恥骨結合とは
以下は「船戸和弥のホームページ」の解説文の一部となる。
「恥骨結合は骨盤前面の正中線において両側の恥骨結合面がうすい硝子軟骨に被われて近づき、その両者の間を線維軟骨性恥骨間円板が連結する。その構造は椎間円板の線維輪に似る。女性では妊娠時にこの結合は弱められ、またこのことは分娩時における児頭の産道通過を助ける。モルモットなどでは、女性ホルモンの投与によって、実験的にこの結合を弱めることができる。 」
また、以下は「Wikipedia」の解説文となる。（概要の部分のみ）
「The pubic symphysis or symphysis pubis is the midline cartilaginous joint (secondary cartilaginous) uniting the superior rami of the left and right pubic bones. It is located anterior to the urinary bladder and superior to the external genitalia; for females it is above the vulva and for males it is above the penis. In males, the suspensory ligament of the penis attaches to the pubic symphysis. In females, the pubic symphysis is intimately close to the clitoris. In normal adults it can be moved roughly 2 mm and with 1 degree rotation. This increases for women at the time of childbirth.」
そして、「Radiopaedia.org」では以下のように解説している。
「The pubic symphysis (or symphysis pubis) is a midline secondary amphiarthrodial, fibrocartilaginous joint of the bony pelvis, uniting both pubic bodies.
Gross anatomy
Articulations
The pubic symphysis is a secondary cartilaginous joint, which means there is a wedge-shaped fibrocartilaginous interpubic disc situated between two layers of hyaline cartilage, which line the oval-shaped medial articular surfaces of the pubic bones 1-2.
The width of the joint space differs at different ages:
- ・~10 mm at 3 years ・~6 mm at 20 years ・~3 mm at 50 years
For physiological reasons, women have a greater thickness of the fibrocartialginous disc, allowing more mobility of the pelvic bones and thereby providing a larger pelvic diameter needed for childbirth.
Attachments
Ligaments
The pubic symphysis is reinforced by four strong ligaments 2-3:
- ・superior pubic ligament: runs from pubic crest to pubic crest
- ・inferior pubic (or subpubic or arcuate) ligament: runs from inferior pubic ramus to inferior pubic ramus
- ・anterior pubic ligament: blends with periosteum laterally as well as the interpubic disc
- ・posterior pubic ligament: blends with periosteum of both pubic bodies posteriorly
- （上記の2つのanterior/posterior pubic ligamentの名称は「日本人体解剖学 (下巻)
」には見られないし、ネットで調べても結果はこのサイト以外に得ることはできない）
Musculotendinous
Relations
- anteriorly
- proximal ends of the penile/clitoral shafts
- inferiorly
- urethra
- deep dorsal vein of penis/clitoris
- posteriorly
- bladder (separated from pubic symphysis by the retropubic fat pad)
- prostate and prostatic venous plexus
Movement
Normally very little movement: up to 2 mm shift and 1 degree rotation 2.
Blood supply
Nerve supply
Variant anatomy
- congenital widening of the pubic symphysis (rare) 5
Radiographic appearance
CT/MRI
- due to anteriorly-situated secondary ossification centres may appear "V-shaped" in adolescents on axial slices but will normally be parallel in adults 1
Related pathology
【参考となるサイト】
・イラストや写真を掲載しているサイト-Ⅰ
・イラストや写真を掲載しているサイト-Ⅱ
・イラストや写真を掲載しているサイト-Ⅲ
