Sunday, 5 June 2011

Prussack space

This space is named after the Russian otologist Alexander Prussak.
This is a small middle ear recess which lies medial to the pars flaccida.
Boundaries:
Superiorly: Scutum and lateral malleolar ligament
Lateral: Pars flaccida
Inferior: Lateral process of malleus
Medial: Neck of the malleus
It communicates with the posterior pouch of Troeltsch.
Clinical significance:
Cholesteatoma invariably starts in this space. It begins as a retraction pocket involving pars flaccida. Cholesteatoma from this space spreads via:
Posterior epitympanum through the superior incudal space to involve the mastoid antrum.
Posterior mesotympanum: Inferiorly via the pouch of Von Troeltsch to involve stapes, round window, sinus tympani and facial recess.
Anterior epitympanum: Anterior to head of malleus it can gain access to supratubal recess via the anterior pouch of Von Troeltsch.

Nasolabial cyst a presentation

Wednesday, 1 June 2011

Left recurrent laryngeal nerve

The course taken by the vagus nerve differs between the right and the left sides. The left vagus nerve follows the carotid artery into the mediastinum crossing anterior to the aortic arch. The left recurrent laryngeal nerve arising from the vagal nerve just below the aortic arch loops medially under the aorta and ascends within the tracheoesophageal groove. The anterior bronchoesophageal artery supplies the left vagus nerve. The approximate length of the left recurrent laryangeal nerve is 12 cms. Considering the extra length and the distance the left recurrent laryngeal nerve has to travel, it is the common nerve affected by diseases / disorders / trauma etc.


Diagram of left recurrent laryngeal nerve

The recurrent laryngeal nerve has significant but varying relationship with the inferior thryoid artery. On the left side, the recurrent laryngeal nerve passes behind the inferior thyroid artery in 50% of the cases and anterior to the artery in 20% of cases and may lie in between the branches of the inferior thyroid artery in 30% of cases.

The left recurrent laryngeal nerve is more susceptible to injuries than the right because of its longer and more extensive course. It also lies superficial in the left tracheoesophageal groove.