Week 6

Question 1

Main function of lower limb

Answer 1

Most efficient means of movement
Walking is a rhythmical motor act
The two lower limbs work together, swapping roles alternatively
One limb is extended to support weight of body, other if flexed as body’s thrown forwards taking a step as it lands it is extended to take the weight of body, process repeated

Question 2

Main bones of lower limb

Answer 2

Bones of pelvis
Hip bone
Femur
Patella
Tibia
Fibula
Bones of foot

Question 3

The hip bone

Answer 3

Innominate bone
Large regularly shaped bone formed by union of 3 bones: ilium, ischium, pubis
Bones of the hip meet to form a laterally-occurring cup shaped socket known as acetabulum articulates with femur
Before puberty bones of hip are separated by cartilage the tri-radiate cartilage
Fusion of hip bones usually complete at 23

Question 4

Acetabulum

Answer 4

Articulating surface of hip bone
Divisible into 2 parts:
An articulatory surface: semi-lunar in shape, articulates with head of femurs, weight bearing part of acetabulum, lined with hyaline cartilage
Non-articulating surface: covered by a pad of fat, it is the non-weight bearing part of acetabulum
The transverse acetabular ligament completes joins the semilunar ends of the articulatory surface to make it circular

Question 5

The ilium

Answer 5

Has an ala (or wing) and body
Iliac fossa is a concavity in the ala and forms part of the pelvic wall
Has an auricular surface for articulation with the sacrum
Forms superior 2/3rd of hip bone
Forms 2/5ths of the acetabulum
Iliac crest is surface landmark when performing lumbar punctures
Iliac crest separates anterior and posterior iliac spines
Below superior iliac crests are inferior iliac spines
Posterior part of the internal surface of ilium articulates with the sacrum at the sacro-iliac joint
Below sacroiliac joint is the large greater sciatic notch
Sciatic nerve passes through greater sciatic notch

Question 6

The ischium

Answer 6

Forms posterior 1/3 of the hip bone
Forms posterior 2/5 acetabulum
Consists of a body and a ramus
Body of ischium:
It’s superior portion is fused with the ilium and pubis at the acetabulum
Inferior end has a rugged blunt projection called ‘ischial tuberosity’
Ischial tuberosity bears the weight of the body when we sit
Ischial spine projects medially and separates the greater sciatic notch superiorly from the lesser sciatic notch inferiorly

Question 7

Sacrospinous ligament

Answer 7

Spans the greater sciatic notch converting it into the greater sciatic foramen

Question 8

Sacrotuberous ligament and sacrospinous ligaments

Answer 8

Convert the lesser sciatic notch into the lesser sciatic foramen

Question 9

The ramus of the ischium

Answer 9

Extends medially from the body and joins the inferior ramus of the pubis to form the ischiopubic ramus which completes the obturator foramen

Question 10

The pubis

Answer 10

L shaped inferior and anterior part of the hip bone and anteromedial 1/5th of the acetabulum
Consists of a body and 2 rami
The superior ramus passes superolaterally to the acetabulum
The inferior ramus passes posteriorly, inferiorly and laterally to join the ramus of the ischium and form half of the pubic arch- the ischiopubic ramus
The body of the pubis joins the body of the opposite pubis at a fibrocartilaginous joint called the pubic symphysis

Question 11

The femur

Answer 11

Longest, strongest and heaviest bone in the body
Extends from hip joint to the knee joint
Consists of:
-the body (shaft)
-proximal extremity
-distal extremity
Articulates with: acetabulum superiorly, tibia inferiorly
Proximal extremity: head, neck, greater and lesser trochanters
Distal extremity: medial epicondyle and lateral epicondyle

Question 12

The greater trochanter

Answer 12

A large rectangular projection from the junction of body and neck
Provides for attachments of several muscles of gluteal region
Lie laterally almost subcutaneously and is palpable

Question 13

The lesser trochanter

Answer 13

Lies more medially and deeper
Not palpable in person
The imaginary line that joins greater and lesser trochanters anteriorly is known as inter-trochanteric line
The line posteriorly is inter-trochanteric crest

Question 14

The body (shaft)

Answer 14

Slightly bowed anteriorly and narrowest at midpoint
Inferior to neck, the body is smooth and featureless except for the Linea aspera (rough line) which has medial and lateral lips
The medial and lateral lips of Linea aspera diverge to form medial and lateral supracondylar lines

Question 15

Distal ends of femur

Answer 15

Broadened for articulation with tibia
Medial and lateral condyles
Broad posteriorly
Blend anteriorly with each other
Blend superiorly with body of femur
Separated by a deep intercondylar notch
Occurs subcutaneously and is palpable

Question 16

Head of femur

Answer 16

It is smooth and forms 2/3 of a sphere
Directed medially, superiorly and slightly anteriorly to fit in acetabulum
At its centre is a fovea capitus (pit)
At fovea- ligamentum teres attaches

Question 17

Neck of femur

Answer 17

Connects head to the body at an angle 125
Limited laterally by greater trochanter
Narrowest in middle
A broad, rough intertrochanteric line runs inferomedially from greatest trochanter
Inter-trochanteric line is produced by attachments of massive iliofemoral ligament
Inter-trochanteric crest unites two trochanters posteriorly
The neck has several prominent pits especially posteriorly for entrance of blood vessels

Question 18

The tibia

Answer 18

Second largest bone of Skeleton
Supports most body weight
Proximal ends are broad and flattened at surface giving rise to medial and lateral tibial plateaus
Articulates with the condyles of femur superiorly
Distal end articulates with the talus of foot inferiorly

Question 19

The fibula

Answer 19

Lies posterolateral to tibia
Joined to tibia by interosseus membrane
Slender shaft has no weight bearing functions
Main function to provide sites for muscle attachments
Allows tibia to withstand twisting and bending actions
Slightly constricted part of body near head is neck
Distal end has a knob-like appearance and constitutes lateral malleolus
The medial surface of the distal end articulates with the lateral side of the tibia and talus

Question 20

Bones of foot

Answer 20

Talus
Calcaneous
Navicular
Cuboid
Cuneiforms
Metatarsals
Phalanges

Question 21

Arches of foot

Answer 21

Transverse arch
Lateral part of longitudinal arch
Medial part of longitudinal arch

Question 22

What is the definition of a joint

Answer 22

Expresses relation of 2 bones or more to one another at their region of contact

Question 23

Anatomical classification of joints

Answer 23

Functional classes of joints: articulation between bones at either: immoveable, slightly moveable, freely moveable
Structural classes:
-fibrous: sutures, symphyses, syndesmosis
-cartilaginous: primary (synchondroses)- transitional cartilage stage followed by complete union, Secondary(symphyses)- retain fibrous tissue or fibrocartilage without ossification at joint
-synovial joints

Question 24

The lower limb during standing

Answer 24

In the erect position
Both hip joints are extended
Both knee joints are also extended
Both limbs undergo extension and there is no propulsion
The knee and hip joints are most stable when in full extension
It is possible to stand for a long time due to the stability of these joints

Question 25

Regions of the lower limb

Answer 25

The hip- between iliac crest and greater trochanter of femur
The thigh- between greater trochanter and knee
The knee joint- between medial and lateral palpable landmarks
The patellar
The leg- below knee above foot
The foot

Question 26

General features of knee joint

Answer 26

Largest joint in body
It connects the thigh to the leg
Synovial hinge joint that allows some limited rotational movements
Supplied by femoral, obturator, common peroneal and tibial nerves

Question 27

The knee joint as a lever

Answer 27

Reinforced by extracapsular ligaments
These derived from tendons of quadriceps
Strengthening quads also strengthens the knee joint
Can be taken to be the fulcrum of a lever that starts with quadriceps and ends with foot
Small contractions of quads can translate to large forces generated by foot and ankle joint
How foot and ankle joint easily lift body weight when we walk

Question 28

Joints constituting the knee joint

Answer 28

2 condylar joints: medial condyles of femur and plateau of tibia and lateral condyles of femur and tibia
1 gliding joint- patella and patella surface fo femur

Question 29

Meniscii

Answer 29

C shaped cartilaginous pieces with triangular x section
Peripherally thick, convex and attached to joint capsule
Centrally thin, concave and forms free border
Main function: to deepen articular surfaces of tibial condyles
Lesser function: serves as cushions between femur and tibia

Question 30

Ligaments of knee joint

Answer 30

Main factors that hold femur and tibia together
2 types are distinguishable
Intracapsular
Extracapsular

Question 31

Injuries meniscus

Answer 31

Medial meniscus is damaged 20x more commonly than lateral meniscus
Lateral meniscus is more mobile
Damaged meniscii can be wholly or partially removed surgically without disability