The junction point of the two triangles – that is where the common base resides – coincides with the position occupied by a fibromuscular structure, called the perineal body. The perineal body is a very important anatomical element for at least two reasons:
It has the task of maintaining the integrity of the pelvic floor, avoiding the prolapse of organs such as the rectum, the bladder, the uterus (in women), etc.
It serves to hook the levator ani muscle
(belonging to the aforementioned pelvic floor) and the muscles attributable to the perineum, i.e. the external anal sphincter muscle, the urethral sphincter muscle, the bulbospongiosus muscle and the two transverse perineal muscles, superficial and deep.
Thanks to the innervation of the so-called pudendal nerve, the perineum represents an erogenous zone, both for the male and the female gender.
DIFFERENCES BETWEEN MAN AND WOMAN
The female pelvis has several differences from the male pelvis. These differences are essentially linked to reproduction and to the fact that the pelvic cavity of women is responsible for hosting the fetus and facilitating its escape at the time of birth.
In the list of differences between the female pelvis and the male pelvis, the following can certainly not be missing:The presence, in the woman, of the uterus, fallopian tubes, ovaries and vagina, fundamental organs for the development of the fetus;
The greater size and width of the female pelvis, compared to the male one, which is not only narrower, but also taller and more compact;The greater diameter of the female pelvic inlet, compared to the male one;The greater thickness and heavier heaviness of the male iliac bones;
The greater length and narrowness of the male sacrum as well as the presence, in the latter, of a wider sacral promontory (N.B: the sacral promontory is the bony prominence that articulates the first sacral vertebra with the last lumbar vertebra);
The greater sharpness, in man, of the angle created by the two lower branches of the pubic bone. In the male, the aforesaid angle is about 70 °; in the female, on the other hand, it is between 90 and 100 °;The greater distance, in women, between the acetabula (N.B: the acetabulum is the concavity of the iliac bone that houses the head of the femur and forms the hip joint).
The pelvis fulfills at least 3 important functions:
It supports the weight of the upper body and, at the same time, discharges it from the axial skeleton to the lower limb skeleton (which represents a part of the so-called appendicular skeleton);It forms joints (eg: hip) and inserts muscles (eg: some hip muscles), both of which are essential for locomotion and the maintenance of upright posture;
It encloses and protects, both through bone structures (the pelvic girdle) and through a solid network of muscles (the so-called abdominals), the so-called pelvic organs (bladder, urethra, rectum, sigmoid, reproductive organs, etc.).
Muscles of the hip that have relations with the bones of the pelvis:Gluteal muscle groupGluteus maximus muscleGluteus medius muscleGluteus minimus muscleTensor fascia lata muscle
Adductor muscle groupAdductor brevis muscleAdductor longus muscleAdductor major musclePectineus muscleGracilis muscleIliacus muscleLateral rotator muscle groupInternal obturator muscleExternal obturator musclePiriformis muscleSuperior twin muscleLower twin muscleSquare muscle of the femur