Brevis And Peroneus Tertius

EXTENSOR DIGITORUM LONGUS AND BREVIS

Patient: Supine or sitting.

Fixation: The examiner stabilizes the foot in slight plantar flexion.

Test: Extension of all joints of the second through fifth digits.

Pressure: Against the dorsal surface of the toes, in the direction of flexion.

Weakness: Allows a tendency toward dropfoot and forefoot varus. Diminishes the ability to dorsiflex the ankle joint and evert the foot. Many cases of flat feet (i.e., collapse of the long arch) also have accompanying weakness of the toe extensors.

Contracture: Hyperextension of the metatarsopha-langeal joints.

PERONEUS TERTIUS

Patient: Supine or sitting.

Fixation: The examiner supports the leg above the ankle joint.

Test: Dorsiflexion of the ankle joint, with eversion of the foot.

Note: The peroneus tertius is assisted in this test by the extensor digitorum longus, of which it is a part.

Pressure: Against the lateral side, dorsal surface of the foot, in the direction of plantar flexion and inversion.

Weakness: Decreases the ability to evert the foot and dorsiflex the ankle joint.

Contracture: Dorsiflexion of the ankle joint and eversion of the foot.

Metatarsal I Medial cuneiform

Metatarsal I Medial cuneiform

TIBIALIS ANTERIOR

Origin: Lateral condyle and proximal half of the lateral surface of the tibia, interosseous membrane, deep fascia and lateral intermuscular septum.

Insertion: Medial and plantar surface of medial cuneiform bone, base of the first metatarsal bone.

Action: Dorsiflexes the ankle joint, and assists in inversion of the foot

Patient: Supine or sitting (with knee flexed if any gas-trocnemius tightness is present).

Fixation: The examiner supports the leg, just above the ankle joint.

lest: Dorsiflexion of the ankle joint and inversion of the foot, without extension of the great toe.

Pressure: Against the medial side, dorsal surface of the foot, in the direction of plantar flexion of the ankle joint and eversiĆ³n of the foot.

Weakness: Decreases the ability to dorsiflex the ankle joint, and allows a tendency toward eversiĆ³n of the foot. This may be seen as a partial dropfoot and tendency toward pronation.

Contracture: Dorsiflexion of ankle joint, with inversion of the foot (i.e., calcaneovarus position of the foot).

Note: Although tibialis anterior weakness may be found in conjunction with a pronated foot, such weakness is seldom found in cases of congenital flatfoot.

Navicular Cuneiforms

Navicular Cuneiforms

TIBIALIS POSTERIOR

Origin: Most of the interosseous membrane, lateral portion of the posterior surface of the tibia, proximal 2/3 of the medial surface of the fibula, adjacent intermuscular septa and deep fascia.

Insertion: Tuberosity of the navicular bone and by fibrous expansions to the sustentaculum tali, three cuneiforms, cuboid, and bases of the second through fourth metatarsal bones.

Action: Inverts the foot, and assists in plantar flexion of the ankle joint.

Patient: Supine, with the extremity in lateral rotation.

Fixation: The examiner supports the leg, above the ankle joint.

Test: Inversion of the foot, with plantar flexion of the ankle joint.

Pressure: Against the medial side and plantar surface of the foot, in the direction of dorsiflexion of the ankle joint and eversion of the foot.

Note: If the flexor hall mis longus and flexor dig-itorum longus are being substituted for the tibialis posterior, the toes will be strongly flexed as pressure is applied.

Weakness: Decreases the ability to invert the foot and plantar flex the ankle joint. Results in pronation of the foot and decreased support of the longitudinal arch. Interferes with the ability to rise on the toes, and inclines toward what is commonly called a gastrocnemius limp.

Contracture: In nonweight bearing, equinovarus position; in weight bearing, a supinated position of the heel with forefoot varus.

412 PERONEUS LONGUS AND BREVIS

Peroneus brevis

Peroneus longus

Peroneus brevis

Peroneus longus

Peroneus longus

PERONEUS LONGUS

Origin: Lateral condyle of the tibia, head and proximal 2/3 of the lateral surface of the fibula, intermuscular septa and adjacent deep fascia.

Insertion: Lateral side of the base of the first metatarsal and of the medial cuneiform bone.

Action: Everts the foot, assists in plantar flexion of the ankle joint and depresses the head of the first metatarsal.

Nerve: Superficial peroneal, L4, 5, SI.

PERONEUS BREVIS

Origin: Distal h of the lateral surface of the fibula and adjacent intermuscular septa.

Insertion: Tuberosity at the base of the fifth metatarsal bone, lateral side.

Action: Everts the foot, and assists in plantar flexion of the ankle.

Nerve: Superficial peroneal, LA, 5, SI.

Patient: Supine, with the extremity medially rotated, or side-lying (on the opposite side).

Fixation: The examiner supports the leg, above the ankle joint.

Test: Eversion of the foot, with plantar flexion of the ankle joint.

Pressure: Against the lateral border and sole of the foot, in the direction of inversion of the foot and dorsiflexion of the ankle joint.

Weakness: Decreases the strength of eversion of the foot and plantar flexion of the ankle joint. Allows a varus position of the foot, and lessens the ability to rise on the toes. Lateral stability of the ankle is decreased.

Contracture: Results in an everted or valgus position of the foot.

Note: In weight bearing, with a strong pull on its insertion at the base of the first metatarsal, the perone us longus causes the head ofthe first metatarsal to be pressed downward, into the supporting surface.

Patient: Prone, with the knee extended and the foot projecting over the end of the table.

Fixation: The weight of the extremity, resting on a firm table, should be sufficient fixation of the part.

Test: Plantar flexion of the foot, with emphasis on pulling the heel upward more than pushing the forefoot downward. This test does not attempt to isolate action of the gastrocnemius from that of the other plantar flexors, but the presence or absence of a gastrocnemius can be determined by careful observation during the test.

Pressure: For maximum pressure in this position, apply pressure against the forefoot as well as against the cal-caneus. If the muscle is very weak, pressure against the calcaneus is sufficient.

The gastrocnemius usually can be seen and always can be palpated if it is contracting during the plantar flexion test. Movements of the toes and forefoot should be observed carefully during the test to detect substitutions. The patient may be able to flex the anterior part of the foot by the toe flexors, tibialis posterior, and per-oneus longus without a direct upward pull on the heel by the tendo calcaneus. If the gastrocnemius and soleus are weak, the heel will be pushed up secondary to flexion of the anterior part of the foot rather than pulled up simultaneously with the flexion of the forepart of the foot. If pressure is applied to the heel rather than to the ball of the foot, it is possible to isolate, at least partially, the combined action of the gastrocnemius and soleus from that of the other plantar flexors. Movement of the foot toward eversion or inversion will show imbalance in the opposing lateral and medial muscles and, if pronounced, will show an attempt to substitute the peroneals or tib-ialis posterior for the gastrocnemius and soleus.

Action of the gastrocnemius often can be demonstrated in the knee flexion test when the hamstrings are weak. In the prone position, with the knees fully extended, the patient is asked to bend the knee against resistance. If the gastrocnemius is strong, plantar flexion at the ankle will occur as the gastrocnemius acts to rni-tiate knee flexion, followed by ankle dorsiflexion as the knee flexes.

Weakness: Permits a calcaneus position of the foot if the gastrocnemius and soleus are weak. In standing, results in hyperextension of the knee and inability to rise on the toes. In walking, the inability to transfer weight normally results in a "gastrocnemius limp."

Contracture: Equinus position of the foot, and flexion of the knee.

Shortness: Restriction of dorsiflexion of the ankle when the knee is extended, and restriction of knee extension when the ankle is dorsiflexed. During the stance phase of walking, shortness limits the normal dorsiflexion of the ankle joint, and the subject toes out during the transfer of weight from heel to forefoot.

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  • Diamanda
    How to isolate the peroneus brevis?
    1 year ago

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