the pelvis
TRANSCRIPT
The PelvisThe PelvisLectured by Bien Eli Nillos, MDLectured by Bien Eli Nillos, MD
1.1. No. of bones composing the bony No. of bones composing the bony pelvispelvis
2.2. What divides the true pelvis from What divides the true pelvis from false pelvisfalse pelvis
3 – 5. What comprises the answer to No. 3 – 5. What comprises the answer to No. 2? (anterior, lateral and posterior)2? (anterior, lateral and posterior)
6. What is the floor of the pelvis?6. What is the floor of the pelvis?
7 – 8. What comprises answer to No. 87 – 8. What comprises answer to No. 8For no. 9 – 10, answer whether it is a male of female For no. 9 – 10, answer whether it is a male of female
pelvis being described.pelvis being described.
9. Pelvic inlet is heart shaped9. Pelvic inlet is heart shaped
10. False pelvis is shallower. 10. False pelvis is shallower.
The PelvisThe Pelvis
The region of the trunk that lies The region of the trunk that lies below the abdomen. The abdominal below the abdomen. The abdominal and pelvic cavities are continuous.and pelvic cavities are continuous.
Surface LandmarksSurface Landmarks
Iliac CrestIliac Crest Anterior Superior Iliac Spine – upper Anterior Superior Iliac Spine – upper
lateral end of the fold of the groinlateral end of the fold of the groin Posterior Superior Iliac Spine – Posterior Superior Iliac Spine –
posterior end of the iliac crest, lies at posterior end of the iliac crest, lies at the bottom of a small skin dimple the bottom of a small skin dimple and on a level with the second sacral and on a level with the second sacral spine.spine.
Pubic Tubercle – upper border of the Pubic Tubercle – upper border of the pubispubis
Symphysis Pubis – cartilaginous joint Symphysis Pubis – cartilaginous joint that lies in the midline between the that lies in the midline between the bodies of the pubic bones. bodies of the pubic bones.
Pubic Crest – ridge of bone on the Pubic Crest – ridge of bone on the superior surface of the pubic bone, superior surface of the pubic bone, medial to the pubic tuberclemedial to the pubic tubercle
Spinous Process of the Sacrum – Spinous Process of the Sacrum – fused in the midline to form the fused in the midline to form the median sacral crestmedian sacral crest
Sacral Hiatus – posterior aspect of Sacral Hiatus – posterior aspect of the lower end of the sacrumthe lower end of the sacrum
Coccyx – inferior surface and tip can Coccyx – inferior surface and tip can be palpated in the natal cleft about 1 be palpated in the natal cleft about 1 inch behind the anusinch behind the anus
PelvisPelvis
Composed of four bones: 2 Composed of four bones: 2 innominate bones, sacrum and innominate bones, sacrum and coccyxcoccyx
Pelvic brim: sacral promontory Pelvic brim: sacral promontory behind, iliopectineal lines laterally, behind, iliopectineal lines laterally, symphysis pubis anteriorly. symphysis pubis anteriorly.
Above the brim is the FALSE PELVIS Above the brim is the FALSE PELVIS (greater pelvis).(greater pelvis).
Below the brim is the TRUE PELVIS Below the brim is the TRUE PELVIS (lesser pelvis)(lesser pelvis)
The Lesser or True Pelvis (pelvis minor).The Lesser or True Pelvis (pelvis minor).—The lesser pelvis is that part of the —The lesser pelvis is that part of the pelvic cavity which is situated below pelvic cavity which is situated below and behind the pelvic brim. Its bony and behind the pelvic brim. Its bony walls are more complete than those of walls are more complete than those of the greater pelvis. For convenience of the greater pelvis. For convenience of description, it is divided into an description, it is divided into an inletinlet bounded by the superior circumference, bounded by the superior circumference, and and outletoutlet bounded by the inferior bounded by the inferior circumference, and a circumference, and a cavitycavity..
The Superior Circumference.—The The Superior Circumference.—The superior circumference forms the brim superior circumference forms the brim of the pelvis, the included space being of the pelvis, the included space being called the superior aperture or inlet called the superior aperture or inlet
The superior aperture is somewhat The superior aperture is somewhat heart-shaped, obtusely pointed in heart-shaped, obtusely pointed in front, diverging on either side, and front, diverging on either side, and encroached upon behind by the encroached upon behind by the projection forward of the promontory projection forward of the promontory of the sacrum.of the sacrum.
It has three principal diameters: It has three principal diameters: antero-posterior, transverse, and antero-posterior, transverse, and oblique.oblique.
The The anteroposterior or conjugate anteroposterior or conjugate diameterdiameter extends from the extends from the sacrovertebral angle to the sacrovertebral angle to the symphysis pubis; its average symphysis pubis; its average measurement is about measurement is about 110 mm110 mm. in . in the female. the female.
The The transverse diametertransverse diameter extends extends across the greatest width of the across the greatest width of the superior aperture, from the middle of superior aperture, from the middle of the brim on one side to the same the brim on one side to the same point on the opposite; its average point on the opposite; its average measurement is about measurement is about 135 mm135 mm. in . in the female. the female.
The The oblique diameteroblique diameter extends from extends from the iliopectineal eminence of one the iliopectineal eminence of one side to the sacroiliac articulation of side to the sacroiliac articulation of the opposite side; its average the opposite side; its average measurement is about measurement is about 125 mm.125 mm. in in the female.the female.
The Lower CircumferenceThe Lower Circumference—The —The lower circumference of the pelvis is lower circumference of the pelvis is very irregular; the space enclosed by very irregular; the space enclosed by it is named the inferior aperture or it is named the inferior aperture or outlet, is bounded behind by the outlet, is bounded behind by the point of the coccyx, and laterally by point of the coccyx, and laterally by the ischial tuberosities.the ischial tuberosities.
The diameters of the outlet of the The diameters of the outlet of the pelvis are two: pelvis are two: antero-posterior antero-posterior and transverse.and transverse.
The The antero-posterior diameterantero-posterior diameter extends from the tip of the coccyx to extends from the tip of the coccyx to the lower part of the pubic the lower part of the pubic symphysis; its measurement is from symphysis; its measurement is from 90 to 115 mm. in the female.90 to 115 mm. in the female.
The The transverse diametertransverse diameter, , measured between the posterior measured between the posterior parts of the ischial tuberosities, is parts of the ischial tuberosities, is about 115 mm. in the female.about 115 mm. in the female.
In the erect posture, the pelvis is In the erect posture, the pelvis is placed obliquely with regard to the placed obliquely with regard to the trunk: the plane of the superior trunk: the plane of the superior aperture forms an angle of from 50° aperture forms an angle of from 50° to 60°, and that of the inferior to 60°, and that of the inferior aperture one of about 15° with the aperture one of about 15° with the horizontal plane.horizontal plane.
The pelvic surface of the symphysis The pelvic surface of the symphysis pubis looks upward and backward, pubis looks upward and backward, the concavity of the sacrum and the concavity of the sacrum and coccyx downward and forward. coccyx downward and forward.
The position of the pelvis in the erect The position of the pelvis in the erect posture may be indicated by holding posture may be indicated by holding it so that the anterior superior iliac it so that the anterior superior iliac spines and the front of the top of the spines and the front of the top of the symphysis pubis are in the same symphysis pubis are in the same vertical plane.vertical plane.
Muscles of the PelvisMuscles of the Pelvis
PiriformisPiriformis– Origin: front of Origin: front of
sacrumsacrum– Insertion: greater Insertion: greater
trochanter of femurtrochanter of femur– Action: lateral Action: lateral
rotator of femur at rotator of femur at hip jointhip joint
Obturator Internus:Obturator Internus:– Origin: obturator Origin: obturator
membrane and membrane and adjoining part of hip adjoining part of hip bonebone
– Insertion: greater Insertion: greater trochanter of femurtrochanter of femur
– Action: lateral Action: lateral rotator of femur at rotator of femur at hip jointhip joint
Levator ani:Levator ani:– Origin: body of pubis, fascia of obturator Origin: body of pubis, fascia of obturator
internus, spine of ischiuminternus, spine of ischium– Insertion: perinela body, anococcygeal Insertion: perinela body, anococcygeal
body, walls of prostate, vagina, rectum body, walls of prostate, vagina, rectum and anal canaland anal canal
– Action: supports pelvic organsAction: supports pelvic organs
Anterior fibers – levator Anterior fibers – levator prostatae/sphincter vaginaeprostatae/sphincter vaginae
Intermediate fibers – puborectalis, Intermediate fibers – puborectalis, pubococcygeus, anococcygeal bodypubococcygeus, anococcygeal body
Posterior fibers - iliococcygeusPosterior fibers - iliococcygeus
Coccygeus:Coccygeus:– Origin: spine of ischiumOrigin: spine of ischium– Insertion: lower end of sacrum; coccyxInsertion: lower end of sacrum; coccyx– Action: assists levator ani to support Action: assists levator ani to support
pelvic organspelvic organs
Male and Female PelvisMale and Female Pelvis
Urinary BladderUrinary Bladder Receptacle for storage of urineReceptacle for storage of urine
UreterUreter Crosses the pelvic inlet in front of the Crosses the pelvic inlet in front of the
bifurcation of the common iliac arterybifurcation of the common iliac artery
Vas DeferensVas Deferens Conveys mature sperm from epididymis Conveys mature sperm from epididymis
to the ejaculatory duct and the urethrato the ejaculatory duct and the urethra
ProstateProstate Inverted pyramid, fibromuscular Inverted pyramid, fibromuscular
glandular organ.glandular organ.
OvaryOvary
Almond-shaped organAlmond-shaped organ
Uterine (Fallopian) TubesUterine (Fallopian) Tubes 4 inches long, four parts: infundibulum, 4 inches long, four parts: infundibulum,
ampulla, isthmus, intramuralampulla, isthmus, intramural
UterusUterus
CervixCervix
VaginaVagina