Anterior abdominal wall and inguinal region Flashcards
Name the three layers of muscle that comprise the anterolateral abdominal wall from superficial to deep.
External oblique, internal oblique, transversus abdominus.
What is the name of the vertical-running muscle that lies in the midline?
Rectus abdominus.
In what direction do the fibres of external oblique run?
P \\ A ie ‘front pocket’ muscles.
In what direction do the fibres of internal oblique run?
P //// A ie ‘back pocket’ muscles.
In what direction do the fibres of transverse abdominus run?
P \\ A except more horizontal near the umbilicus.
What is an aponeurosis?
A thin, sheet-like tendon, analogous to a cord-like tendon.
What are the functions of the anterior abdominal wall muscles?
Flexing the trunk forwards, flexing the trunk from side to side, compressing the abdominal contents, supporting and containing abdominal contents.
What is the nerve supply to the skin and muscle of the anterior abdominal wall?
Anterior cutaneous branches of T7-12 from segmented spinal nerves.
What is the name of the anterior abdominal fascia?
Scarpa’s fascia
What is the name of the name of the fascia of the perineum continuous with Scarpa’s fascia?
Colle’s fascia
How is the the inguinal ligament formed?
The lower border of the external oblique aponeurosis forms the inguinal ligament on each side. This thickened reinforced free edge of the external oblique aponeurosis passes between the anterior superior iliac spine laterally and the pubic tubercle medially. It folds under itself forming a trough, which plays an important role in the formation of the inguinal canal.
How do the fibres of transversus abdominus relate to the inguinal ligament?
The roof of the inguinal canal is formed by the arching fibres of the transversus abdominus and the internal oblique muscle. They pass from their lateral points of origin from the inguinal ligament to their common medial attachment as the conjoint tendon.
What and where is the conjoint tendon?
The combined insertion of transversus abdominus and internal oblique muscles into the pubic crest.
What are the attachments of rectus abdominus?
Pubic symphysis and costal margin.
Describe the arrangement of the rectus sheath above the umbilicus.
External oblique aponeurosis is superficial to rectus abdominus. Internal oblique aponeurosis splits - one layer is superficial to rectus abdominus, one layer deep. Transversus abdominus aponeurosis lies deep to rectus abdominus.
Describe the arrangement of the rectus sheath below the umbilicus.
All aponeuroses lie superficial to rectus abdominus.
Define the arcuate line.
Horizontal line that demarcates lower limit of the rectus sheath. Point at which the aponeuroses change their configuration over the rectus sheath.
Name the three coverings of the spermatic cord from superficial to deep.
External spermatic fascia, cremasteric fascia, internal spermatic fascia.
Name the covering of the testicle. What is its embryological origin?
Tunica vaginalis. Originates from processus vaginalis.
What is the cremasteric reflex?
Contraction of the cremaster muscle and elevation of the testes. Reflex arc occurs when you touch the skin at and around the anterior aspect of superior thigh. Sensory fibres enter spinal cord at L1, where they stimulate motor fibres carried in genital branch of genitofemoral nerve.
What does the spermatic cord contain?
Ductus deferens, artery of ductus deferens, testicular artery, cremestaric artery, pampiniform venous plexus, sympathetic nerve fibres, genital branch of genitofemoral nerve, lymphatic vessels
What lies at the medial and lateral borders of the deep inguinal ring
Medial border: inderior epigastric artery Lateral: inguinal ligament
Where does the deep inguinal ring lie?
Midway between the ASIS and the pubic tubercule.
What are the boundaries of the superficial inguinal ring?
Superior: Aponeurosis of external oblique Inferior: Pubic tubercule Lateral: Inguinal ligament Medial: Conjoint tendon
What is the approximate length of the inguinal canal?
4cm
What forms the roof of the inguinal canal?
Arching fibers of the transversus abdominus and internal oblique muscles
What forms the floor of the inguinal canal?
The medial one-half of the inguinal ligament.
What forms the posterior wall of the inguinal canal?
Transversalis fascia reinforced by the conjoint tendon.
What forms the anterior wall of the inguinal canal?
Aponeurosis of external oblique.
How does the ilioinguinal nerve enter the inguinal canal and what does it supply?
Pierces the internal oblique then accompanies the spermatic cord through the superficial ring.
Describe in indirect inguinal hernia.
The abdominal contents protrude through the deep inguinal ring, lateral to the inferior epigastric vessels and can enter the scrotum. Can be caused by a failure of the processus vaginalis to close.
Describe a direct inguinal hernia.
Occur medial to the inferior epigastric vessels. When bowel protrudes through a weak spot in the transversalis fascia and can exit through the superficial inguinal ring. They are incapable of protruding into the scrotum.
