Biomedical Engineering Reference
In-Depth Information
(
Figure 4.12A,B
). These recesses can be approached
laterally through the inferior portion of the lower inter-
costal spaces if the probe is fairly shallow and does not
penetrate the diaphragm. Both the ribs and sternum retain
active hemopoietic tissue throughout the life cycle and thus
bone marrow can be obtained for biopsy by entering the
middle table of these flat bones.
ABDOMINAL AND PELVIC
MORPHOLOGY
External Morphology and Position of
Organs
The abdominal wall protects both the abdominal and pelvic
viscera. The muscles of the ventro-lateral (anterolateral)
abdominal wall (
Howell and Straus, 1933a
)includethemm.
rectus abdominis, obliquus abdominis externus and internus,
and transversus abdominis. The fiber directions, positions,
innervations, and vascular supply to these muscles are
similar to other mammals, including humans. In primates the
subcutaneous fat, which covers the muscular wall, is yellow
as is most of the other fat in the body.
The position of the organs in the abdomen and pelvis of
nonhuman primates is very similar to that of humans. The
stomach occupies the cranial (upper) left quadrant and the
liver occupies the cranial (upper) right and left quadrants.
The transverse colon is fused to the dorsal aspect of the
greater omentum and lies immediately caudal (inferior) to
the stomach. The spleen generally lies dorsally in the
cranial (upper) left quadrant of the abdomen adjacent to the
fundus of the stomach. The kidneys are retroperitoneal and,
unlike in humans, the left kidney lies considerably more
caudal (inferior) than the right one to accommodate the
large left lateral lobe of the liver. The pancreas lies
immediately dorsal (posterior) to the stomach and is
oriented transversely. The pelvic reproductive organs of the
female nonhuman primate differ markedly from those of
most other mammals both in form and position. The uterus
of both the human and nonhuman higher primate female is
a simplex uterus (
Figure 4.13
). The position of the female
organs in monkeys and apes is very similar to that found in
humans, despite their obvious differences in the bony
pelvis.
FIGURE 4.13
Ovaries, uterine tubes, and uterus of a great ape
(Gorilla gorilla). (A) Cranial (superior) view; (B) ventral (anterior)
view. Note the simplex uterus, the dorsal (posterior) position of the
ovaries, the superolateral position of the ovarian vessels (ov. ves.), and the
superolateral entrance of the uterine tubes (ut. tube) into the uterus.
Peritoneal reflections cover the female genital system and form most of its
ligaments, including the broad ligament (bd. lig.). The round ligament (rd.
lig.) is a remnant of the gubernaculum and traverses the broad ligament
between the uterus and the deep inguinal ring. The cervix projects into the
ventral (anterior) aspect of the cranial (superior) vagina. (Adapted from
Wislocki, 1932
; drawings by Nancy Hong.)
and most of the other abdominal organs. The lesser
omentum lies between the stomach and proximal
duodenum and the liver. Dorsal (posterior) to the lesser
omentum and stomach and within the double folds of the
greater omentum lies the lesser omental sac. The primary
difference between humans and nonhuman primates in the
locations of the contents and mesenteries of the peritoneal
cavity is that the latter have more free mesenteries. In
humans the mesentery of the duodenum from the middle of
the first part on through the fourth part is fused to the
posterior abdominal wall. These segments are thus
secondarily retroperitoneal as are both the ascending and
descending colon. In nonhuman primates this secondary
fusion is not as complete. For example, in rhesus macaques
only the first part of the duodenum and the first part of the
colon have fused mesenteries. The remaining small and
large intestines are suspended by free mesenteries.
Peritoneal Cavity
The peritoneal cavity of nonhuman primates is divided into
greater and lesser omental (peritoneal) sacs. As in other
mammals, these are the result of embryonic differential
growth of mesenteries and the rotation of various parts of
the digestive system. The greater omentum is suspended
caudally from the greater curvature of the stomach and
covers the transverse colon as well as the jejuneum, ileum,
Pelvis
The abdominal and pelvic cavities are bounded by the
respiratory diaphragm cranially (superiorly), the inferior
