Skull and TMJ — Palpation Landmarks

Palpation Landmarks

External Occipital Protuberance (EOP) — "The Bump"

• How to find it: With the client prone or seated, place your fingertip at the midline of the back of the head. Slide inferiorly from the crown along the midline. The EOP is the prominent bony bump you encounter at the center of the occiput, approximately at the level of the ear canal. It is the most prominent midline projection on the posterior skull.
• What it feels like: A distinct, rounded bony knob approximately 1–2 cm in diameter. It varies considerably in size — in some individuals it is very prominent, in others it is subtle. It is always in the exact midline.
• Client position: Prone with the face in the face cradle, or seated with the head slightly flexed forward.
• Confirmation: The EOP is in the exact midline and does not move. The superior nuchal lines radiate laterally from both sides of it — you can trace these ridges laterally with your fingertips to confirm you are at their central origin point.
• Common errors: Confusing the EOP with the spinous process of C2 (axis), which is the first prominent midline bony point below the occiput. The EOP is on the skull itself, above the suboccipital region. If you feel a gap (the suboccipital space) below your finger before the next bony prominence, you are on the EOP and the next point inferiorly is C2.
• Clinical significance: Attachment point for the ligamentum nuchae and upper trapezius. Tenderness here is common in tension-type headaches and cervicogenic headache. Starting point for locating the superior nuchal line.

Superior Nuchal Line

• How to find it: From the EOP, slide your fingertip laterally in either direction. The superior nuchal line is a bony ridge running laterally from the EOP toward the mastoid process on each side. It curves slightly superiorly as it extends laterally.
• What it feels like: A subtle, curved bony ridge on the posterior skull. It is less prominent than the EOP itself — you feel it as a slight raised edge or change in contour rather than a sharp ridge. In some clients it is barely perceptible; in others it is clearly palpable.
• Client position: Prone or seated with the head slightly flexed.
• Confirmation: The ridge runs in a consistent curved line from the EOP toward the mastoid process. The suboccipital muscles (rectus capitis posterior major and minor, obliquus capitis superior) attach just below this line — if you drop your finger slightly inferior to the ridge, you enter the soft tissue of the suboccipital triangle.
• Common errors: Confusing the superior nuchal line with the inferior nuchal line, which sits approximately 1 cm below and is rarely palpable through the overlying muscle. If you are deep in muscle tissue rather than on a bony ridge, you have dropped below the superior nuchal line.
• Clinical significance: Boundary between the scalp and the cervical extensor attachments. The trapezius and sternocleidomastoid attach along this line. Tenderness along the superior nuchal line is a consistent finding in tension-type headaches and occipital neuralgia. Defines the superior boundary of the suboccipital triangle.

Mastoid Process

• How to find it: Locate the earlobe. The mastoid process is the prominent bony projection immediately posterior and inferior to the earlobe. Place your fingertip directly behind the earlobe and press — the mastoid process is the hard, rounded bone you feel.
• What it feels like: A broad, rounded, conical bony projection approximately 2 cm in diameter. Its tip points inferiorly. It is easily palpable and typically quite prominent.
• Client position: Prone with the head turned to one side, side-lying, or supine with the head turned. The mastoid is accessible in virtually any position.
• Confirmation: The mastoid process does not move with any head or jaw motion (it is part of the temporal bone of the skull). If the structure moves when the client opens the jaw, you are too far anterior and may be on the mandibular condyle. The mastoid is posterior to the ear; the condyle is anterior to the ear.
• Common errors: Palpating the transverse process of C1 (atlas) and mistaking it for the mastoid. The C1 TP is inferior and slightly anterior to the mastoid tip, in the soft tissue between the mastoid and the mandibular angle. The mastoid is larger and directly behind the ear.
• Clinical significance: Attachment for the sternocleidomastoid and splenius capitis (see Muscle Attachments). Tenderness at the mastoid tip suggests SCM hypertonicity or splenius capitis involvement. The greater occipital nerve emerges near the superior nuchal line medial to the mastoid — irritation here produces occipital neuralgia.

Zygomatic Arch

• How to find it: Place your finger on the cheekbone (zygomatic bone) below the lateral corner of the eye. Slide posteriorly along the bony ridge. The zygomatic arch is the horizontal bar of bone running from the cheekbone to the temporal bone, just anterior to the ear. It is subcutaneous for its entire length.
• What it feels like: A thin, horizontal bony bar approximately 4–5 cm long. It feels like a narrow bridge of bone running from the cheek to the ear. The superior surface is smooth; the inferior surface has the masseter originating from it.
• Client position: Supine or seated. The zygomatic arch is accessible in any position.
• Confirmation: Ask the client to clench the jaw — the masseter contracts directly inferior to the zygomatic arch and you can feel the muscle belly bulge below the bony bar. The arch itself does not move.
• Common errors: Pressing too hard — the zygomatic arch is relatively thin and sensitive to direct pressure. Use light palpation to trace it. Also, confusing the arch with the temporal line above it — the arch is inferior and more horizontal.
• Clinical significance: Origin of the masseter (see Muscle Attachments). Tenderness of the masseter along the arch is common in TMJ dysfunction and bruxism. The arch defines the inferior boundary of the temporal fossa where the temporalis muscle fills the space.

Mandibular Angle (Angle of the Jaw)

• How to find it: Place your fingers along the inferior border of the mandible (the jawline). Follow the jawline posteriorly toward the ear. The mandibular angle is the corner where the body of the mandible turns upward to become the ramus — the sharp posterior-inferior corner of the jaw. It is approximately 2 cm anterior and inferior to the earlobe.
• What it feels like: A broad, angular bony corner. It is prominent in lean individuals and often visible as the "corner" of the jaw. The bone is thicker here than along the body of the mandible.
• Client position: Supine or seated.
• Confirmation: Ask the client to clench the jaw — the masseter and medial pterygoid both attach at the mandibular angle (see Muscle Attachments). You can feel the masseter tighten over the lateral surface of the angle during clenching.
• Common errors: Placing the finger too far posteriorly and ending up on the ramus rather than the angle itself. The angle is the actual corner point — the ramus extends superiorly from it.
• Clinical significance: Insertion for the masseter (lateral surface) and medial pterygoid (medial surface). Tenderness at the angle is a hallmark of bruxism and masseter hypertonicity. Palpation of the medial pterygoid requires reaching around the medial surface of the angle — this is an advanced technique.

Mandibular Condyle — The TMJ

• How to find it: Place your fingertip directly anterior to the tragus of the ear (the small cartilaginous flap in front of the ear canal). Press gently. You are now on the mandibular condyle. Alternatively, ask the client to open and close the mouth while your fingertip is in this position — you will feel the condyle translate forward (anteriorly) during mouth opening and return during closing.
• What it feels like: A small, rounded bony prominence approximately the size of a fingertip. It sits in the mandibular fossa of the temporal bone when the mouth is closed. During mouth opening, it glides anteriorly out of the fossa and onto the articular eminence — you can feel it slide forward under your finger.
• Client position: Supine or seated. Jaw relaxed.
• Confirmation: The definitive confirmation is movement with jaw opening. Ask the client to slowly open wide — the condyle translates anteriorly approximately 1–2 cm. No other structure in this region moves with jaw opening. You can also place a fingertip in each ear canal (with client consent) and press anteriorly — you will feel the condyle through the anterior wall of the ear canal.
• Common errors: Pressing too far posteriorly (into the ear canal) or too far anteriorly (onto the ramus). The condyle is at the very top of the ramus, directly in front of the tragus. If you do not feel movement with jaw opening, reposition anteriorly.
• Clinical significance: This is the TMJ. Tenderness, clicking, or crepitus during jaw opening are primary findings in TMJ dysfunction. Deviation of the mandible during opening (the jaw shifts to one side) suggests unilateral disc displacement or lateral pterygoid asymmetry. See Joint Associations.

Temporal Lines

• How to find it: Place your fingertips on the lateral surface of the skull, approximately 3–4 cm above the zygomatic arch. The temporal lines are two faint curved ridges (superior and inferior) running across the lateral skull in an arc from the zygomatic process of the frontal bone toward the posterior skull. The inferior temporal line is more clinically relevant — it marks the attachment of the temporalis muscle.
• What it feels like: A very subtle bony ridge — more of a change in contour than a distinct line. In many clients it is barely palpable. You may feel it best by running your fingertip upward from the zygomatic arch — the temporal fossa (concavity) gives way to the convexity of the skull at approximately the temporal line.
• Client position: Supine or seated.
• Confirmation: Ask the client to clench the jaw. The temporalis muscle fills the temporal fossa below the temporal line — you can feel it contract during clenching. The temporal line is where the muscle's fascial attachment ends and the bare skull begins.
• Common errors: Expecting a prominent ridge — the temporal lines are subtle in most people. They are orientation landmarks rather than easily palpable structures.
• Clinical significance: Marks the superior boundary of the temporalis muscle. Tenderness of the temporalis along the temporal lines is common in TMJ dysfunction, tension headaches, and bruxism. The temporal region is a common site for temporal arteritis (giant cell arteritis) — a painful, thickened temporal artery overlying the temporalis should raise suspicion.

Hyoid Bone

• How to find it: With the client supine and the neck in a neutral or slightly extended position, locate the thyroid cartilage (Adam's apple) in the midline of the anterior neck. The hyoid bone sits above the thyroid cartilage, at approximately the C3 vertebral level. From the thyroid cartilage, slide your thumb and index finger superiorly approximately 1–2 cm until you feel a small, U-shaped bone. You can gently grasp the hyoid between your thumb and index finger from the sides and move it slightly side to side.
• What it feels like: A small, horseshoe-shaped bone approximately 3–4 cm wide. The greater horns project posterolaterally and are the most palpable parts — they feel like two small bony points on either side of the midline. The body is in the midline but is smaller and less distinct.
• Client position: Supine with the neck neutral or slightly extended. The client must be relaxed — any guarding of the anterior neck muscles makes the hyoid difficult to palpate.
• Confirmation: Gently grasp the greater horns between your thumb and finger and move the hyoid laterally — it should glide smoothly side to side with a small range of motion (approximately 1 cm). No other structure in the anterior neck moves this way. The thyroid cartilage below is larger and less mobile laterally.
• Common errors: Confusing the hyoid with the superior border of the thyroid cartilage. The thyroid cartilage is larger, has a midline notch (thyroid notch), and does not move as freely side to side. The hyoid is smaller and sits distinctly above the thyroid cartilage. Also, pressing too firmly — the anterior neck is sensitive and contains the carotid arteries, internal jugular veins, and vagus nerve. Use gentle pressure only.
• Clinical significance: The hyoid anchors the suprahyoid muscles (digastric, mylohyoid, geniohyoid, stylohyoid) and infrahyoid muscles (sternohyoid, omohyoid, thyrohyoid). Hyoid position and mobility are relevant in swallowing disorders and anterior neck tension. Tenderness may accompany voice strain or post-intubation irritation. Caution: The carotid arteries run lateral to the hyoid — never apply sustained bilateral pressure to both sides simultaneously.

TMJ Palpation — Dynamic Assessment

• How to find it: Place your index or middle fingertip directly anterior to the tragus of each ear simultaneously (bilateral palpation). Ask the client to slowly open and close the mouth. You are assessing the TMJ through the condylar movement.
• What it feels like: During normal opening, you feel both condyles translate smoothly and simultaneously forward, then return. The movement should be symmetrical and painless.
• Client position: Supine or seated. The jaw must be completely relaxed before beginning.
• Confirmation: Normal TMJ opening follows a straight path — observe the mandible from the front as the client opens. The incisors should track in a straight vertical line. Any lateral deviation or S-curve during opening indicates asymmetric condylar movement.
• Common errors: Pressing too hard against the condyle, which can cause discomfort and protective muscle guarding that alters the movement pattern. Use light touch — you are feeling for movement quality, not probing the joint.
• Clinical significance: Clicking during opening suggests disc displacement with reduction — the condyle catches and then slides over the displaced disc. Crepitus (grinding) suggests degenerative changes in the articular surfaces. Pain on palpation is a primary diagnostic criterion for TMJ dysfunction. Limited opening (<40 mm, measured between the upper and lower incisors) suggests capsular restriction or muscle hypertonicity.