Skeletal Muscle Anatomy

Question 1

What bone makes up the optic canal and what travels through it?

Answer 1

Lesser wing of the sphenoid. The optic nerves and the opthalmic arteries travel through this space.

Question 2

What bones surround the superior orbital fissure and what goes through it?

Answer 2

CNs 3, 4, V1 (opthalmic), 6
Also, opthalmic veins

Surrounded by the lesser and greater wings of the sphenoid

Question 3

Where is the carotid canal and what goes through it?

Answer 3

The ICA

Between the temporal (petrous portion) and the greater wing of the sphenoid

Question 4

Where is the foramen rotundum and what goes through it?

Answer 4

In the greater wing of the sphenoid. V2 (maxillary) goes through it

Question 5

Where is the foramen ovale and what goes through it?

Answer 5

V3 (Mandibular) goes through it, as well as the accessory meningeal artery, lesser petrosal nerve, and emissary veins.

Located in the greater wing of the sphenoid

Question 6

What goes through the foramen spinosum and where is it?

Answer 6

Located in the greater wing of the sphenoid. The MMA and vein go through it

Question 7

What goes through the foramen lacerum and where is it?

Answer 7

Nothing actually goes through this one, but the ICA lays on top of it.

It is between the temporal (petrous portion) and sphenoid

Question 8

Where is the internal acoustic meatus and what goes through it?

Answer 8

In the petrous portion of the temporal bone. CNs 7 and 8 go through it

Question 9

Where is the jugular foramen and what goes through it?

Answer 9

Between the petrous portion of the temporal bone and the occipital bone. CNs 9, 10,11, the IJV and the sigmoid sinus all go through this guy.

Question 10

What goes through the hypoglossal canal and what bone is it in?

Answer 10

Occipital bone

CN12 (hypoglossal nerve)

Question 11

Besides a lot of the normal big junk, what CN goes through the foramen magnum?

Answer 11

Spinal roots of 11

Question 12

Where is the mastoid foramen and what goes through it?

Answer 12

Petrous portion of the temporal bone. The mastoid emissary vein goes through it.

Question 13

What four parts make up the upper extremities?

Answer 13

• Pectoral girdle: Scapula, clavicle
• Arm: Humerus
• Forearm: Ulna (medial), radius (lateral)
• Hand: Carpus, metacarpus, phalanges

Question 14

Where does the axial nerve run?

Answer 14

Along the surgical neck of the humerus

Question 15

Where does the ulnar nerve run?

Answer 15

Runs posterior to the medial epicondyle (making the nerve responsible for the “funny bone” sensation)

Question 16

The greater pelvis contains:

Answer 16

Abdominal organs like the ileum and the sigmoid colon

Question 17

The lesser pelvis contains:

Answer 17

Pelvic viscera (thus making it the “true” pelvis) such as the bladder, uterus and ovaries

Question 18

There are many types of skull fractures. Describe what causes a linear skull fracture

Answer 18

These are the most common and usually result from blunt trauma

Question 19

There are many types of skull fractures. Describe what causes a basilar skull fracture and what signs we look for (4)

Answer 19

Are usually linear, and often involve the temporal bone.

• Raccoon eyes (blood in orbits)
• Battle sign (blood collecting behind the ears)
• Blood in the sinuses
• CSF leakage through the nose and ears

Question 20

A contrecoup fracture occurs where with respect to impact?

Answer 20

Opposite side

Question 21

What typically causes a fracture or dislocation of the vertebrae?

Answer 21

Hyperflexion of the neck, typically from car accidents or direct trauma to the back of the head.

Question 22

What are the three things that hold the dens of C2 with the foramen of C1?

Answer 22

The cruciform, alar and apical ligaments hold these two together, as well as the tectorial membrane (continuation of the posterior longitudinal ligament)

Trauma and RA can damage the cruciform ligament. Posterior movement of the dens results in damage to the cervical spinal cord and superior dens movement hits the medulla.

Result is typically quadriplegia.

Question 23

Elderly vs. young herniations

Answer 23

Typically in the elderly, the posterior longitudinal ligament and annulus fibrosis can deteriorate in the L5/S1 area, leading to herniation of the pulposus. Leads to sciatica.

In the young, it is typically trauma such as whiplash, leading to a C5 area tear of the PLL secondary to hyperflexion of the neck.

Question 24

Spondylolysis vs. spondylolisthesis

Answer 24

Spondylolysis is when one side of the vertebrae fractures at the pars interarticularis, which connects the articular processes of the inferior and the superior vertebrae, leading to no symptoms or at worst, low back pain.

If this happens bilaterally, the vertebrae can displace, leading to spondylolisthesis.

Question 25

What is ankylosing spondylitis?

Answer 25

Chronic progressive arthritis that usually begins at the lumbar vertebrae and sacroiliac joints, moving upwards to the cervical spine.

Annulus fibrosus of several vertebrae become ossified, leading to vertebral fusions, showing up on plain film as a “bamboo spine.”

Question 26

Most patients with Ankylosing spondylitis have this marker

Answer 26

HLA-B27

Question 27

What are the three most common ways for the pelvis to fracture?

Answer 27

Anteroposterior compression fracture (like when you smash between the steering wheel and seat in an accident), leading to fractures of the pubic symphysis and pubic rami

Lateral compression is possible, and involves the pubic rami as well, along with the ala of the ileum

Elderly typically get the third type, the acetabular fractures, after a fall onto their feet with both legs extended, leading to the acetabulum to push through (protrusio acetabuli). This one is particularly dangerous because my entering the pelvic girdle, we can get damage to nerves, organs and vessels, which can present with the pathognomonic vaginal/urethral bleeding.

Question 28

Discuss what happens with a clavicle fracture

Answer 28

Most commonly in the middle one third of the bone. The SCM lifts the proximal piece and the weight of the arm pulls down the distal piece

Question 29

Discuss a fracture of the greater tuberosity

Answer 29

Often associated with separation of the shoulder as three of the four rotator cuff muscles attach here (Supra/Infraspinatus and teres minor)

Question 30

What do we worry about with fractures to the surgical neck of the humerus?

Answer 30

Axillary nerve damage

Question 31

What dowe worry about with fractures to the distal portion of the humerus?

Answer 31

Injury to the radial nerve in the radial/spiral groove

Question 32

What do we worry about with humerus fractures that are just superior to the elbow, as with a supracondylar fracture?

Answer 32

May injure the brachial artery and median nerve. Can lead to Volkmann Ischemic contracture in which ischemia from the brachial artery disruption leads to scar tissue formation and hand and forearm muscle flexion contractures

Question 33

What do we worry about with medial epicondyle fractures?

Answer 33

Ulnar nerve damage

Question 34

What is a Colles fracture and what do we worry about with it?

Answer 34

This is a fracture to the distal radius and often includes a distal ulna fracture at the styloid process.

Leads to dinner fork deformity (dorsal displacement of bone fragments distal to the fracture.

Question 35

Discuss how a femoral neck fracture typically presents

Answer 35

Occurs more often in women due to their greater risk of osteoporosis. The blood vessels (medial circumflex femoral artery) that supply the femoral head are frequently ruptured in this fracture, resulting in avascular necrosis. On presentation, the lower limb is usually shortened and laterally rotated.

Question 36

What is a pott fracture?

Answer 36

The medial (deltoid) ligament is overly stretched during severe foot eversion. The strong medial ligament does not tear, but causes fractures of the medial malleolus (transverse avulsion) and the fibula.

Question 37

How do we get a fifth metatarsal fracture and what does it result in?

Answer 37

Occurs during extreme inversion of the foot. This tears the lateral ligament and can fracture the lateral malleolus. This is a common sports injury.

Question 38

Coxa Valga vs. Coxa Vara

Answer 38

The angle between the shaft of the femur and the head of the femur varies among people. When the angle is large, it is coxa valga. Too short is coxa vara and can lead to shortening of the leg, making it difficult to completely abduct.

Question 39

Discuss the cause and presentation of a Slipped Capital Femoral Epiphysis

Answer 39

If an adolescent has a weakened epiphyseal plate due to trauma, the femoral head epiphysis can slowly slip away from the femoral neck causing a coxa vara.

We see this in obese adolescents during a growth spurt, and the pain can refer to the knee.