Week 2 Flashcards
A 19 year old male bodybuilder incorporates hammer curls in his weight training program to target the highlighted muscle.
Which of the following nerves of the brachial plexus supplies this muscle?
- Median nerve
- Ulnar nerve
- Axillary nerve
- Musculocutaneous nerve
- Radial nerve
Answer: This is the brachioradialis and is the only elbow flexor to be supplied by the radial nerve. All other muscles of the radial nerve are elbow, wrist and finger extensors: all three heads of triceps, extensor carpi radialis longus and brevis, supinator, and all of the extensor components of the forearm (extensor carpi ulnaris, etc.) This is all regarding motor innervation
- Median nerve supplies the following: pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, first two portions of flexor digitorum profundus, flexor pollicis longus, pronator quadratus, abductor pollicis brevis, part of flexor pollicis brevis, opponens pollicis and the first two lumbricals
- Ulnar nerve supplies the following: flexor carpi ulnaris, third and fourth portion of flexor digitorum profundus, and all the intrinsic muscles of the hand not supplied by the median nerve
- Axillary nerve supplies teres minor, and the deltoid
- Musculocutaneous nerve supplies all of the flexors of the arm and forearm except brachioradialis: coracobrachialis, brachialis and the biceps brachii
- Radial nerve is the correct response
Lecture: Anatomy and organization of the upper limb
Learning Objective: By the end of the unit, know the location, function, and innervation of the major muscles of the limbs. Approach this by organizing the muscles into compartments. MKS1a
50 year old construction worker presents with pain and paresthesia of the right leg after a sledgehammer had fallen on the anterior aspect of his leg between the tibia and fibula. On exam, this right leg is severely swollen and the patient endorses extreme pain and pin-prick feeling over the whole anterior leg. Which of the following muscles is at risk to be compromised first?
- Soleus
- Tibialis anterior
- Tibialis posterior
- Peroneus brevis
- Peroneus longus
Answer: This is compartment syndrome, a surgical emergency, and an emergent fasciotomy needs to be done. The patient has compartment syndrome in the anterior compartment and the only muscle in the choices that is in this compartment is Tibialis anterior (Choice B). The figure below gives the four main compartments and muscles of each.
Lecture: Anatomy and organization of the lower limb
Learning Objective: By the end of the unit, know the attachments, function, and innervation of the major muscles of the hindlimb. Approach this by organizing the muscles into compartments. MKS1a
17 yo M with a presents with pain on right proximal tibia. X-ray shows the following and further history taking shows a familial connection. Which of the following genes may be implicated in this?
- Rb tumor suppressor gene
- DCC gene
- TSC 1 gene
- ADPKD gene
- BRCA 1 gene
- BRCA 2 gene
Answer:
- Rb tumor suppressor gene- osteosarcoma expected in Rb defect along with retinoblastoma, breast cancer, etc.—correct response
- DCC gene – deleted in colon cancer
- TSC 1 gene- tuberous sclerosis 1 gene
- PKD1 gene- ADPKD by mutation in PKD1 in c16
- PKD2 gene- ADPKD by mutation in PKD2 in c4
- BRCA 1 gene- risk of breast and ovarian cancer in c17
- BRCA 2 gene- risk of breast and ovarian cancer in c13
Lecture: Neoplasia
Learning objective: Explain the salient clinical, radiologic, and pathologic features of common benign and malignant bone tumors and current treatment modalities for the lesion. (MKS 1b, 1d)
A 5 year old male presents with rapid growth since birth. He is currently in the 99th percentile for height and weight. A diagnosis of gigantism is considered. This can be caused by which of the following?
- FGFR3 activating mutation
- Kallman’s syndrome
- 5-alpha-reductase deficiency
- MEN 2B
- Aromatase deficiency
Answer: Gigantism has many causes. The most common one being a GH secreting pituitary adenoma. However, an aromatase deficiency can cause a decrease in baseline estrogen. Estrogen is the main hormone that is responsible for the closure of epiphyseal growth plates even in males. Therefore, an aromatase deficiency can lead to delayed closure of the growth plates giving gigantism-like syndrome.
- FGFR3 activating mutation- cause of achondroplasia
- Kallman’s syndrome- assoc. w/anosmia and hypogonadotrophic hypogonadism
- 5-alpha-reductase deficiency- enzyme necessary for DHT conversion from testosterone
- MEN 2B- mucosal neuromas, Marfinoid habitus, medullary thyroid carcinoma and pheochromocytomas
- Aromatase deficiency- estrogen required to properly close growth plates—correct response
Learning objective: Identify the embryological/developmental basis of bone defects such as spina bifida, osteogenesis imperfecta, dwarfism, and gigantism. (MKS1a)
(Vincenzo Rochira, Lucia Zirilli, Laura Maffei, Valeria Premrou, Claudio Aranda, Matteo Baldi, Ezio Ghigo, Gianluca Aimaretti, Cesare Carani, Fabio Lanfranco, Tall Stature without Growth Hormone: Four Male Patients with Aromatase Deficiency, The Journal of Clinical Endocrinology & Metabolism, Volume 95, Issue 4, 1 April 2010, Pages 1626–1633, https://doi.org/10.1210/jc.2009-1743)
The hands of a 9 yo F are shown below. What are some other things you most likely expect from her workup?
- Bicuspid aorta
- Pectus carinatum
- Cystic hygromas
- Low serum calcium
- Lymphedema
- Horseshoe kidney
D: low serum calcium
Learning objective: Identify the embryological/developmental basis of bone defects such as spina bifida, osteogenesis imperfecta, dwarfism, and gigantism. (MKS1a). This question is geared more towards integration of endocrine, renal and MSK for Step I
A 19 year old male falls while skateboarding on outstretched hands and has acute right wrist pain after the fall. X-ray of his wrist is shown below.
The patient is at risk of which of the following?
- Carpal tunnel syndrome
- Loss of hypothenar muscles
- Compartment syndrome
- Avascular necrosis
Answer: This patient has a fracture of the scaphoid bone, and because of the vasculature, at a high risk of avascular necrosis of the scaphoid bone (Choice D). Because the vascular supply of the scaphoid involves two different branches of the radial artery, a “watershed” like reduction in supply from the fracture can cause the necrosis. The median nerve is rarely affected in falls and breaks like this (Choice A-C)
Lecture: Functional anatomy of the hand
Learning Objective: Identify the arterial supply via the brachial, radial, ulnar, interosseus (common, anterior, posterior), and digital arteries. Describe the formation and relationships between the superficial and deep palmar arches. (MKS1a)
A 60 year old male presents with polyneuropathy multiplex with weakness of the left hand. Which digit can convey information of radial, medial and ulnar nerve function?
- First digit
- Second digit
- Third digit
- Fourth digit
- Fifth digit
Answer: The thumb (first digit) is the only digit that can convey information of all three of these nerves (Choice A). In general, thumb extension is mediated by the radial nerve, adduction of the thumb towards the second digit is mediated by the ulnar nerve, and flexion/opposition of the thumb is mediated by the median nerve. As challenge, try to list the muscles involved in each movement of the thumb.
Lecture: Functional anatomy of the hand
Learning objective: Describe the bones, their prominent features, and the movements possible at the joints. (MKS1a)
The pulse can be palpated in the anatomical snuff box because of the course of the radial artery. Which tendons form the palmar and dorsal margin of the anatomical snuff box, respectively?
- Extensor digitorum superficialis and extensor indicis
- Abductor pollicis longus and extensor pollicis longus
- Abductor pollicis longus and extensor pollicis brevis
- Extensor pollicis brevis and extensor pollicis longus
Answer: Choice D is the correct answer
Lecture: Functional anatomy of the hand
Learning objectives: Identify the major muscle groups, their general attachments and functions, and their innervation. (Learning to identify many of the individual muscles is an objective of lab.) (MKS1a) Identify the arterial supply via the brachial, radial, ulnar, interosseus (common, anterior, posterior), and digital arteries. Describe the formation and relationships between the superficial and deep palmar arches. (MKS1a)
An 8 year old female presents with an erythematous palpable purpura/rash. The urinalysis shows protein and red blood cells. Upon further questioning, the patient endorses joint pain and viral infection about a week prior. The patient is diagnosed with Henoch-Schonlein purpura. Which of the following immunologic mechanisms is the mediator of this?
- Type I hypersensitivity
- Type II hypersensitivity
- Type III hypersensitivity
- Type IV hypersensitivity
- Graft vs. host disease
Answer: Henoch-Schonlein pupura (HSP) and IgA nephropathy are associated and some classify them as the same disease. The pathophysiology seems to be an antigen-antibody complex mediated destruction of local tissue by complement which is the definition of type III hypersensitivity. (Choice C). A preceding viral infection with palpable purpura with kidney involvement suggests HSP. Also, any time “palpable purpura” is mentioned, think antigen-antibody type III hypersensitivity deposition. IgA nephropathy can sometimes be the kidney manifestation of HSP where the antigen-antibody deposition occurs in the glomeruli
- Type I hypersensitivity – This is mediated by mast cells and IgE cross-linkage and is thought of as anaphylactic reactions
- Type II hypersensitivity –This is the process of antibody mediated/opsonization destruction
- Type III hypersensitivity—The correct response
- Type IV hypersensitivity—This is mediated by T-cell responses to infected/altered endogenous cells such as cancer and viral infections and is also important in poison-ivy reactions, nickel allergy, etc.
- Graft vs. host disease—post transplantation with many graft lymphocytes (usually stem cell allo-transplants) that mount a destructive immunologic defense against the host’s native tissue
Lecture: Pediatric Rheumatology
Learning objective: Compare the rashes of Kawasaki disease, systemic onset juvenile idiopathic arthritis, IgA vasculitis and juvenile dermatomyositis (MKS1d)
