Musculoskeletal Flashcards
In thoracic outlet syndrome, the lower trunk of the brachial plexus and the subclavian artery are compressed between the anterior scalene muscle and the middle scalene muscle. Incision of the anterior scalene muscle will relieve this compression. What nerve is at greatest risk of injury during decompression?
Phrenic nerve lies on the anterior surface of the anterior scalene muscle, deep to the prevertebral fascia. If this nerve is cut, the diaphragm on that side of the body will be paralyzed.
The recurrent laryngeal nerve is a branch of the vagus nerve that innervates which muscles?
all of the intrinsic laryngeal muscles except the cricothyroid muscle.
The cricothyroid muscle is innervated by the external branch of the superior laryngeal nerve.
Pseudogout vs gout?
Pseudo: caused by deposition of calcium pyrophosphate crystals within the joint space. crystals are weakly positively birefringent (basophilic) and rhomboid when viewed with polarized light. Usually older pt’s. typically involves the knee or other large joints, such as the wrist.
Gout: Monosodium urate is deposited as needle-shaped, negatively birefringent (yellow) crystals. Acute gout can present with podagra (inflammation and swelling in first metatarsophalangeal joint). In addition, other joint involvement, in decreasing order, includes ankle, knee, wrist and fingers
Histo characteristics of Basal cell carcinoma?
palisading pattern of basal cell-like nuclei at the periphery of tumor nests can be appreciated
Immediate changes caused by immobilization of a muscle include:
Long-term immobilization additionally causes:
Muscle atrophy Decreased capillarity
Decreased metabolic rate
Decreased use of ATP
Decreased adenosine
Decreased blood flow
Increased myoglobin oxygen saturation
Increased intracellular PO2
Muscle atrophy Decreased capillarity
What is the inheritance pattern of DMD?
X recessive!
Damage to the surgical neck of the humerus or dislocation of the shoulder can cause injury to which nerve, and produce what symptoms
the axillary nerve.
Axillary nerve injury will cause loss of abduction of the arm to the horizontal plane. (innervates deltoid and teres minor)
During drainage of a Baker’s cyst, which nerve lies directly adjacent to the tendon and may be commonly injured?
In the lateral part of the fossa, the common fibular (peroneal) nerve lies immediately adjacent to the tendon of the biceps femoris and might be injured in this procedure
responsible for dorsiflexion of the ankle
Describe the differences between
Red fibers (type I):
and
White fibers (type II):
Endurance and posture-maintaining muscles
Increased myoglobin (red color)
Increased mitochondrial content
Increased capacity for aerobic metabolism
Fast responses; sprinter’s legs
Decreased myoglobin
Decreased mitochondrial content
Decreased capacity for aerobic metabolism
Larger diameter and more hypertrophy with strength conditioning
Explain the mechanism behind NO vasodilation and smooth muscle relaxation.
Nitric oxide (NO): Short-acting physiologic messenger
NO is released, diffuses to smooth muscle cells, enters the cells, and activates guanylate cyclase.
Soluble guanylate cyclase makes cGMP, which triggers smooth-muscle relaxation.
Vasodilation in the corpus cavernosum of the penis causes erection.
Brachial cysts result from failure of obliteration of what?
second (or third or fourth) pharyngeal cleft.
They are always laterally placed, and are usually situated along the anterior border of the sternocleidomastoid muscle.
What is the trendelberg sign and what muscle weakness produces this?
A positive Trendelenburg sign occurs when a patient stands on one leg, and the hip on the unsupported side drops.
A positive Trendelenburg sign can be caused by weakness of the abductors of the hip, the gluteus medius and gluteus minimus, on the supported side.
What are the two common areas for ulnar nerve injury and what symptoms do you see?
Medial epicondyle of the humerus “funny bone” or in Guyon’s canal (near hook of the hamate and pisiform bone in the wrist)
Sensory loss over medial 1 1/2 digits and hypothenar eminence, weakness on the wrist flexion/adduction, finger abduction/adduction, and flexion of the fourth/fifth digits. The hypothenar eminence may flatten due to muscle atrophy.
Most common ankle sprains involve which ligaments and present with pain and ecchymosis at the anterolateral aspect of the ankle?
anterior talofibular ligament
What are T-tubules and what are their functions?
invaginations of the sarcolemma the extend into each muscle fiber. They transmit depolarization signals to the sarcoplasmic reticulum and trigger the release of caclium. The uniform distribution of T-tubules ensure coordinated contraction of all myofibrils
