Human Locomotor Systems MST 2

What is the pelvic girdle?

Interface b/w axial skeleton and lower limb

Ring structure permits force transfer and protection of pelvic contents

Lateral shift of 'ala' of ilium allowed upright bipedal locomotion

Compare the male and female pelvis...

Male is narrower and longer

Males have a smaller subpubic angle

males -> actute

females -> obtuse

What are the pelvic bone landmarks?

Gluteal lines (posterior, anterior, inferior)

Iliac crest

Ala

Posterior superior iliac spine

Posterior inferior iliac spine

Greater/lesser sciatic notch

Ischial spine

Lesser sciatic notch

Ischial tuberosity

Obturator foramen

Ischiopubic ramus

ASIS

AIIS

Pubic tubercle

Superior pubic ramus

Where does the pelvic brim face?

Anteriorly

What are the alignments of the pelvis?

ASIS and public tubercles are vertical |

Left and right ASIS are horizontal -

How do spinal nerves fit into the sacrum?

Exit via anterior and posterior sacral foramina

What is the coccyx?

Small bone @ bottom of pelvis

What are the bony landmarks on the femur?

What are the pelvic girdle joints?

Sacroiliac joint

-> plane synovial

-> has strong ligamentous support (sacrospinous and sacrotuberous ligaments)

-> sacroiliac ligaments (ant., post., interosseus)

-> small movement, nutation and counternutation

Pubic symphysis

-> secondary cartilaginous

-> anterior joining of pubic bodies

Sacrococcygeal joint

-> secondary cartilaginous

What is nutation?

Sacroiliac joint permits small degree of motion

Nutation -> anterior tilt of sacrum on ilium

Ligaments limit extent of nutation

What is counternutation?

Reverse of nutation

Superior sacrum moves superiorly and posteriorly

What are the sacral ligaments?

Sacroiliac ligaments restrict lateral movement of ilia and anterior movement of sacrum

- posterior ligament

- anterior ligament

- interosseus ligament

What do the sacrotuberous and sacrispinous ligaments do?

Resist nutation by limiting posterior rotation of sacrum during weight bearing

How does force transmit down the pelvis?

Down and then latero-inferiorly

What is the hip joint?

Ball and socket

-> large articular surfaces 'congruent'

-> head of femur is 2/3 of a sphere, fits into acetabulum

Superior acetabulum has v.thick cartilage

Tapered neck increases ROM

What are the support features of the hip joint?

Strong fibrous capsule

Ligaments: iliofemoral, pubofemoral, ischiofemoral ligaments (blend into capsule)

-> taut during hip extension

Specialised fibrocartilage: acetabular labrum

Fat pad

What is the acetabulum?

Lunate surface makes up the hyaline articular area

Acetabular fossa - non articular area

1/5 of pubis, 2/5 of ischium and ilium

Angled obliquely in a lateral, anterior and inferior direction

What is the acetabular notch?

Inferior deficiency bridged by transverse ligament to create the socket

What's the acetabular labrum?

Fibrocartilaginous rim

Deepens cup and increases SA for articulation

-> more stability

What's the ligament of head of femur?

Transmits branch of obturator artery to femoral head

-> artery fibrosis after puberty

Artery is within so the head of the femur has blood supply

-> from obturator artery

What is the transverse acetabular ligament?

Spans across acetabular notch

What is the fat pad in the acetabulum?

Non-articular but fills acetabular fossa

What are the ligaments of the hip joint?

Taut during extension

All draw femoral head into acetabulum

-> iliofemoral

-> ischiofemoral

-> pubofemoral

What position puts the most tension on the hip joint ligaments?

Closed packed position

-> extension, abduction and internal rotation

What are bursae around the hip joint?

Spread synovial fluid

Repeated stress or altered biomechanics can damage and inflame them

- trochanteric bursa

- gluteofemoral bursa

- ischial bursa

What are open chain movements at the hip joint?

Femur moves on pelvis

What are closed chain movements at the hip joint?

Pelvis moves on femur

How can the pelvis tilt?

Anterior pelvic tilt - forward

Posterior pelvic tilt - pelvis tilts backwards

Lateral pelvic tilt - pelvis tilts to one side

Pelvic rotation - pelvic girdle rotates on femur

What is anterior pelvic tilt?

Lordosis is increased

Concentric: erector spinae, hip flexors

What is posterior pelvic tilt?

Lordosis is decreased

Concentric: abdominal muscles, hip extensors

What are lumbopelvic mechanics?

Movements that differ based on the goal

- Ipsidirectional lumbopelvic rhythm

- Contradirectional lumbopelvic rhythm

Mechanics are interlinked thus dysfunction in one area implicates the other

What is ipsidirectional lumbopelvic rhythm?

Involves the same direction of motion e.g. alterior pelvic tilt and lumbar flexion

What is contradirectional lumbopelvic rhythm?

Involves opposing direction of motion e.g. anterior pelvic tilt and lumbar extension

What is the hip joint congruency and angle of torsion?

1. acetabulum is directed laterally, inferiorly and anteriorly

2. femoral head is directed medially, superiorly but anteriorly

-> not fully congruent

Anterior part of femoral head is 'exposed' and is supported by the anterior joint capsule & iliofemoral ligament

Thus in any position, the hip is still supported

What is the angle of inclination?

Long axis of head and neck to the shaft

Femoral head lies above the intercondylar fossa

-> returns centre of gravity inferior to the trunk

What inclination is better for bipedalism?

What could result from malalignment from abnormal angles?

Dislocation and degeneration

What are hip fractures?

Normally @ femoral head, neck or trochanters

-> femoral neck is weakest

-> higher risk in osteoporotic and older individuals

-> disruption of retinacular arteries poses large risk of avascular necrosis of the femoral head

What is the gluteus maximus?

Hip extensor and external rotator

What do the gluteus minimus and medius do?

Abductors and rotators(internal and external based on fibres)

What's a lateral view of gluteus medius and minimus?

Where does the gluteus maximus attach?

Proximal: posterior ilium, sacrum and sacrotuberous ligament

Distal: iliotibial band(ITB) and gluteal tuberosity

Where does gluteus medius attach?

Proximal: Ilium b/w posterior and anterior gluteal lines

Distal: greater trochanter

Where does gluteus minimus attach?

Proximal: ilium b/w inferior and anterior gluteal lines

Distal: greater trochanter

How do the gluteus muscles look like from a posterolateral position?

How does the musculature appear from a superior view?

'Rotator cuff' of the hip

-> lateral rotators traverse posterior to the hip

-> strong ligamentous support anteriorly

Where does the piriformis attach?

Proximal: anterior sacrum

Distal: greater trochanter superiorly

Where does the superior gemellus attach?

Proximal: ischial spine

Distal: trochanteric fossa

Where does the obturator internus attach?

Proximal: obturator membrane and rim(internal surface)

Distal: trochanteric fossa

Where does the inferior gemellus attach?

Proximal: ischial tuberosity

Distal: trochanteric fossa

Where does quadratus femoris attach?

Proximal: ischial tuberosity

Distal: intertrochanteric crest

What are the anterior thigh muscles?

Most traverse anteior to the hip w/ a vertical fibre direction

Only quad muscle (rectus femoris) that contributes to hip flexion

Where does psoas major attach?

Proximal: lumbar vertebrae and intervertebral discs

Distal: lesser trochanter

Where does the iliacus attach?

Proximal: iliac fossa

Distal: lesser trochanter

Where does tensor fascia latae attach?

Proximal: anterior superior iliac spine

Distal: iliotibial band

Where does the sartorius attach?

Proximal: ASIS

Distal: proximal anteromedial tibal and crural fascia

"Crossing legs movement"

Flexed, abducted and externally rotated

Crosses the knee posteriorly thus is a flexor

Where does the quadriceps femoris attach proximally?

Rectus femoris - AIIS

Vastus lateralis - lateral lip of linea aspera

Vastus intermedius - anterior femoral shaft

Vastus medialis - medial lip of linea aspera

Where do the quadriceps femoris attach distally?

Quadriceps tendon->patella->patella ligament-> tibial tuberosity

V.L and V.M blend lateral and medial into patella retincula

Where does pectineus attach?

Proximal: superior pubic ramus

Distal: pectineal line (femur)

What muscles are major hip flexors?

Primary hip flexors = psoas major and iliacus

What are vastus medialis components split into?

Vastus medialis oblique

-> fibre direction is almost transverse

Vastus medialis longus

What makes up the posterior thigh compartment?

Hamstring muscles

-> semitendinosus

-> semimembranosus

-> biceps femoris (long and short heads)

L.head of biceps femoris is most commonly strained

S.head of biceps femoris is only involved in knee motion

What component of the hamstrings is only involved in knee motion?

S.head of biceps femoris

Where does semitendinosus attach?

Proximal: ischial tuberosity

Distal: proximal anteromedial tibia and crural fascia

Where does semimembranosus attach?

Proximal: ischial tuberosity

Distal: medial tibial condyle posteriorly and reflects as oblique poplitea ligament

Where does biceps femoris attach?

Long head proximal: ischial tuberosity

Short head proximal: linea aspera and lateral supracondylar line of femur

Distal: fibular head laterally

What is the tibiofemoral joint?

Modified hinge joint

-> tibial rotation on fixed femur can occur when knee is flexed (best at 90 degrees)

What muscles form the medial thigh?

Adductor

-> more than just adduction though

Eccentric load during lateral movements

Sagittal plane actions during large hip flexed/extended positions

E.g. big stride sprint, deep squats

Injury prone in running, jumping and change of directions

What muscles form the medial thigh?

Pectineus

Adductor longus

Gracilis

Adductor brevis

Adductor magnus

Obturator externus

Where does gracilis attach?

Proximal: pubic body and inferior ramus

Distal: proximal anteromedial tibia and crural fascia

Where does adductor longus attach?

Proximal: pubic body

Distal: middle linea aspera

Where does adductor brevis attach?

Proximal: pubic body and inferior ramus

Distal: proximal linea aspera

Where does adductor magnus attach?

Proximal adductor attachment: ischiopubic ramus

Proximal hamstring attachment: ischial tuberosity

Distal adductor attachment: linea aspera and medial supracondylar line

Distal hamstring attachment: adductor tubercle

Where does obturator externus attach?

Proximal: obturator membrane and rim (external surface)

Distal: trochanteric fossa

Where do all the leg muscles act?

What are the adduction plane actions?

How do adductors work in the sagittal plane?

Sprinting involves adduction

Adductor longus has many jobs

-> hip extensor(front foot) and flexor(behind foot)

What are two joint muscles?

A muscle that crosses and acts on two joints e.g. hip and knee, knee and ankle

Contraction produces movement @ both joints

-> performing both weakens the combined effect(active insufficiency)

More effective @ one joint when the position of the other joint stretches the muscle slightly

Both joints need to be tested individually when testing for ROM of that particular muscle

What is muscle insufficiency?

Optimal muscle tension occurs @ optimal sarcomere length

-> when too short or long, the overlap is no longer active and a progressive decrease in force occurs

What is active insufficiency?

Two joint muscle is shortened to its minimum contracted length @ both joints

-> no longer able to develop effective tension (too shrinked)

What is passive insuffiency?

Two joint muscle is lengthened to its maximum passive length over both joints

-> is insuffient to allow full ROM @ both joints simultaneously (too stretched)

What is Pes Anserine?

"Goose's foot"

Sartorius, gracilis and semitendinosus

3 tendons distally blent into eachother w/ interconnected webbing

Distal attachments:

-> proximal anteromedial tibia

-> crural fascia

What is the Q angle?

1. tibial tuberosity to medial aspect of patella

2. median patella to ASIS

-> represents quadriceps femoris line of pull

Increased angle = increased lateral pull on patella

-> disolcation and degeneration

Are the femur condyles equal in size?

No, the medial femoral condyle is larger than the lateral one

What are the bony landmarks on the tibia and fibula?

1. tibial plateau

2. indercondylar eminence

4. tibial tuberosity

5. soleal line

6. trochlear notch

7. medial malleolus

3. fibular head

8. lateral malleolus

What does the tibia and fibula look like from a superior view?

Compare the tibia and fibula...

Tibia - weight bearing

Fibula - non weight bearing, not @ knee joint

What is the patella?

Circular/triangular sesamoid bone

Increases leverage of quadriceps, subject to dislocation (mostly laterally)

Lateral facet larger than medial facet

What two synovial joints are within the knee joint?

Patellofemoral

Tibiofemoral

What soft tissue support does the knee joint have?

Menisci

Cruciate ligaments

Collateral ligaments

Retinaculum

What is the patellofemoral joint?

Patella facets articulates w/ patella groove of femur

Slides in femoral groove during flexion and extension

What is the Q angle at the patellafemoral joint?

12-15 degrees in males

15-18 degrees in females

Predisposes subluxation and dislocation

What structures maintain the knee joint?

1. vastus medialis (oblique)

2. medial patellar retinaculum

3. raised lip in the lateral femoral condyle

What surfaces support the tibiofemoral joint?

Incongruent surface

Thus require:

-> menisci

-> cruciate and collateral ligaments

-> fully extended position (most stable, ligaments and capsule taut)

Bones roll and slide during motion to maintain contact

Prone to injury w/ flexion and rotation

Where are collateral ligaments often seen?

On hinge joints

What are menisci?

Weight bearing fibrocartilaginous discs

-> lateral and medial

What are menisci functions?

Crescent shape improves joint congruency

-> weight distribution, shock absorption and syn. fluid spreading

Where do menisci attach?

Anchored to horns (on tibia)

Medial meniscus is anchored to MCL

- Coronary ligaments(to tibia)

- Transverse ligament

- Posterior meniscofemoral ligament

Blood is only supplied to peripheral aspects

What meniscus is more prone to injury?

Medial - less mobile and more prone to injury

Do the menisci move?

Yes, they move posteriorly when flexed

They move anteriorly when knee extends