Lecture 4 - Abdomen and Pelvis Flashcards
What are the boundaries of the abdominal cavity?
Boundaries:
• Superiorly: Diaphragm
• Posteriorly: Lumbar vertebrae and posterior
abdominal wall muscles
• Antero-laterally: Muscles of the
anterolateral abdominal wall
• Inferiorly: continuous with the pelvic cavity
What are the different movements of the trunk?
External oblique.
Name the attachments, actions and nerve.
Internal oblique
Name the attachments, actions and nerve.
Transverse abdominis.
Name the attachments, actions and nerve.
Rectus abdominis
Name the attachments, actions and nerve.
Aponeuroses of the External oblique, Internal oblique and Transversus
abdominis muscles contribute to the formation of the__________
Aponeuroses of the External oblique, Internal oblique and Transversus
abdominis muscles contribute to the formation of the rectus sheath.
Functional considerations:
What are the actions of the anterior abdominal wall muscles?
- Movement: flexion, lateral flexion and rotation of the trunk.
Note: the obliques act as muscle couples to accomplish rotation:
left external oblique and right internal oblique rotate the trunk to the right;
right external oblique and left internal oblique rotate the trunk to the left. - Support to the abdominal viscera:
Abdominal cavity acts as a pressure cylinder. Contraction of abdominal
muscles increases intraabdominal pressure, important in:
• normal micturition, defecation, parturition and respiration;
• forced expiration, i.e., coughing, sneezing;
• normal posture and weight lifting.
Identify the structures in this image.
Antero-lateral abdominal wall layers.
What is the inguinal canal and its components?
The inguinal canal is a passage in the anterior abdominal wall. It is important
because the testes descend through it in males during development, and loops of gut may be forced through it as well.
Openings of the inguinal canal:
superficial and deep inguinal rings.
Contents of the inguinal canal in males?
vas deferens (ductus deferens), testicular artery and vein, ilioinguinal nerve, genital branch of the genitofemoral nerve, autonomic nerves to the testis and lymph drainage from the testis. These structures descend with the testis and form the spermatic cord.
Contents of the inguinal canal in females?
Round ligament of the uterus – supports the position of the uterus.
What is a hernia?
An abnormal prolapse (exit) of tissues or organs through the wall of the
cavity they normally reside in is called a hernia. Hernias most commonly
involve the abdomen.
Explain what is a indirect and direct hernia. + the statistics
Approximately 90% of all hernias are
inguinal hernias = in the groin
(inguinal) region.
• 75% of all inguinal hernias are in
males.
• Inguinal hernias:
1. Direct
2. Indirect
Indirect inguinal hernias pass through the deep inguinal ring, inguinal canal and
superficial inguinal ring. They are 20x more common in males than females.
Direct inguinal hernias do not pass through the inguinal canal, they push directly through the superficial inguinal ring. They are most common in males over 40.
Identify which of the images are indirect inguinal hernia and direct inguinal hernia.
Other types of hernias?
Abdominal digestive tract: _____________ (duodenum, jejunum and
ileum), and ____________ (caecum, appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum).
Organs, glands and other structures associated with the alimentary tract:
1.
2.
3.
Abdominal digestive tract: stomach, small intestine (duodenum, jejunum and
ileum), and large intestine (caecum, appendix, ascending colon, transverse colon,
descending colon, sigmoid colon, rectum).
Organs, glands and other structures associated with the alimentary tract:
• liver, gallbladder, pancreas, spleen
• abdominal aorta and its branches
• portal vein
Development of the alimentary tract. Name and describe the structures.
What is the blood supply to digestive tract and related organs?
So what are the branches of the abdominal aorta?
IDENTIFY
Explain the innervation of the digestive tract: ANS
- Sympathetic innervation:
Thoracic splanchnic nerves
from sympathetic chain.
Innervation of the digestive tract: ANS - Parasympathetic: (“Rest and digest”)
Cranio-sacral origin of parasympathetic
innervation:
- Vagus nerve (CN X) and
- Pelvic splanchnic nerves
(S2, S3, S4).
Identify the bones of the pelvis.
Bony pelvis: 2 hip bones (L + R), each consisting of:
- Ilium
- Pubis
- Ischium
Explain the pelvic floor.
Lack of ________can lead to
incontinence (male and female).
Muscles of the pelvic floor are
__________________.
Pelvic floor is a muscular layer that separates
the abdomino-pelvic cavity from the perineum
(area of external genitalia).
Pelvic floor muscles support pelvic viscera;
their contractions also control/tighten the
sphincter muscles around the openings of the
urethra, anus and vagina. Relaxing the pelvic
floor muscles allows passage of urine and
feces.
Lack of exercise can lead to
incontinence (male and female).
Muscles of the pelvic floor are
stretched during child birth.
What are the Pelvic floor muscles?
1) Levator ani muscle, composed of two muscles:
• Pubococcygeus (a)
• Iliococcygeus (b)
2) Coccygeus (or Ischiococcygeus) (c)
Explain the pudendal nerve and its branches.
Nerve to the pelvic floor muscles. The origin of the pudendal nerve is from sacral
spinal nerves S2, S3, S4.
• Pudendal nerve motor
branches supply muscles of
the pelvic floor (Levator ani,
Coccygeus) and sphincters
surrounding the orifices
(urethra, vagina, anal canal).
• Pudendal nerve sensory
branches carry sensation
from the skin of the
perineum and the external
genitalia.
