Protrusive movements of less than 7 mm are considered to be restricted, although they are not always signs of pathology that urgently calls for treatment. It is especially important to test patients for restriction of lateral and protrusive movements following temporomandibular joint surgery and orthodontic or orthognathic surgery.
The determination of active movements is followed by an investigation of passive movements. This is to be done only on patients with limited but painless jaw opening, because painful joints will not permit the procedures needed for differential diagnosis of a limitation.
148 Endfeel during passive jaw opening
At the end of an active movement every healthy joint can be moved farther through a certain amount of space. This can occur only through the application of external force and is therefore referred to as passive movement (Kimberly 1979). In the early days of manual functional analysis all the mandibular movements were followed by tests of further passive movement. However, as 10 years of clinical experience has shown, this provided no additional diagnostic or therapeutic information so that passive tests are now applied only to the jaw-opening movement.
The extent of passive jaw opening, also referred to by some authors (Hesse et al. 1990) as the “endfeel distance,” has been reported in one study (Westling and Helkimo 1992) as 1.2 mm and in another (Agerberg and Österberg 1974) as 2.1 mm. Still more specific measurements can be found in the work of Hesse (1996), who reports an endfeel distance in men of 3.0 ± 1.1 mm under a force of 44.6 ± 7.2 N and in women, 3.8 ± 1.4 mm under 37.1 ± 2.1 N. The extent of mandibular movement is influenced by the ligaments, capsule, intra-articular structures, muscles, fascia, and the skin (Evjenth and Hamberg 1985, Hesse 1996).
Limitation of jaw opening is always accompanied by shortening one of more of the above-mentioned structures (Schneider et al. 1988). Therefore, at the end of passive jaw opening the so-called endfeel is recorded (Fig. 156ff).
The endfeel is the feeling that the examiner detects at the end of a passive movement. It is always determined by the structures that are limiting the movement (Groot Landeweer and Bumann 1991). In healthy joints the endfeel is “hard ligamentary” and is not accompanied by pain (Cyriax 1979, Kaltenborn 1974, Janda 1974. Lewitt 1977, McCarroll et al. 1987, Hesse et al. 1990, Groot Landeweer and Bumann 1991, Bumann et al. 1993, Bumann and Groot Landeweer 1996b, Hesse 1996).
There are various classifications of the endfeel in the temporomandibular joint (Cyriax 1979, Evjenth and Hamberg 1985, Groot Landeweer and Bumann 1991, Hesse 1996). Clinically a distinction is made between physiological and structurally pathological endfeels (Figs. 148 and 161). Although there has been little inter-examiner agreement on the concept of the endfeel (Lobbezzoo-Scholte et al. 1994), Hesse (1996) could demonstrate a distinct correlation between the endfeel and the so-called “craniomandibular stiffness.” The evaluation of a combination of the extent of passive movement and the clinical endfeel is therefore a reliable parameter for the differential diagnosis of limitations of movement. Neither the endfeel nor the extent of passive movement helps to differentiate between myogenic and arthrogenic problems, as, for example, claimed by Fuhr and Reiber (1989).
149 Active jaw opening
incisors at the level of the incisal edge of an upper incisor in maximal occlusion. Active jaw opening can be measured directly or by measuring the incisal edge distance as shown here and adding to it the anterior vertical overlap (“overbite”).
Right: In the record of findings, green ink is used to enter the amount of pain-free movement and red Is used for painful movements.
150 Active movement of the mandible to the left
To measure lateral mandibular movements the upper midline is first projected onto the labial surface of a lower incisor. Then the patient executes a maximal lateral movement and the distance between the upper midline and the mark on the lower tooth is measured.
Right: The measurement is entered in the chart in the same way as the jaw-opening distance. The “normal” range is 10.5 ± 2.7 mm.
151 Active movement of the mandible to the right
After a maximal movement of the mandible to the right, the distance from the upper midline to the lower mark is measured.
Right: Again, the specific entry is the jaw-opening value. The norm for men is 10.2 ± 2.3 mm and for women 10.3 ± 3.4 mm. The normal values given here for the two sides are taken from studies by Hesse (1996).
152 Active protrusive movement
To determine the extent of protrusion, the horizontal overlap ( over-jet”) is measured first and then added to the distance between the upper labial surface and the lower incisal edge after maximal protrusion. This can be done with either a simple ruler or with the back side of a commercial sliding caliper.
Right: Entry in the patient’s record is made in green or red. Normal values are 9.0 ± 2.8 mm for men and 9.1 ± 1.8 mm for women.
153 Active retrusive movement
First the horizontal overjet is measured in habitual occlusion with a ruler or sliding caliper. Then the patient is Instructed to “pull the lower jaw back” or -push the upper jaw forward” as far as possible. The read directly, although this is of no importance in making a differential diagnosis. Left: The chart entry is made in the usual manner. Values range from 0 to 2 mm.
154 Translation of the condyles during active jaw opening
A qualitative evaluation of condylar translation can be made by palpation. Normally during jaw opening the condyles move only to the crest of the articular eminence. The mobility (✓), hypomobility (-), or hypermobility (+). Left: Example of chart notations using the corresponding symbols. Upon jaw opening, mobility of the right condyle was normal while there was hypermobility of the left condyle.
155 Translation of the condyles during active protrusion
The extent of condylar translation during protrusive movement is also determined. A movement that stops just short of the crest of the but a condyle that passes beyond the eminence is considered hypermobile. If the condyle moves out of the fossa only slightly or not at all, it is hypomobile.
Left: This entry in the examination form indicates that the right condyle was hypomobile and the left had normal mobility. This test replaces the documentation of deviation and deflection.