Breast - lymphatic drainage

The lymphatic and venous drainages of the breast are of great importance in the spread of carcinoma. 

About three quarters of the lymphatic drainage is to the axillary nodes: 

(1) Lymphatics pass around the edge of the pectoralis major and reach the pectoral group of axillary nodes; 

(2) routes through or between the pectoral muscles may lead directly to the apical nodes of the axilla; 

(3) lymphatics follow the blood vessels through the pectoralis major and enter the parasternal (internal thoracic) nodes; 

(4) connections may lead across the median plane and hence to the contralateral breast; 

(5) lymphatics may reach the sheath of the rectus abdominis and the subperitoneal and subhepatic plexuses.

It should be noted that free communication exists between nodes below and above the clavicle and between the axillary and cervical nodes.

Perineal body

The perineal body (or central tendon of perineum) is a pyramidal fibromuscular mass in the middle line of the perineum at the junction between the urogenital triangle and the anal triangle . It is found in both males and females. In males, it is found between the bulb of penis and the anus; in females, is found between the vagina and anus, and about 1.25 cm in front of the latter.

The perineal body is essential for the integrity of the pelvic floor, particularly in females. Its rupture during delivery leads to widening of the gap between the anterior free borders of levator ani muscle of both sides, thus predisposing the woman to prolapse of the uterus, rectum, or even the urinary bladder.

At this point, the following muscles converge and are attached:

* External anal sphincter 
* Fibers from external urinary sphincter
* Superficial transverse perineal muscle
* Deep transverse perineal muscle
* Anterior fibers of the levator ani 
* Bulbospongiosus

Urogenital diaphragm

Most of the support of the perineum is provided by the pelvic and urogenital diaphragms.


The urogenital diaphragm is external to the pelvic diaphragm and includes the triangular area between the ischial tuberosities and the symphysis. The urogenital diaphragm is made up of the deep transverse perineal muscles, the constrictor of the urethra, and the internal and external fascial coverings (perineal membrane).

Pelvic diaphragm

The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus(ishciococcygeus), and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the levatores ani and coccygei, with which may be included the parietal pelvic fascia on their upper and lower aspects. The pelvic floor separates the pelvic cavity above from the perineal region (including perineum) below.

The right and left levator ani lie almost horizontally in the floor of the pelvis, separated by a narrow gap that transmits the urethra, vagina, and anal canal. The levator ani is usually considered in three parts: pubococcygeus, puborectalis, and iliococcygeus. The pubococcygeus, the main part of the levator, runs backward from the body of the pubis toward the coccyx and may be damaged during parturition. Some fibers are inserted into the prostate, urethra, and vagina. The right and left puborectalis unite behind the anorectal junction to form a muscular sling . Some regard them as a part of the sphincter ani externus. The iliococcygeus, the most posterior part of the levator ani, is often poorly developed.

The coccygeus(ischiococcygeus), situated behind the levator ani and frequently tendinous as much as muscular, extends from the ischial spine to the lateral margin of the sacrum and coccyx.

The pelvic cavity of the true pelvis has the pelvic floor as its inferior border (and the pelvic brim as its superior border.) The perineum has the pelvic floor as its superior border.

Some sources do not consider "pelvic floor" and "pelvic diaphragm" to be identical, with the "diaphragm" consisting of only the levator ani and coccygeus, while the "floor" also includes the perineal membrane and deep perineal pouch. However, other sources include the fascia as part of the diaphragm. In practice, the two terms are often used interchangeably.

Inferiorly, the pelvic floor extends into the anal triangle.

Uterine artery

*The uterine artery arises from the anterior trunk of the internal iliac artery(hypogastric artery) .
*Its course is at first downwards and forwards until it reaches the parametrium when it turns medially towards the uterus.
*It reaches the uterus at the level of the internal os, where it turns upwards, at right angles, and follows a spiral course along the lateral border of the uterus to the region of the uterine cornu.
*Here it sends a branch to supply the fallopian tube and ends by anastomosing with the ovarian artery.
*The tortuosity is lost when the uterus enlarges during pregnancy.
*During the vertical part of its course it sends branches which run transversely and pass into the myometrium. These are called the arcuate arteries.
*From these arcuate arteries, a series of radial arteries arise, almost at right angles.
*These radial arteries reach the basal layers of the endometrium, where they are termed as the basal arteries.
*From these are derived the terminal spiral and straight arterioles of the endometrium.
*THE LEAST VASCULAR PART OF THE UTERUS IS THE MIDLINE.

*The branches of the uterine artery are :
1. Ureteric artery
2. Descending vaginal artery- These unite to form the anterior and posterior azygos artery of the vagina. This is of great importance during the Total hysterectomy.
3. Circular cervical
4. Arcuate -- radial -- basal -- spiral and straight arterioles of the functional layer of the endometrium.
5. Anastomotic branch with the ovarian artery

*The relation of the uterine artery to the ureter is of great importance.
*The uterine artery crosses above the ureter in the parametrium where it gives off an important ureteric branch to that structure.
*The artery runs transversely while the ureter runs approximately anteroposteriorly through the ureteric canal of the parametrium.

*The ovarian artery is derived from the AORTA.

Pelvic bone