Syndactyly involves abnormal fusion of fingers and toes. Cleft hand (lobster claw deformity) consists of an abnormal cleft between the 2nd and 4th metacarpal bones, with the 3rd metacarpal and phalangeal bones being absent and with digits 1–2 and 4–5 being fused. Polydactyly involves extra fingers or toes, while ectrodactyly involves the absence of a digit. Mutations in HOXA13 result in hand-foot-genital syndrome, where carpals and short digits are fused and the genitalia have altered structures
The axillary nerve is damaged. What is the likely result?
The deltoid atrophies when the axillary nerve (C5–C6) is damaged. Therefore, the rounded contour of the shoulder often disappears. A loss of sensation may occur on the lateral side of the proximal part of the arm
Which of the following is correct regarding the triangle of auscultation?
The triangle of auscultation, a good place to examine lung sounds, is bounded by the superior horizontal border of the latissimus dorsi, the medial border of the scapula, and the inferolat eral border of the trapezius. The 6th and 7th ribs and the 6th intercostal space is subcutaneous
Which of the following is NOT correct?
During development, dorsal cells organize as the epimere and ventral cells organize as the hypomere. Dorsal rami innervate muscles derived from the epimere, whereas ventral rami innervate muscles derived from the hypomere. Myoblasts of the epimere form the extensor muscles of the vertebral column, and those of the hypomere give rise to muscles of the limbs and body wall. Somites and somitomeres form the musculature of the limbs
. A patient cannot raise the trunk (as in climbing). What is most likely the problem?
With paralysis of the latissimus dorsi, the patient is unable to raise the trunk as necessary for climbing. The cause could be injury to the thoracodorsal nerve
Which of the following is true regarding rotator cuff injuries?
Please select 2 correct answers
Injury or disease may damage the rotator cuff, causing instability of the glenohumeral joint. The supraspinatus tendon is the most commonly torn part of the rotator cuff. Acute tears are uncommon in young persons
“Winging” of the scapula is most likely caused by which of the following?
Damage to the long thoracic nerve results in “winging” of the scapula
Which of the following parts of the humerus is matched correctly with the nerve with which it is in direct contact?
The surgical neck of the humerus is in direct contact with the axillary nerve, the radial nerve runs in the radial groove, the distal end of the humerus is in direct contact with the median nerve, and the medial epicondyle is in contact with the ulnar nerve
A patient receives a knife wound to the axilla. What problems do you expect?
A knife wound to the axilla would damage the musculocutaneous nerve and result in paralysis of the coracobrachialis, biceps, and brachialis. Therefore, flexion of the elbow joint and supination of the forearm would be weak ened. The patient would also lose sensation on the lateral surface of the forearm
A patient in surgery has no pectoralis major. What do you suspect?
Partial or complete absence of one or more muscles is rather common. One of the bestknown examples is total or partial absence of the pectoralis major (Poland anomaly). Similarly, the palmaris longus, serratus anterior, and quadratus femoris may be partially or entirely absent
A patient tries to make a fist, but digits 2 and 3 remain partially extended. What nerve is injured?
When the median nerve is injured, the patient often exhibits the “hand of benediction.” When the patient tries to make a fist, digits 2 and 3 remain partially extended because flexion of the PIP joints is lost in digits 1–3 and weakened in digits 4–5. Flexion of the DIP joints is lost in digits 2–3 but maintained in digits 4–5 (since the ulnar nerve controls the medial part of the flexor digitorum profundus). Flexion of the MCP joints of digits 2-3 will also be affected due to a loss of the lumbricals 1 and 2
Which of the following is true in respect to ulnar nerve injuries?
Fractures of the scapula typically involve
Fractures of the scapula typically involve the protruding subcutaneous acromion. The remainder of the scapula is well protected by muscles and the thoracic wall itself
A patient has been thrown from a motorcycle, landing on the shoulder such that the neck and shoulder are widely separated. You suspect an upper brachial plexus injury. What signs do you expect?
In an upper brachial plexus injury causing Erb-Duchenne palsy, one would expect damage to C5–C6, resulting in “waiter’s tip position” (adducted shoulder, medially rotated arm, and extended elbow). This results from paralysis of the deltoid, biceps, brachialis, and brachioradialis. The lateral aspect of the upper limb also experiences loss of sensation
The scapula on one side of a patient is located farther from the midline than that on the normal side. What might be the problem?
Injury to the dorsal scapular nerve (C4–C5) can paralyze the rhomboids, causing the scapula on one side to be located farther from the midline than that on the normal side
A patient exhibits “clawhand.” What might have happened?
Damage to the inferior trunks of the brachial plexus (C8–T1) affects the short muscles of the hand, resulting in “clawhand.” The patient might have grabbed a tree limb to catch himself while falling to cause this injury. “Clawhand” may also be caused by an injury to the ulnar nerve
Which limb defect is correctly matched with its definition?
Amelia is the complete absence of one or more extremities while meromelia is the partial absence of one or more extremities. All segments of extremities are present but abnormally short in micromelia. In phocomelia, long bones are absent, and small hands or feet are attached to the trunk by short, irregular bones. In cleft hand (lobster claw deformity), the third metacarpal is absent and digits 1–2 and 4–5 are fused
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