Lecture 3.2 - Bones, Gluteal Region Flashcards
What are the functions of the lower extremity?
- support body weight
- locomotion
- maintaining equilibrium
What are the 4 regions of the lower extremity and their bones?
- Hip/gluteal = hip bones, sacrum, coccyx
- Thigh = femur, patella
- Leg = tibia, fibula
- Foot = tarsus, metatarsus, phalanges
How does extension occur in lower limbs in relation to upper limbs? Why?
due to developmental differences between upper and lower limbs, extension occurs in the opposite direction in upper and lower limbs.
What is the function of the bony pelvis? What bones form it?
- functions to transfer weight from upper body to lower extremities
- formed by 4 bones: hip bones (2), sacrum, coccyx
When and how does the hip bone form? What are its 3 parts?
- forms in young adult by fusion of three bones
- ilium, ischium, pubis
What are the characteristics of the ilium?
- fan shaped, ala (wing), body (handle) that forms superior part of acetabulum
- iliac crest is the superior margin that runs between anterior and posterior superior iliac spines
- iliac fossa is concave, internal surface
What are the characteristics of the ischium?
- body: posterior part of acetabulum
- ramus: inferior boundary of the obturator foramen
- ischial tuberosity/spine
What are the characteristics of the pubis?
- body: lies medially and articulates with pubis of other side at pubic symphysis
- superior ramus: anterior part of acetabulum
- inferior ramus: inferior boundary of the obturator foramen
What closes the obturator foramen in the living body?
obturator membrane
What are the characteristics of the hip bones?
- anteriorly joined at pubic symphysis (symphysis joint)
- posteriorly joined to sacrum at sacroiliac joint (suture joint)
- forms pelvic girdle
What is the sacrum formed by?
fusion of 5 originally separated sacral vertebrae
What is the coccyx formed by?
fusion of 4 coccygeal vertebrae
What are the pelvic joints?
- lumbrosacral = L5 and S1
- sacroiliac
- sacrococcygeal
- pubic symphysis
What are the pelvic ligaments?
- iliolumbar
- inguinal
- sacrospinous
- sacrotuberous
- posterior sacrococcygeal
- posterior sacroiliac
What are the characteristics of sacroiliac joint movement?
- small movements, limited by many sacroiliac ligaments
- greater movement in females
- “nutation” is the term for rotation in the sagittal plane
- “anterior rotation of the sacrum” increases size of pelvic outlet
- most important during child birth
What may cause a fracture to the femur? When is it most common at the neck?
- violent direct injury may fracture the femur
- fracture of neck of femur common over the age of 60
- more common in women due to postmenopausal osteoporosis (usually referred as “fracture of hip”)
What are the characteristics of the femur?
- longest, strongest, and heaviest bone in the body
- roughly 4 times the length of femur determines the height of individual
What are the characteristics of the tibia?
- weight bearing bone
- medially located
- articulations:
- femur superiorly
- talus inferiorly
- fibula laterally
What are the characteristics of the fibula?
- no function in weight bearing
- serves mainly for muscle attachments and as support for tibia
Where is the gluteal region? What is it made of? What is the intergluteal cleft?
- lies posterior to pelvis between iliac crest and gluteal fold
- region made primarily of gluteal muscles and a thick layer of superficial fat
- intergluteal cleft: division between buttocks
What are the similar characteristics between all gluteal muscles?
- all insert on or near the greater trochanter of the femur
- action is mostly abduction and/or lateral rotation of the thigh
- often used in a smooth continuum
- stabilize the hip joint
Tensor fasciae latae (OINA)
O: anterior superior iliac spine
I: iliotibial tract
N: superior gluteal n.
A: flexes thigh
Gluteus maximus (OINA)
largest, heaviest and most coarsely fibered muscle in the body
O: ilium, sacrum, coccyx, and sacrotuberous ligaments
I: iliotibial tract and gluteal tuberosity
N: inferior gluteal nerve
A: laterally rotates thigh, active during powerful extension (stairclimbing, getting up from squatting position)
Gluteus medius (OINA)
O: ilium between anterior and posterior gluteal lines
I: greater trochanter
N: superior gluteal nerve
A: posterior fibers = adducts, extends, and laterally rotates thigh; anterior fibers = abduct, flex and medially rotate thigh; steadies the pelvis, keeps hip from collapsing into adduction when on one leg
Gluteus minimus (OINA)
O: ilium between anterior and posterior gluteal lines
I: greater trochanter
N: superior gluteal nerve
A: posterior fibers = adducts, extends, and laterally rotates thigh; anterior fibers = abduct, flex and medially rotate thigh; steadies the pelvis, keeps hip from collapsing into adduction when on one leg
How do gluteus medius and minimus work together?
- they help control posture
- active when femur is bearing weight
- if inactive, then pelvis drops on opposite side
What is Trendelenburg sign?
- subject stands on one leg
- if ASIS and AIIS droops on opposite side, then gluteus medius and minimus on the stance side are weak
Piriformis (OINA)
O: 2nd-4th sacral segment
I: greater trochanter
N: S1-S2
A: rotates thigh laterally; abducts thigh; holds head of femur in acetabulum
Piriformis is the landmark muscle for which artery/nerve?
superior/inferior gluteal artery/nerve and sciatic nerve
Obturator internus (OINA)
O: ilium and ischium, obturator membrane
I: greater trochanter
N: nerve to obturator internus
A: rotates thigh laterally; holds head of femur in acetabulum i.e. it stabilizes hip joint
What part of obturator internus does gluteal dissection reveal?
only the distal end of obturator internus
Superior/Inferior gemellus
O: ischial spine/tuberosity
I: greater trochanter
N: superior = nerve to obturator internus; inferior = nerve to quadratus femoris
A: laterally rotates thigh
Quadratus femoris (OINA)
O: ischial tuberosit
I: intertrochanteric crest
N: nerve to quadratus femoris
A: laterally rotates thigh
