Julia tells Sawyer about almost having had an abortion. Julia and Sean were at the abortion clinic in the season 3 episode Joy Kringle.
Julia confronts Sean about calling a sex line. Sean then explains about giving a phone sex operator a voice-lift; this was the featured procedure in Season 4 opener Cindy Plumb.
When Sean and Christian are talking about Matt picking up rubbish, Sean says 'at least he's not dating Nazis or transsexuals anymore', referring to Matt's previous girlfriends- white supremacist Ariel (Brittany Snow, Season 3) and secret transsexual Ava (Famke Janssen, Season 2).
Dawn mentions that she was on Maury after she won the Powerball lottery. Maury has never had a show featuring lotto winners.
It's revealed that Sawyer's first name is Marlowe.
Christian's suggestion on dealing with Burt involves 'a 12-gauge and a bunch of hams'. This refers to the Pilot episode when they get rid of Silvio Perez's body by weighting his body with hams and dumping him in the Everglades.
When Dawn is having her initial consult with Sean and Christian, she mentions Dwight and Mallory, her husband and her daughter who were seen in the episode Dawn Budge.
As Sean and Christian do the surgery at the start of the episode, reference is made to the episode Blu Mondae, where Christian did pro-bono work on the title character after sleeping with her.
It's revealed that Mrs. Grubman's first name is Hedda.
Mrs. Grubman refers to Christian being in her bedroom under 'slightly different circumstances' and also regretting that she didn't sleep with him when she had the chance. This refers back to the Season 1 episode Nanette Babcock where Christian- under duress from Sean- offered to sleep with her if she would drop a lawsuit against McNamara/Troy.
It's revealed that Michelle is 30 years old.
Christian mentions 'a woman who won the lottery' who paid him four hundred thousand dollars for sex – this happens in Dawn Budge (the woman being the title character played by Rosie O'Donnell)
When Sean suggests Christian picks someone up from a bar, Christian replies 'no risk there, just ask Lizzie'. This refers back to Shari Noble where Liz met a girl in a lesbian bar, went home with her and ended up having her kidney stolen.
When Sean suggests Christian picks someone up from a bar, he mentioned 'another mother-daughter team'. In the season opener, Cindy Plumb, Christian slept with a mother and daughter that he met in a bar.
Liz mentions Mike Hamoui, the surgeon (played by Mario Lopez) that Christian had liposuction off in the episode entitled Monica Wilder.
Goof: Bobolit mentions his previous abuse of/addiction to inhaled anesthetics, specifying nitrous oxide. Nitrous oxide is actually a dissociative analgesic, which is not potent enough to provide general anesthesia for surgery patients. The effects wear off almost immediately upon cessation of inhalation. Bobolit was certainly under something stronger when he attempted to swap faces with Christian in Season 2.
Additionally, addiction to nitrous isn't technically possible.
When Sean and Christian go to see Escobar in the prison hospital, Escobar mentions that his face was "burned off" by a MS 13 gang member, this stands for Mara Salvatrucha, "Salvadoran Gang".
When Escobar mentioned Silvio Perez and dumping his body in a swamp, there is a flashback to the Pilot episode, where these events occurred.
When Sean and Christian go to see Escobar in the prison hospital, Escobar mentions them turning him into 'the FBI's most wanted'. This happened in the Season 1 finale entitled Escobar Gallardo.
Christian admits to sleeping with Kimber recently. This happens in the episode entitled Burt Landau.