MPT Anatomy and Kinesiology 2 — Questions and Answers

Question 1: During normal gait, which phase of the gait cycle requires the greatest quadriceps activity?

Terminal swing
Loading response (early stance) (Correct answer)
Mid-stance
Pre-swing

Correct answer: Loading response (early stance)

The loading response (initial 0-12% of gait cycle) demands peak quadriceps activity to control knee flexion and accept body weight during weight acceptance.

During loading response, the limb accepts body weight as the knee flexes 15-20 degrees. The quadriceps eccentrically contract to control this flexion and prevent knee collapse. Insufficient quadriceps strength at this phase results in a vaulting or lateral trunk lean compensatory gait deviation. This knowledge guides PT intervention after knee surgery or in conditions like Parkinson disease where loading response mechanics are impaired.

Question 2: The carrying angle of the elbow is formed between which two bones?

Humerus and radius
Humerus and ulna (Correct answer)
Radius and ulna
Humerus and both forearm bones equally

Correct answer: Humerus and ulna

The carrying angle is the valgus angle formed between the long axis of the humerus and the long axis of the ulna when the elbow is fully extended and the forearm supinated. Normal values are 5-15 degrees in men and 10-25 degrees in women.

The carrying angle results from the oblique orientation of the trochlea. An angle greater than 20 degrees is termed cubitus valgus (common after lateral condyle fractures), while less than 5 degrees is cubitus varus. Physical therapists measure the carrying angle post-fracture or following lateral epicondylitis. Altered carrying angles affect ulnar collateral ligament stress and nerve tension, particularly ulnar nerve susceptibility at the cubital tunnel.

Question 3: The screw-home mechanism of the knee occurs during the last degrees of extension and involves which rotation?

Medial rotation of the femur on the tibia
Lateral rotation of the femur on the tibia (Correct answer)
Anterior glide of the tibia
Posterior glide of the tibia

Correct answer: Lateral rotation of the femur on the tibia

The screw-home mechanism involves lateral rotation of the femur (or medial rotation of the tibia in open kinetic chain) during the last 30 degrees of knee extension, locking the knee for weight-bearing.

The screw-home mechanism occurs because the medial femoral condyle is larger than the lateral. As the knee nears full extension, the lateral compartment finishes its arc first, causing the femur to rotate laterally (or tibia medially in open chain). This locks the knee passively for standing without continuous quadriceps activity. To unlock, the popliteus internally rotates the femur. Failure of this mechanism contributes to knee instability and is clinically relevant post-meniscectomy.

Question 4: Which rotator cuff muscle is most likely to be torn in a classic degenerative rotator cuff injury?

Subscapularis
Infraspinatus
Supraspinatus (Correct answer)
Teres minor

Correct answer: Supraspinatus

The supraspinatus is most commonly torn, often at its critical zone — a relatively avascular area approximately 1 cm proximal to its insertion on the greater tuberosity.

The supraspinatus tendon is most vulnerable due to its passage through the subacromial space and a hypovascular region (critical zone) near its insertion. Degenerative changes begin in this zone with repetitive compression between the greater tuberosity and acromion. Full-thickness supraspinatus tears present with weakness in the empty can position and positive drop arm test. PT management focuses on strengthening the remaining cuff and periscapular muscles to reduce superior humeral head migration.

Question 5: In the spine, which ligament runs within the vertebral canal on the posterior surface of the vertebral bodies?

Anterior longitudinal ligament
Posterior longitudinal ligament (Correct answer)
Ligamentum flavum
Interspinous ligament

Correct answer: Posterior longitudinal ligament

The posterior longitudinal ligament runs along the posterior surface of the vertebral bodies inside the vertebral canal, resisting spinal flexion and posterior disc herniation.

The posterior longitudinal ligament (PLL) runs from C2 to the sacrum along the posterior aspect of the vertebral bodies within the spinal canal. It is widest in the cervical region and narrows in the lumbar region, which partly explains why disc herniations are more common posterolaterally in the lumbar spine. The PLL resists excessive flexion and helps contain nucleus pulposus. Calcification of the PLL can cause myelopathy, especially in Asian populations.

Question 6: Which of the following describes the concave-convex rule for joint mobilization?

A convex surface glides in the same direction as bone movement; a concave surface glides opposite
A concave surface glides in the same direction as bone movement; a convex surface glides opposite (Correct answer)
Both surfaces always glide in the same direction as bone movement
Glide direction is determined by ligamentous tension alone

Correct answer: A concave surface glides in the same direction as bone movement; a convex surface glides opposite

Per Kaltenborn's concave-convex rule: when a concave surface moves on a convex surface, glide and roll occur in the same direction. When a convex surface moves on a concave surface, glide occurs opposite to roll and bone movement.

This biomechanical principle guides manual therapy decisions. For example, at the glenohumeral joint during shoulder abduction (convex humeral head moving on concave glenoid), the humeral head must glide inferiorly while rolling superiorly. Failure of this inferior glide contributes to subacromial impingement. PTs apply inferior glide mobilizations to restore this motion. At the tibiofemoral joint in open-chain knee extension, the convex femoral condyles glide posteriorly as they roll anteriorly.

MPT Anatomy and Kinesiology 2

During normal gait, which phase of the gait cycle requires the greatest quadriceps activity?