First Pass Miss Flashcards
Origin, insertion, innervation, and action of rhomboid major?
Origin: Spinous processes of T2-T5
Insertion: Medial border of scapula
Innervation: Dorsal scapular nerve (root of C5)
Action: Retracts, elevates, and rotates scapula
Origin, insertion, innervation, and action of teres minor?
Origin: lateral scapular border superior to teres major
Insertion: Inferior facet of greater tubercle
Innervation: Axillary nerve (C5, C6) (along with deltoid)
Action: Chief external rotator of arm at 90 degrees abduction.
What muscles does the ulnar nerve innervate proximal to the wrist?
Flexor carpi ulnarus
Flexor digitorum profundus (medial 1/2)
What muscles does the ulnar nerve innervate distal to the wrist?
Adductor pollicius -> note that ADduction of the thumb is preserved in CTS
DEEP head of flexor pollicis brevis
Dorsal / palmar interossei
Medial two lumbricals
Hypothenar muscles (adductor, opponens, flexor)
What are the contents of the quadrangular space?
Axillary nerve
Posterior circumflex humeral artery
What are the borders and contents of the triangular interval?
Superior: Teres major
Medial: Long head of triceps
Lateral: Shaft of humerus
Contents: Radial nerve and profunda brachii artery (deep brachii)
What nerves are affected in Klumpke’s Palsy?
kLumpke’s = Lower trunk tear or traction = C8-T1
Affects especially the ulnar nerve, as well as the distal median nerve (proximal flexors affected less than distal hand muscles)
What is the cause of Klumpke’s palsy mechanically and what defect is typically seen?
Traction / forced abduction of arm -> i.e. catching a treebranch in adulthood or forcing arm upward during delivery of an infant
Total claw hand is seen: loss of medial and lateral lumbricals
- > extension and MCP joints and flexion and PIP and DIP joints
- > wrist is also extended (loss of FCU)
What is thoracic outlet syndrome and what causes it?
Compression of lower trunk of the brachial plexus (like Klumpke’s palsy) also with involvement of subclavian vessels
Causes: Pancoast tumor, cervical rib (rib growing from C7)
What nerves are injured in extension type supracondylar fractures? What direction will injure each?
Extension type: Humerus is displaced anteriorly -> damage nerves anterior to elbow.
Anteromedial -> median nerve is injured
Anterolateral -> radial nerve is injured
What is a Greenstick fracture?
Pediatric fracture which extends only partway through the width of the bone
-> bent like a green twig
A torus fracture is buckle fracture which is due to compression
What are common causes of carpal tunnel syndrome? What is one test for CTS which you haven’t heard before?
- Pregnancy - progesterone swells the synovium (edema)
- Repetitive activity
- Endocrine causes: i.e. acromegaly, myxedema
Remember: Durkan’s test -> press on median nerve for 30 sec
What typically causes a scaphoid fracture and how can you tell when it has happened?
Falling on outstretched hands
Anatomical snuffbox will be palpable
What gene is mutated in holoprosencephaly?
Sonic hedgehog gene -> also needed for CNS development. Disrupted in trisomy 13
What is the progression of cells at the growth plate during bone formation?
- Zone of reserve cartilage (closer to epiphysis)
- Zone of proliferation -> longitudinal columns of chondrocytes
- Zone of hypertrophy -> hypertrophy of chondrocytes
- Zone of degeneration -> dying chondrocytes (apoptosis) with calcification of cartilage matrix
- Zone of ossification -> in the metaphysis, where vessels and boneforming cells invade and deposit immature bone matrix over cartilage remnants.
Why does decreased estrogen predispose to osteoporosis?
Estrogen serves to decrease osteoclast activity and inhibit apoptosis of osteoblasts.
Loss of this hormone leads to -> increased cycles of remodeling and bone resorption -> progressive loss of bone
How does vitamin D deficiency present in adulthood?
Osteomalacia, which his osteopenia with loss of bone density and cortical thickness, with increased susceptibility to fractures, weakness, and bone pain.
Looser zones - pseudofractures which are linear areas of unmineralized osteoid seen in bone.
What is pathognomonic of the third stage of Paget disease histologically?
Mosaic, tile-like arrangement of lamellar bone separated by prominent cement lines
-> cement lines were formed by crazy osteoclasts
What is meant by procallus and soft callus in fracture repair?
Procallus - acute inflammation and edema with phagocytosis and ingrowth of granulation tissue. This forms an organizing hematoma.
Soft callus -> first stage in formation of a bony callus -> cartilaginous scaffold assembled by activated chondroblasts. Will appear as a black area (cartilage) on X-ray
What is the most common way that osteomyelitis occurs / infection spreads to bone? Common spot in bone?
Minor skin or mucosal injury leads to a bacteremia which seeds bone (hematogenously spread)
Commonly seeds metaphysis, especially in children if the growth plate is open (lots of blood flow to growing growth plate, with decreased blood flow rate)
When will the chronic phase be seen in osteomyelitis? What structure forms?
Seen with inadequate treatment or decreased host immune response
Granulation tissue influxes, along with chronic inflammatory infiltrate. Will form the involucrum -> new subperiosteal bone which surrounds the sequestrum. Sequestrum gradually resorbed by osteoclasts.
What is sclerosing osteomyelitis of Garre?
Excessive, reparative bone formation caused by osteomyelitis which affects predominately the jaw (mandible)
Will appear like areas of Paget disease in the jaw.
What will occur due to obliteration of marrow space in osteopetrosis? What is the treatment for this condition?
Anemia and pancytopenia, leading to increased susceptibility for infections.
Extramedullary hematopoiesis will cause hepatosplenomegaly.
Treatment is hematopoietic stem cell transplant -> osteoclasts are derived from monocytes.
What is osteonecrosis also called, what is it, and what are the three most common causes?
Avascular necrosis - Ischemic necrosis of bone due to compromised blood supply.
- Trauma
- Glucocorticoid use -> dyslipidemia = fat emboli. Increased intramedullary adiposity -> compress the vasculature
- Excessive alcohol intake -> increases VLDL -> fat emboli. Increased adiposity also compress vasculature (like Gaucher)