Lacertus Syndrome is pain disorder seen in pitchers and other throwing athletes. It is named for the lacertus fibrosus fascia.

Patient selection: frequently throwing athlete, especially those with frequent terminal pronation


Mechanism: post-exertional compartment syndrome


Clinical features:

(1) medial elbow pain

(2) involves the flexor-pronator muscles after a period of throwing

(3) absence of distal neurologic findings

(4) slow onset of symptoms after the start of throwing

(5) relief with rest, from several hours of rest initially to several days later in course

(6) slowly progressive over time, with presentation only after it starts to cause the athlete problems


Surgery to release the lacertus fibrosus fascia where it crosses over the flexor pronator muscles provides pain relief.


Differential diagnosis:

(1) trauma to the elbow

(2) pronator teres syndrome

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