Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Biomechanics of Shoulder Stability-Static Stability Factor

The glenohumeral joint is inherently unstable, with the large humeral head articulating with the small and shallow glenoid. Static stability is provided by the orientation of the articular surfaces, the articular conformity of humerus and the glenoid, the glenoid labrum, the negative intra-articular pressure, the adhesion-cohesion of synovial joint fluid, and the glenohumeral joint capsule […]

Combined plantar flexion-eversion

Significance.

This movement stretches all the medial ligaments of the ankle.

Positioning.

The heel rests on the couch, the knee is slightly Aexed and the ankle is in neutral position. The examiner is distal to the foot. His contralateral hand fixes the leg at the distal and lateral side. The ipSilateral hand encircles the […]

Passive supination

Procedure.

Perform an abduction movement in the shoulder: the thumb pulls the inner side of the foot upwards while the fingers push the outer side downwards.

Common mistakes.

The ankle and subtalar joints are not stabilized.

Normal functional anatomy:

• Rallge: 45-90° • End-feel: soft ligamentous • Limiting structures: medial and lateral midtarsal ligaments.

Passive pronation

Procedure.

Perform an adduction movement in the shoulder: the hand pulls the inner side of the foot downwards while the thumb pushes the outer side upwards.

Common mistakes.

The ankle and subtalar joints are not stabilized.

Normal functional anatomy:

• Range: 30-60° • Elld-feel: soft ligamentous • Limitiug structures: medial and dorsal midtarsal ligaments.

Passive adduction

Procedure.

Perform the adduction movement in the wrist: the fingertips pull the outer side of the forefoot in a medial direction; meanwhile the fifth metacarpal bone provides counter-pressure.

Common mistakes.

The ankle and subtalar joints are not stabilized.

Normal functional anatomy:

• Rallge: 10-15° • End-feel: hard ligamentous • Umitiflg structures: lateral midtarsal ligaments

Passive abduction

Procedure.

Perform the abduction movement in the wrist: the web of the thumb presses the medial aspect of the first metatarsal bone in a lateral direction; meanwhile the fingertips provide counter-pressure at the outer side of the forefoot.

Common mistakes.

The ankle and subtalar joints are not stabilized.

Normal functional anatomy:

• Rallge: 10-150 […]

Passive plantar flexion

Procedure:

Press the fingers downwards by a pronation of the wrist.

Common mistakes.

The ankle and subtalar joints are not stabilized.

Normal functional anatomy:

• Rallge: 10-150 • Elld-feel: hard ligamentous • Lilllilillg sln/etL/res: dorsal midtarsal ligaments.

Passive dorsiflexion

Procedure.

Press the thumb upwards by a supination of the wrist.

Common mistakes.

The ankle and subtalar joints are not stabilized. Normal functional anatomy:

• Rallge: 10-15° • End-feel: hard ligamentous • Umitiu8 structures: – plantar midtarsal ligaments – plantar fascia.

Passive dorsiflexion

Positioning.

The ankle is in neutral position with the heel resting on the couch. The knee is slightly flexed. The examiner is distal to the foot. He places one hand at the plantar aspect of the forefoot. The other hand is at the back of the heel.

Procedure..

Move the foot in the dorsal direction, […]

PASSIVE TESTS OF THE ANKLE JOINT-Passive plantar flexion

Positioning.

The subject lies supine with the leg on the couch and the ankle in neutral position. The examiner is distal to the foot. One hand supports the heel, the other is at the dorsum of the foot.

Procedure.

A simultaneous movement of both hands pulls and pushes the ankle into plantar flexion.

Common […]