Osteology of Pelvis and Gluteal Region Flashcards
Acetabulum
Hip bone
- Cup shaped depression articulates with head of femur
Acetabular fossa
Non-articular fossa
Lunate surface
Peripheral acetabulum is articular portion
Acetabular notch
- The acetabular notch is a deep notch in the acetabulum of the hip bone. - Continuous with the circular non-articular depression (acetabular fossa) at the bottom of the cavity
- Contains a mass of fat and allows passage of acetabular ligament, nutreint vessels and nerves
- The margins of the notch serve as the attachment for the ligament of the head of the femur
Two portions of ilium
- Wing (ala) of ileum
- Body of ileum
External surface of wing
AKA dorsum
- Posterior gluteal line
- Anterior gluteal line
- Inferior gluteal line
Posterior gluteal line
- Shortest line
- Gluteus maximus takes its origin posterior to the posterior gluteal line
Anterior gluteal line
- Longest line
- Gluteus medius originates between the posterior and anterior gluteal lines
Inferior gluteal line
- Least distinct line
- Gluteus minimus originates between the anterior and inferior gluteal line
What originates between the inferior gluteal line and the margin of the acetabulum?
Rectus femoris
Internal surface of wing of ilium
- Superior border = iliac crest
- Inferior border = arcuate line
- Anterior border = ASIS and AIIS
- Posterior border = PSIS
- Other features = iliac fossa, sacroiliac joint, iliac tuberosity
Iliac crest
- Anterior point = ASIS
- Posterior point = PSIS
- External lip is the attachment for fascia lata and tensor fascia lata
- Internal lip is the attachent for iliac fascia and iliacus muscle
Inferior border of internal surface of ilium
Arcuate line
Anterior border of wing of ilium
- ASIS
- AIIS
There is a notch between the two spines
Attachments to ASIS
“SITI”
- S = sartorius m.
- I = iliacus m.
- T = tensor fascia latae m.
- I = inguinal ligament
Attachments to AIIS
“ISP” - Is St. Paul
- I = iliofemoral ligament
- S = straight head of rectus femoris
- P = portion of iliacus m.
There is a groove medial to the AIIS for psoas major and iliacus muscles to pass
Iliopectineal eminence
- Site of fusion between pubis and ilium
- Located medial to groove for iliopsoas
PSIS
- Posterior border of ilium
- Attachment for sacroiliac ligament
- S for “See” - See SITI Is St. Paul
There is also a PIIS
Iliac fossa
Concave area
o Nutrient foramen in its center
o Iliacus m. inserts here
Sacroiliac joint
o Posterior to iliac fossa
o Articulation between sacrum and ilium
Iliac tuberosity
Attachment sacroiliac ligaments
o Posterior to articular area
Body of ilium
External Surface
o Forms portion acetabulum
Internal Surface
o Part wall bony pelvis
o Obturator internus takes origin here
General ilium notes
- No ramus of ilium
- Body of ilium joins lateral projection of superior ramus of pubis at the acetabulum
- The body and wing are sparated - externally by the margin of the acetabulum and internally by the arcuate line
Greater sciatic notch
o Both ischium and ilium contribute to the greater sciatic notch
o Greater sciatic notch begins proximally inferior to PIIS
o Greater sciatic notch ends distally as the ischial spine
Ischium
• Ischium possesses a single ramus
• Body of ischium joins lateral projection of superior ramus of pubis at the acetabulum
• Ischium is the strongest, most inferior hip bone
- Two parts: body of ischium, ischial ramus
Body of ischium
External surface
- Forms part of acetabular fossa, including part of the lunate surface
- Includes ischial spine and ischial tuberosity
Ischial spine
Separates greater and lesser sciatic notches
Attachments: “SaraSota”
o Sacrospinalis ligament
o Superior gemellus muscle
Ischial tuberosity
Attachments
o Quadratus femoris - lateral tuberosity teardrop-shaped facet
o Inferior gemellus - superomedial tuberosity
Quadrilateral portion (upper part)
o Oblique line – separates hamstring origins
o Semimebranosus - upper lateral attachment
o Long head biceps femoris & semitendinosus - lower medial attachment
Triangular portion (lower region)
- Adductor magnus
- Sacrotuberous ligament
Internal surface of body of ischium
Obturator internus attaches here
Ischial ramus
o Directed anteriorly from ischial tuberosity
o Joins inferior pubic ramus
Muscles attach on external surface, internal surface, lateral border and medial border
External surface attachments
- Adductor magnus
- Obturator externus
Internal surface attachments
- Obturator internus
Lateral border attachments
- Sharp/thin
- Forms margin obturator foramen
Medial border attachments
- Perineum attachments
Pubis
- Body
- Superior rami
- Inferior rami
Body of pubis attachments
o Gracilis
o Adductor longus
o Adductor brevis
Superior rami
Medial to lateral portion
- Pubic crest - most medial
- Pubic tubercle - lateral to pubic crest, inguinal ligament attachment
Lateral portion
- Pectin Pubis – laeral to pubic tubercle (pectineus m. attaches here)
- Iliopectineal line- lateral extension pubic crest
Inferior rami
o Fused to ischial ramus, so it is sometimes referred to as the “ischiopubic ramus”
o Directed posterolateral from pubic symphysis
o Adductor compartment attachments
Adductor compartment attachments to inferior rami
- Gracilis
- Adductor brevis
- Adductor magnus
- Obturator externus
3 primary ossification centers
3 primary ossification centers
- Ilium above sciatic notch (8th week)
- Ischium in body (4th month)
- Pubis in superior pubic ramus (4th or 5th month)
ALL meet at acetabulum to fuse at 13 to 14 years
5 secondary ossification centers
“PS IC IT And IPA”
- PS = pubic symphysis
- IC = iliac crest
- IT = ischial tuberosity
- And = ASIS
- IPA = inferior portion of acetabulum
Sacrum
5 fused sacral vertebrae
Parts of sacrum
- Base
- Apex
- Vertebral canal
- Anterior surface
- Posterior surface
- Lateral surface (x2)
Base of sacrum
Articulates with 5th lumbar vertebrae
- ALAE = large triangular areas located laterally
- Suports psoas major and lumbosacral trunks
- Anterior 3/4 of each ala are costal processes
- Posterior 1/4 of each ala are transverse processes
Apex of sacrum
- Inferior end
- Articulates with coccyx bone
Vertebral canal
- Dorsal, ventral rootlets of spinal nerve run through
Surfaces of sacrum
- Anterior (“pelvic surface”)
- Posterior
- Lateral (x2)
Anterior “pelvic surface” of sacrum
- Iliacus origin - superolateral
- Piriformis orgin - segments 1-4
Posterior surface of sacrum
- Convex, narrower surface
- Middle sacral crest- midline longitudinal ridge (Rudimentary spinous processes of sacral vertebrae)
- Sacral grooves (laminae of vertebrae, between middle sacral crest and articular crest there is the longitudinal ridge of articular processes)
- Posterior sacral foramina (Lateral to articular crests)
Lateral surface of sacrum
- Broad superior, thin inferior
- Auricular surface (covered hyaline cartilage, articulates with ilium at sacroiliac joint)
- Sacral Tuberosity (Posterior to auricular suface, 3 depressions for dorsal sacroiliac ligament)
- Thin Inferior (Gluteus Maximus, Sacrospinous, Sacrotuberous)
Ossification of sacrum
o Primary center & 2 epiphyseal plates: body each sacral vertebra
o 2 ossifcation centers: each vertebral arch
o 2 epiphyseal plates: each lateral seface
o 1 ossifcation center: lateral portion each upper 3 vertebrae
Coccyx
- 4 verebrae (can range 3-5)
- No laminae, pedicles, spinous processes
- Contains lateral processes for attachment, anterior and posterior surfaces
Lateral processes of coccyx for attachment
o Sacrotuberous lig
o sacrospinous lig
o Gluteus Maximus
Anterior surface of coccyx
- Concave
- Sacrococcygeal ligament is attached here
Posterior surface of coccyx
- Cocygeal coruna, which are a large pair of superior articular processes
Ossification centers of the coccyx
- 1st vertebra - 1-4 years
- 2nd vertebra = 5-10 years
- 3rd vertebra = 10-15 years
- 4th vertebra = 15-20 years
Male vs female pelvis
Male pelvis
- Larger, heart shaped
Female pelvis
- Wider pubic angle
- Shorter and wider sacrum bone
- Larger pelvic inlet (oval-shaped)
- Smaller, triangular obturator foramina
- Ilia are less sloped
- ASIS is wider
- Siatic notch is wider
- Ischia spines are less pointed
