Skeletal Muscle Anatomy Flashcards
What bone makes up the optic canal and what travels through it?
Lesser wing of the sphenoid. The optic nerves and the opthalmic arteries travel through this space.
What bones surround the superior orbital fissure and what goes through it?
CNs 3, 4, V1 (opthalmic), 6
Also, opthalmic veins
Surrounded by the lesser and greater wings of the sphenoid
Where is the carotid canal and what goes through it?
The ICA
Between the temporal (petrous portion) and the greater wing of the sphenoid
Where is the foramen rotundum and what goes through it?
In the greater wing of the sphenoid. V2 (maxillary) goes through it
Where is the foramen ovale and what goes through it?
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
What goes through the foramen spinosum and where is it?
Located in the greater wing of the sphenoid. The MMA and vein go through it
What goes through the foramen lacerum and where is it?
Nothing actually goes through this one, but the ICA lays on top of it.
It is between the temporal (petrous portion) and sphenoid
Where is the internal acoustic meatus and what goes through it?
In the petrous portion of the temporal bone. CNs 7 and 8 go through it
Where is the jugular foramen and what goes through it?
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.
What goes through the hypoglossal canal and what bone is it in?
Occipital bone
CN12 (hypoglossal nerve)
Besides a lot of the normal big junk, what CN goes through the foramen magnum?
Spinal roots of 11
Where is the mastoid foramen and what goes through it?
Petrous portion of the temporal bone. The mastoid emissary vein goes through it.
What four parts make up the upper extremities?
- Pectoral girdle: Scapula, clavicle
- Arm: Humerus
- Forearm: Ulna (medial), radius (lateral)
- Hand: Carpus, metacarpus, phalanges
Where does the axial nerve run?
Along the surgical neck of the humerus
Where does the ulnar nerve run?
Runs posterior to the medial epicondyle (making the nerve responsible for the “funny bone” sensation)
The greater pelvis contains:
Abdominal organs like the ileum and the sigmoid colon
The lesser pelvis contains:
Pelvic viscera (thus making it the “true” pelvis) such as the bladder, uterus and ovaries
There are many types of skull fractures. Describe what causes a linear skull fracture
These are the most common and usually result from blunt trauma
There are many types of skull fractures. Describe what causes a basilar skull fracture and what signs we look for (4)
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
A contrecoup fracture occurs where with respect to impact?
Opposite side
What typically causes a fracture or dislocation of the vertebrae?
Hyperflexion of the neck, typically from car accidents or direct trauma to the back of the head.
What are the three things that hold the dens of C2 with the foramen of C1?
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.
Elderly vs. young herniations
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.
Spondylolysis vs. spondylolisthesis
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.
What is ankylosing spondylitis?
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.”
Most patients with Ankylosing spondylitis have this marker
HLA-B27
What are the three most common ways for the pelvis to fracture?
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.
Discuss what happens with a clavicle fracture
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
Discuss a fracture of the greater tuberosity
Often associated with separation of the shoulder as three of the four rotator cuff muscles attach here (Supra/Infraspinatus and teres minor)
What do we worry about with fractures to the surgical neck of the humerus?
Axillary nerve damage
What dowe worry about with fractures to the distal portion of the humerus?
Injury to the radial nerve in the radial/spiral groove
What do we worry about with humerus fractures that are just superior to the elbow, as with a supracondylar fracture?
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
What do we worry about with medial epicondyle fractures?
Ulnar nerve damage
What is a Colles fracture and what do we worry about with it?
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.
Discuss how a femoral neck fracture typically presents
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.
What is a pott fracture?
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.
How do we get a fifth metatarsal fracture and what does it result in?
Occurs during extreme inversion of the foot. This tears the lateral ligament and can fracture the lateral malleolus. This is a common sports injury.
Coxa Valga vs. Coxa Vara
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.
Discuss the cause and presentation of a Slipped Capital Femoral Epiphysis
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.
