Download Organization of the nervous system

The abdomen
Anterior Abdominal Wall
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Superior Border
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Infrasternal notch
Costal Margins and Arch
Anterior Abdominal Wall
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Inferior Borders
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Inguinal Ligament
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What is it?
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Where does it attach?
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What does it separate?
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Inguinal fold
Surface Anatomy
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Umbilicus
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Level
Variety
Anterior Median line
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Linea alba
Levels of Markers and Planes
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Subcostal plane
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Transtubercular plane
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Midclavicular plane
Zones of the Abdomen
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Hypochondriac, Epigastric
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Lumbar (Lateral), Umbilical
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Iliac (Inguinal), Hypogastric
Fascia of the abdominal wall
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Two layers
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Superficial Fascia
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Over most of body
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In lower abdominal region
Deep Fascia
Nerves and blood vessels
Organization of the nervous
system
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Dorsal roots
Dorsal root ganglia
Ventral roots
Meninges
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Dura mater
Arachnoid membrane
Pia mater
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Filum terminale – extension of pia
mater
Coccygeal ligament – filum terminale
fuses with dura mater and attaches to
coccyx
Organization of Nerves
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As they exit the vertebral column, the
dorsal and ventral roots join to form the
spinal nerve (a mixed nerve)
The spinal nerve then divides into a
posterior (dorsal) primary ramus and an
anterior (ventral) primary ramus
Dorsal and Ventral Rami
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The dorsal primary ramus innervates
the skin and muscles around the spine
The ventral primary ramus innervates
the skin and muscles for the rest of the
body
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Lateral and anterior trunk
Upper and lower extremities
Anterior Rami
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Nerve plexuses
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Cervical: C1-C4
Brachial: C5-T1
Lumbar: branch from T12, and L1-L4
Sacral: L4-S3
Pudendal: Parts of S2 and S3, and all of S4
– important for control of bowel, bladder
and sexual function
Anterior Rami in the Thoracic
Region
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Do NOT form a nerve plexus
T1-T11: Intercostal nerves
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T12: Subcostal nerve
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Travel between ribs
Travels below 12th rib
L1: Follow similar direction as intercostal and
subcostal nerves
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Iliohypogastric nerve: lowest cut. nerve in
abdomen
Ilioinguinal nerve
Branches of T1-L1
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Motor branches to intercostal and
abdominal muscles
Lateral cutaneous branch – sensory to
skin
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Anterior and posterior branches
Anterior cutaneous branch – sensory to
skin
Walls of Inguinal Canal
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Anterior wall
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Part of aponeurosis of external oblique
Reinforced laterally by fibers of int. oblique
and sometimes the transversus abdominis
Posterior wall
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Fascia transversalis
Medially by fibers of conjoint tendon, the
common tendon of int. oblique and
transversus abdominis muscles
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Superior wall (roof)
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Arching fibers of IO and TA
Inferior wall (floor)
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Superior surface of inguinal ligament
Lacunar ligament
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Medial part of inguinal ligament that is reflected
back and attaches to pectineal line
Superficial Inguinal Ring
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Medial crus – pubic bone and pubic
crest medial to pubic tubercle
Lateral crus – pubic tubercle
Center point of ring superior to pubic
tubercle
Intercrural fibers
Deep inguinal ring
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Slit-like opening in fascia transversalis
Immediately superior to midpoint of
inguinal ligament
Inguinal Canal
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Male: spermatic cord
Female: Round ligament of uterus
Hernias
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More common in men
Indirect: hernia follows path from deep
ring to canal to superficial ring
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More common
Direct: hernia directly through
weakness in abdominal wall
Linea alba and rectus sheath
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See handout