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Flashcards in Trunk and Pelvis 2 Deck (52):

What is the purpose of the ischial tuberosity?

It is the location of attachment of the hamstring muscles.


What structure forms from the ischial spine's protrusion?

The lesser sciatic notch


Where is the pubic crest located?

Anterolaterally to the pubic symphysis


What does the pubic crest do?

Provides attachment point for the abdominal muscles


What line of the pelvic inlet is formed by the pubis?

The pectineal line


What 2 structures are joined by the inguinal ligament?

The anterior superior iliac spine and the pubic tubercle (lateral side of the pubic crest)


What structures are joined by the sacrotuberous ligament?

The ischial tuberosity and the sacrum (posterior part of the sacrum and ilium)


What structures are joined by the sacrospinous ligament?

The ischial spine and the sacrum


What does origin and insertion typically refer to?

Origin refers to the more stable end of the attachment

Insertion refers to mobile end of attachment


What do erector spinae muscles do?

They extend the trunk


What are the main parts of the erector spinae muscles?

Spinalis muscles are near the midline. (Spinalis cervicis are located in cervical part and spinalis thoracis is located in the thoracic part)

Longissimus muscles are more lateral to the spinalis and contain thick fascia (include longissimus capitis, cervicis, and thoracis)

Iliocostalis is the most lateral part (cervicis, thoracis, and lumborum)


What are the abdominal muscles?

External oblique
Internal oblique

Transversus abdominis

rectus abdominis


What do external oblique muscles do?

Most superficial and fibers run downwards in V shape towards pelvis and they flex + rotate the trunk.


What do the internal oblique muscles do?

They run towards the ribcage in A shape. They also flex and rotate the trunk. External and internal obliques work together


What do the transversus abdominus muscles do?

They compress and constrict the abdomen. Important role in maintaining core stability.


What are the main muscles of respiration?

Diaphragm (controls intrathoracic pressure)

Internal and external intercostals

Innermost intercostals


Where are the external and internal intercostals located relative to thoracic cavity?

External intercostals are located more posteriorly near the spinal cord

Internal intercostals are located more anteriorly near the sternum


What is the function of quadratus lumborum?

Connects the iliac crest with L1 - L4 and last rib. It is responsible for lateral flexion of the trunk


Where does iliacus originat and insert? What is the resulting action?

Origin: Iliac fossa

Insertion: Lesser tuberosity of the femur

It flexes the thigh


Where does psoas major originate and insert? What is the resulting action?

Origin at T12 - L5

Insertion at joint tendon with iliacus onto lesser tuberosity of the femur


What is the clinical significance of the origin and insertion of psoas?

Hypertrophy in psoas can result in lower back pain because the muscle pulls on the vertebrae of the lower back.


What is the origin and insertion of psoas minor?

Origin: T12 - L1

Insertion: Iliopectineal eminence

Action: Weak flexion of the trunk.

Psoas minor is an inconsistent muscle and is absent in many people


Where does gluteas maximus originate and insert and what is its action?

Originates from posterior glueteal line of sacrum and coccyx.

Inserts onto gluteal tuberosity of femur and fascia lata (iliotibeal tract)

It extends the thigh


Where does gluteas medius originate and insert and what is its action?

Originates between posterior and anterior gluteal lines and inserts onto greater trochanter of the femur.

It abducts the thigh. it also holds the hip in place when walking.


Where does gluteas minimus originate and insert and what is its action?

Deep muscle and originates in space between anterior and inferior gluteal lines.

Inserts onto greater trochater of the femur

Also abducts the thigh and holds hip in place when walking.


Where is gluteas minimus located relative to the other gluteal muscles?

Deep to them


What muscle stabilises the iliotibial band when gluteas maximus is acting on it?

Tensor fasciae lata


Where does tensor fascia lata originate and insert?

Origin: ASIS

Insertion: IT tract of the fascia lata

Flexes the thigh (weak) as well as stabilising the iliotibial tract for gluteus maximus action.


Between which 2 pelvic muscles does the sciatic nerve emerge?

Piriformis is above

Gemellus superior is below


What muscles are located inferior to piriformis?

Gemellus superior

Obturator internus

Gemellus inferior

Obturator externus

Quadratus femoris



What do the GOGOQ muscles do?

Laterally rotate the head of the femur and hold the head of the femur in the acetabulum.


How are there 8 cervical nerve roots and only 7 cervical vertebrae?

The first nerve root exits above C1.


How many nerve roots are there?

8 Cervical

12 thoracic

5 lumbar

5 sacral

1 coccygeal


What pathways are present in spinal nerves? Afferent or efferent?



Where are grey and white matter located in the spinal cord?

Grey matter inside

White matter outside


Why is the dorsal root ganglion a swelling?

Cell bodies of those nerves lies outside of the spinal cord in that ganglion. (sensory nerves)


Why is there a lumbar and cervical enlargement?

There is a massive amount of cell bodies supplying the upper limbs.

Lumbar enlargement also exists for lower limbs


What follows the lumbar enlargement distally?

The conus medullaris is a tapering down of the size of the lumbar enlargement which then ends up becoming a ligament that joins the spinal cord to the bottom of the vertebral canal.


What is the cauda equina?

Collection of spinal nerves going all the way down.


What kind of divisions are seen in lumbar nerves exiting to enter the lower limbs?

Anterior and posterior divisions to supply the flexor and extensor parts of the limbs.


What nerve roots is the lumbosacral plexus composed of?

T12 - S4

Lumbar portion is T12 - L4

Sacral portion is L4 - S4


What nerve comes from the anterior divisions of the lumbosacral plexus?

Femoral nerve


What nerve arises from L3 and supplies the area around the iliac crest?

The lateral femoral cutaneous nerve


What nerve arises from the lumbar plexus and passes through obturator foramen to supply medial part of the thigh?

The obturator nerve


What divisions form from the sacral plexus?

Anterior and posterior divisions (like the lumbar portion)


What nerves arise from the sacral plexus?

Sciatic nerve (composed of common peroneal and tibial nerves):

Common peroneal (anterior divisions)

Tibial nerve (posterior divisions)

Sciatic nerve is a sheath that encompasses both tibial and common peroneal nerves


What are the small arteries that leave the descending aorta before reaching the abdomen?

The intercostal arteries


What artery travels alongside the sternum and provides a redundant blood supply to the intercostal muscles and ribs? Where does this artery come from?

The internal thoracic, it arises from the subclavian artery (found on both sides)


What does the descending aorta split into?

2 common iliac arteries which further divide into internal and external iliac arteries


What happens to the external iliac artery after it passes the inguinal ligament?

It becomes the femoral artery.


What veins collect blood from intercostal veins?

Left side = hemiazygous

Right side = azygous vein

Hemiazygous vein drains into the azygous vein

Azygous vein drains into superior vena cava


Venous drainage of the legs?

Femoral vein -> External iliac vein -> Internal iliac vein -> Common iliac vein -> Inferior vena cava

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