Landmarks Flashcards
Which spinal nerves do the Ansa cervicalis arise from?
What does it innervate?
It is a neural loop arising from (C1-C3 spinal nerves)
It innervates the infrahyoid muscles except for thyrohyoid
Where does the cervical plexus arise from?
From spinal nerve C1 - C4
Sensory fibres carry proprioceptive info.
Motor fibres innervate the diaphragm
Where do the phrenic nerves arise?
What do they innervate?
What can cause related referred pain?
Spinal nerves C3-C5
They innervate the diaphragm
Spinal cord segments C3-C5 also receive somatic sensory information from the skin over the shoulder. Therefore, gallbladder pathology involving the diaphragm may also be felt in the right shoulder
Which spinal nerves innervate the skin of the thoracic wall?
T1-T12
What fibres innervate the skeletal muscles of the thoracic wall?
Somatic motor fibres (T1-T12) - intercostal nerves
What spinal nerves give rise to the cardiopulmonary splanchnic nerves?
T1-T5
(Visceral and somatic sensory from the heart, skin of chest wall, neck and arm)- T1-T5
Where do preganglionic sympathetic fibres exit the spinal cord?
Spinal nerves T1-L2/L3
What is the level of the sternal angle?
T4
At what level is the mediastinum divided into superior and inferior compartments?
Anteriorly- sternal angle
Posteriorly- T4-T5 spinal cord segments
At what level does the trachea bifurcate?
at the junction between T4-T5
Where do the greater splanchnic nerves arise?
Spinal nerves T5-T9
epigastric pain suggests foregut pathology as T5-T9 innervates the foregut
Where do the thoraco-abdominal nerves arise from and what do they innervate?
Continuation of the intercostal nerves (T7-T11)
They supply the skin and muscles of the thoracic wall, intercostal muscles and anterolateral abdominal wall
Innervation of the anterolateral abdominal wall
Where do each of the nerves arise from?
External oblique (1&2), internal oblique (1,2,3), transversus abdominis, (1,2,3) rectus abdominis (1)
Innervation: 1) Thoracoabdominal nerves (T7-T11), 2) subcostal nerve (T12), 3) iliohypogastric and ilioinguinal (L1)
Where does the oesophagus pass through the oesophageal hiatus?
What is it continuous with here?
It passes through the oesophageal hiatus at T10 (diaphragm) - it is continuous with the cardia of the stomach here
Where do the lesser splanchnic nerves originate?
Spinal nerve T10-T11
umbilical region pain suggests midgut pathology
Where does the aorta pass through the diaphragm?
T12
Where do the least splanchnic nerves originate?
T12 - They innervate the hindgut
Pain in the suprapubic region could be an indication of hindgut pathology (as dermatome T12 also innervates the suprapubic region)
Where does the subcostal nerve arise and what does it innervate?
T12 spinal nerve
Provides motor supply to the rectus abdominis, intercostal muscles and anterior abdominal wall muscles
Where does the celiac trunk leave the abdominal aorta?
T12
Just take note of where the pain fibres supplying the ureters originate
T12-L2
So pain caused by kidney stones are referred to and felt in the T12-L2 dermatomes
Where do the lumbar splanchnic nerves arise from?
Spinal nerves L1-L2
Where do the azygos system of veins arise?
In the abdomen at the level of L1/L2
Where do the iliohypogastric and ilioinguinal nerves arise and what do they innervate?
Motor innervation of the transversus abdominis and internal oblique muscles
They arise at level of L1
At what level does the superior mesenteric artery leave the aorta?
L1
At what level does the pancreas lie?
Pancreas lies horizontally at L1, on the posterior abdominal wall
What level is the conus medullaris?
L1
The terminal end of the spinal cord
What is cauda equina syndrome?
When there is compression of nerve roots below the conus medullaris - usually caused by disc prolapse at L4/L5 or L5/S1
Where does the lumbar plexus arise from? What are the nerves and which spinal nerves do they arise from?
L1-L4
Femoral nerve - L2-L4
Obturator nerve- L2-L4
Iliohypogastric and Ilioinguinal nerve- L1
(Genitofemoral L1,L2) (lateral cutaneous nerve of thigh, L2,L3)
What level is the transumbilical plane
L3
How can the transpyloric plane be drawn?
- Horizontal line passing through the tips of the right and left 9th costal cartilage, transecting the pylorus of the stomach, the gallbladder, the pancreas and hila of the kidneys
L1-L3 - Also lies in between the pubic symphysis and manubrium
How can the intercristal plane be drawn?
A horizontal line between the highest points of the right and left iliac crests (used to guide lumbar puncture)
At what level does the inferior mesenteric artery leave the aorta?
L3
What is the highest point of the iliac crest?
What procedure is performed here? Which layer?
Interval between L3-L4
Lumbar puncture is done here in the subarachnoid space in L3-L4 interspace
Which spinal nerves does the sciatic nerve arise from?
L4-S3
At what level does the abdominal aorta bifurcate? What does it bifurcate into?
L4
Into the left and right common iliac arteries
At what level does the inferior vena cava form? What is it formed by?
L5
Formed by the union of the left and right common iliac veins
What can be found to arise from S2-S4?
- Parasympathetic pelvic splanchnic nerves
- Somatic pudendal nerve
- Dorsal nerve of penis (supplies penis)- branch of pudendal nerve
- Sacral plexus (supplies lower limb) S2-S4 but receives contribution from L4-L5
What happens at the 1,2,3,4 part of the duodenum?
1st part- the bile duct, gastroduodenal artery and hepatic portal vein lie posterior
2nd part- major duodenal papilla
3rd part- superior mesenteric artery lies anterior
4th part- meets jejunum at duodenojejunal flexure
Dermatome for C4
Upper shoulder
Dermatome for C5
C5 - lateral side of the anterior and posterior aspects of the arm
Test- upper lateral arm
Dermatome for C6
How would you test?
C6 - lateral side of the anterior and posterior aspects of the forearm, the lateral sides of the anterior and posterior aspects of the palm, and the anterior and posterior surfaces of the thumb and index fingers
Test- Thumb
Dermatome for C7
C7- the anterior and posterior surfaces of the middle finger and middle of palm (3rd metacarpal)
Test- middle finger
Dermatome for C8
C8 - the medial side of the anterior and posterior surfaces of the forearm and palm, the anterior and posterior surfaces of the fourth and fifth fingers
Test- medial border of hand
Dermatome for T1
T1 - the medial side of the anterior and posterior surfaces of the arm
Test- medial border of the arm
Dermatome for L1
L1- Region over inguinal ligament
Test- region over inguinal ligament
Dermatome for L2
L2- Upper half of anterior thigh
Test- upper anterior thigh
Dermatome for L3
L3- Lower anterior thigh and medial aspect of the knee
Test- medial aspect of the knee
Dermatome for L4
L4- From the anterior surface of the lower limb, lateral aspect of lower thigh, knee and upper leg, the dermatome extends obliquely, inferiorly and medially to cover the anterior knee, anteromedial leg, dorsum of the medial aspect of the foot and skin over dorsum and plantar surface of the big toe
Test- Anteromedial leg
Dermatome for L5, test?
L5- On the anterior surface of the lower limb. Laterally - the lower ⅔ of the leg, excluding skin over the lateral ankle. Extends obliquely to cover the dorsum of the middle of the foot and the dorsum of toes 2-4. Also covers the plantar surface of the corresponding area.
Posteriorly- vertical strip of skin laterally, extending from the buttock of the upper leg
Test- Anteriorlateral leg
Dermatome for S1
S1- posteriorly, a vertical strip of skin in the middle of the thigh extending over the lateral part of the posterior leg. The lateral aspect of the ankle, the lateral aspect of the dorsum and sole of the foot. Skin over dorsum and plantar aspect of little toe.
Test- 5th digit (toe)
Dermatome for S2
S2- posteriorly, vertical strip of skin over the medial thigh and leg, extending onto the medial aspect of the sole of the foot, excluding the plantar surface of big toe.
Horizontal fissure of lung level
Rib 4
Inferior border of lungs landmark
6 anteriorly (mid clavicular line), 8 laterally (mid axillary line), 10 (vertebral column)
Oblique fissure of lung level
Rib 4 posteriorly, 5 laterally, 6 anteriorly
