Osteology of the Hip Flashcards
What shape is the hip bone?
Large, flat
What is the hip bone formed by?
Fusion of three primary bones- ilium, ischium and pubis
When do the three primary bones of the hips fuse?
At the end of the teenage years
What is each of the three primary bones of the hip formed from?
It’s own primary centre of ossification
How many secondary centres of ossification appear in the hip bone later?
5
How are the three primary hip bones joined at birth?
By hyaline cartilage
What separates the three primary bones at puberty?
A Y-shaped triradiate cartilage
Where is the triradiate cartilage centred?
In the acetabulum
When do the two parts of the ischiopubic rami fuse?
By the 9th year
When do the primary hip bones begin to fuse?
Between 15 and 17 years
When is fusion of the hip bones complete?
Between 20 and 25 years
How do the lines of fusion of primary bones appear in older adults?
There is little or no trace
What forms the largest part of the hip bone?
Ilium
What does the ilium contribute to?
The superior part of the acetabulum
Describe the structure of the ilium?
Thick medial portions
Thin, wing-like posterolateral portions
What are the thick medial portions of the ilium for?
Weight bearing
What are the thin, wing like posterolateral portions called?
Alae
What are the alae for?
Providing broad surfaces for the flesh attachments of muscles
What does the body of the pubis do?
Joins the pubis and ischium to form the acetabulum
What does the ilium have anteriorly?
Stout anterior superior and anterior inferior iliac spines
What is the purpose of the iliac spines?
Providing attachments for ligaments and tendons of the lower limb muscles
What begins at the anterior superior iliac spine?
The iliac crest
What is the iliac crest?
The long curved and thickened superior border of the ala of the ilium
Where does the iliac crest terminate?
The posterior superior iliac spine
What does the iliac crest serve as?
A protective ‘bumper’
What is the iliac crest an important site of?
Aponeurotic attachment for thin, sheet-like muscles and deep fascia
What is the tubercle of the iliac crest?
A prominence on the external lip of the crest
Where does the iliac tubercle lie?
5-6cm posterior to the ASIS
What does the posterior inferior iliac spine mark?
The superior end of the greater sciatic notch
What does the lateral surface of the ala of the ilium have?
Three rough curved lines- the posterior, anterior and inferior gluteal lines
What do the three gluteal lines demarcate?
The proximal attachments of the three large glural muscles
What does each ala have medially?
The iliac fossa
What is the iliac fossa?
A large, smooth depression
What is the purpose of the iliac fossa?
Provides proximal attachment for the iliacus muscle
What can happen to the bone forming the superior part of the iliac fossa?
It may become thin and translucent, especially in older women with osteoporosis
What is the auricular surface?
An ear-shaped articular area
Where is the auricular surface found?
Posteriorly, on the medial aspect of the ilium
What is found superior to the auricular surface?
An even rougher iliac tuberosity
What is the purpose of the iliac tuberosity?
For synovial and syndesmotic articulation with the reciprocal surfaces of the sacrum at the sarco-iliac joint
What does the ischium form?
The posterio-inferior part of the hip bone
What does the superior part of the body of the ischium fuse with?
The pubis and the ilium
What is formed with the fusion of the superior part of the body of the ischium and the pubis and ilium?
The postero-inferior aspect of the acetebulum
What is the ischiorabic ramus?
A bar of bone
What forms the ischiopubic ramus?
The joining of the ramus of the ischium with the inferior ramus of the pubis
What does the ischiopubic ramus constitute?
The inferiomedial boundary of the obturator foramen
What does the posterior border of the ischium form?
The inferior margin of a deep indentation called the greater sciatic notch
What shape is the ischial spine?
Large, triangular
Where is the ischial spine found?
At the inferior margin of the greater sciatic notch
What does the ischial spine provide?
A ligamentous attachment
What does the ligamenteous attachment separate?
The greater sciatic notch from the lesser sciatic notch
How does the lesser sciatic notch differ from the greater?
It is more inferior, rounded, smaller, and smooth-surfaced
What does the lesser sciatic notch serve as?
A trochlea or pulley for a muscle that emerges from the bony pelvis
What is the ischial tuberosity?
A rough bony projection
Where is the ischial tuberosity found?
At the junction of the inferior end of the body of the ischium and its ramus
What is the purpose of the ischial tuberosity?
Bodys weight rests on this when sitting
Provides proximal, tendinous attachment of posterior thigh muscles
What does the pubis form?
The anteromedial part of the hip bone
What does the pubis contribute to?
The anterior part of the acetabulum
What does the pubis provide?
Proximal attachment for the muscles of the medial thigh
What is the pubis divided into?
A flattened, medially placed body, and the superior and inferior rami
How do the superior and inferior rami project?
Laterally from the body
What does the symphysial surface of the body of the pubis articulate with medially?
The corresponding surface of the body of the contralateral pubis
How does the symphysial surface articulate with the contralateral pubis?
By means of the pubic symphysis
What forms the pubic crest?
The anterosuperior border of the united bodies and symphysis
What does the pubic crest provide?
Attachent for abdominal muscles
What are pubic tubercles?
Small projections at the lateral ends of the pubic crest
Why are the pubic tubercles important?
As landmarks of the inguinal regions
What do the pubic tubercles provide?
Attachment for the main part of the inguinal ligament, and thereby indirect muscle attachments
What is the pecten pubis?
A sharp raised edge
What forms the pecten pubis?
The posterior margin of the superior ramus of the pubis
What does the pecten pubis form?
Part of the pelvic brim
What is the obturator foramen?
A large oval or irregularly triangular opening in the hip bone
What is the obturator foramen bounded by?
The pubis and the ischium and their rami
Is the obturator foramen open or closed?
Closed, apart from a small passageway
What is the passageway in the obturator foramen called?
The obturator canal
What is the purpose of the obturator canal?
To allow passage of the obturator nerve and vessels
What closes the obturator foramen?
The thin, strong obturator membrane
What is the advantage of the presence of the foramen?
It minimises bony mass while its closure by the obturator membrane still provides extensive surface area on both sides for fleshy muscle attachment
What is the acetabulum?
The large cup-shaped cavity or sock on the lateral aspect of the hip bone
What does the acetabulum articulate with?
The head of the femur
What does the articulation of the acetabulum and the femur form?
The joint
What is the acetabular notch?
Where the margin of the acetabulum is incomplete inferiorly
What is the acetabular fossa?
The rough depression in the floor of the acetabulum extending superiorly from the acetabular notch
What do the acetabular notch and fossa create?
A deficit in the smooth lunate surface of the acetabulum
What is the lunate surface of the acetabulum?
The articular surface receiving the head of the femur
How is the isolated hip bone or bony pelvis placed in the anatomical position?
The ASIS and the anterosuperior aspect of the pubis lie in the same coronal plane
Symphysial surface of the pubis is vertical, parallel to the median plane
How does the acetabulum face in the anatomical position?
Inferolaterally, with the acetabular notch directly inferiorly
How does the obturator foramen lie in the anatomical position?
Inferiomedial to the acetabulum
How does the internal aspect of the body of the pubis face in the anatomical position?
Almost directly superiorly
