Groin anatomy Flashcards
(24 cards)
What is the inguinal canal?
A muscular channel that crosses the anterior abdominal wall.
What is the approximate length of the inguinal canal?
Approximately 4cm.
Where is the inguinal canal located?
Above the medial half of the inguinal ligament.
What are the contents of the inguinal canal?
- Ilioinguinal nerve
- Spermatic cord (men)
- Round ligament (women)
How does the ilioinguinal nerve enter the inguinal canal?
It pierces the internal oblique at the side and runs in the inguinal canal, in front of the spermatic cord.
Where does the ilioinguinal nerve exit the inguinal canal?
At the superficial ring.
What areas does the ilioinguinal nerve supply?
- Skin of inguinal regions
- Upper thigh
- Anterior 1/3 of scrotum or labia majora
What is the location of the deep ring
Deep ring - is ~2cm above the mid-point between ASIS and pubic tubercle
Ends
Superficial Ring
+ Re-enforces, therefore areas of weakness are posterior laterally!
What makes up the floor of the inguinal canal?
Floor
Inguinal ligament +
Lacunar ligmant (medially)
Transversalis fascia (laterally)
Lacunar ligament (medially)
Extends from inguinal ligament to pectineal line of pubic bone passes upwards because pectineal line of pubic bone is superior to the inguinal ligament
Crescentic free edge is medial margin of femoral ring
Inguinal ligament (middle)
Transversalis fascia (laterally) – Fused w/ inguinal ligament
What makes up the roof of the inguinal canal?
Internal oblique & Tranversus Abdominus → conjoint tendon
Formed by arched lower borders of:
Internal Oblique → Form conjoint tendon which inserts along pubic crest, and
Transversus abdominis → extends laterally along pectineal line (as far as edge of lacunar lig)
NB// Each arises from inguinal ligament (IO from lateral 2/3; TA from lateral ½)
NB// Conjoint tendon and pectineal line lie in planes at right angles to each other
Arch of roof starts in anterior wall of canal (muscular) passes over canal (becoming tendinous) passes down in posterior wall of the canal (behind to the cord) arrives at pectineal line
NB// Oblique course of canal thru the muscular layers of the abdo wall gives canal strength
Lowermost fibres of these 2 muscles are supplied by iliohypogastric and ilioinguinal nerves (L1) contraction tightens conjoint tendon and lowers roof of the canal (division of ilioinguinal nerve above this level predisposes to direct inguinal hernia)
NB// Damage to ilioinguinal nerve as it lies in the inguinal canal only causes sensory loss (over anterior part of scrotum/ labium majus and adjacent thigh)
What makes up the anterior wall of the inguinal canal
External oblique + internal oblique laterally
EO aponeurosis IO muscle laterally (arises from lateral 2/3 of inguinal ligament covers deep inguinal ring, which is at midpoint of inguinal ligament)
What makes up the posterior wall of the inguinal canal
Transversalis fascia +Conjiont Tendon medially
Posterior wall of the inguinal canal formed by:
Conjoint tendon (medially)
Transversalis fascia + peritoneum (laterally)
Integrity of the inguinal canal depends upon strength of it’s: (1) Anterior wall laterally, and (2) Posterior wall medially canal is pressed flat when: (1) Aponeurosis is under tension, and (2) Intra-abdo pressure is raised
why is the inguinal canal weak in the posterior-lateral region?
Because the posterior wall here is not coinjoint tendon, it is just transversalis fascia
What is the shape and what are the margins of the superficial ring?
V-shaped (triangular, not circular)
Lateral crus. pubic tubercle; medial crus, pubic crest (near symphysis)
NB// Intervening part of pubic crest receives no attachment from EO aponeurosis rather, forms the base of the superficial inguinal ring
Intercrural fibres – Exist at point of junction of lateral and medial crura run perpendicularly to aponeurotic fibres prevent separation of crura
Reflected part of the inguinal ligament – Some of the fibres of the lateral crus, pass from pubic tubercle superomedially behind the cord and medial crus to blend into rectus sheath NB// Constitute a posterior crus, of aponeurosis of the contralateral EO
Cord overlies pubic tubercle at superficial ring to palpate the pubic tubercle, one must invaginate the scrotum behind the cord.
What is the location of and margins of the deep inguinal ring?
Deep inguinal ring lies in transversalis fascia
Located above midpoint of inguinal ligament (6 cm from superficial ring)
Bounded:
Laterally - By the angle b/w the edge of TA and the inguinal ligament
Medially - By the transversalis fascia (projected along canal as internal spermatic fascia) thickened as the interfoveolar ligament (Netter 245)
NB// Interfoveolar ligament (= medial edge of deep ring) – Fibers derived from TA which strengthen transversalis fascia in the posterior wall of the canal arch down from lower border TA around the vas to the inguinal ligament
NB// IO lies anterior to the deep inguinal ring
Spermatic cord/ round ligament of the uterus passing thru the deep inguinal ring
What are the boundaries of the Inguinal (Hesselbach’s) triangle
Lateral boundary – inferior epigastric artery
Medial boundary – lateral border of rectus abdominis
Inferior boundary – inguinal ligament
Where do direct, indirect, and femoral hernias arise?
Lateral to artery (thru deep ring) = Indirect
Medial to artery (thru inguinal triangle) = Direct Stretches out conjoint tendon
NB// Femoral hernia – Enters femoral canal via femoral ring below inguinal ligament, lateral to lacunar ligament
What is the embryological origin of and course of the medial umbilical ligament?
Medial umbilical ligament (obliterated umbilical artery) – Passes obliquely across posterior wall (medial to inferior epigastric artery)
What are the superior, medial, and lateral boundaries of the femoral triangle?
What makes up the floor and roof of the femoral triangle?
Superior: inguinal Liagment
Lateral: sartorius, medial border of..
Medial :Adductor longus, Medial border of.
Roof: Fascia Lata
Floor : liacus, Psoas, Pectinus, Adductor longus
What are the contents of the femoral triangle?
NAVL:
Femoral Nerve
Femoral Artery
Femoral Vein
Femoral Lymph Nodes
List the boundaries of the femoral canal
Anterior Inguinal Ligament
Posterior Pectineal ligament
Medial Lacunar ligament
Lateral Femoral vein
When a hernia is strangulated in femoral canal, what can be incised to release it?
Lacunar ligament
Clinically: what structure can be damaged during repair of femoral hernia?
Abbarent obturator artery: that arises from the external iliac artery - and not the usually internal iliac
What makes up the anterior and posterior layers of the femoral sheath?
What does the femoral sheath contain?
What does it NOT contain?
Anterior - from transversalis fascia
Posterior - layer from fascia over psoas
Contains - artery, vein, lymphatics, femoral branch of genitofemoral nerve, femoral canal
Omits - femoral nerve.
