - psoas major, iliacus, sartorius, rectus femoris, pectineus - L2-L3

Hip extension - gluteus maximus, hamstrings - L4-L5

Hip abduction - gluteus medius, gluteus minimus, tensor fascia latae, sartorius - L4-L5

Hip adduction - adductor brevis, adductor longus, adductor magnus, pectineus, gracilis - L2-L3

Hip medial rotation - anterior fibres of gluteus medius and minimus, tensor fascia latae - L2-L3

Hip lateral rotation - piriformis, obturator internus, obturator externus, gemellus superior, gemellus inferior, quadratus femoris - L4-L5

Question 13

The trochanteric anastomosis in the neck of femur involves 4 arteries. Name the arteries.

Which artery supplies the femoral head.

Answer 13

1. medial circumflex femoral A
2. lateral circumflex femoral A
3. superior gluteal A
4. inferior gluteal A

Femoral head blood supply:
Adults - medial circumflex femoral A
Children - obturator A

Question 14

State the arteries involved in the blood supply to (1) Head and (2) Neck of femur.

Answer 14

HEAD
- Obturator A
- Profunda femoris A (femoral A) –> Medial and Lateral Circumflex A

NECK
- Profunda femoris A (femoral A) –> Medial and Lateral Circumflex A

Others - superior and inferior gluteal A (trochanteric and cruciate anastomosis)

Question 15

State everything you know about neck of femur fractures.

Answer 15

Fracture of neck of femur leads to AVASCULAR NECROSIS of HEAD of femur
- Medial circumflex A supplies most of the blood to head and neck of femur –> retinacular arteries (branch of MCA) are torn during fracture
- Blood supply to head of femur only occurs through obturator A –> inadequate –> avascular necrosis
- Common in elderly >60 year olds + post-menopausal women (femoral necks weak due to osteoporosis exacerbated by decreased oestrogen)

Question 16

Summarise the difference between neck of femur fracture and trochanteric fracture

Answer 16

Question 17

State everything you know about dislocation of head of femur from acetabulum

Answer 17

Dislocation of head of femur
- Femoral head is likely to be forced out of the acetabulum (posterior dislocation of hip joint)
- Sciatic nerve injured (compressed or stretched) –> paralysis of hamstrings and muscles distal to knee joint

Question 18

Identify structures of tibia (anterior aspect)

Answer 18

Question 19

Identify structures of tibia (posterior aspect)

Answer 19

Question 20

State everything you know about the fibula

Answer 20

• common fibular N wraps around the head of fibula
• fibula does not take part in transmission of body weight
• fibula provides attachment to all muscles of the leg except tibialis anterior, gastrocnemius, plantaris

Question 21

State everything you know about the patella bone

Answer 21

• largest sessamoid bone in tendon of the quadriceps femoris
• flat, triangular bone with apex facing down and base facing upwards
• anterior aspect = convex and rough
• posterior aspect = medial and lateral articular surfaces –> lateral articular surface articulates with femoral lateral condyle

Question 22

State everything you know about patella dislocation

Answer 22

PATELLA DISLOCATION
- There is natural tendency of the patella to dislocate laterally due to upward and lateral pull of quadriceps
- Factors that prevent lateral dislocation include:
(1) Most forward projection of lateral femoral condyle
(2) More prolonged insertion of vastus medialis to medial border of patella than of vastus lateralis to lateral border of patella
(3) Medial pull exerted by medial patellar retinaculum

Question 23

KNEE JOINT
- Function
- Type of Joint
- Articulation
- Capsule
- Ligaments involved

Answer 23

KNEE JOINT
- Function = flexion and extension of knee
- Type of Joint = modified hinge synovial joint
- Articulation = lateral and medial femorotibial condyles + femoropatellar articulation
- Capsule = attached to margins of articular surfaces at the sides and posterior of knee joint (front of joint is capsule deficient)
- Ligaments involved =
(1) Extracapsular ligaments - ligamentum patellae, oblique popliteal ligament, medial collateral ligament, lateral collateral ligament
(2) Intra-articular ligaments - cruciate ligaments (ACL,PCL), menisci

Question 24

State 4 factors that cause the knee joint to be structurally weak.

Answer 24

Knee joint is structurally weak because…
1. Incongruence of articular surfaces
2. Tibial condyles are small and shallow to hold large convex femoral condyles
3. Shallow articular surface of femur and patella
4. Outward angulation between long axes of femur and tibia

Question 25

State 4 factors that maintain stability of the knee joint.

Answer 25

1. **Strength and actions of the surrounding muscles** (quadriceps femoris) **and tendons** 2. **Medial and lateral collateral ligaments maintain side to side stability** --> taut when knee is fully extended 3. **Cruciate ligaments maintain anteroposterior stability**- ACL prevents posterior displacement of femur on tibia + hyperextension of knee joint + anterior displacement of tibia when knee flexed / PCL prevents anterior displacement of femur on tibia + hyperflexion of knee joint + posterior displacment of tibia when knee flexed 4. **Iliotibial tract helps in stabilising partially flexed knee**

Question 26

State the 3 bursa formed from the ____ of the ____ membrane.

Answer 26

The 3 bursa formed from the **OUTPOCKETING** of the **SYNOVIAL** membrane. 1. Semimembranous bursa 2. Popliteal bursa 3. Suprapatellar bursa - outpouching of synovial membrane beneath the quadriceps tendon since front of knee joint is capsule deficient

Question 27

State the conditions where medial and lateral collateral ligaments are injured. State the test for integrity of each ligament.

Answer 27

MCL (medial collateral ligament) injury --> due to blow to the lateral site of the knee - Test = excessive gapping on medial side of joint when one attempts to adduct tibia on the femur LCL (lateral collateral ligament) injury --> due to blow to the medial side of the knee - Test = excesive gapping on lateral side of joint hwen one attempts to adduct tibia on femur

Question 28

State the 3 intra-articular ligaments within the knee joint

Answer 28

1. Cruciate ligaments - ACL, PCL 2. Menisci - medial and lateral menisci 3. Popliteal tendon

Question 29

ANTERIOR CRUCIATE LIGAMENT (ACL) - ____ of the two ligaments - has relatively ____ blood supply - o = anterior ____ area of tibia - extends ____ + ____ + ____ to attach to posterior part of ____ surface of ____ condyle of femur - FUNCTIONS: (1) (2) (3) (4)

Answer 29

**ANTERIOR CRUCIATE LIGAMENT (ACL)** - **WEAKER** of the two ligaments - has relatively **POOR** blood supply - o = anterior **INTERCONDYLAR** area of tibia - extends **SUPERIOR** + **POSTERIOR** + **LATERALLY** to attach to posterior part of **MEDIAL** surface of **LATERAL** condyle of femur - **FUNCTIONS**: (1) ***Prevents posterior displacement of the femur on tibia*** (2) ***Prevents hyperextension of knee*** (3) ***Prevents anterior displacement of tibia when knee flexed*** (4) ***Serves as pivot for rotatory movements of the knee --> ACL is taut during flexion***

Question 30

State everything you know about **ACL Injury**

Answer 30

**ACL INJURY** - ***More common*** than PCL injury as PCL is ***thicker*** and hence ***stronger*** --> has ***higher tensile strength*** - Most common knee injuries in skiing accidents --> causes ***free tibia to slide anteriorly under femur*** --> anterior drawer sign - Occurs when there is ***hyperextension*** or severe force directed anteriorly

Question 31

POSTERIOR CRUCIATE LIGAMENT (PCL) - ____ of the 2 ligaments - o = ____ intercondylar area of tibia - extends ____ + ____ + ____ to attach to anterior surface of the ____ condyle of femur - FUNCTIONS: (1) (2) (3) (4)

Answer 31

**POSTERIOR CRUCIATE LIGAMENT (PCL)** - **STRONGER** of the 2 ligaments - o = **POSTERIOR** intercondylar area of tibia - extends **SUPERIOR** + **ANTERIOR** + **MEDIALLY** to attach to anterior surface of the **MEDIAL** condyle of femur - **FUNCTIONS**: (1) ***Prevents anterior displacement of femur on tibia (when tibia on ground)*** (2) ***Prevents hyperflexion of knee*** (3) ***Prevents posterior displacement of tibia on femur (when tibia off ground)*** (4) ***Main stabilising factor of femur in weight-bearing knee***

Question 32

State everything you know about PCL Injury

Answer 32

**PCL INJURY** - Although PCL is **strong**, PCL rupture can occur when a **person lands on the tibial tuberosity** when **knee is flexed** - PCL rupture usually occurs in conjunction with **tibial or fibular ligament tears** - **Posterior drawer sign** present --> free **tibia** slides **posteriorly** under **fixed femur**

Question 33

MENISCI - ____-shaped sheets of ____ - ____ articular surface - has role in ____ ____ - ____ at external margin, ____ & ____ in interior of joint - firmly attached to their ends of ____ area of tibia - ____ margin attached to ____ layer of capsule of knee joint

Answer 33

**MENISCI** - **C**-shaped sheets of **FIBROCARTILAGE** - **DEEPENS** articular surface - has role in **SHOCK ABSORPTION** - **THICKER** at external margin, **THIN** & **UNATTACHED** in interior of joint - firmly attached to their ends of **INTERCONDYLAR** area of tibia - **EXTERNAL** margin attached to **FIBROUS** layer of capsule of knee joint

Question 34

**MEDIAL MENISCUS** - C-shaped and broader ____ than ____ - Attachment = ____ end attached to ____ intercondylar area of tibia (anterior to ACL attachment site) - Attachment = ____ end attached to ____ intercondylar area (anterior to PCL attachment site) - Firmly laterally adhered to ____ surface of tibial collateral ligament

Answer 34

**MEDIAL MENISCUS** - C-shaped and broader **POSTERIORLY** than **ANTERIORLY** - Attachment = **ANTERIOR** end attached to **ANTERIOR** intercondylar area of tibia (anterior to ACL attachment site) - Attachment = **POSTERIOR** end attached to **POSTERIOR** intercondylar area (anterior to PCL attachment site) - Firmly laterally adhered to **DEEP** surface of tibial collateral ligament

Question 35

**LATERAL MENSICUS** - Nearly ____ and is ____ and more freely movable than medial meniscus - Attachment = ____ tendon (separates lateral meniscus from ____ collateral ligament)

Answer 35

**LATERAL MENSICUS** - Nearly **CIRCULAR** and is **SMALLER** and more freely movable than medial meniscus - Attachment = **POPLITEUS** tendon (separates lateral meniscus from **FIBULAR(LATERAL)** collateral ligament)

Question 36

**MENISCAL TEARS** - ____ meniscus is more prone to injury because of its ____ fixity to ____ collateral ligament + greater ____ during rotatory movements - ____ meniscus is protected by ____ because its medial fibres pull the ____ horn of meniscus backwards so that it is not crushed between the articular surfaces

Answer 36

**MENISCAL TEARS** - **MEDIAL** meniscus is more prone to injury because of its **FIRM** fixity to **TIBIAL (MEDIAL)** collateral ligament + greater **EXCURSION** during rotatory movements - **LATERAL** meniscus is protected by **POLITEUS** because its medial fibres pull the **POSTERIOR** horn of meniscus backwards so that it is not crushed between the articular surfaces

Question 37

TIBIOFIBULAR JOINT - Superior: plane ____ joint between head of fibular and ____ condyle of tibia - Middle: ____ joint connected by ____ - Inferior: ____ variety of fibrous joints --> ____ of all joints

Answer 37

**TIBIOFIBULAR JOINT** - Superior: plane **SYNOVIAL** joint between head of fibular and LATERAL condyle of tibia - Middle: **FIBROUS** joint connected by **INTEROSSEOUS MEMBRANE** - Inferior: **SYNDESMOSIS** variety of fibrous joints --> **STRONGEST** of all joints

Question 38

**ANKLE JOINT** - Articulation - Type - Capsule - Innervation - Movements

Answer 38

**ANKLE JOINT** - Articulation = lower end of tibia and malleoli + body of talus - Type = synovial hinge joint - Capsule = enclosed by capsule which is attached to articular margins, lined by synovial membrane - Innervation = deep peroneal N + tibial N - Movements = plantarflexion and dorsiflexion

Question 39

State the 4 factors that maintain the stability of the ankle joint

Answer 39

1. Close interlocking of articular surfaces 2. Capsule, medial and lateral collateral ligaments 3. Inferior transverse tibiofibular ligaments (Syndesmosis) --> strongest interosseous ligament 4. Tendons crossing in front and behind ankle joint

Question 40

Identify structures in foot

Answer 40

Question 41

ARCHES (1) Medial Arch: - ____ than lateral arch - More ____ due to presence of ____ and ____ joints - More involved in ____ (2) Transverse Arch: - Formed by ____, ____ and base of ____ - Formed by ____ part of ____ and ____ joints - ____ and ____ arches serve as pillars for transverse arch

Answer 41

**ARCHES** ***(1) Medial Arch:*** - **HIGHER** than lateral arch - More **PLIANT** due to presence of **TALOCALCANEONAVICULAR** and **SUBTALAR** joints - More involved in **PROPULSION** ***(2) Transverse Arch:*** - Formed by **CUBOID**, **3 CUNEIFORMS** and base of **METATARSALS** - Formed by **TALONAVICULAR** part of **TALOCALCANEONAVICULAR** and **CALCANEOCUBOID** joints - **MEDIAL** and **LATERAL LONGITUDINAL** arches serve as pillars for transverse arch

Question 42

State the 5 functions of arches.

Answer 42

1. Distribute the body weight to the weight bearing points of the sole 2. Shock absorber while jumping 3. Medial longitudinal arch provides propulsive power during locomotion 4. Lateral longitudinal arch functions as static support and helps in weight transmission 5. Concavity of arches protects nerves and vessels of the sole

Question 43

pes cavus = pes planus =

Answer 43

pes cavus = high arched foot pes planus = flat foot