usmle usmle Search USMLE WEB Site Contact USMLE WEB USMLE WEB Forum Home USMLE Step 1 USMLE Step 2 CK USMLE Step 2 CS USMLE Step 3 Fellowship
Usmle forum usmle question
 
IV. Myology
< Previous

Next >

4c. The Muscles of the Nose
The muscles of the nose (Fig. 378). comprise:   1
Procerus.
Depressor septi.
Nasalis.
Dilatator naris posterior.
Dilatator naris anterior.
  The Procerus (Pyramidalis nasi) is a small pyramidal slip arising by tendinous fibers from the fascia covering the lower part of the nasal bone and upper part of the lateral nasal cartilage; it is inserted into the skin over the lower part of the forehead between the two eyebrows, its fibers decussating with those of the Frontalis.   2
  The Nasalis (Compressor naris) consists of two parts, transverse and alar. The transverse part arises from the maxilla, above and lateral to the incisive fossa; its fibers proceed upward and medialward, expanding into a thin aponeurosis which is continuous on the bridge of the nose with that of the muscle of the opposite side, and with the aponeurosis of the Procerus. The alar part is attached by one end to the greater alar cartilage, and by the other to the integument at the point of the nose.   3
  The Depressor septi (Depressor alœ nasi) arises from the incisive fossa of the maxilla; its fibers ascend to be inserted into the septum and back part of the ala of the nose. It lies between the mucous membrane and muscular structure of the lip.   4
  The Dilatator naris posterior is placed partly beneath the Quadratus labii superioris. It arises from the margin of the nasal notch of the maxilla, and from the lesser alar cartilages, and is inserted into the skin near the margin of the nostril.   5
  The Dilatator naris anterior is a delicate fasciculus, passing from the greater alar cartilage to the integument near the margin of the nostril; it is situated in front of the preceding.   6
 
Variations.—These muscles vary in size and strength or may be absent.   7
 
Nerves.—All the muscles of this group are supplied by the facial nerve.   8
 
Actions.—The Procerus draws down the medial angle of the eyebrows and produces transverse wrinkles over the bridge of the nose. The two Dilatatores enlarge the aperture of the nares. Their action in ordinary breathing is to resist the tendency of the nostrils to close from atmospheric pressure, but in difficult breathing, as well as in some emotions, such as anger, they contract strongly. The Depressor septi is a direct antagonist of the other muscles of the nose, drawing the ala of the nose downward, and thereby constricting the aperture of the nares. The Nasalis depresses the cartilaginous part of the nose and draws the ala toward the septum.   9


 

You are welcome to ask for hospital review for residency. We will be providing them to those who ask them first.

Need help regarding USMLE process ?

Please post your questions here.

Check out this FAQ before submitting the question.

About USMLE

The United States Medical Licensing Examination (USMLE) is a three-step examination for medical licensure in the United States. The Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME) sponsors USMLE.
The Three Steps of the USMLE
Step 1 tests the important concepts of basic sciences basic to the practice of medicine. It also places special emphasis on principles and mechanisms underlying health, disease, and modes of therapy. Step 1 ensures mastery of the sciences that provide a foundation for the safe and competent practice of medicine. It also tests the scientific principles required for maintenance of competence through lifelong learning.
Step 2 CK tests the medical knowledge, skills, and understanding of clinical science essential for the provision of patient care under supervision. It also includes emphasis on health promotion and disease prevention. Step 2 CK ensures that due attention is devoted to principles of clinical sciences and basic patient-centered skills.
Step 2 CS tests your capacity to practice and provide good medical service in real-life situations. It also tests your communication skills.
Step 3 tests your medical knowledge and understanding of biomedical and clinical science essential for the unsupervised practice of medicine. Step 3 provides a final assessment of physicians assuming independent responsibility for delivering general medical care.