The pelvic area includes the pelvic bones, sacrum, coccyx, pubic symphysis, as well as ligaments, joints and membranes. Some experts relate the buttock area to it.
The article discusses the anatomy of the pelvis: the skeletal system, muscles, genital and excretory organs.
Bone pelvic system
The pelvic skeleton consists of the pelvic bones, sacrum and coccygeal bone. Each of them is firmly fixed. The ilium and the coccygeal bone are articulated with the sacrum.
The pelvis is divided into large and small departments.
The first consists of sides with the wings of the ilium. On the inner surface there is an iliac pit, and on the outside there are buttock pits.
The small pelvis consists of a cylindrical cavity with upper and lower openings (i.e., inlet and outlet).
The coccygeal bone is slightly mobile, which helps women during childbirth. Pelvic bone anatomy has the following differences between men and women:
- the male pelvis is long and narrow, in women it is shorter and wider;
- the male pelvic cavity is conical, the female is cylindrical;
- the ilium wings in men are more vertical, in women - more horizontally;
- the branches of the pubic bones in men make an angle of 70-75 degrees, in women - 90-100 degrees;
- in men, the entry form resembles a heart (as on cards), in women it is rounded, although it happens that in women there is an entrance as a “card heart”.
Ligaments
Well-developed ligaments fix four pelvic bones, the anatomy of which is discussed above. Three joints help to connect them together: pubic fusion (two unpaired), sacroiliac (pair) and sacrococcygeal fusion.
One is located on the pubic bones from the upper edge, the other from the bottom. The third ligaments strengthen the joints of the sacral and iliac bones.
Muscular pelvic system
In this section, the anatomy of the pelvis is represented by the parietal and visceral muscles. In the first part, in the pelvis there is a muscle, consisting of three interconnected m.iliacus, m.psoas major and m.psoas minor. In the small pelvis, the same parietal muscles are represented by the piriformis muscle, internal obstructive and coccygeal.
Visceral muscles take part in the formation of the diaphragm of the pelvis. It includes paired muscles that raise the anus and unpaired m.sphincter ani extremus.
Here are the pubic-coccygeal muscle, the iliac-coccygeal muscle, as well as the powerfully developed circular muscle of the distal part of the rectum.
Blood supply and lymphatic system
Blood enters the pelvis (the anatomy here involves the participation of the walls of the pelvis and internal organs) from the hypogastric artery. It is divided first into the front and back, and then into other branches.
Blood enters the soft tissues of the pelvis through a single vessel a.iliolumbalis, which branches into two terminal branches.
The walls of the pelvic provide four arteries:
- lateral sacral;
- obturator;
- upper buttock;
- lower buttock.
The vessels of the abdominal walls and retroperitoneal space are involved in the circulatory circulation. In the roundabout venous circle, the main veins pass between the large and small pelvis. There are abundant venous anastomoses located near the wall of the rectum and in its thickness, as well as under the peritoneum of the pelvis. With blockade of the large pelvic veins, the veins of the spine, lower back, anterior abdominal wall and retroperitoneal fiber serve as roundabouts.
Anatomy of the pelvis, like other systems, suggests the variability of vascular morphology in lymph.
The main lymphatic collectors from the pelvic organs are the iliac lymph nodes, distracting lymph.
Lymphatic vessels under the peritoneum mainly pass at the level of the middle floor of the pelvis.
Innervation
The nerves of this area are divided into:
- somatic;
- vegetative (parasympathetic and sympathetic).
The somatic system of nerves is represented by the sacral plexus associated with the lumbar. Sympathetic - with the sacral part of the border trunks and the unpaired coccygeal node. Parasympathetic nerves are nn.pelvici s.splanchnici sacrales.
Buttocks
Often the buttock anatomy is not included in the pelvis. However, topographically, it should be attributed here, and not to the lower extremities. Therefore, we briefly touch on her.
The gluteal region above is limited by the iliac crest, and below the gluteal fold, under which the gluteal groove is located. On the lateral side, you can imagine a vertical line of a number of bones, and on the medial side, both areas are separated by an intergluteal fissure.
Consider the anatomy here in layers:
- the skin of this area is thick and dense;
- subcutaneous tissue with superficial, middle and lower nerves is well developed;
- then follows the surface plate of the gluteal fascia;
- gluteus maximus muscle;
- gluteal fascia plate;
- fatty tissue between the large muscle and the middle layer of muscles;
- middle layer of muscles;
- deep layer of muscles;
- bones.
Excretory organs
The anatomy of the small pelvis includes an unpaired muscle organ - the bladder. It consists of the top, body, bottom and neck. One department here goes into another. The bottom is fixed with the urogenital diaphragm. When the bladder begins to fill up, its shape becomes ovoid. With an empty bubble, the shape is close to saucer-shaped.
Blood supply comes from the hypogastric artery system, and the venous outflow is directed into the dense cystic plexus, which is adjacent to the lateral surfaces and the prostate gland.
Innervation is carried out by somatic and vegetative fibers.
The rectum begins to develop from the embryonic germ. The upper section is derived from the endoderm, and the lower one appears by screwing from the surface of the ectoderm layer.
The rectum is located at the level of the posterior pelvic region. It is divided into three departments: upper, middle and lower.
The muscles on the outside are represented by powerful longitudinal fibers, and inside - circular. The mucosa consists of numerous folds. Innervation here is similar to what happens in the bladder.
Reproductive system
Without the reproductive system, it is impossible to consider the pelvis (structure). The anatomy of this area in both sexes consists of the sexual gland, wolf body, canal, Muller duct, genitourinary and genital tubercles, folds and ridges.
The sex gland is laid in the lower back and turns into a testicle or ovary, respectively. The Wolf body, channel and duct of the mullers are also laid here. However, further on, the mueller channels differentiate in the female, and in the male, the wolf body and ducts.
The remaining primordia are reflected on the external organs.
The testicle and ovary grow behind the peritoneum.
The male reproductive system is represented by:
- testicular cover, consisting of skin, fleshy membrane, cooper fascia, cremaster, common and own vaginal membrane, albumen;
- seminal gland;
- lymphatic system;
- appendage, consisting of three departments (head, body and tail);
- spermatic cord;
- seminal vesicles (hollow tubes with bay-like protrusions);
- prostate gland (glandular-muscular organ between the diaphragm and the bottom of the bladder);
- penis, consisting of three departments (root, body and head);
- urethra
The anatomy of the female pelvis includes the reproductive system of:
- uterus (a derivative of the Muller canals);
- ovaries located in a special ovarian fossa;
- fallopian tubes, consisting of four sections (funnel, expanded part, isthmus and part perforating the wall);
- vagina
- external genitalia, consisting of the labia majora and vulva.
Crotch
This area is located from the pubic hill to the top of the coccygeal bone of the pelvis.
The anatomy of the perineum in both men and women is divided into 2 areas: shameful (front) and anal (back). In front of the area corresponds to the urogenital triangle, and behind the rectum.
Conclusion
This is the structure of the pelvis as a whole. The anatomy of this area is certainly a complex system. The article gives only a brief overview of what it consists of and how it works.