Exam IV: Abdomen II Flashcards
Abdominal Wall: Superficial Fatty Fascia
Superficial Fascia- fatty layer called Camper’s fascia with veins that run through it - well vascularized
Male: continuous with dartos fascia of the scrotum.
Female: continuous with superficial fat of the labia majora
As we get closer to the groin region, the fatty layer becomes more membranous
Dartos fascia is a layer under the skin that passes through the scrotum; is another name for superficial fascia
Superficial in abdomen is Camper’s, but groin area is called Dartos
Abdominal Wall: Superficial Membranous Fascia
Superficial fascia: deep layer is membranous that covers the muscles
Thigh: fascia lata
Perineum: superficial perineal fascia
Fundiform ligament
Deep superficial fascia is continuous with the thigh and peritoneum, called fascia lata in the thigh
Coming down from the abdomen to the clitoris or penis = forms the fundiform ligament
For males/females: comes down and splits over the penis/clitoris to support and strengthen both sides
External Oblique
Attachment: outer surface of the lower 8 ribs (ribs V to XII) and lateral iliac crest aponeurosis ending in midline (linea alba)
Innervation: anterior rami of lower 6 thoracic spinal nerve (T7 to T12)
Function: compress abdominal contents
Both muscles- flex trunk
Each side- bend trunk and turn anterior part to opposite side
Orientation of the muscle: lateral superior to medial inferior “hands in pockets”
External Oblique Ligaments: Inguinal and Lacunar
Associated ligaments- External Oblique
Inguinal ligament: inferior border of aponeurosis of external oblique
Lacunar ligament: extension off of inguinal ligament and attaches to the pectin pubis (pubic bone)
External Oblique: Pectin Pubis and Pectineal Ligament
Pectin pubis
Pectineal ligament
Pectineal line with the ligament associated with it to provide support
Internal Oblique
Attachments: thoracolumbar fascia, iliac crests, lateral 2/3 of inguinal ligament, inferior border of lower 3 or 4 ribs, aponeurosis ending in linea alba, pubic crest and pectineal line
Innervation: anterior rami of lower 6 thoracic spinal nerves (T7 to T12) and L1
Function: compression of abdominal contents
Both muscles- flex trunk
Each site- bend trunk and turn anterior part to same side
Transversus Abdominis
Attachment: thoracolumbar fascia, medial lip of iliac crest, lateral 1/3 of inguinal ligament, costal cartilage of lower 6 ribs (ribs VII to XII), aponeurosis ends in linea alba, pubic crest and pectineal line
Innervation: anterior rami of lower 6 thoracic spinal nerves and L1
Function: compresses abdominal contents
Rectus Abdominis
Attachments: pubic crest, pubic tubercle, pubic symphysis, costal cartilage or rib V to VII, xiphoid process
Innervation: anterior rami of lower six or seven throacic spinal nerves (T6~ T7 to T12)
Function: compress abdominal contents, flex vertebral column, tense abdominal wall
Anterior muscle “6 pack”
Pyrimidalis
Attachments: front of the pubis, pubic symphysis, linea alba
Innervation: anterior ramus of T12
Function: tenses the linea alba
Very tiny muscle – 3-3.5 inches
Rectus Sheath
Aponeurotic tendinous sheath formed by a unique layering of the aponeurosis of the external and internal obliques and transversus abdominis muscles
Depending on the location in the abdomen:
The muscles go in different directions
All muscles fuse anteriorly = forms the arcuate line where all of a sudden all the aponeurosis go in front
Aponeurosis went from being behind to being in front= arcuate line and turn into the transversalis fascia instead of rectus sheath
Abdominal Wall Layers
Skin Superficial fascia: fatty layer + deep membranous layer External oblique Internal oblique Transversus abdominis Transversalis fascia Extra peritoneal fascia Parietal peritoneum
Functions of Anterior Abdominal Muscles
- Curvature of waist: external and internal oblique form a “girdle”
- Rotation: external oblique vs internal oblique
Mechanical efficiency increased by fiber direction in each layer
Synergistic – e.g. rotation to left contraction of rt. External oblique and left internal oblique - Flexion: powerful because of lever action
- Lumbar curvature: depends on abdominal and paravertebral muscle + lower back muscles
Relaxed muscles accentuates all 3 curvatures, e.g. posture of elderly because they are not counteracting the back muscles if they are relaxed/weakened
Forward tilt of pelvis counteracted by rectus abdominis.
Innervation of the Abdomen: Cutaneous Branches
T6 – xiphoid
T10 – umbilicus
T11, T12, L1 – below umbilicus
L1- scrotum/labia majora and thigh
Spinal nerves are passing cutaneous branches running deep to the skin- run on top of the external oblique muscles
Give us our dermatome pattern
Innervation of the Abdomen: Muscular Branches
T7 to T12 passes between internal oblique and transversus
L1 passes between internal oblique and external oblique (does not innervate rectus abdominis)
Autonomic nerves: T5-L2 is where they originate from; delivering them from skin and muscles via mixed GVA, GVE, GSA, GSE… no parasympathetic, which only innervates blood vessels
Blood Supply
Internal thoracic artery: musculophreic and superior epigastric both following the costal margin
Aorta: lower intercostal and T12/subcostal artery
External iliac artery: inferior epigastric and deep circumflex iliac; supplies abdominal wall and lower limb
Inferior epigastric is the landmark to define hernia types
Deep circumflex artery: deep and runs across the iliac crest and supplies the iliacis muscle as well as muscles attached to iliac crest
Femoral artery: superficial circumflex iliac and superficial epigastric
Superficial Drainage
Superficial veins:
Above umbilicus → axillary v.
Below umbilicus → femoral v.
Paraumbilical vein- get backed up and pressure= capitis medusa formation
Superficial lymph vessels:
Above umbilicus → anterior axillary nodes
Below umbilicus → superficial inguinal nodes
Venous and Lymphatic Drainage
Deep veins: follow the arterial pattern
Deep lymph vessels: follow the deep arteries → parasternal nodes , lumbar nodes, and external iliac nodes
Groin: Descent of Gonads
Processes vaginalis and descent of gonads into scrotum/labrum majora
External oblique, internal oblique, transversus abdominis, transversalis, testes and gubernaculum = layers
When gonads descend, the muscle layers descend with it and contribute to surrounding scrotum musculature
Ovaries to pelvis or testes to scrotum
We don’t want abdominal contents to go into the scrotum so need to close it off after descent or inguinal hernia can occur
Inguinal Canal
Consequences of testes movement outside of the abdominal cavity in scrotum
Position of blood vessels and nerves of testis pass from abdominal cavity, through inguinal canal into scrotum
Ovaries become located in pelvis
Carries layers of anterior abdominal wall forward to form spermatic cord and round ligament
Oblique path remains in anterior abdominal wall through which gubernaculum and testes passed (inguinal canal)
Deep Inguinal Ring
Deep inguinal ring
Transversalis fascia → internal spermatid fascia (male) and Inner layer (female)
Lateral to epigastric vessels
Superficial to connective tissue layer (extra peritoneal fat) and peritoneum
First structure: deep inguinal ring- opening on inside of abdomen where structures that pass through spermatic cord go through and formed via transversalis fascia, which is the innermost layer of spermatid fascia for males and inner layer for females
Deep inguinal ring occurs lateral to the epigastric artery
Peritoneum gets drawn in and remains
Superficial (Exterior) Inguinal Ring
Superficial (external) inguinal ring consists of:
1. External oblique aponeurosis with spermatic cord passing through
- Crura:
Lateral crus – lateral side of superficial ring
Medial crus – medial side of superficial ring - Inguinal ligament – folded inferior border of external oblique
- Forms external spermatic fascia of spermatic cord/round ligament
Borders of the Inguinal Canal
Anterior Wall: external oblique aponeurosis
Lateral wall: internal oblique muscle, which forms cremaster fascia and muscle / fascia of spermatic cord/round ligament
Posterior wall: transversalis fascia (full length) and conjoint tendon (medial 1/3)
Roof: formed by the arching fibers of the transversus abdominis and internal oblique muscles
Floor: inguinal ligament
Spermatic Cord
Ductus/ Vas deferens- passes through spermatic cord
Artery to the ductus deferens (branch from inferior vesical artery)
Testicular artery (from the abdominal aorta)
Pampiniform plexus and veins (testicular vein)
Cremasteric artery and vein (small vesicles associated with cremasteric fascia)
Genital branch of the genitofemoral nerve (innervation to the cremasteric muscle)
Sympathetic and visceral afferent nerve fibers
Lymphatics
Remnants of the processus vaginalis
External Oblique Aponeurosis
makes the:
Spermatic Cord/Male: external spermatic fascia
Round Ligament/ Female: outer layer
Internal Oblique Muscle
makes the:
Spermatic Cord/ Male: cremaster fascia and muscle
Round Ligament/ Female: diminishes from proximal to distal
Transversalis Fascia
makes the:
Spermatic Cord/Male: internal spermatic fascia
Round Ligament/Female: inner layer
Superior Vesicle Artery
makes the:
Spermatic Cord/Male: ductus deferens artery
Aorta
makes the:
Spermatic Cord/Male: testicular artery
Round Ligament/Female: ovarian artery
Right: Inferior Vena Cava
Left: Left Renal Vein
makes the:
Spermatic Cord/Male: pampiniform plexus
Round Ligament/Female: ovarian vein
L1 and L2
makes the:
Spermatic Cord/Male: genitofemoral nerve
Round Ligament/Female: genitofemoral nerve
Genital Branch in Inguinal Canal
makes the:
Spermatic Cord/Male: cremasteric muscle innervation
Round Ligament/Female: supplies round ligament
Femoral Branch
makes the:
Spermatic Cord/Male: sensory medial thigh
Round Ligament/Female: sensory medial thigh
Ilioinguinal Nerve from L1
makes the:
Spermatic Cord/Male: prosimomedial aspect of thigh + perineal region
Round Ligament/Female: prosimomedial aspect of thigh + perineal region
Inguinal/Hasselbach’s Triangle
Rectus abdominis, epigastric vessels, inguinal ligament forms the borders
Lateral to that is the deep inguinal ring
Inguinal Hernias
- Indirect: goes through deep inguinal ring; more common congenital condition; if you have one hernia on one side probably have it on the other side as well and need to fix both
Indirect + elderly = inferior epigastric vessels are the key!
Lateral to epigastric vessels: deep inguinal ring down to spermatic cord - Direct: people that have weak abdominal wall muscles, or older men predominantly
Women can get both as well
Medial to epigastric vessels: inguinal/Hassalbach’s triangle (DOES NOT GO THROUGH the deep inguinal ring)
